[PATCH 2/4] gpio: Add raspberrypi exp gpio driver

[Sascha Hauer <s.hauer@pengutronix.de>]

Taken from the kernel adopted to barebox.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/mach-bcm283x/include/mach/mbox.h |   4 +
 drivers/gpio/Kconfig                      |   7 +
 drivers/gpio/Makefile                     |   1 +
 drivers/gpio/gpio-raspberrypi-exp.c       | 273 ++++++++++++++++++++++
 4 files changed, 285 insertions(+)
 create mode 100644 drivers/gpio/gpio-raspberrypi-exp.c

diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
index 6db961b807..f10f5bc148 100644
--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
+++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
@@ -126,6 +126,10 @@ struct bcm2835_mbox_tag_hdr {
  */
 
 #define BCM2835_MBOX_TAG_GET_BOARD_REV	0x00010002
+#define BCM2835_MBOX_TAG_GET_GPIO_STATE 0x00030041
+#define BCM2835_MBOX_TAG_SET_GPIO_STATE 0x00038041
+#define BCM2835_MBOX_TAG_GET_GPIO_CONFIG 0x00030043
+#define BCM2835_MBOX_TAG_SET_GPIO_CONFIG 0x00038043
 
 /*
  * ids
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 0f924d135f..7e4fc90d39 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -129,6 +129,13 @@ config GPIO_PL061
 	help
 	  Say yes here to support the PrimeCell PL061 GPIO device
 
