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Commit a98d90e7 authored by Dave Stevenson's avatar Dave Stevenson Committed by Linus Walleij
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gpio: raspberrypi-exp: Driver for RPi3 GPIO expander via mailbox service 



Pi3 and Compute Module 3 have a GPIO expander that the
VPU communicates with.
There is a mailbox service that now allows control of this
expander, so add a kernel driver that can make use of it.

Reviewed-by: default avatarStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: default avatarDave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 9777d809

drivers/gpio/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -122,6 +122,15 @@ config GPIO_ATH79 
	  Select this option to enable GPIO driver for

	  Atheros AR71XX/AR724X/AR913X SoC devices.



config GPIO_RASPBERRYPI_EXP

	tristate "Raspberry Pi 3 GPIO Expander"

	default RASPBERRYPI_FIRMWARE

	depends on OF_GPIO

	depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || COMPILE_TEST

	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_BCM_KONA

	bool "Broadcom Kona GPIO"

	depends on OF_GPIO && (ARCH_BCM_MOBILE || COMPILE_TEST)

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ obj-$(CONFIG_GPIO_AMDPT) += gpio-amdpt.o 
obj-$(CONFIG_GPIO_ARIZONA)	+= gpio-arizona.o

obj-$(CONFIG_GPIO_ATH79)	+= gpio-ath79.o

obj-$(CONFIG_GPIO_ASPEED)	+= gpio-aspeed.o

obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)	+= gpio-raspberrypi-exp.o

obj-$(CONFIG_GPIO_BCM_KONA)	+= gpio-bcm-kona.o

obj-$(CONFIG_GPIO_BD9571MWV)	+= gpio-bd9571mwv.o

obj-$(CONFIG_GPIO_BRCMSTB)	+= gpio-brcmstb.o

drivers/gpio/gpio-raspberrypi-exp.c

0 → 100644
+252 −0
Original line number Diff line number Diff line 
// 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 <linux/err.h>

#include <linux/gpio/driver.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <soc/bcm2835/raspberrypi-firmware.h>



#define MODULE_NAME "raspberrypi-exp-gpio"

#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 {

	u32 gpio;

	u32 direction;

	u32 polarity;

	u32 term_en;

	u32 term_pull_up;

	u32 state;

};



struct gpio_get_config {

	u32 gpio;

	u32 direction;

	u32 polarity;

	u32 term_en;

	u32 term_pull_up;

};



struct gpio_get_set_state {

	u32 gpio;

	u32 state;

};



static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)

{

	struct rpi_exp_gpio *gpio;

	struct gpio_get_config get;

	int ret;



	gpio = gpiochip_get_data(gc);



	get.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,

				    &get, sizeof(get));

	if (ret || get.gpio != 0) {

		dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n",

			off, ret, get.gpio);

		return ret ? ret : -EIO;

	}

	return get.polarity;

}



static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)

{

	struct rpi_exp_gpio *gpio;

	struct gpio_set_config set_in;

	int ret;



	gpio = gpiochip_get_data(gc);



	set_in.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */

	set_in.direction = RPI_EXP_GPIO_DIR_IN;

	set_in.term_en = 0;		/* termination disabled */

	set_in.term_pull_up = 0;	/* n/a as termination disabled */

	set_in.state = 0;		/* n/a as configured as an input */



	ret = rpi_exp_gpio_get_polarity(gc, off);

	if (ret < 0)

		return ret;

	set_in.polarity = ret;		/* Retain existing setting */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,

				    &set_in, sizeof(set_in));

	if (ret || set_in.gpio != 0) {

		dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n",

			off, ret, set_in.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;

	struct gpio_set_config set_out;

	int ret;



	gpio = gpiochip_get_data(gc);



	set_out.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */

	set_out.direction = RPI_EXP_GPIO_DIR_OUT;

	set_out.term_en = 0;		/* n/a as an output */

	set_out.term_pull_up = 0;	/* n/a as termination disabled */

	set_out.state = val;		/* Output state */



	ret = rpi_exp_gpio_get_polarity(gc, off);

	if (ret < 0)

		return ret;

	set_out.polarity = ret;		/* Retain existing setting */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,

				    &set_out, sizeof(set_out));

	if (ret || set_out.gpio != 0) {

		dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n",

			off, ret, set_out.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;

	struct gpio_get_config get;

	int ret;



	gpio = gpiochip_get_data(gc);



	get.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,

				    &get, sizeof(get));

	if (ret || get.gpio != 0) {

		dev_err(gc->parent,

			"Failed to get GPIO %u config (%d %x)\n", off, ret,

			get.gpio);

		return ret ? ret : -EIO;

	}

	return !get.direction;

}



static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)

{

	struct rpi_exp_gpio *gpio;

	struct gpio_get_set_state get;

	int ret;



	gpio = gpiochip_get_data(gc);



	get.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */

	get.state = 0;		/* storage for returned value */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,

					 &get, sizeof(get));

	if (ret || get.gpio != 0) {

		dev_err(gc->parent,

			"Failed to get GPIO %u state (%d %x)\n", off, ret,

			get.gpio);

		return ret ? ret : -EIO;

	}

	return !!get.state;

}



static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)

{

	struct rpi_exp_gpio *gpio;

	struct gpio_get_set_state set;

	int ret;



	gpio = gpiochip_get_data(gc);



	set.gpio = off + RPI_EXP_GPIO_BASE;	/* GPIO to update */

	set.state = val;	/* Output state */



	ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE,

					 &set, sizeof(set));

	if (ret || set.gpio != 0)

		dev_err(gc->parent,

			"Failed to set GPIO %u state (%d %x)\n", off, ret,

			set.gpio);

}



static int rpi_exp_gpio_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct device_node *np = dev->of_node;

	struct device_node *fw_node;

	struct rpi_firmware *fw;

	struct rpi_exp_gpio *rpi_gpio;



	fw_node = of_get_parent(np);

	if (!fw_node) {

		dev_err(dev, "Missing firmware node\n");

		return -ENOENT;

	}



	fw = rpi_firmware_get(fw_node);

	if (!fw)

		return -EPROBE_DEFER;



	rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL);

	if (!rpi_gpio)

		return -ENOMEM;



	rpi_gpio->fw = fw;

	rpi_gpio->gc.parent = dev;

	rpi_gpio->gc.label = MODULE_NAME;

	rpi_gpio->gc.owner = THIS_MODULE;

	rpi_gpio->gc.of_node = np;

	rpi_gpio->gc.base = -1;

	rpi_gpio->gc.ngpio = NUM_GPIO;



	rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;

	rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;

	rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;

	rpi_gpio->gc.get = rpi_exp_gpio_get;

	rpi_gpio->gc.set = rpi_exp_gpio_set;

	rpi_gpio->gc.can_sleep = true;



	return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);

}



static const struct of_device_id rpi_exp_gpio_ids[] = {

	{ .compatible = "raspberrypi,firmware-gpio" },

	{ }

};

MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);



static struct platform_driver rpi_exp_gpio_driver = {

	.driver	= {

		.name		= MODULE_NAME,

		.of_match_table	= of_match_ptr(rpi_exp_gpio_ids),

	},

	.probe	= rpi_exp_gpio_probe,

};

module_platform_driver(rpi_exp_gpio_driver);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>");

MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");

MODULE_ALIAS("platform:rpi-exp-gpio");