[PATCH 0/5 v2] add 1-wire support

[PATCH 0/5 v2] add 1-wire support

[Jean-Christophe PLAGNIOL-VILLARD]

Hi,

	v2: use is_non_interruptible_timeout as name
	use is_non_interruptible_timeout for ndelay as we will never call poller_cal anyway

The following changes since commit 72703410feff9ed44779b54a41ff30312e781279:

  misc JTAG: include fixes (2012-10-26 09:08:51 +0200)

are available in the git repository at:

  git://git.jcrosoft.org/barebox.git tags/w1

for you to fetch changes up to acaa716bce8cd1373cb5dabff54332fb1da7355b:

  1-wire: add ds2433 support (2012-10-29 04:46:21 +0800)

----------------------------------------------------------------
add 1-wire support

export for each device via param
the familly id (fid)
the id
the full reg_num

so for simple 64bit memory rom(ds2401/ds2411/ds1990*) no need driver.

with ds2431 and ds2433 eeprom support

Based on linux implementation, cleaned and re-implement the master/slave
support to use the device/driver model correctly.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

----------------------------------------------------------------
Jean-Christophe PLAGNIOL-VILLARD (5):
      clock: introduce non interruptible timeout
      add 1-wire support
      1-wire: add gpio bus
      1-wire: add ds2431 support
      1-wire: add ds2433 support

 common/clock.c                |   16 ++-
 drivers/Kconfig               |    1 +
 drivers/Makefile              |    1 +
 drivers/w1/Kconfig            |   14 +++
 drivers/w1/Makefile           |    6 +
 drivers/w1/masters/Kconfig    |   14 +++
 drivers/w1/masters/Makefile   |    5 +
 drivers/w1/masters/w1-gpio.c  |  116 ++++++++++++++++++++
 drivers/w1/slaves/Kconfig     |   27 +++++
 drivers/w1/slaves/Makefile    |    6 +
 drivers/w1/slaves/w1_ds2431.c |  294 +++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/w1/slaves/w1_ds2433.c |  196 +++++++++++++++++++++++++++++++++
 drivers/w1/w1.c               |  621 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/w1/w1.h               |  152 ++++++++++++++++++++++++++
 include/clock.h               |    1 +
 include/linux/w1-gpio.h       |   25 +++++
 16 files changed, 1490 insertions(+), 5 deletions(-)
 create mode 100644 drivers/w1/Kconfig
 create mode 100644 drivers/w1/Makefile
 create mode 100644 drivers/w1/masters/Kconfig
 create mode 100644 drivers/w1/masters/Makefile
 create mode 100644 drivers/w1/masters/w1-gpio.c
 create mode 100644 drivers/w1/slaves/Kconfig
 create mode 100644 drivers/w1/slaves/Makefile
 create mode 100644 drivers/w1/slaves/w1_ds2431.c
 create mode 100644 drivers/w1/slaves/w1_ds2433.c
 create mode 100644 drivers/w1/w1.c
 create mode 100644 drivers/w1/w1.h
 create mode 100644 include/linux/w1-gpio.h

Best Regards,
J.

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[PATCH 1/5] clock: introduce non interruptible timeout

[Jean-Christophe PLAGNIOL-VILLARD]

is_timeout call poller_call if the timeout is >= 100us

but on 1-wire bus we need to wait 500us and not more than 930us
for the bus reset. So if the poller_call is caller we can not guarantee it.

So for this introduce is_non_interruptible_timeout than we only wait.

Use it for ndelay too.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 common/clock.c  |   16 +++++++++++-----
 include/clock.h |    1 +
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/common/clock.c b/common/clock.c
index 8adbeaf..9c7c1ba 100644
--- a/common/clock.c
+++ b/common/clock.c
@@ -135,23 +135,29 @@ uint32_t clocksource_hz2mult(uint32_t hz, uint32_t shift_constant)
         return (uint32_t)tmp;
 }
 
-int is_timeout(uint64_t start_ns, uint64_t time_offset_ns)
+int is_timeout_non_interruptible(uint64_t start_ns, uint64_t time_offset_ns)
 {
-	if (time_offset_ns >= 100 * USECOND)
-		poller_call();
-
 	if ((int64_t)(start_ns + time_offset_ns - get_time_ns()) < 0)
 		return 1;
 	else
 		return 0;
 }
+EXPORT_SYMBOL(is_timeout_non_interruptible);
+
+int is_timeout(uint64_t start_ns, uint64_t time_offset_ns)
+{
+	if (time_offset_ns >= 100 * USECOND)
+		poller_call();
+
+	return is_timeout_non_interruptible(start_ns, time_offset_ns);
+}
 EXPORT_SYMBOL(is_timeout);
 
 void ndelay(unsigned long nsecs)
 {
 	uint64_t start = get_time_ns();
 
-	while(!is_timeout(start, nsecs));
+	while(!is_timeout_non_interruptible(start, nsecs));
 }
 EXPORT_SYMBOL(ndelay);
 
diff --git a/include/clock.h b/include/clock.h
index c01a8d0..a169790 100644
--- a/include/clock.h
+++ b/include/clock.h
@@ -32,6 +32,7 @@ void clocks_calc_mult_shift(uint32_t *mult, uint32_t *shift, uint32_t from, uint
 uint32_t clocksource_hz2mult(uint32_t hz, uint32_t shift_constant);
 
 int is_timeout(uint64_t start_ns, uint64_t time_offset_ns);
+int is_timeout_non_interruptible(uint64_t start_ns, uint64_t time_offset_ns);
 
 // void udelay(unsigned long usecs);
 
-- 
1.7.10.4


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[PATCH 2/5] add 1-wire support

[Jean-Christophe PLAGNIOL-VILLARD]

export for each device via param
the familly id (fid)
the id
the full reg_num

so for simple 64bit memory rom(ds2401/ds2411/ds1990*) no need driver.

Based on linux implementation, cleaned and re-implement the master/slave
support to use the device/driver model correctly.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 drivers/Kconfig             |    1 +
 drivers/Makefile            |    1 +
 drivers/w1/Kconfig          |   14 +
 drivers/w1/Makefile         |    6 +
 drivers/w1/masters/Kconfig  |    7 +
 drivers/w1/masters/Makefile |    4 +
 drivers/w1/slaves/Kconfig   |    7 +
 drivers/w1/slaves/Makefile  |    4 +
 drivers/w1/w1.c             |  621 +++++++++++++++++++++++++++++++++++++++++++
 drivers/w1/w1.h             |  152 +++++++++++
 10 files changed, 817 insertions(+)
 create mode 100644 drivers/w1/Kconfig
 create mode 100644 drivers/w1/Makefile
 create mode 100644 drivers/w1/masters/Kconfig
 create mode 100644 drivers/w1/masters/Makefile
 create mode 100644 drivers/w1/slaves/Kconfig
 create mode 100644 drivers/w1/slaves/Makefile
 create mode 100644 drivers/w1/w1.c
 create mode 100644 drivers/w1/w1.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index d0b5e3a..945fe02 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -21,5 +21,6 @@ source "drivers/pwm/Kconfig"
 source "drivers/dma/Kconfig"
 source "drivers/gpio/Kconfig"
 source "drivers/of/Kconfig"
+source "drivers/w1/Kconfig"
 
