| 1 | /* |
| 2 | * Driver for buttons on GPIO lines not capable of generating interrupts |
| 3 | * |
| 4 | * Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org> |
| 5 | * Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com> |
| 6 | * |
| 7 | * This file was based on: /drivers/input/misc/cobalt_btns.c |
| 8 | * Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> |
| 9 | * |
| 10 | * also was based on: /drivers/input/keyboard/gpio_keys.c |
| 11 | * Copyright 2005 Phil Blundell |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or modify |
| 14 | * it under the terms of the GNU General Public License version 2 as |
| 15 | * published by the Free Software Foundation. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/init.h> |
| 22 | |
| 23 | #include <linux/input.h> |
| 24 | #include <linux/input-polldev.h> |
| 25 | #include <linux/ioport.h> |
| 26 | #include <linux/platform_device.h> |
| 27 | |
| 28 | #include <linux/gpio_buttons.h> |
| 29 | |
| 30 | #include <asm/gpio.h> |
| 31 | |
| 32 | #define DRV_NAME "gpio-buttons" |
| 33 | #define DRV_VERSION "0.1.2" |
| 34 | #define PFX DRV_NAME ": " |
| 35 | |
| 36 | struct gpio_button_data { |
| 37 | int last_state; |
| 38 | int count; |
| 39 | }; |
| 40 | |
| 41 | struct gpio_buttons_dev { |
| 42 | struct input_polled_dev *poll_dev; |
| 43 | struct gpio_buttons_platform_data *pdata; |
| 44 | struct gpio_button_data *data; |
| 45 | }; |
| 46 | |
| 47 | static void gpio_buttons_poll(struct input_polled_dev *dev) |
| 48 | { |
| 49 | struct gpio_buttons_dev *bdev = dev->private; |
| 50 | struct gpio_buttons_platform_data *pdata = bdev->pdata; |
| 51 | struct input_dev *input = dev->input; |
| 52 | int i; |
| 53 | |
| 54 | for (i = 0; i < bdev->pdata->nbuttons; i++) { |
| 55 | struct gpio_button *button = &pdata->buttons[i]; |
| 56 | unsigned int type = button->type ?: EV_KEY; |
| 57 | int state; |
| 58 | |
| 59 | if (bdev->data[i].count < button->threshold) { |
| 60 | bdev->data[i].count++; |
| 61 | continue; |
| 62 | } |
| 63 | |
| 64 | state = gpio_get_value(button->gpio) ? 1 : 0; |
| 65 | if (state != bdev->data[i].last_state) { |
| 66 | input_event(input, type, button->code, |
| 67 | !!(state ^ button->active_low)); |
| 68 | input_sync(input); |
| 69 | bdev->data[i].count = 0; |
| 70 | bdev->data[i].last_state = state; |
| 71 | } |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | static int __devinit gpio_buttons_probe(struct platform_device *pdev) |
| 76 | { |
| 77 | struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data; |
| 78 | struct gpio_buttons_dev *bdev; |
| 79 | struct input_polled_dev *poll_dev; |
| 80 | struct input_dev *input; |
| 81 | int error, i; |
| 82 | |
| 83 | if (!pdata) |
| 84 | return -ENXIO; |
| 85 | |
| 86 | bdev = kzalloc(sizeof(struct gpio_buttons_dev) + |
| 87 | sizeof(struct gpio_button_data) * pdata->nbuttons, |
| 88 | GFP_KERNEL); |
| 89 | if (!bdev) { |
| 90 | printk(KERN_ERR DRV_NAME "no memory for device\n"); |
| 91 | return -ENOMEM; |
| 92 | } |
| 93 | |
| 94 | bdev->data = (struct gpio_button_data *) &bdev[1]; |
| 95 | |
| 96 | poll_dev = input_allocate_polled_device(); |
| 97 | if (!poll_dev) { |
| 98 | printk(KERN_ERR DRV_NAME "no memory for polled device\n"); |
| 99 | error = -ENOMEM; |
| 100 | goto err_free_bdev; |
| 101 | } |
| 102 | |
| 103 | poll_dev->private = bdev; |
| 104 | poll_dev->poll = gpio_buttons_poll; |
| 105 | poll_dev->poll_interval = pdata->poll_interval; |
| 106 | |
| 107 | input = poll_dev->input; |
