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->dev.parent = &pdev->dev;
  67
  68         input->id.bustype = BUS_HOST;
  69         input->id.vendor = 0x0001;
  70         input->id.product = 0x0001;
  71         input->id.version = 0x0100;
  72
  73         for (i = 0; i < pdata->nbuttons; i++) {
  74                 int code = pdata->buttons[i].keycode;
  75                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
  76
  77                 set_irq_type(irq, IRQ_TYPE_EDGE_BOTH);
  78                 error = request_irq(irq, gpio_keys_isr, IRQF_SAMPLE_RANDOM,
  79                                      pdata->buttons[i].desc ? pdata->buttons[i].desc : "gpio_keys",
  80                                      pdev);
  81                 if (error) {
  82                         printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n",
  83                                 irq, error);
  84                         goto fail;
  85                 }
  86                 set_bit(code, input->keybit);
  87         }
  88
  89         error = input_register_device(input);
  90         if (error) {
  91                 printk(KERN_ERR "Unable to register gpio-keys input device\n");
  92                 goto fail;
  93         }
  94
  95         return 0;
  96
  97  fail:
  98         for (i = i - 1; i >= 0; i--)
  99                 free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
 100
 101         input_free_device(input);
 102
 103         return error;
 104 }
 105
 106 static int __devexit gpio_keys_remove(struct platform_device *pdev)
 107 {
 108         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 109         struct input_dev *input = platform_get_drvdata(pdev);
 110         int i;
 111
 112         for (i = 0; i < pdata->nbuttons; i++) {
 113                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
 114                 free_irq(irq, pdev);
 115         }
 116
 117         input_unregister_device(input);
 118
 119         return 0;
 120 }
 121
 122 struct platform_driver gpio_keys_device_driver = {
 123         .probe          = gpio_keys_probe,
 124         .remove         = __devexit_p(gpio_keys_remove),
 125         .driver         = {
 126                 .name   = "gpio-keys",
 127         }
 128 };
 129
 130 static int __init gpio_keys_init(void)
 131 {
 132         return platform_driver_register(&gpio_keys_device_driver);
 133 }
 134
 135 static void __exit gpio_keys_exit(void)
 136 {
 137         platform_driver_unregister(&gpio_keys_device_driver);
 138 }
 139
 140 module_init(gpio_keys_init);
 141 module_exit(gpio_keys_exit);
 142
 143 MODULE_LICENSE("GPL");
 144 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
 145 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");