drivers/input/keyboard/gpio_keys.c

   1 /*
   2  * Driver for keys on GPIO lines capable of generating interrupts.
   3  *
   4  * Copyright 2005 Phil Blundell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/version.h>
  13
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irq.h>
  18 #include <linux/sched.h>
  19 #include <linux/pm.h>
  20 #include <linux/sysctl.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/delay.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/input.h>
  25 #include <linux/irq.h>
  26 #include <linux/gpio_keys.h>
  27
  28 #include <asm/gpio.h>
  29
  30 static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
  31 {
  32         int i;
  33         struct platform_device *pdev = dev_id;
  34         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
  35         struct input_dev *input = platform_get_drvdata(pdev);
  36
  37         for (i = 0; i < pdata->nbuttons; i++) {
  38                 int gpio = pdata->buttons[i].gpio;
  39                 if (irq == gpio_to_irq(gpio)) {
  40                         int state = (gpio_get_value(gpio) ? 1 : 0) ^ (pdata->buttons[i].active_low);
  41
  42                         input_report_key(input, pdata->buttons[i].keycode, state);
  43                         input_sync(input);
  44                 }
  45         }
  46
  47         return IRQ_HANDLED;
  48 }
  49
  50 static int __devinit gpio_keys_probe(struct platform_device *pdev)
  51 {
  52         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
  53         struct input_dev *input;
  54         int i, error;
  55
  56         input = input_allocate_device();
  57         if (!input)
  58                 return -ENOMEM;
  59
  60         platform_set_drvdata(pdev, input);
  61
  62         input->evbit[0] = BIT(EV_KEY);
  63
  64         input->name = pdev->name;
  65         input->phys = "gpio-keys/input0";
  66         input->cdev.dev = &pdev->dev;
  67         input->private = pdata;
  68
  69         input->id.bustype = BUS_HOST;
  70         input->id.vendor = 0x0001;
  71         input->id.product = 0x0001;
  72         input->id.version = 0x0100;
  73
  74         for (i = 0; i < pdata->nbuttons; i++) {
  75                 int code = pdata->buttons[i].keycode;
  76                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
  77
  78                 set_irq_type(irq, IRQ_TYPE_EDGE_BOTH);
  79                 error = request_irq(irq, gpio_keys_isr, IRQF_SAMPLE_RANDOM,
  80                                      pdata->buttons[i].desc ? pdata->buttons[i].desc : "gpio_keys",
  81                                      pdev);
  82                 if (error) {
  83                         printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n",
  84                                 irq, error);
  85                         goto fail;
  86                 }
  87                 set_bit(code, input->keybit);
  88         }
  89
  90         error = input_register_device(input);
  91         if (error) {
  92                 printk(KERN_ERR "Unable to register gpio-keys input device\n");
  93                 goto fail;
  94         }
  95
  96         return 0;
  97
  98  fail:
  99         for (i = i - 1; i >= 0; i--)
 100                 free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
 101
 102         input_free_device(input);
 103
 104         return error;
 105 }
 106
 107 static int __devexit gpio_keys_remove(struct platform_device *pdev)
 108 {
 109         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 110         struct input_dev *input = platform_get_drvdata(pdev);
 111         int i;
 112
 113         for (i = 0; i < pdata->nbuttons; i++) {
 114                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
 115                 free_irq(irq, pdev);
 116         }
 117
 118         input_unregister_device(input);
 119
 120         return 0;
 121 }
 122
 123 struct platform_driver gpio_keys_device_driver = {
 124         .probe          = gpio_keys_probe,
 125         .remove         = __devexit_p(gpio_keys_remove),
 126         .driver         = {
 127                 .name   = "gpio-keys",
 128         }
 129 };
 130
 131 static int __init gpio_keys_init(void)
 132 {
 133         return platform_driver_register(&gpio_keys_device_driver);
 134 }
 135
 136 static void __exit gpio_keys_exit(void)
 137 {
 138         platform_driver_unregister(&gpio_keys_device_driver);
 139 }
 140
 141 module_init(gpio_keys_init);
 142 module_exit(gpio_keys_exit);
 143
 144 MODULE_LICENSE("GPL");
 145 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
 146 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");