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Linux/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/slab.h>
 20 #include <linux/input.h>
 21 #include <linux/input-polldev.h>
 22 #include <linux/ioport.h>
 23 #include <linux/platform_device.h>
 24 #include <linux/gpio.h>
 25 #include <linux/input/gpio_tilt.h>
 26 
 27 #define DRV_NAME        "gpio-tilt-polled"
 28 
 29 struct gpio_tilt_polled_dev {
 30         struct input_polled_dev *poll_dev;
 31         struct device *dev;
 32         const struct gpio_tilt_platform_data *pdata;
 33 
 34         int last_state;
 35 
 36         int threshold;
 37         int count;
 38 };
 39 
 40 static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
 41 {
 42         struct gpio_tilt_polled_dev *tdev = dev->private;
 43         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 44         struct input_dev *input = dev->input;
 45         struct gpio_tilt_state *tilt_state = NULL;
 46         int state, i;
 47 
 48         if (tdev->count < tdev->threshold) {
 49                 tdev->count++;
 50         } else {
 51                 state = 0;
 52                 for (i = 0; i < pdata->nr_gpios; i++)
 53                         state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
 54 
 55                 if (state != tdev->last_state) {
 56                         for (i = 0; i < pdata->nr_states; i++)
 57                                 if (pdata->states[i].gpios == state)
 58                                         tilt_state = &pdata->states[i];
 59 
 60                         if (tilt_state) {
 61                                 for (i = 0; i < pdata->nr_axes; i++)
 62                                         input_report_abs(input,
 63                                                          pdata->axes[i].axis,
 64                                                          tilt_state->axes[i]);
 65 
 66                                 input_sync(input);
 67                         }
 68 
 69                         tdev->count = 0;
 70                         tdev->last_state = state;
 71                 }
 72         }
 73 }
 74 
 75 static void gpio_tilt_polled_open(struct input_polled_dev *dev)
 76 {
 77         struct gpio_tilt_polled_dev *tdev = dev->private;
 78         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 79 
 80         if (pdata->enable)
 81                 pdata->enable(tdev->dev);
 82 
 83         /* report initial state of the axes */
 84         tdev->last_state = -1;
 85         tdev->count = tdev->threshold;
 86         gpio_tilt_polled_poll(tdev->poll_dev);
 87 }
 88 
 89 static void gpio_tilt_polled_close(struct input_polled_dev *dev)
 90 {
 91         struct gpio_tilt_polled_dev *tdev = dev->private;
 92         const struct gpio_tilt_platform_data *pdata = tdev->pdata;
 93 
 94         if (pdata->disable)
 95                 pdata->disable(tdev->dev);
 96 }
 97 
 98 static int gpio_tilt_polled_probe(struct platform_device *pdev)
 99 {
100         const struct gpio_tilt_platform_data *pdata =
101                         dev_get_platdata(&pdev->dev);
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         input_unregister_polled_device(tdev->poll_dev);
188         input_free_polled_device(tdev->poll_dev);
189 
190         gpio_free_array(pdata->gpios, pdata->nr_gpios);
191 
192         kfree(tdev);
193 
194         return 0;
195 }
196 
197 static struct platform_driver gpio_tilt_polled_driver = {
198         .probe  = gpio_tilt_polled_probe,
199         .remove = gpio_tilt_polled_remove,
200         .driver = {
201                 .name   = DRV_NAME,
202                 .owner  = THIS_MODULE,
203         },
204 };
205 
206 module_platform_driver(gpio_tilt_polled_driver);
207 
208 MODULE_LICENSE("GPL v2");
209 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
210 MODULE_DESCRIPTION("Polled GPIO tilt driver");
211 MODULE_ALIAS("platform:" DRV_NAME);
212 

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