linux/drivers/input/misc/gpio_tilt_polled.c
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   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
  30struct 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
  41static 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
  76static 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
  90static 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
  99static 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
 172err_free_polldev:
 173        input_free_polled_device(poll_dev);
 174err_free_gpios:
 175        gpio_free_array(pdata->gpios, pdata->nr_gpios);
 176err_free_tdev:
 177        kfree(tdev);
 178
 179        return error;
 180}
 181
 182static 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
 199static 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
 208module_platform_driver(gpio_tilt_polled_driver);
 209
 210MODULE_LICENSE("GPL v2");
 211MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 212MODULE_DESCRIPTION("Polled GPIO tilt driver");
 213MODULE_ALIAS("platform:" DRV_NAME);
 214