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 2a1f8b0..e6cdf39 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -21,3 +21,4 @@ obj-y	+= dma/
 obj-y  += watchdog/
 obj-y	+= gpio/
 obj-$(CONFIG_OFDEVICE) += of/
+obj-$(CONFIG_W1) += w1/
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
new file mode 100644
index 0000000..ab34997
--- /dev/null
+++ b/drivers/w1/Kconfig
@@ -0,0 +1,14 @@
+menuconfig W1
+	bool "Dallas's 1-wire support"
+	---help---
+	  Dallas' 1-wire bus is useful to connect slow 1-pin devices
+	  such as iButtons and thermal sensors.
+
+	  If you want W1 support, you should say Y here.
+
+if W1
+
+source drivers/w1/masters/Kconfig
+source drivers/w1/slaves/Kconfig
+
+endif # W1
diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile
new file mode 100644
index 0000000..3e36d2f
--- /dev/null
+++ b/drivers/w1/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for the Dallas's 1-wire bus.
+#
+
+obj-$(CONFIG_W1)	+= w1.o
+obj-y			+= masters/ slaves/
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
new file mode 100644
index 0000000..86aa8df
--- /dev/null
+++ b/drivers/w1/masters/Kconfig
@@ -0,0 +1,7 @@
+#
+# 1-wire bus master configuration
+#
+
+menu "1-wire Bus Masters"
+
+endmenu
diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
new file mode 100644
index 0000000..ed1b9d9
--- /dev/null
+++ b/drivers/w1/masters/Makefile
@@ -0,0 +1,4 @@
+#
+# Makefile for 1-wire bus master drivers.
+#
+
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
new file mode 100644
index 0000000..f35eedf
--- /dev/null
+++ b/drivers/w1/slaves/Kconfig
@@ -0,0 +1,7 @@
+#
+# 1-wire slaves configuration
+#
+
+menu "1-wire Slaves"
+
+endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
new file mode 100644
index 0000000..ac9a5a7
--- /dev/null
+++ b/drivers/w1/slaves/Makefile
@@ -0,0 +1,4 @@
+#
+# Makefile for the Dallas's 1-wire slaves.
+#
+
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
new file mode 100644
index 0000000..11b8320
--- /dev/null
+++ b/drivers/w1/w1.c
@@ -0,0 +1,621 @@
+/*
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <clock.h>
+
+#include "w1.h"
+
+static LIST_HEAD(w1_buses);
+
+static void w1_pre_write(struct w1_bus *bus);
+static void w1_post_write(struct w1_bus *bus);
+
+static void w1_delay(unsigned long usecs)
+{
+	uint64_t start = get_time_ns();
+
+	while(!is_timeout_non_interruptible(start, usecs * USECOND));
+}
+
+static u8 w1_crc8_table[] = {
+	0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
+	157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
+	35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
+	190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
+	70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
+	219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
+	101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
+	248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
+	140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
+	17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
+	175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
+	50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
+	202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
+	87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
+	233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
+	116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
+};
+
+u8 w1_calc_crc8(u8 * data, int len)
+{
+	u8 crc = 0;
+
+	while (len--)
+		crc = w1_crc8_table[crc ^ *data++];
+
+	return crc;
+}
+
+/**
+ * Issues a reset bus sequence.
+ *
+ * @param  dev The bus master pointer
+ * @return     0=Device present, 1=No device present or error
+ */
+int w1_reset_bus(struct w1_bus *bus)
+{
+	return bus->reset_bus(bus) & 0x1;
+}
+
+static u8 w1_soft_reset_bus(struct w1_bus *bus)
+{
+	int result;
+
+	bus->write_bit(bus, 0);
+	/* minimum 480, max ? us
+	 * be nice and sleep, except 18b20 spec lists 960us maximum,
+	 * so until we can sleep with microsecond accuracy, spin.
+	 * Feel free to come up with some other way to give up the
+	 * cpu for such a short amount of time AND get it back in
+	 * the maximum amount of time.
+	 */
+	w1_delay(500);
+	bus->write_bit(bus, 1);
+	w1_delay(70);
+
+	result = bus->read_bit(bus) & 0x1;
+	/* minmum 70 (above) + 430 = 500 us
+	 * There aren't any timing requirements between a reset and
+	 * the following transactions.  Sleeping is safe here.
+	 */
+	/* w1_delay(430); min required time */
+	mdelay(1);
+
+	return result;
+}
+
+/**
+ * Generates a write-0 or write-1 cycle and samples the level.
+ */
+static u8 w1_touch_bit(struct w1_bus *bus, int bit)
+{
+	return bus->touch_bit(bus, bit);
+}
+
+/**
+ * Generates a write-0 or write-1 cycle.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static void w1_write_bit(struct w1_bus *bus, int bit)
+{
+	if (bit) {
+		bus->write_bit(bus, 0);
+		w1_delay(6);
+		bus->write_bit(bus, 1);
+		w1_delay(64);
+	} else {
+		bus->write_bit(bus, 0);
+		w1_delay(60);
+		bus->write_bit(bus, 1);
+		w1_delay(10);
+	}
+}
+
+/**
+ * Reads 8 bits.
+ *
+ * @param dev     the master device
+ * @return        the byte read
+ */
+u8 w1_read_8(struct w1_bus *bus)
+{
+	return bus->read_byte(bus);
+}
+
+static u8 w1_soft_read_8(struct w1_bus *bus)
+{
+	int i;
+	u8 res = 0;
+
+	for (i = 0; i < 8; ++i)
+		res |= (w1_touch_bit(bus, 1) << i);
+
+	return res;
+}
+
+/**
+ * Writes a series of bytes.
+ *
+ * @param dev     the master device
+ * @param buf     pointer to the data to write
+ * @param len     the number of bytes to write
+ */
+void w1_write_block(struct w1_bus *bus, const u8 *buf, int len)
+{
+	int i;
+
+	if (bus->write_block) {
+		w1_pre_write(bus);
+		bus->write_block(bus, buf, len);
+	} else {
+		for (i = 0; i < len; ++i)
+			w1_write_8(bus, buf[i]); /* calls w1_pre_write */
+	}
+	w1_post_write(bus);
+}
+
+/**
+ * Touches a series of bytes.
+ *
+ * @param dev     the master device
+ * @param buf     pointer to the data to write
+ * @param len     the number of bytes to write
+ */
+void w1_touch_block(struct w1_bus *bus, u8 *buf, int len)
+{
+	int i, j;
+	u8 tmp;
+
+	for (i = 0; i < len; ++i) {
+		tmp = 0;
+		for (j = 0; j < 8; ++j) {
+			if (j == 7)
+				w1_pre_write(bus);
+			tmp |= w1_touch_bit(bus, (buf[i] >> j) & 0x1) << j;
+		}
+
+		buf[i] = tmp;
+	}
+}
+
+/**
+ * Generates a write-1 cycle and samples the level.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static u8 w1_read_bit(struct w1_bus *bus)
+{
+	int result;
+
+	/* sample timing is critical here */
+	bus->write_bit(bus, 0);
+	w1_delay(6);
+	bus->write_bit(bus, 1);
+	w1_delay(9);
+
+	result = bus->read_bit(bus);
+
+	w1_delay(55);
+
+	return result & 0x1;
+}
+
+/**