+config GPIO_RASPBERRYPI_EXP
+	bool "Raspberry Pi 3 GPIO Expander"
+	depends on ARCH_BCM283X
+	help
+	  Turn on GPIO support for the expander on Raspberry Pi 3 boards, using
+	  the firmware mailbox to communicate with VideoCore on BCM283x chips.
+
 config GPIO_STMPE
 	depends on MFD_STMPE
 	bool "STMPE GPIO Expander"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index bc5c500e4d..77dcf58f64 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_GPIO_TEGRA)	+= gpio-tegra.o
 obj-$(CONFIG_GPIO_DESIGNWARE)	+= gpio-dw.o
 obj-$(CONFIG_GPIO_SX150X)	+= gpio-sx150x.o
 obj-$(CONFIG_GPIO_VF610)	+= gpio-vf610.o
+obj-$(CONFIG_GPIO_RASPBERRYPI_EXP) += gpio-raspberrypi-exp.o
diff --git a/drivers/gpio/gpio-raspberrypi-exp.c b/drivers/gpio/gpio-raspberrypi-exp.c
new file mode 100644
index 0000000000..f03a2a2579
--- /dev/null
+++ b/drivers/gpio/gpio-raspberrypi-exp.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Raspberry Pi 3 expander GPIO driver
+ *
+ *  Uses the firmware mailbox service to communicate with the
+ *  GPIO expander on the VPU.
+ *
+ *  Copyright (C) 2017 Raspberry Pi Trading Ltd.
+ */
+
+#include <common.h>
+#include <gpio.h>
+#include <init.h>
+#include <mach/mbox.h>
+
+#define NUM_GPIO 8
+
+#define RPI_EXP_GPIO_BASE	128
+
+#define RPI_EXP_GPIO_DIR_IN	0
+#define RPI_EXP_GPIO_DIR_OUT	1
+
+struct rpi_exp_gpio {
+	struct gpio_chip gc;
+	struct rpi_firmware *fw;
+};
+
+/* VC4 firmware mailbox interface data structures */
+struct gpio_set_config {
+	struct bcm2835_mbox_hdr hdr;		/* buf_size, code */
+	struct bcm2835_mbox_tag_hdr tag_hdr;	/* tag, val_buf_size, val_len */
+        union {
+                struct {
+			u32 gpio;
+			u32 direction;
+			u32 polarity;
+			u32 term_en;
+			u32 term_pull_up;
+			u32 state;
+                } req;
+	} body;
+	u32 end_tag;
+};
+
+struct gpio_get_config {
+	struct bcm2835_mbox_hdr hdr;
+	struct bcm2835_mbox_tag_hdr tag_hdr;
+        union {
+                struct {
+			u32 gpio;
+			u32 direction;
+			u32 polarity;
+			u32 term_en;
+			u32 term_pull_up;
+                } req;
+	} body;
+	u32 end_tag;
+};
+
+struct gpio_get_set_state {
+	struct bcm2835_mbox_hdr hdr;
+	struct bcm2835_mbox_tag_hdr tag_hdr;
+        union {
+                struct {
+			u32 gpio;
+			u32 state;
+                } req;
+	} body;
+	u32 end_tag;
+};
+
+static inline struct rpi_exp_gpio *to_rpi_gpio(struct gpio_chip *gc)
+{
+	return container_of(gc, struct rpi_exp_gpio, gc);
+}
+
+static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_get_config, get);
+	BCM2835_MBOX_INIT_HDR(get);
+	BCM2835_MBOX_INIT_TAG(get, GET_GPIO_CONFIG);
+
+	gpio = to_rpi_gpio(gc);
+
+	get->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &get->hdr);
+	if (ret || get->body.req.gpio != 0) {
+		dev_err(gc->dev, "Failed to get GPIO %u config (%d %x)\n",
+			off, ret, get->body.req.gpio);
+		return ret ? ret : -EIO;
+	}
+	return get->body.req.polarity;
+}
+
+static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_set_config, set_in);
+	BCM2835_MBOX_INIT_HDR(set_in);
+	BCM2835_MBOX_INIT_TAG(set_in, SET_GPIO_CONFIG);
+
+	gpio = to_rpi_gpio(gc);
+
+	set_in->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+	set_in->body.req.direction = RPI_EXP_GPIO_DIR_IN;
+	set_in->body.req.term_en = 0;		/* termination disabled */
+	set_in->body.req.term_pull_up = 0;	/* n/a as termination disabled */
+	set_in->body.req.state = 0;		/* n/a as configured as an input */
+
+	ret = rpi_exp_gpio_get_polarity(gc, off);
+	if (ret < 0)
+		return ret;
+
+	set_in->body.req.polarity = ret;		/* Retain existing setting */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &set_in->hdr);
+	if (ret || set_in->body.req.gpio != 0) {
+		dev_err(gc->dev, "Failed to set GPIO %u to input (%d %x)\n",
+			off, ret, set_in->body.req.gpio);
+		return ret ? ret : -EIO;
+	}
+
+	return 0;
+}
+
+static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_set_config, set_out);
+	BCM2835_MBOX_INIT_HDR(set_out);
+	BCM2835_MBOX_INIT_TAG(set_out, SET_GPIO_CONFIG);
+
+	gpio = to_rpi_gpio(gc);
+
+	set_out->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+	set_out->body.req.direction = RPI_EXP_GPIO_DIR_OUT;
+	set_out->body.req.term_en = 0;		/* n/a as an output */
+	set_out->body.req.term_pull_up = 0;	/* n/a as termination disabled */
+	set_out->body.req.state = val;		/* Output state */
+
+	ret = rpi_exp_gpio_get_polarity(gc, off);
+	if (ret < 0)
+		return ret;
+	set_out->body.req.polarity = ret;		/* Retain existing setting */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &set_out->hdr);
+	if (ret || set_out->body.req.gpio != 0) {
+		dev_err(gc->dev, "Failed to set GPIO %u to output (%d %x)\n",
+			off, ret, set_out->body.req.gpio);
+		return ret ? ret : -EIO;
+	}
+	return 0;
+}
+
+static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_get_config, get);
+	BCM2835_MBOX_INIT_HDR(get);
+	BCM2835_MBOX_INIT_TAG(get, GET_GPIO_CONFIG);
+
+	gpio = to_rpi_gpio(gc);
+
+	get->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &get->hdr);
+	if (ret || get->body.req.gpio != 0) {
+		dev_err(gc->dev,
+			"Failed to get GPIO %u config (%d %x)\n", off, ret,
+			get->body.req.gpio);
+		return ret ? ret : -EIO;
+	}
+	if (get->body.req.direction)
+		return GPIOF_DIR_OUT;
+
+	return GPIOF_DIR_IN;
+}
+
+static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_get_set_state, get);
+	BCM2835_MBOX_INIT_HDR(get);
+	BCM2835_MBOX_INIT_TAG(get, GET_GPIO_STATE);
+
+	gpio = to_rpi_gpio(gc);
+
+	get->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+	get->body.req.state = 0;		/* storage for returned value */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &get->hdr);
+	if (ret || get->body.req.gpio != 0) {
+		dev_err(gc->dev,
+			"Failed to get GPIO %u state (%d %x)\n", off, ret,
+			get->body.req.gpio);
+		return ret ? ret : -EIO;
+	}
+	return !!get->body.req.state;
+}
+
+static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
+{
+	struct rpi_exp_gpio *gpio;
+	int ret;
+	BCM2835_MBOX_STACK_ALIGN(struct gpio_get_set_state, set);
+	BCM2835_MBOX_INIT_HDR(set);
+	BCM2835_MBOX_INIT_TAG(set, SET_GPIO_STATE);
+
+	gpio = to_rpi_gpio(gc);
+
+	set->body.req.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */
+	set->body.req.state = val;	/* Output state */
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &set->hdr);
+	if (ret || set->body.req.gpio != 0)
+		dev_err(gc->dev,
+			"Failed to set GPIO %u state (%d %x)\n", off, ret,
+			set->body.req.gpio);
+}
+
+static struct gpio_ops rpi_exp_gpio_ops = {
+	.direction_input = rpi_exp_gpio_dir_in,
+	.direction_output = rpi_exp_gpio_dir_out,
+	.get_direction = rpi_exp_gpio_get_direction,
+	.get = rpi_exp_gpio_get,
+	.set = rpi_exp_gpio_set,
+};
+
+static int rpi_exp_gpio_probe(struct device_d *dev)
+{
+	struct device_node *np = dev->device_node;
+	struct rpi_exp_gpio *rpi_gpio;
+	int ret;
+
+	rpi_gpio = xzalloc(sizeof(*rpi_gpio));
+
+	rpi_gpio->gc.dev = dev;
+	rpi_gpio->gc.base = -1;
+	rpi_gpio->gc.ngpio = NUM_GPIO;
+	rpi_gpio->gc.ops = &rpi_exp_gpio_ops;
+
+	ret = gpiochip_add(&rpi_gpio->gc);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "probed gpiochip with %d gpios, base %d\n",
+			rpi_gpio->gc.ngpio, rpi_gpio->gc.base);
+
+	return 0;
+}
+
+static __maybe_unused struct of_device_id rpi_exp_gpio_ids[] = {
+	{
+		.compatible = "raspberrypi,firmware-gpio",
+	}, {
+		/* sentinel */
+	},
+};
+
+static struct driver_d rpi_exp_gpio_driver = {
+	.name = "dw-apb-gpio",
+	.probe = rpi_exp_gpio_probe,
+	.of_compatible = DRV_OF_COMPAT(rpi_exp_gpio_ids),
+};
+
+device_platform_driver(rpi_exp_gpio_driver);
-- 
2.24.0


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