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                 struct gpio_keys_button *button = &pdata->buttons[i];
  39                 int gpio = button->gpio;
  40
  41                 if (irq == gpio_to_irq(gpio)) {
  42                         unsigned int type = button->type ?: EV_KEY;
  43                         int state = (gpio_get_value(gpio) ? 1 : 0) ^ button->active_low;
  44
  45                         input_event(input, type, button->code, !!state);
  46                         input_sync(input);
  47                 }
  48         }
  49
  50         return IRQ_HANDLED;
  51 }
  52
  53 static int __devinit gpio_keys_probe(struct platform_device *pdev)
  54 {
  55         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
  56         struct input_dev *input;
  57         int i, error;
  58
  59         input = input_allocate_device();
  60         if (!input)
  61                 return -ENOMEM;
  62
  63         platform_set_drvdata(pdev, input);
  64
  65         input->evbit[0] = BIT(EV_KEY);
  66
  67         input->name = pdev->name;
  68         input->phys = "gpio-keys/input0";
  69         input->dev.parent = &pdev->dev;
  70
  71         input->id.bustype = BUS_HOST;
  72         input->id.vendor = 0x0001;
  73         input->id.product = 0x0001;
  74         input->id.version = 0x0100;
  75
  76         for (i = 0; i < pdata->nbuttons; i++) {
  77                 struct gpio_keys_button *button = &pdata->buttons[i];
  78                 int irq = gpio_to_irq(button->gpio);
  79                 unsigned int type = button->type ?: EV_KEY;
  80
  81                 set_irq_type(irq, IRQ_TYPE_EDGE_BOTH);
  82                 error = request_irq(irq, gpio_keys_isr, IRQF_SAMPLE_RANDOM,
  83                                      button->desc ? button->desc : "gpio_keys",
  84                                      pdev);
  85                 if (error) {
  86                         printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n",
  87                                 irq, error);
  88                         goto fail;
  89                 }
  90
  91                 input_set_capability(input, type, button->code);
  92         }
  93
  94         error = input_register_device(input);
  95         if (error) {
  96                 printk(KERN_ERR "Unable to register gpio-keys input device\n");
  97                 goto fail;
  98         }
  99
 100         return 0;
 101
 102  fail:
 103         for (i = i - 1; i >= 0; i--)
 104                 free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
 105
 106         input_free_device(input);
 107
 108         return error;
 109 }
 110
 111 static int __devexit gpio_keys_remove(struct platform_device *pdev)
 112 {
 113         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 114         struct input_dev *input = platform_get_drvdata(pdev);
 115         int i;
 116
 117         for (i = 0; i < pdata->nbuttons; i++) {
 118                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
 119                 free_irq(irq, pdev);
 120         }
 121
 122         input_unregister_device(input);
 123
 124         return 0;
 125 }
 126
 127 struct platform_driver gpio_keys_device_driver = {
 128         .probe          = gpio_keys_probe,
 129         .remove         = __devexit_p(gpio_keys_remove),
 130         .driver         = {
 131                 .name   = "gpio-keys",
 132         }
 133 };
 134
 135 static int __init gpio_keys_init(void)
 136 {
 137         return platform_driver_register(&gpio_keys_device_driver);
 138 }
 139
 140 static void __exit gpio_keys_exit(void)
 141 {
 142         platform_driver_unregister(&gpio_keys_device_driver);
 143 }
 144
 145 module_init(gpio_keys_init);
 146 module_exit(gpio_keys_exit);
 147
 148 MODULE_LICENSE("GPL");
 149 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
 150 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");