+ * Does a triplet - used for searching ROM addresses.
+ * Return bits:
+ *  bit 0 = id_bit
+ *  bit 1 = comp_bit
+ *  bit 2 = dir_taken
+ * If both bits 0 & 1 are set, the search should be restarted.
+ *
+ * @param dev     the master device
+ * @param bdir    the bit to write if both id_bit and comp_bit are 0
+ * @return        bit fields - see above
+ */
+u8 w1_triplet(struct w1_bus *bus, int bdir)
+{
+	return bus->triplet(bus, bdir);
+}
+
+static u8 w1_soft_triplet(struct w1_bus *bus, u8 bdir)
+{
+	u8 id_bit   = w1_touch_bit(bus, 1);
+	u8 comp_bit = w1_touch_bit(bus, 1);
+	u8 retval;
+
+	if (id_bit && comp_bit)
+		return 0x03;  /* error */
+
+	if (!id_bit && !comp_bit) {
+		/* Both bits are valid, take the direction given */
+		retval = bdir ? 0x04 : 0;
+	} else {
+		/* Only one bit is valid, take that direction */
+		bdir = id_bit;
+		retval = id_bit ? 0x05 : 0x02;
+	}
+
+	w1_touch_bit(bus, bdir);
+	return retval;
+}
+
+static u8 w1_soft_touch_bit(struct w1_bus *bus, u8 bit)
+{
+	if (bit)
+		return w1_read_bit(bus);
+
+	w1_write_bit(bus, 0);
+	return 0;
+}
+
+/**
+ * Pre-write operation, currently only supporting strong pullups.
+ * Program the hardware for a strong pullup, if one has been requested and
+ * the hardware supports it.
+ *
+ * @param dev     the master device
+ */
+static void w1_pre_write(struct w1_bus *bus)
+{
+	if (!bus->set_pullup)
+		return;
+
+	if (bus->pullup_duration && bus->enable_pullup)
+		bus->set_pullup(bus, bus->pullup_duration);
+}
+
+/**
+ * Post-write operation, currently only supporting strong pullups.
+ * If a strong pullup was requested, clear it if the hardware supports
+ * them, or execute the delay otherwise, in either case clear the request.
+ *
+ * @param dev     the master device
+ */
+static void w1_post_write(struct w1_bus *bus)
+{
+	if (!bus->pullup_duration)
+		return;
+
+	if (bus->enable_pullup && bus->set_pullup)
+		bus->set_pullup(bus, 0);
+	else
+		mdelay(bus->pullup_duration);
+	bus->pullup_duration = 0;
+}
+
+/**
+ * Writes 8 bits.
+ *
+ * @param dev     the master device
+ * @param byte    the byte to write
+ */
+void w1_write_8(struct w1_bus *bus, u8 byte)
+{
+	if (bus->write_byte) {
+		w1_pre_write(bus);
+		bus->write_byte(bus, byte);
+	} else {
+		int i;
+
+		for (i = 0; i < 8; ++i) {
+			if (i == 7)
+				w1_pre_write(bus);
+			w1_touch_bit(bus, (byte >> i) & 0x1);
+		}
+	}
+	w1_post_write(bus);
+}
+
+/**
+ * Reads a series of bytes.
+ *
+ * @param dev     the master device
+ * @param buf     pointer to the buffer to fill
+ * @param len     the number of bytes to read
+ * @return        the number of bytes read
+ */
+u8 w1_read_block(struct w1_bus *bus, u8 *buf, int len)
+{
+	return bus->read_block(bus, buf, len);
+}
+
+static u8 w1_soft_read_block(struct w1_bus *bus, u8 *buf, int len)
+{
+	int i;
+
+	for (i = 0; i < len; ++i)
+		buf[i] = w1_read_8(bus);
+	return len;
+}
+
+/**
+ * Resets the bus and then selects the slave by sending either a skip rom
+ * or a rom match.
+ * The w1 master lock must be held.
+ *
+ * @param sl	the slave to select
+ * @return 	0=success, anything else=error
+ */
+int w1_reset_select_slave(struct w1_device *dev)
+{
+	struct w1_bus *bus = dev->bus;
+
+	if (w1_reset_bus(bus))
+		return -1;
+
+	if (bus->slave_count == 1)
+		w1_write_8(bus, W1_SKIP_ROM);
+	else {
+		u8 match[9] = {W1_MATCH_ROM, };
+		u64 rn = le64_to_cpu(*((u64*)&dev->reg_num));
+
+		memcpy(&match[1], &rn, 8);
+		w1_write_block(bus, match, 9);
+	}
+	return 0;
+}
+
+#define to_w1_device(d)	container_of(d, struct w1_device, dev)
+#define to_w1_driver(d) container_of(d, struct w1_driver, drv)
+
+static int w1_bus_match(struct device_d *_dev, struct driver_d *_drv)
+{
+	struct w1_device *dev = to_w1_device(_dev);
+	struct w1_driver *drv = to_w1_driver(_drv);
+
+	return !(drv->fid == dev->fid);
+}
+
+static int w1_bus_probe(struct device_d *_dev)
+{
+	struct w1_driver *drv = to_w1_driver(_dev->driver);
+	struct w1_device *dev = to_w1_device(_dev);
+
+	return drv->probe(dev);
+}
+
+static void w1_bus_remove(struct device_d *_dev)
+{
+	struct w1_driver *drv = to_w1_driver(_dev->driver);
+	struct w1_device *dev = to_w1_device(_dev);
+
+	return drv->remove(dev);
+}
+
+struct bus_type w1_bustype= {
+	.name = "w1_bus",
+	.match = w1_bus_match,
+	.probe = w1_bus_probe,
+	.remove = w1_bus_remove,
+};
+
+static int w1_device_register(struct w1_bus *bus, struct w1_device *dev)
+{
+	char str[18];
+	int ret;
+
+	sprintf(dev->dev.name, "w1-%x-", dev->fid);
+	dev->dev.id = DEVICE_ID_DYNAMIC;
+	dev->dev.bus = &w1_bustype;
+	dev->bus = bus;
+
+	dev->dev.parent = &bus->dev;
+	dev_add_child(dev->dev.parent, &dev->dev);
+
+	ret = register_device(&dev->dev);
+	if (ret)
+		return ret;
+
+	sprintf(str, "0x%x", dev->fid);
+	dev_add_param_fixed(&dev->dev, "fid", str);
+	sprintf(str, "0x%llx", dev->id);
+	dev_add_param_fixed(&dev->dev, "id", str);
+	sprintf(str, "0x%llx", dev->reg_num);
+	dev_add_param_fixed(&dev->dev, "reg_num", str);
+
+	return ret;
+}
+
+int w1_driver_register(struct w1_driver *drv)
+{
+	drv->drv.bus = &w1_bustype;
+
+	if (drv->probe)
+		drv->drv.probe = w1_bus_probe;
+	if (drv->remove)
+		drv->drv.remove = w1_bus_remove;
+
+	return register_driver(&drv->drv);
+}
+
+void w1_found(struct w1_bus *bus, u64 rn)
+{
+	struct w1_device *dev = xzalloc(sizeof(*dev));
+	u64 tmp = be64_to_cpu(rn);
+
+	dev->reg_num = rn;
+	dev->fid = tmp >> 56;
+	dev->id = (tmp >> 8) & 0xffffffffffff;
+	dev->crc = tmp & 0xff;
+
+	dev_dbg(&bus->dev, "%s:  familly = 0x%x, id = 0x%llx, crc = 0x%x\n",
+		__func__, dev->fid, dev->id, dev->crc);
+
+	if (dev->crc != w1_calc_crc8((u8 *)&rn, 7)) {
+		dev_err(&bus->dev, "0x%llx crc error\n", rn);
+		return;
+	}
+
+	w1_device_register(bus, dev);
+}
+
+/**
+ * Performs a ROM Search & registers any devices found.
+ * The 1-wire search is a simple binary tree search.
+ * For each bit of the address, we read two bits and write one bit.
+ * The bit written will put to sleep all devies that don't match that bit.
+ * When the two reads differ, the direction choice is obvious.
+ * When both bits are 0, we must choose a path to take.
+ * When we can scan all 64 bits without having to choose a path, we are done.
+ *
+ * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
+ *
+ * @dev        The master device to search
+ * @cb         Function to call when a device is found
+ */
+static void w1_search(struct w1_bus *bus, u8 search_type)
+{
+	u64 last_rn, rn, tmp64;
+	int i, slave_count = 0;
+	int last_zero, last_device;
+	int search_bit, desc_bit;
+	u8  triplet_ret = 0;
+
+	search_bit = 0;
+	rn = last_rn = 0;
+	last_device = 0;
+	last_zero = -1;
+
+	desc_bit = 64;
+
+	while ( !last_device && (slave_count++ < bus->max_slave_count) ) {
