gpio: raspberrypi-exp: Driver for RPi3 GPIO expander via mailbox service (a98d90e7) · Commits · 戴 / test

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

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		@@ -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");

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