drivers/input/misc/gpio_tilt_polled.c

   1 /*
   2  *  Driver for tilt switches connected via GPIO lines
   3  *  not capable of generating interrupts
   4  *
   5  *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
   6  *
   7  *  based on: drivers/input/keyboard/gpio_keys_polled.c
   8  *
   9  *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
  10  *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License version 2 as
  14  *  published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <linux/input.h>
  22 #include <linux/input-polldev.h>
  23 #include <linux/ioport.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/gpio.h>
  26 #include <linux/input/gpio_tilt.h>
  27
  28 #define DRV_NAME        "gpio-tilt-polled"
  29
  30 struct gpio_tilt_polled_dev {
  31         struct input_polled_dev *poll_dev;
  32         struct device *dev;
  33         const struct gpio_tilt_platform_data *pdata;
  34
  35         int last_state;
  36
  37         int threshold;
  38         int count;
  39 };
  40
  41 static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
  42 {
  43         struct gpio_tilt_polled_dev *tdev = dev->private;
  44         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
  45         struct input_dev *input = dev->input;
  46         struct gpio_tilt_state *tilt_state = NULL;
  47         int state, i;
  48
  49         if (tdev->count < tdev->threshold) {
  50                 tdev->count++;
  51         } else {
  52                 state = 0;
  53                 for (i = 0; i < pdata->nr_gpios; i++)
  54                         state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
  55
  56                 if (state != tdev->last_state) {
  57                         for (i = 0; i < pdata->nr_states; i++)
  58                                 if (pdata->states[i].gpios == state)
  59                                         tilt_state = &pdata->states[i];
  60
  61                         if (tilt_state) {
  62                                 for (i = 0; i < pdata->nr_axes; i++)
  63                                         input_report_abs(input,
  64                                                          pdata->axes[i].axis,
  65                                                          tilt_state->axes[i]);
  66
  67                                 input_sync(input);
  68                         }
  69
  70                         tdev->count = 0;
  71                         tdev->last_state = state;
  72                 }
  73         }
  74 }
  75
  76 static void gpio_tilt_polled_open(struct input_polled_dev *dev)
  77 {
  78         struct gpio_tilt_polled_dev *tdev = dev->private;
  79         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
  80
  81         if (pdata->enable)
  82                 pdata->enable(tdev->dev);
  83
  84         /* report initial state of the axes */
  85         tdev->last_state = -1;
  86         tdev->count = tdev->threshold;
  87         gpio_tilt_polled_poll(tdev->poll_dev);
  88 }
  89
  90 static void gpio_tilt_polled_close(struct input_polled_dev *dev)
  91 {
  92         struct gpio_tilt_polled_dev *tdev = dev->private;
  93         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
  94
  95         if (pdata->disable)
  96                 pdata->disable(tdev->dev);
  97 }
  98
  99 static int gpio_tilt_polled_probe(struct platform_device *pdev)
 100 {
 101         const struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
 102         struct device *dev = &pdev->dev;
 103         struct gpio_tilt_polled_dev *tdev;
 104         struct input_polled_dev *poll_dev;
 105         struct input_dev *input;
 106         int error, i;
 107
 108         if (!pdata || !pdata->poll_interval)
 109                 return -EINVAL;
 110
 111         tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
 112         if (!tdev) {
 113                 dev_err(dev, "no memory for private data\n");
 114                 return -ENOMEM;
 115         }
 116
 117         error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
 118         if (error) {
 119                 dev_err(dev,
 120                         "Could not request tilt GPIOs: %d\n", error);
 121                 goto err_free_tdev;
 122         }
 123
 124         poll_dev = input_allocate_polled_device();
 125         if (!poll_dev) {
 126                 dev_err(dev, "no memory for polled device\n");
 127                 error = -ENOMEM;
 128                 goto err_free_gpios;
 129         }
 130
 131         poll_dev->private = tdev;
 132         poll_dev->poll = gpio_tilt_polled_poll;
 133         poll_dev->poll_interval = pdata->poll_interval;
 134         poll_dev->open = gpio_tilt_polled_open;
 135         poll_dev->close = gpio_tilt_polled_close;
 136
 137         input = poll_dev->input;
 138
 139         input->name = pdev->name;
 140         input->phys = DRV_NAME"/input0";
 141         input->dev.parent = &pdev->dev;
 142
 143         input->id.bustype = BUS_HOST;
 144         input->id.vendor = 0x0001;
 145         input->id.product = 0x0001;
 146         input->id.version = 0x0100;
 147
 148         __set_bit(EV_ABS, input->evbit);
 149         for (i = 0; i < pdata->nr_axes; i++)
 150                 input_set_abs_params(input, pdata->axes[i].axis,
 151                                      pdata->axes[i].min, pdata->axes[i].max,
 152                                      pdata->axes[i].fuzz, pdata->axes[i].flat);
 153
 154         tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
 155                                        pdata->poll_interval);
 156
 157         tdev->poll_dev = poll_dev;
 158         tdev->dev = dev;
 159         tdev->pdata = pdata;
 160
 161         error = input_register_polled_device(poll_dev);
 162         if (error) {
 163                 dev_err(dev, "unable to register polled device, err=%d\n",
 164                         error);
 165                 goto err_free_polldev;
 166         }
 167
 168         platform_set_drvdata(pdev, tdev);
 169
 170         return 0;
 171
 172 err_free_polldev:
 173         input_free_polled_device(poll_dev);
 174 err_free_gpios:
 175         gpio_free_array(pdata->gpios, pdata->nr_gpios);
 176 err_free_tdev:
 177         kfree(tdev);
 178
 179         return error;
 180 }
 181
 182 static int gpio_tilt_polled_remove(struct platform_device *pdev)
 183 {
 184         struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
 185         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 186
 187         platform_set_drvdata(pdev, NULL);
 188
 189         input_unregister_polled_device(tdev->poll_dev);
 190         input_free_polled_device(tdev->poll_dev);
 191
 192         gpio_free_array(pdata->gpios, pdata->nr_gpios);
 193
 194         kfree(tdev);
 195
 196         return 0;
 197 }
 198
 199 static struct platform_driver gpio_tilt_polled_driver = {
 200         .probe  = gpio_tilt_polled_probe,
 201         .remove = gpio_tilt_polled_remove,
 202         .driver = {
 203                 .name   = DRV_NAME,
 204                 .owner  = THIS_MODULE,
 205         },
 206 };
 207
 208 module_platform_driver(gpio_tilt_polled_driver);
 209
 210 MODULE_LICENSE("GPL v2");
 211 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 212 MODULE_DESCRIPTION("Polled GPIO tilt driver");
 213 MODULE_ALIAS("platform:" DRV_NAME);