+		last_rn = rn;
+		rn = 0;
+
+		/*
+		 * Reset bus and all 1-wire device state machines
+		 * so they can respond to our requests.
+		 *
+		 * Return 0 - device(s) present, 1 - no devices present.
+		 */
+		if (w1_reset_bus(bus)) {
+			dev_dbg(&bus->dev, "No devices present on the wire.\n");
+			break;
+		}
+
+		/* Do fast search on single slave bus */
+		if (bus->max_slave_count == 1) {
+			int rv;
+			w1_write_8(bus, W1_READ_ROM);
+			rv = w1_read_block(bus, (u8 *)&rn, 8);
+
+			if (rv == 8 && rn)
+				w1_found(bus, rn);
+
+			break;
+		}
+
+		/* Start the search */
+		w1_write_8(bus, search_type);
+		for (i = 0; i < 64; ++i) {
+			/* Determine the direction/search bit */
+			if (i == desc_bit)
+				search_bit = 1;	  /* took the 0 path last time, so take the 1 path */
+			else if (i > desc_bit)
+				search_bit = 0;	  /* take the 0 path on the next branch */
+			else
+				search_bit = ((last_rn >> i) & 0x1);
+
+			/** Read two bits and write one bit */
+			triplet_ret = w1_triplet(bus, search_bit);
+
+			/* quit if no device responded */
+			if ( (triplet_ret & 0x03) == 0x03 )
+				break;
+
+			/* If both directions were valid, and we took the 0 path... */
+			if (triplet_ret == 0)
+				last_zero = i;
+
+			/* extract the direction taken & update the device number */
+			tmp64 = (triplet_ret >> 2);
+			rn |= (tmp64 << i);
+		}
+
+		if ( (triplet_ret & 0x03) != 0x03 ) {
+			if ( (desc_bit == last_zero) || (last_zero < 0))
+				last_device = 1;
+			desc_bit = last_zero;
+			w1_found(bus, rn);
+		}
+	}
+
+	w1_reset_bus(bus);
+}
+
+int w1_bus_register(struct w1_bus *bus)
+{
+	int ret;
+
+	/* validate minimum functionality */
+	if (!(bus->touch_bit && bus->reset_bus) &&
+	    !(bus->write_bit && bus->read_bit)) {
+		pr_err("w1_bus_register: invalid function set\n");
+		return -EINVAL;
+	}
+	/* While it would be electrically possible to make a device that
+	 * generated a strong pullup in bit bang mode, only hardware that
+	 * controls 1-wire time frames are even expected to support a strong
+	 * pullup.  w1_io.c would need to support calling set_pullup before
+	 * the last write_bit operation of a w1_write_8 which it currently
+	 * doesn't.
+	 */
+	if (!bus->touch_bit && bus->set_pullup) {
+		pr_err("w1_add_bus_device: set_pullup requires touch_bit, disabling\n");
+		bus->set_pullup = NULL;
+	}
+
+	if (!bus->reset_bus)
+		bus->reset_bus = w1_soft_reset_bus;
+
+	if (!bus->touch_bit)
+		bus->touch_bit = w1_soft_touch_bit;
+
+	if (!bus->read_block)
+		bus->read_block = w1_soft_read_block;
+
+	if (!bus->read_byte)
+		bus->read_byte = w1_soft_read_8;
+
+	if (!bus->triplet)
+		bus->triplet = w1_soft_triplet;
+
+	if (!bus->max_slave_count)
+		bus->max_slave_count = 10;
+
+	list_add_tail(&bus->list, &w1_buses);
+
+	strcpy(bus->dev.name, "w1_bus");
+	bus->dev.id = DEVICE_ID_DYNAMIC;
+
+	bus->dev.parent = bus->parent;
+	if (bus->parent)
+		dev_add_child(bus->parent, &bus->dev);
+
+	ret = register_device(&bus->dev);
+	if (ret)
+		return ret;
+
+	w1_search(bus, W1_SEARCH);
+
+	return 0;
+}
+
+static int w1_bus_init(void)
+{
+	return bus_register(&w1_bustype);
+}
+pure_initcall(w1_bus_init);
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
new file mode 100644
index 0000000..1373f69
--- /dev/null
+++ b/drivers/w1/w1.h
@@ -0,0 +1,152 @@
+/*
+ *	w1.h
+ *
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __W1_H
+#define __W1_H
+
+#include <common.h>
+#include <driver.h>
+
+struct w1_device {
+	u64	reg_num;
+	u8	fid;
+	u64	id;
+	u8	crc;
+
+	struct w1_bus	*bus;
+	struct device_d dev;
+};
+
+struct w1_driver {
+	u8	fid;
+	u64	id;
+
+	int	(*probe) (struct w1_device *dev);
+	void	(*remove) (struct w1_device *dev);
+	struct driver_d drv;
+};
+
+int w1_driver_register(struct w1_driver *drv);
+
+extern struct bus_type w1_bustype;
+
+#define W1_MAXNAMELEN		32
+
+#define W1_SEARCH		0xF0
+#define W1_ALARM_SEARCH		0xEC
+#define W1_CONVERT_TEMP		0x44
+#define W1_SKIP_ROM		0xCC
+#define W1_READ_SCRATCHPAD	0xBE
+#define W1_READ_ROM		0x33
+#define W1_READ_PSUPPLY		0xB4
+#define W1_MATCH_ROM		0x55
+#define W1_RESUME_CMD		0xA5
+
+#define W1_SLAVE_ACTIVE		0
+
+/**
+ * Note: read_bit and write_bit are very low level functions and should only
+ * be used with hardware that doesn't really support 1-wire operations,
+ * like a parallel/serial port.
+ * Either define read_bit and write_bit OR define, at minimum, touch_bit and
+ * reset_bus.
+ */
+struct w1_bus
+{
+	struct device_d	dev;
+	struct device_d	*parent;
+
+	/**
+	 * Sample the line level
+	 * @return the level read (0 or 1)
+	 */
+	u8		(*read_bit)(struct w1_bus *);
+
+	/** Sets the line level */
+	void		(*write_bit)(struct w1_bus *, u8);
+
+	/**
+	 * touch_bit is the lowest-level function for devices that really
+	 * support the 1-wire protocol.
+	 * touch_bit(0) = write-0 cycle
+	 * touch_bit(1) = write-1 / read cycle
+	 * @return the bit read (0 or 1)
+	 */
+	u8		(*touch_bit)(struct w1_bus *, u8);
+
+	/**
+	 * Reads a bytes. Same as 8 touch_bit(1) calls.
+	 * @return the byte read
+	 */
+	u8		(*read_byte)(struct w1_bus *);
+
+	/**
+	 * Writes a byte. Same as 8 touch_bit(x) calls.
+	 */
+	void		(*write_byte)(struct w1_bus *, u8);
+
+	/**
+	 * Same as a series of read_byte() calls
+	 * @return the number of bytes read
+	 */
+	u8		(*read_block)(struct w1_bus *, u8 *, int);
+
+	/** Same as a series of write_byte() calls */
+	void		(*write_block)(struct w1_bus *, const u8 *, int);
+
+	/**
+	 * Combines two reads and a smart write for ROM searches
+	 * @return bit0=Id bit1=comp_id bit2=dir_taken
+	 */
+	u8		(*triplet)(struct w1_bus *, u8);
+
+	/**
+	 * long write-0 with a read for the presence pulse detection
+	 * @return -1=Error, 0=Device present, 1=No device present
+	 */
+	u8		(*reset_bus)(struct w1_bus *);
+
+	/**
+	 * Put out a strong pull-up pulse of the specified duration.
+	 * @return -1=Error, 0=completed
+	 */
+	u8		(*set_pullup)(struct w1_bus *, int);
+
+	/** 5V strong pullup enabled flag, 1 enabled, zero disabled. */
+	int		enable_pullup;
+	/** 5V strong pullup duration in milliseconds, zero disabled. */
+	int		pullup_duration;
+
+	int		max_slave_count, slave_count;
+
+	void		*data;
+	struct list_head list;
+};
+
+u8 w1_read_block(struct w1_bus *bus, u8 *buf, int len);
+void w1_write_block(struct w1_bus *bus, const u8 *buf, int len);
+void w1_touch_block(struct w1_bus *bus, u8 *buf, int len);
+u8 w1_triplet(struct w1_bus *bus, int bdir);
+u8 w1_read_8(struct w1_bus *bus);
+void w1_write_8(struct w1_bus *bus, u8 byte);
+int w1_reset_select_slave(struct w1_device *dev);
+int w1_reset_bus(struct w1_bus *bus);
+u8 w1_calc_crc8(u8 * data, int len);
+
+int w1_bus_register(struct w1_bus *bus);
+
+#endif /* __W1_H */
-- 
1.7.10.4