| 108 | |
| 109 | input->evbit[0] = BIT(EV_KEY); |
| 110 | input->name = pdev->name; |
| 111 | input->phys = "gpio-buttons/input0"; |
| 112 | input->dev.parent = &pdev->dev; |
| 113 | |
| 114 | input->id.bustype = BUS_HOST; |
| 115 | input->id.vendor = 0x0001; |
| 116 | input->id.product = 0x0001; |
| 117 | input->id.version = 0x0100; |
| 118 | |
| 119 | for (i = 0; i < pdata->nbuttons; i++) { |
| 120 | struct gpio_button *button = &pdata->buttons[i]; |
| 121 | unsigned int gpio = button->gpio; |
| 122 | unsigned int type = button->type ?: EV_KEY; |
| 123 | |
| 124 | error = gpio_request(gpio, button->desc ? |
| 125 | button->desc : DRV_NAME); |
| 126 | if (error) { |
| 127 | printk(KERN_ERR PFX "unable to claim gpio %u, " |
| 128 | "error %d\n", gpio, error); |
| 129 | goto err_free_gpio; |
| 130 | } |
| 131 | |
| 132 | error = gpio_direction_input(gpio); |
| 133 | if (error) { |
| 134 | printk(KERN_ERR PFX "unable to set direction on " |
| 135 | "gpio %u, error %d\n", gpio, error); |
| 136 | goto err_free_gpio; |
| 137 | } |
| 138 | |
| 139 | input_set_capability(input, type, button->code); |
| 140 | bdev->data[i].last_state = gpio_get_value(button->gpio) ? 1 : 0; |
| 141 | } |
| 142 | |
| 143 | bdev->poll_dev = poll_dev; |
| 144 | bdev->pdata = pdata; |
| 145 | platform_set_drvdata(pdev, bdev); |
| 146 | |
| 147 | error = input_register_polled_device(poll_dev); |
| 148 | if (error) { |
| 149 | printk(KERN_ERR PFX "unable to register polled device, " |
| 150 | "error %d\n", error); |
| 151 | goto err_free_gpio; |
| 152 | } |
| 153 | |
| 154 | return 0; |
| 155 | |
| 156 | err_free_gpio: |
| 157 | for (i = i - 1; i >= 0; i--) |
| 158 | gpio_free(pdata->buttons[i].gpio); |
| 159 | |
| 160 | input_free_polled_device(poll_dev); |
| 161 | |
| 162 | err_free_bdev: |
| 163 | kfree(bdev); |
| 164 | |
| 165 | platform_set_drvdata(pdev, NULL); |
| 166 | return error; |
| 167 | } |
| 168 | |
| 169 | static int __devexit gpio_buttons_remove(struct platform_device *pdev) |
| 170 | { |
| 171 | struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev); |
| 172 | struct gpio_buttons_platform_data *pdata = bdev->pdata; |
| 173 | int i; |
| 174 | |
| 175 | input_unregister_polled_device(bdev->poll_dev); |
| 176 | |
| 177 | for (i = 0; i < pdata->nbuttons; i++) |
| 178 | gpio_free(pdata->buttons[i].gpio); |
| 179 | |
| 180 | input_free_polled_device(bdev->poll_dev); |
| 181 | |
| 182 | kfree(bdev); |
| 183 | platform_set_drvdata(pdev, NULL); |
| 184 | |
| 185 | return 0; |
| 186 | } |
| 187 | |
| 188 | static struct platform_driver gpio_buttons_driver = { |
| 189 | .probe = gpio_buttons_probe, |
| 190 | .remove = __devexit_p(gpio_buttons_remove), |
| 191 | .driver = { |
| 192 | .name = DRV_NAME, |
| 193 | .owner = THIS_MODULE, |
| 194 | }, |
| 195 | }; |
| 196 | |
| 197 | static int __init gpio_buttons_init(void) |
| 198 | { |
| 199 | printk(KERN_INFO DRV_NAME " driver version " DRV_VERSION "\n"); |
| 200 | return platform_driver_register(&gpio_buttons_driver); |
| 201 | } |
| 202 | |
| 203 | static void __exit gpio_buttons_exit(void) |
| 204 | { |
| 205 | platform_driver_unregister(&gpio_buttons_driver); |
| 206 | } |
| 207 | |
| 208 | module_init(gpio_buttons_init); |
| 209 | module_exit(gpio_buttons_exit); |
| 210 | |
| 211 | MODULE_LICENSE("GPL"); |
| 212 | MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>"); |
| 213 | MODULE_VERSION(DRV_VERSION); |
| 214 | MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs"); |
| 215 | |
| 216 | |
