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gpio_keys.c

/*
 * Driver for keys on GPIO lines capable of generating interrupts.
 *
 * Copyright 2005 Phil Blundell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/version.h>

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/gpio_keys.h>

#include <asm/gpio.h>

static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
{
      int i;
      struct platform_device *pdev = dev_id;
      struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
      struct input_dev *input = platform_get_drvdata(pdev);

      for (i = 0; i < pdata->nbuttons; i++) {
            struct gpio_keys_button *button = &pdata->buttons[i];
            int gpio = button->gpio;

            if (irq == gpio_to_irq(gpio)) {
                  unsigned int type = button->type ?: EV_KEY;
                  int state = (gpio_get_value(gpio) ? 1 : 0) ^ button->active_low;

                  input_event(input, type, button->code, !!state);
                  input_sync(input);
            }
      }

      return IRQ_HANDLED;
}

static int __devinit gpio_keys_probe(struct platform_device *pdev)
{
      struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
      struct input_dev *input;
      int i, error;
      int wakeup = 0;

      input = input_allocate_device();
      if (!input)
            return -ENOMEM;

      platform_set_drvdata(pdev, input);

      input->evbit[0] = BIT_MASK(EV_KEY);

      input->name = pdev->name;
      input->phys = "gpio-keys/input0";
      input->dev.parent = &pdev->dev;

      input->id.bustype = BUS_HOST;
      input->id.vendor = 0x0001;
      input->id.product = 0x0001;
      input->id.version = 0x0100;

      for (i = 0; i < pdata->nbuttons; i++) {
            struct gpio_keys_button *button = &pdata->buttons[i];
            int irq;
            unsigned int type = button->type ?: EV_KEY;

            error = gpio_request(button->gpio, button->desc ?: "gpio_keys");
            if (error < 0) {
                  pr_err("gpio-keys: failed to request GPIO %d,"
                        " error %d\n", button->gpio, error);
                  goto fail;
            }

            error = gpio_direction_input(button->gpio);
            if (error < 0) {
                  pr_err("gpio-keys: failed to configure input"
                        " direction for GPIO %d, error %d\n",
                        button->gpio, error);
                  gpio_free(button->gpio);
                  goto fail;
            }

            irq = gpio_to_irq(button->gpio);
            if (irq < 0) {
                  error = irq;
                  pr_err("gpio-keys: Unable to get irq number"
                        " for GPIO %d, error %d\n",
                        button->gpio, error);
                  gpio_free(button->gpio);
                  goto fail;
            }

            error = request_irq(irq, gpio_keys_isr,
                            IRQF_SAMPLE_RANDOM | IRQF_TRIGGER_RISING |
                              IRQF_TRIGGER_FALLING,
                            button->desc ? button->desc : "gpio_keys",
                            pdev);
            if (error) {
                  pr_err("gpio-keys: Unable to claim irq %d; error %d\n",
                        irq, error);
                  gpio_free(button->gpio);
                  goto fail;
            }

            if (button->wakeup)
                  wakeup = 1;

            input_set_capability(input, type, button->code);
      }

      error = input_register_device(input);
      if (error) {
            pr_err("gpio-keys: Unable to register input device, "
                  "error: %d\n", error);
            goto fail;
      }

      device_init_wakeup(&pdev->dev, wakeup);

      return 0;

 fail:
      while (--i >= 0) {
            free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
            gpio_free(pdata->buttons[i].gpio);
      }

      platform_set_drvdata(pdev, NULL);
      input_free_device(input);

      return error;
}

static int __devexit gpio_keys_remove(struct platform_device *pdev)
{
      struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
      struct input_dev *input = platform_get_drvdata(pdev);
      int i;

      device_init_wakeup(&pdev->dev, 0);

      for (i = 0; i < pdata->nbuttons; i++) {
            int irq = gpio_to_irq(pdata->buttons[i].gpio);
            free_irq(irq, pdev);
            gpio_free(pdata->buttons[i].gpio);
      }

      input_unregister_device(input);

      return 0;
}


#ifdef CONFIG_PM
static int gpio_keys_suspend(struct platform_device *pdev, pm_message_t state)
{
      struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
      int i;

      if (device_may_wakeup(&pdev->dev)) {
            for (i = 0; i < pdata->nbuttons; i++) {
                  struct gpio_keys_button *button = &pdata->buttons[i];
                  if (button->wakeup) {
                        int irq = gpio_to_irq(button->gpio);
                        enable_irq_wake(irq);
                  }
            }
      }

      return 0;
}

static int gpio_keys_resume(struct platform_device *pdev)
{
      struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
      int i;

      if (device_may_wakeup(&pdev->dev)) {
            for (i = 0; i < pdata->nbuttons; i++) {
                  struct gpio_keys_button *button = &pdata->buttons[i];
                  if (button->wakeup) {
                        int irq = gpio_to_irq(button->gpio);
                        disable_irq_wake(irq);
                  }
            }
      }

      return 0;
}
#else
#define gpio_keys_suspend     NULL
#define gpio_keys_resume      NULL
#endif

struct platform_driver gpio_keys_device_driver = {
      .probe            = gpio_keys_probe,
      .remove           = __devexit_p(gpio_keys_remove),
      .suspend    = gpio_keys_suspend,
      .resume           = gpio_keys_resume,
      .driver           = {
            .name = "gpio-keys",
      }
};

static int __init gpio_keys_init(void)
{
      return platform_driver_register(&gpio_keys_device_driver);
}

static void __exit gpio_keys_exit(void)
{
      platform_driver_unregister(&gpio_keys_device_driver);
}

module_init(gpio_keys_init);
module_exit(gpio_keys_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");

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