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[PATCH 3/5] 1-wire: add gpio bus

[Jean-Christophe PLAGNIOL-VILLARD]

Based on linux implementation.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 drivers/w1/masters/Kconfig   |    7 +++
 drivers/w1/masters/Makefile  |    1 +
 drivers/w1/masters/w1-gpio.c |  116 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/w1-gpio.h      |   25 +++++++++
 4 files changed, 149 insertions(+)
 create mode 100644 drivers/w1/masters/w1-gpio.c
 create mode 100644 include/linux/w1-gpio.h

diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 86aa8df..e429c14 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -4,4 +4,11 @@
 
 menu "1-wire Bus Masters"
 
+config W1_MASTER_GPIO
+	bool "GPIO 1-wire busmaster"
+	depends on GENERIC_GPIO
+	help
+	  Say Y here if you want to communicate with your 1-wire devices using
+	  GPIO pins. This driver uses the GPIO API to control the wire.
+
 endmenu
diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index ed1b9d9..84b35bb 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -2,3 +2,4 @@
 # Makefile for 1-wire bus master drivers.
 #
 
+obj-$(CONFIG_W1_MASTER_GPIO)		+= w1-gpio.o
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
new file mode 100644
index 0000000..0a3794d
--- /dev/null
+++ b/drivers/w1/masters/w1-gpio.c
@@ -0,0 +1,116 @@
+/*
+ * w1-gpio - GPIO w1 bus master driver
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <malloc.h>
+#include <xfuncs.h>
+#include <driver.h>
+#include <linux/w1-gpio.h>
+#include <gpio.h>
+
+#include "../w1.h"
+
+static void w1_gpio_write_bit_dir(struct w1_bus *bus, u8 bit)
+{
+	struct w1_gpio_platform_data *pdata = bus->data;
+
+	if (bit)
+		gpio_direction_input(pdata->pin);
+	else
+		gpio_direction_output(pdata->pin, 0);
+}
+
+static void w1_gpio_write_bit_val(struct w1_bus *bus, u8 bit)
+{
+	struct w1_gpio_platform_data *pdata = bus->data;
+
+	gpio_set_value(pdata->pin, bit);
+}
+
+static u8 w1_gpio_read_bit(struct w1_bus *bus)
+{
+	struct w1_gpio_platform_data *pdata = bus->data;
+
+	return gpio_get_value(pdata->pin) ? 1 : 0;
+}
+
+static int __init w1_gpio_probe(struct device_d *dev)
+{
+	struct w1_bus *master;
+	struct w1_gpio_platform_data *pdata;
+	int err;
+
+	pdata = dev->platform_data;
+
+	if (!pdata)
+		return -ENXIO;
+
+	master = xzalloc(sizeof(struct w1_bus));
+
+	err = gpio_request(pdata->pin, "w1");
+	if (err)
+		goto free_master;
+
+	if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
+		err = gpio_request(pdata->pin, "w1 pullup");
+		if (err < 0)
+			goto free_gpio;
+
+		gpio_direction_output(pdata->pin, 0);
+	}
+
+	master->data = pdata;
+	master->read_bit = w1_gpio_read_bit;
+
+	if (pdata->is_open_drain) {
+		gpio_direction_output(pdata->pin, 1);
+		master->write_bit = w1_gpio_write_bit_val;
+	} else {
+		gpio_direction_input(pdata->pin);
+		master->write_bit = w1_gpio_write_bit_dir;
+	}
+
+	master->parent = dev;
+
+	err = w1_bus_register(master);
+	if (err)
+		goto free_gpio_ext_pu;
+
+	if (pdata->enable_external_pullup)
+		pdata->enable_external_pullup(1);
+
+	if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+		gpio_set_value(pdata->ext_pullup_enable_pin, 1);
+
+	return 0;
+
+ free_gpio_ext_pu:
+	if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+		gpio_free(pdata->ext_pullup_enable_pin);
+ free_gpio:
+	gpio_free(pdata->pin);
+ free_master:
+	kfree(master);
+
+	return err;
+}
+
+static struct driver_d w1_gpio_driver = {
+	.name	= "w1-gpio",
+	.probe	= w1_gpio_probe,
+};
+
+static int __init w1_gpio_init(void)
+{
+	return platform_driver_register(&w1_gpio_driver);
+}
+device_initcall(w1_gpio_init);
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
new file mode 100644
index 0000000..065e3ae
--- /dev/null
+++ b/include/linux/w1-gpio.h
@@ -0,0 +1,25 @@
+/*
+ * w1-gpio interface to platform code
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+#ifndef _LINUX_W1_GPIO_H
+#define _LINUX_W1_GPIO_H
+
+/**
+ * struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
+ * @pin: GPIO pin to use
+ * @is_open_drain: GPIO pin is configured as open drain
+ */
+struct w1_gpio_platform_data {
+	unsigned int pin;
+	unsigned int is_open_drain:1;
+	void (*enable_external_pullup)(int enable);
+	unsigned int ext_pullup_enable_pin;
+};
+
+#endif /* _LINUX_W1_GPIO_H */
-- 
1.7.10.4


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[PATCH 4/5] 1-wire: add ds2431 support

[Jean-Christophe PLAGNIOL-VILLARD]

Based on linux implementation.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 drivers/w1/slaves/Kconfig     |   10 ++
 drivers/w1/slaves/Makefile    |    1 +
 drivers/w1/slaves/w1_ds2431.c |  294 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/w1/slaves/w1_ds2431.c

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index f35eedf..26150a2 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -4,4 +4,14 @@
 
 menu "1-wire Slaves"
 
+config W1_SLAVE_DS2431
+	bool "1kb EEPROM family support (DS2431)"
+	help
+	  Say Y here if you want to use a 1-wire
+	  1kb EEPROM family device (DS2431)
+
+config W1_SLAVE_DS2431_WRITE
+	bool "write support"
+	depends on W1_SLAVE_DS2431
+
 endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index ac9a5a7..65804e0 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -2,3 +2,4 @@
 # Makefile for the Dallas's 1-wire slaves.
 #
 
+obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
new file mode 100644
index 0000000..30e6e1d
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -0,0 +1,294 @@
+/*
+ * w1_ds2431.c - w1 family 2d (DS2431) driver
+ *
+ * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <init.h>
+#include "../w1.h"
+
+#define W1_F2D_EEPROM_SIZE	128
+#define W1_F2D_PAGE_COUNT	4
+#define W1_F2D_PAGE_BITS	5
+#define W1_F2D_PAGE_SIZE	(1 << W1_F2D_PAGE_BITS)
+#define W1_F2D_PAGE_MASK	0x1F
+
+#define W1_F2D_SCRATCH_BITS	3
+#define W1_F2D_SCRATCH_SIZE	(1 << W1_F2D_SCRATCH_BITS)
+#define W1_F2D_SCRATCH_MASK 	(W1_F2D_SCRATCH_SIZE - 1)
+
+#define W1_F2D_READ_EEPROM	0xF0
+#define W1_F2D_WRITE_SCRATCH	0x0F
+#define W1_F2D_READ_SCRATCH	0xAA
+#define W1_F2D_COPY_SCRATCH	0x55
+
+
+#define W1_F2D_TPROG_MS		11
+
+#define W1_F2D_READ_RETRIES	10
+#define W1_F2D_READ_MAXLEN	8
+
+#define DRIVERNAME	"ds2431"
+
+static int ds2431_count = 0;
+
+/*
+ * Check the file size bounds and adjusts count as needed.
+ * This would not be needed if the file size didn't reset to 0 after a write.
+ */
+static inline size_t ds2431_fix_count(loff_t off, size_t count, size_t size)
+{
+	if (off > size)
+		return 0;
+
+	if ((off + count) > size)
+		return size - off;
+
+	return count;
+}
+
+/*
+ * Read a block from W1 ROM two times and compares the results.
+ * If they are equal they are returned, otherwise the read
+ * is repeated W1_F2D_READ_RETRIES times.
+ *
+ * count must not exceed W1_F2D_READ_MAXLEN.
+ */
+int ds2431_readblock(struct w1_device *dev, int off, int count, char *buf)
+{
+	struct w1_bus *bus = dev->bus;
+	u8 wrbuf[3];
+	u8 cmp[W1_F2D_READ_MAXLEN];
+	int tries = W1_F2D_READ_RETRIES;
+
+	do {
+		wrbuf[0] = W1_F2D_READ_EEPROM;
+		wrbuf[1] = off & 0xff;
+		wrbuf[2] = off >> 8;
+
+		if (w1_reset_select_slave(dev))
+			return -1;
+
+		w1_write_block(bus, wrbuf, 3);
+		w1_read_block(bus, buf, count);
+
+		if (w1_reset_select_slave(dev))
+			return -1;
+
+		w1_write_block(bus, wrbuf, 3);
+		w1_read_block(bus, cmp, count);
+
+		if (!memcmp(cmp, buf, count))
+			return 0;
+	} while (--tries);
+
+	dev_err(&dev->dev, "proof reading failed %d times\n",
+			W1_F2D_READ_RETRIES);
+
+	return -1;
+}
+
+static ssize_t ds2431_cdev_read(struct cdev *cdev, void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	int todo = count;
+
+	count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+	if (count == 0)
+		return 0;
+
+	/* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
+	while (todo > 0) {
+		int block_read;
+
+		if (todo >= W1_F2D_READ_MAXLEN)
+			block_read = W1_F2D_READ_MAXLEN;
+		else
+			block_read = todo;
+
+		if (ds2431_readblock(dev, off, block_read, buf) < 0)
+			count = -EIO;
+
+		todo -= W1_F2D_READ_MAXLEN;
+		buf += W1_F2D_READ_MAXLEN;
+		off += W1_F2D_READ_MAXLEN;
+	}
+
+	return count;
+}
+
+#ifdef CONFIG_W1_SLAVE_DS2431_WRITE
+/*
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and
+ * must be W1_F2D_SCRATCH_SIZE bytes long.
+ * The master must be locked.
+ *
+ * @param sl	The slave structure
+ * @param addr	Address for the write
+ * @param len   length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
+ * @param data	The data to write
+ * @return	0=Success -1=failure
+ */
+static int ds2431_write(struct w1_device *dev, int addr, int len, const u8 *data)
+{
+	struct w1_bus *bus = dev->bus;
+	int tries = W1_F2D_READ_RETRIES;
+	u8 wrbuf[4];
+	u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
+	u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;
+
+retry:
+
+	/* Write the data to the scratchpad */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F2D_WRITE_SCRATCH;
+	wrbuf[1] = addr & 0xff;
+	wrbuf[2] = addr >> 8;
+
+	w1_write_block(bus, wrbuf, 3);
+	w1_write_block(bus, data, len);
+
+	/* Read the scratchpad and verify */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	w1_write_8(bus, W1_F2D_READ_SCRATCH);
+	w1_read_block(bus, rdbuf, len + 3);
+
+	/* Compare what was read against the data written */
+	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
+	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) {
+
+		if (--tries)
+			goto retry;
+
+		dev_err(&dev->dev,
+			"could not write to eeprom, scratchpad compare failed %d times\n",
+			W1_F2D_READ_RETRIES);
+
+		return -1;
+	}
+
+	/* Copy the scratchpad to EEPROM */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F2D_COPY_SCRATCH;
+	wrbuf[3] = es;
+	w1_write_block(bus, wrbuf, 4);
+
+	/* Sleep for tprog ms to wait for the write to complete */
+	mdelay(W1_F2D_TPROG_MS);
+
+	/* Reset the bus to wake up the EEPROM  */
+	w1_reset_bus(bus);
+
+	return 0;
+}
+
+static ssize_t ds2431_cdev_write(struct cdev *cdev, const void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	int addr, len;
+	int copy;
+
+	count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+	if (count == 0)
+		return 0;
+
+	/* Can only write data in blocks of the size of the scratchpad */
+	addr = off;
+	len = count;
+	while (len > 0) {
+
+		/* if len too short or addr not aligned */
+		if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) {
+			char tmp[W1_F2D_SCRATCH_SIZE];
+
+			/* read the block and update the parts to be written */
+			if (ds2431_readblock(dev, addr & ~W1_F2D_SCRATCH_MASK,
+					W1_F2D_SCRATCH_SIZE, tmp)) {
+				count = -EIO;
+				goto out_up;
+			}
+
+			/* copy at most to the boundary of the PAGE or len */
+			copy = W1_F2D_SCRATCH_SIZE -
+				(addr & W1_F2D_SCRATCH_MASK);
+
+			if (copy > len)
+				copy = len;
+
+			memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy);
+			if (ds2431_write(dev, addr & ~W1_F2D_SCRATCH_MASK,
+					W1_F2D_SCRATCH_SIZE, tmp) < 0) {
+				count = -EIO;
+				goto out_up;
+			}
+		} else {
+
+			copy = W1_F2D_SCRATCH_SIZE;
+			if (ds2431_write(dev, addr, copy, buf) < 0) {
+				count = -EIO;
+				goto out_up;
+			}
+		}
+		buf += copy;
+		addr += copy;
+		len -= copy;
+	}
+
+out_up:
+	return count;
+}
+#else
+#define ds2431_cdev_write NULL
+#endif
+
+static struct file_operations ds2431_ops = {
+	.read	= ds2431_cdev_read,
+	.write	= ds2431_cdev_write,
+	.lseek	= dev_lseek_default,
+};
+
+static int ds2431_probe(struct w1_device *dev)
+{
+	struct cdev *cdev;
+
+	cdev = xzalloc(sizeof(*cdev));
+	cdev->dev	= &dev->dev;
+	cdev->priv	= dev;
+	cdev->ops	= &ds2431_ops;
+	cdev->size	= W1_F2D_EEPROM_SIZE;
+	cdev->name	= asprintf(DRIVERNAME"%d", ds2431_count++);
+	if (cdev->name == NULL)
+		return -ENOMEM;
+
+	return devfs_create(cdev);
+}
+
+struct w1_driver ds2431_driver = {
+	.drv = {
+		.name = DRIVERNAME,
+	},
+	.probe		= ds2431_probe,
+	.fid		= 0x2d,
+};
+
+static int w1_ds2431_init(void)
+{
+	return w1_driver_register(&ds2431_driver);
+}
+device_initcall(w1_ds2431_init);
-- 
1.7.10.4


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[PATCH 5/5] 1-wire: add ds2433 support

[Jean-Christophe PLAGNIOL-VILLARD]

Based on linux implementation.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 drivers/w1/slaves/Kconfig     |   10 +++
 drivers/w1/slaves/Makefile    |    1 +
 drivers/w1/slaves/w1_ds2433.c |  196 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 207 insertions(+)
 create mode 100644 drivers/w1/slaves/w1_ds2433.c

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index 26150a2..946a0b3 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -14,4 +14,14 @@ config W1_SLAVE_DS2431_WRITE
 	bool "write support"
 	depends on W1_SLAVE_DS2431
 
