linux_kernel/net/rfkill/rfkill-gpio.c

/*
 * Copyright (c) 2011, NVIDIA Corporation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rfkill.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/gpio/consumer.h>

#include <linux/rfkill-gpio.h>

struct rfkill_gpio_data {
	const char		*name;
	enum rfkill_type	type;
	struct gpio_desc	*reset_gpio;
	struct gpio_desc	*shutdown_gpio;

	struct rfkill		*rfkill_dev;
	char			*reset_name;
	char			*shutdown_name;
	struct clk		*clk;

	bool			clk_enabled;
};

static int rfkill_gpio_set_power(void *data, bool blocked)
{
	struct rfkill_gpio_data *rfkill = data;

	if (blocked) {
		gpiod_set_value(rfkill->shutdown_gpio, 0);
		gpiod_set_value(rfkill->reset_gpio, 0);
		if (!IS_ERR(rfkill->clk) && rfkill->clk_enabled)
			clk_disable(rfkill->clk);
	} else {
		if (!IS_ERR(rfkill->clk) && !rfkill->clk_enabled)
			clk_enable(rfkill->clk);
		gpiod_set_value(rfkill->reset_gpio, 1);
		gpiod_set_value(rfkill->shutdown_gpio, 1);
	}

	rfkill->clk_enabled = blocked;

	return 0;
}

static const struct rfkill_ops rfkill_gpio_ops = {
	.set_block = rfkill_gpio_set_power,
};

static int rfkill_gpio_acpi_probe(struct device *dev,
				  struct rfkill_gpio_data *rfkill)
{
	const struct acpi_device_id *id;

	id = acpi_match_device(dev->driver->acpi_match_table, dev);
	if (!id)
		return -ENODEV;

	rfkill->name = dev_name(dev);
	rfkill->type = (unsigned)id->driver_data;

	return 0;
}

static int rfkill_gpio_probe(struct platform_device *pdev)
{
	struct rfkill_gpio_platform_data *pdata = pdev->dev.platform_data;
	struct rfkill_gpio_data *rfkill;
	const char *clk_name = NULL;
	struct gpio_desc *gpio;
	int ret;
	int len;

	rfkill = devm_kzalloc(&pdev->dev, sizeof(*rfkill), GFP_KERNEL);
	if (!rfkill)
		return -ENOMEM;

	if (ACPI_HANDLE(&pdev->dev)) {
		ret = rfkill_gpio_acpi_probe(&pdev->dev, rfkill);
		if (ret)
			return ret;
	} else if (pdata) {
		clk_name = pdata->power_clk_name;
		rfkill->name = pdata->name;
		rfkill->type = pdata->type;
	} else {
		return -ENODEV;
	}

	len = strlen(rfkill->name);
	rfkill->reset_name = devm_kzalloc(&pdev->dev, len + 7, GFP_KERNEL);
	if (!rfkill->reset_name)
		return -ENOMEM;

	rfkill->shutdown_name = devm_kzalloc(&pdev->dev, len + 10, GFP_KERNEL);
	if (!rfkill->shutdown_name)
		return -ENOMEM;

	snprintf(rfkill->reset_name, len + 6 , "%s_reset", rfkill->name);
	snprintf(rfkill->shutdown_name, len + 9, "%s_shutdown", rfkill->name);

	rfkill->clk = devm_clk_get(&pdev->dev, clk_name);

	gpio = devm_gpiod_get_index(&pdev->dev, rfkill->reset_name, 0);
	if (!IS_ERR(gpio)) {
		ret = gpiod_direction_output(gpio, 0);
		if (ret)
			return ret;
		rfkill->reset_gpio = gpio;
	}

	gpio = devm_gpiod_get_index(&pdev->dev, rfkill->shutdown_name, 1);
	if (!IS_ERR(gpio)) {
		ret = gpiod_direction_output(gpio, 0);
		if (ret)
			return ret;
		rfkill->shutdown_gpio = gpio;
	}

	/* Make sure at-least one of the GPIO is defined and that
	 * a name is specified for this instance
	 */
	if ((!rfkill->reset_gpio && !rfkill->shutdown_gpio) || !rfkill->name) {
		dev_err(&pdev->dev, "invalid platform data\n");
		return -EINVAL;
	}

	if (pdata && pdata->gpio_runtime_setup) {
		ret = pdata->gpio_runtime_setup(pdev);
		if (ret) {
			dev_err(&pdev->dev, "can't set up gpio\n");
			return ret;
		}
	}

	rfkill->rfkill_dev = rfkill_alloc(rfkill->name, &pdev->dev,
					  rfkill->type, &rfkill_gpio_ops,
					  rfkill);
	if (!rfkill->rfkill_dev)
		return -ENOMEM;

	ret = rfkill_register(rfkill->rfkill_dev);
	if (ret < 0)
		return ret;

	platform_set_drvdata(pdev, rfkill);

	dev_info(&pdev->dev, "%s device registered.\n", rfkill->name);

	return 0;
}

static int rfkill_gpio_remove(struct platform_device *pdev)
{
	struct rfkill_gpio_data *rfkill = platform_get_drvdata(pdev);
	struct rfkill_gpio_platform_data *pdata = pdev->dev.platform_data;

	if (pdata && pdata->gpio_runtime_close)
		pdata->gpio_runtime_close(pdev);
	rfkill_unregister(rfkill->rfkill_dev);
	rfkill_destroy(rfkill->rfkill_dev);

	return 0;
}

static const struct acpi_device_id rfkill_acpi_match[] = {
	{ "BCM4752", RFKILL_TYPE_GPS },
	{ },
};

static struct platform_driver rfkill_gpio_driver = {
	.probe = rfkill_gpio_probe,
	.remove = rfkill_gpio_remove,
	.driver = {
		.name = "rfkill_gpio",
		.owner = THIS_MODULE,
		.acpi_match_table = ACPI_PTR(rfkill_acpi_match),
	},
};

module_platform_driver(rfkill_gpio_driver);

MODULE_DESCRIPTION("gpio rfkill");
MODULE_AUTHOR("NVIDIA");
MODULE_LICENSE("GPL");