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

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

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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