+config W1_SLAVE_DS2433
+	bool "4kb EEPROM family support (DS2433)"
+	help
+	  Say Y here if you want to use a 1-wire
+	  4kb EEPROM family device (DS2433).
+
+config W1_SLAVE_DS2433_WRITE
+	bool "write support"
+	depends on W1_SLAVE_DS2433
+
 endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index 65804e0..dd7160a 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o
+obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o
diff --git a/drivers/w1/slaves/w1_ds2433.c b/drivers/w1/slaves/w1_ds2433.c
new file mode 100644
index 0000000..51279fb
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2433.c
@@ -0,0 +1,196 @@
+/*
+ *	w1_ds2433.c - w1 family 23 (DS2433) driver
+ *
+ * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <init.h>
+#include "../w1.h"
+
+#define W1_EEPROM_SIZE		512
+#define W1_PAGE_COUNT		16
+#define W1_PAGE_SIZE		32
+#define W1_PAGE_BITS		5
+#define W1_PAGE_MASK		0x1F
+
+#define W1_F23_TIME		300
+
+#define W1_F23_READ_EEPROM	0xF0
+#define W1_F23_WRITE_SCRATCH	0x0F
+#define W1_F23_READ_SCRATCH	0xAA
+#define W1_F23_COPY_SCRATCH	0x55
+
+#define DRIVERNAME	"ds2433"
+
+static int ds2433_count = 0;
+
+/**
+ * Check the file size bounds and adjusts count as needed.
+ * This would not be needed if the file size didn't reset to 0 after a write.
+ */
+static inline size_t ds2433_fix_count(loff_t off, size_t count, size_t size)
+{
+	if (off > size)
+		return 0;
+
+	if ((off + count) > size)
+		return (size - off);
+
+	return count;
+}
+
+static ssize_t ds2433_cdev_read(struct cdev *cdev, void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	struct w1_bus *bus = dev->bus;
+	u8 wrbuf[3];
+
+	if ((count = ds2433_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+		return 0;
+
+	/* read directly from the EEPROM */
+	if (w1_reset_select_slave(dev)) {
+		count = -EIO;
+		goto out_up;
+	}
+
+	wrbuf[0] = W1_F23_READ_EEPROM;
+	wrbuf[1] = off & 0xff;
+	wrbuf[2] = off >> 8;
+	w1_write_block(bus, wrbuf, 3);
+	w1_read_block(bus, buf, count);
+
+out_up:
+	return count;
+}
+
+#ifdef CONFIG_W1_SLAVE_DS2433_WRITE
+/**
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be on one page.
+ * The master must be locked.
+ *
+ * @param sl	The slave structure
+ * @param addr	Address for the write
+ * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
+ * @param data	The data to write
+ * @return	0=Success -1=failure
+ */
+static int ds2433_write(struct w1_device *dev, int addr, int len, const u8 *data)
+{
+	struct w1_bus *bus = dev->bus;
+	u8 wrbuf[4];
+	u8 rdbuf[W1_PAGE_SIZE + 3];
+	u8 es = (addr + len - 1) & 0x1f;
+
+	/* Write the data to the scratchpad */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F23_WRITE_SCRATCH;
+	wrbuf[1] = addr & 0xff;
+	wrbuf[2] = addr >> 8;
+
+	w1_write_block(bus, wrbuf, 3);
+	w1_write_block(bus, data, len);
+
+	/* Read the scratchpad and verify */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	w1_write_8(bus, W1_F23_READ_SCRATCH);
+	w1_read_block(bus, rdbuf, len + 3);
+
+	/* Compare what was read against the data written */
+	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
+	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
+		return -1;
+
+	/* Copy the scratchpad to EEPROM */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F23_COPY_SCRATCH;
+	wrbuf[3] = es;
+	w1_write_block(bus, wrbuf, 4);
+
+	/* Sleep for 5 ms to wait for the write to complete */
+	mdelay(5);
+
+	/* Reset the bus to wake up the EEPROM (this may not be needed) */
+	w1_reset_bus(bus);
+	return 0;
+}
+
+static ssize_t ds2433_cdev_write(struct cdev *cdev, const void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	int addr, len, idx;
+	const u8 *buf8 = buf;
+
+	if ((count = ds2433_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
+		return 0;
+
+	/* Can only write data to one page at a time */
+	idx = 0;
+	while (idx < count) {
+		addr = off + idx;
+		len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
+		if (len > (count - idx))
+			len = count - idx;
+
+		if (ds2433_write(dev, addr, len, &buf8[idx]) < 0) {
+			count = -EIO;
+			goto out_up;
+		}
+		idx += len;
+	}
+
+out_up:
+	return count;
+}
+#else
+#define ds2433_cdev_write NULL
+#endif
+
+static struct file_operations ds2433_ops = {
+	.read	= ds2433_cdev_read,
+	.write	= ds2433_cdev_write,
+	.lseek	= dev_lseek_default,
+};
+
+static int ds2433_probe(struct w1_device *dev)
+{
+	struct cdev *cdev;
+
+	cdev = xzalloc(sizeof(*cdev));
+	cdev->dev	= &dev->dev;
+	cdev->priv	= dev;
+	cdev->ops	= &ds2433_ops;
+	cdev->size	= W1_EEPROM_SIZE;
+	cdev->name	= asprintf(DRIVERNAME"%d", ds2433_count++);
+	if (cdev->name == NULL)
+		return -ENOMEM;
+
+	return devfs_create(cdev);
+}
+
+struct w1_driver ds2433_driver = {
+	.drv = {
+		.name = DRIVERNAME,
+	},
+	.probe		= ds2433_probe,
+	.fid		= 0x23,
+};
+
+static int w1_ds2433_init(void)
+{
+	return w1_driver_register(&ds2433_driver);
+}
+device_initcall(w1_ds2433_init);
-- 
1.7.10.4


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Re: [PATCH 0/5 v2] add 1-wire support

[Sascha Hauer]

On Mon, Oct 29, 2012 at 01:46:09PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> Hi,
> 
> 	v2: use is_non_interruptible_timeout as name
> 	use is_non_interruptible_timeout for ndelay as we will never call poller_cal anyway
> 
> The following changes since commit 72703410feff9ed44779b54a41ff30312e781279:
> 
>   misc JTAG: include fixes (2012-10-26 09:08:51 +0200)
> 
> are available in the git repository at:
> 
>   git://git.jcrosoft.org/barebox.git tags/w1
> 

Applied, thanks

Sascha

> for you to fetch changes up to acaa716bce8cd1373cb5dabff54332fb1da7355b:
> 
>   1-wire: add ds2433 support (2012-10-29 04:46:21 +0800)
> 
> ----------------------------------------------------------------
> add 1-wire support
> 
> export for each device via param
> the familly id (fid)
> the id
> the full reg_num
> 
> so for simple 64bit memory rom(ds2401/ds2411/ds1990*) no need driver.
> 
> with ds2431 and ds2433 eeprom support
> 
> Based on linux implementation, cleaned and re-implement the master/slave
> support to use the device/driver model correctly.
> 
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> 
> ----------------------------------------------------------------
> Jean-Christophe PLAGNIOL-VILLARD (5):
>       clock: introduce non interruptible timeout
>       add 1-wire support
>       1-wire: add gpio bus
>       1-wire: add ds2431 support
>       1-wire: add ds2433 support
> 
>  common/clock.c                |   16 ++-
>  drivers/Kconfig               |    1 +
>  drivers/Makefile              |    1 +
>  drivers/w1/Kconfig            |   14 +++
>  drivers/w1/Makefile           |    6 +
>  drivers/w1/masters/Kconfig    |   14 +++
>  drivers/w1/masters/Makefile   |    5 +
>  drivers/w1/masters/w1-gpio.c  |  116 ++++++++++++++++++++
>  drivers/w1/slaves/Kconfig     |   27 +++++
>  drivers/w1/slaves/Makefile    |    6 +
>  drivers/w1/slaves/w1_ds2431.c |  294 +++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/w1/slaves/w1_ds2433.c |  196 +++++++++++++++++++++++++++++++++
>  drivers/w1/w1.c               |  621 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/w1/w1.h               |  152 ++++++++++++++++++++++++++
>  include/clock.h               |    1 +
>  include/linux/w1-gpio.h       |   25 +++++
>  16 files changed, 1490 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/w1/Kconfig
>  create mode 100644 drivers/w1/Makefile
>  create mode 100644 drivers/w1/masters/Kconfig
>  create mode 100644 drivers/w1/masters/Makefile
>  create mode 100644 drivers/w1/masters/w1-gpio.c
>  create mode 100644 drivers/w1/slaves/Kconfig
>  create mode 100644 drivers/w1/slaves/Makefile
>  create mode 100644 drivers/w1/slaves/w1_ds2431.c
>  create mode 100644 drivers/w1/slaves/w1_ds2433.c
>  create mode 100644 drivers/w1/w1.c
>  create mode 100644 drivers/w1/w1.h
>  create mode 100644 include/linux/w1-gpio.h
> 
> Best Regards,
> J.
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

-- 
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Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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[PATCH 4/5] 1-wire: add ds2431 support

[Jean-Christophe PLAGNIOL-VILLARD]

Based on linux implementation.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
---
 drivers/w1/slaves/Kconfig     |   10 ++
 drivers/w1/slaves/Makefile    |    1 +
 drivers/w1/slaves/w1_ds2431.c |  294 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/w1/slaves/w1_ds2431.c

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index f35eedf..26150a2 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -4,4 +4,14 @@
 
 menu "1-wire Slaves"
 
+config W1_SLAVE_DS2431
+	bool "1kb EEPROM family support (DS2431)"
+	help
+	  Say Y here if you want to use a 1-wire
+	  1kb EEPROM family device (DS2431)
+
+config W1_SLAVE_DS2431_WRITE
+	bool "write support"
+	depends on W1_SLAVE_DS2431
+
 endmenu
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index ac9a5a7..65804e0 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -2,3 +2,4 @@
 # Makefile for the Dallas's 1-wire slaves.
 #
 
+obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
new file mode 100644
index 0000000..30e6e1d
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -0,0 +1,294 @@
+/*
+ * w1_ds2431.c - w1 family 2d (DS2431) driver
+ *
+ * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <init.h>
+#include "../w1.h"
+
+#define W1_F2D_EEPROM_SIZE	128
+#define W1_F2D_PAGE_COUNT	4
+#define W1_F2D_PAGE_BITS	5
+#define W1_F2D_PAGE_SIZE	(1 << W1_F2D_PAGE_BITS)
+#define W1_F2D_PAGE_MASK	0x1F
+
+#define W1_F2D_SCRATCH_BITS	3
+#define W1_F2D_SCRATCH_SIZE	(1 << W1_F2D_SCRATCH_BITS)
+#define W1_F2D_SCRATCH_MASK 	(W1_F2D_SCRATCH_SIZE - 1)
+
+#define W1_F2D_READ_EEPROM	0xF0
+#define W1_F2D_WRITE_SCRATCH	0x0F
+#define W1_F2D_READ_SCRATCH	0xAA
+#define W1_F2D_COPY_SCRATCH	0x55
+
+
+#define W1_F2D_TPROG_MS		11
+
+#define W1_F2D_READ_RETRIES	10
+#define W1_F2D_READ_MAXLEN	8
+
+#define DRIVERNAME	"ds2431"
+
+static int ds2431_count = 0;
+
+/*
+ * Check the file size bounds and adjusts count as needed.
+ * This would not be needed if the file size didn't reset to 0 after a write.
+ */
+static inline size_t ds2431_fix_count(loff_t off, size_t count, size_t size)
+{
+	if (off > size)
+		return 0;
+
+	if ((off + count) > size)
+		return size - off;
+
+	return count;
+}
+
+/*
+ * Read a block from W1 ROM two times and compares the results.
+ * If they are equal they are returned, otherwise the read
+ * is repeated W1_F2D_READ_RETRIES times.
+ *
+ * count must not exceed W1_F2D_READ_MAXLEN.
+ */
+int ds2431_readblock(struct w1_device *dev, int off, int count, char *buf)
+{
+	struct w1_bus *bus = dev->bus;
+	u8 wrbuf[3];
+	u8 cmp[W1_F2D_READ_MAXLEN];
+	int tries = W1_F2D_READ_RETRIES;
+
+	do {
+		wrbuf[0] = W1_F2D_READ_EEPROM;
+		wrbuf[1] = off & 0xff;
+		wrbuf[2] = off >> 8;
+
+		if (w1_reset_select_slave(dev))
+			return -1;
+
+		w1_write_block(bus, wrbuf, 3);
+		w1_read_block(bus, buf, count);
+
+		if (w1_reset_select_slave(dev))
+			return -1;
+
+		w1_write_block(bus, wrbuf, 3);
+		w1_read_block(bus, cmp, count);
+
+		if (!memcmp(cmp, buf, count))
+			return 0;
+	} while (--tries);
+
+	dev_err(&dev->dev, "proof reading failed %d times\n",
+			W1_F2D_READ_RETRIES);
+
+	return -1;
+}
+
+static ssize_t ds2431_cdev_read(struct cdev *cdev, void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	int todo = count;
+
+	count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+	if (count == 0)
+		return 0;
+
+	/* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
+	while (todo > 0) {
+		int block_read;
+
+		if (todo >= W1_F2D_READ_MAXLEN)
+			block_read = W1_F2D_READ_MAXLEN;
+		else
+			block_read = todo;
+
+		if (ds2431_readblock(dev, off, block_read, buf) < 0)
+			count = -EIO;
+
+		todo -= W1_F2D_READ_MAXLEN;
+		buf += W1_F2D_READ_MAXLEN;
+		off += W1_F2D_READ_MAXLEN;
+	}
+
+	return count;
+}
+
+#ifdef CONFIG_W1_SLAVE_DS2431_WRITE
+/*
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and
+ * must be W1_F2D_SCRATCH_SIZE bytes long.
+ * The master must be locked.
+ *
+ * @param sl	The slave structure
+ * @param addr	Address for the write
+ * @param len   length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
+ * @param data	The data to write
+ * @return	0=Success -1=failure
+ */
+static int ds2431_write(struct w1_device *dev, int addr, int len, const u8 *data)
+{
+	struct w1_bus *bus = dev->bus;
+	int tries = W1_F2D_READ_RETRIES;
+	u8 wrbuf[4];
+	u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
+	u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;
+
+retry:
+
+	/* Write the data to the scratchpad */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F2D_WRITE_SCRATCH;
+	wrbuf[1] = addr & 0xff;
+	wrbuf[2] = addr >> 8;
+
+	w1_write_block(bus, wrbuf, 3);
+	w1_write_block(bus, data, len);
+
+	/* Read the scratchpad and verify */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	w1_write_8(bus, W1_F2D_READ_SCRATCH);
+	w1_read_block(bus, rdbuf, len + 3);
+
+	/* Compare what was read against the data written */
+	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
+	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) {
+
+		if (--tries)
+			goto retry;
+
+		dev_err(&dev->dev,
+			"could not write to eeprom, scratchpad compare failed %d times\n",
+			W1_F2D_READ_RETRIES);
+
+		return -1;
+	}
+
+	/* Copy the scratchpad to EEPROM */
+	if (w1_reset_select_slave(dev))
+		return -1;
+
+	wrbuf[0] = W1_F2D_COPY_SCRATCH;
+	wrbuf[3] = es;
+	w1_write_block(bus, wrbuf, 4);
+
+	/* Sleep for tprog ms to wait for the write to complete */
+	mdelay(W1_F2D_TPROG_MS);
+
+	/* Reset the bus to wake up the EEPROM  */
+	w1_reset_bus(bus);
+
+	return 0;
+}
+
+static ssize_t ds2431_cdev_write(struct cdev *cdev, const void *buf, size_t count,
+		loff_t off, ulong flags)
+{
+	struct w1_device *dev = cdev->priv;
+	int addr, len;
+	int copy;
+
+	count = ds2431_fix_count(off, count, W1_F2D_EEPROM_SIZE);
+	if (count == 0)
+		return 0;
+
+	/* Can only write data in blocks of the size of the scratchpad */
+	addr = off;
+	len = count;
+	while (len > 0) {
+
+		/* if len too short or addr not aligned */
+		if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) {
+			char tmp[W1_F2D_SCRATCH_SIZE];
+
+			/* read the block and update the parts to be written */
+			if (ds2431_readblock(dev, addr & ~W1_F2D_SCRATCH_MASK,
+					W1_F2D_SCRATCH_SIZE, tmp)) {
+				count = -EIO;
+				goto out_up;
+			}
+
+			/* copy at most to the boundary of the PAGE or len */
+			copy = W1_F2D_SCRATCH_SIZE -
+				(addr & W1_F2D_SCRATCH_MASK);
+
+			if (copy > len)
+				copy = len;
+
+			memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy);
+			if (ds2431_write(dev, addr & ~W1_F2D_SCRATCH_MASK,
+					W1_F2D_SCRATCH_SIZE, tmp) < 0) {
+				count = -EIO;
+				goto out_up;
+			}
+		} else {
+
+			copy = W1_F2D_SCRATCH_SIZE;
+			if (ds2431_write(dev, addr, copy, buf) < 0) {
+				count = -EIO;
+				goto out_up;
+			}
+		}
+		buf += copy;
+		addr += copy;
+		len -= copy;
+	}
+
+out_up:
+	return count;
+}
+#else
+#define ds2431_cdev_write NULL
+#endif
+
+static struct file_operations ds2431_ops = {
+	.read	= ds2431_cdev_read,
+	.write	= ds2431_cdev_write,
+	.lseek	= dev_lseek_default,
+};
+
+static int ds2431_probe(struct w1_device *dev)
+{
+	struct cdev *cdev;
+
+	cdev = xzalloc(sizeof(*cdev));
+	cdev->dev	= &dev->dev;
+	cdev->priv	= dev;
+	cdev->ops	= &ds2431_ops;
+	cdev->size	= W1_F2D_EEPROM_SIZE;
+	cdev->name	= asprintf(DRIVERNAME"%d", ds2431_count++);
+	if (cdev->name == NULL)
+		return -ENOMEM;
+
+	return devfs_create(cdev);
+}
+
+struct w1_driver ds2431_driver = {
+	.drv = {
+		.name = DRIVERNAME,
+	},
+	.probe		= ds2431_probe,
+	.fid		= 0x2d,
+};
+
+static int w1_ds2431_init(void)
+{
+	return w1_driver_register(&ds2431_driver);
+}
+device_initcall(w1_ds2431_init);
-- 
1.7.10.4


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