pcmcia: do not use io_req_t after call to pcmcia_request_io()
[linux-2.6.git] / drivers / input / misc / rotary_encoder.c
1 /*
2  * rotary_encoder.c
3  *
4  * (c) 2009 Daniel Mack <daniel@caiaq.de>
5  *
6  * state machine code inspired by code from Tim Ruetz
7  *
8  * A generic driver for rotary encoders connected to GPIO lines.
9  * See file:Documentation/input/rotary_encoder.txt for more information
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/input.h>
21 #include <linux/device.h>
22 #include <linux/platform_device.h>
23 #include <linux/gpio.h>
24 #include <linux/rotary_encoder.h>
25 #include <linux/slab.h>
26
27 #define DRV_NAME "rotary-encoder"
28
29 struct rotary_encoder {
30         struct input_dev *input;
31         struct rotary_encoder_platform_data *pdata;
32
33         unsigned int axis;
34         unsigned int pos;
35
36         unsigned int irq_a;
37         unsigned int irq_b;
38
39         bool armed;
40         unsigned char dir;      /* 0 - clockwise, 1 - CCW */
41 };
42
43 static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
44 {
45         struct rotary_encoder *encoder = dev_id;
46         struct rotary_encoder_platform_data *pdata = encoder->pdata;
47         int a = !!gpio_get_value(pdata->gpio_a);
48         int b = !!gpio_get_value(pdata->gpio_b);
49         int state;
50
51         a ^= pdata->inverted_a;
52         b ^= pdata->inverted_b;
53         state = (a << 1) | b;
54
55         switch (state) {
56
57         case 0x0:
58                 if (!encoder->armed)
59                         break;
60
61                 if (pdata->relative_axis) {
62                         input_report_rel(encoder->input, pdata->axis,
63                                          encoder->dir ? -1 : 1);
64                 } else {
65                         unsigned int pos = encoder->pos;
66
67                         if (encoder->dir) {
68                                 /* turning counter-clockwise */
69                                 if (pdata->rollover)
70                                         pos += pdata->steps;
71                                 if (pos)
72                                         pos--;
73                         } else {
74                                 /* turning clockwise */
75                                 if (pdata->rollover || pos < pdata->steps)
76                                         pos++;
77                         }
78                         if (pdata->rollover)
79                                 pos %= pdata->steps;
80                         encoder->pos = pos;
81                         input_report_abs(encoder->input, pdata->axis,
82                                          encoder->pos);
83                 }
84                 input_sync(encoder->input);
85
86                 encoder->armed = false;
87                 break;
88
89         case 0x1:
90         case 0x2:
91                 if (encoder->armed)
92                         encoder->dir = state - 1;
93                 break;
94
95         case 0x3:
96                 encoder->armed = true;
97                 break;
98         }
99
100         return IRQ_HANDLED;
101 }
102
103 static int __devinit rotary_encoder_probe(struct platform_device *pdev)
104 {
105         struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
106         struct rotary_encoder *encoder;
107         struct input_dev *input;
108         int err;
109
110         if (!pdata) {
111                 dev_err(&pdev->dev, "missing platform data\n");
112                 return -ENOENT;
113         }
114
115         encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
116         input = input_allocate_device();
117         if (!encoder || !input) {
118                 dev_err(&pdev->dev, "failed to allocate memory for device\n");
119                 err = -ENOMEM;
120                 goto exit_free_mem;
121         }
122
123         encoder->input = input;
124         encoder->pdata = pdata;
125         encoder->irq_a = gpio_to_irq(pdata->gpio_a);
126         encoder->irq_b = gpio_to_irq(pdata->gpio_b);
127
128         /* create and register the input driver */
129         input->name = pdev->name;
130         input->id.bustype = BUS_HOST;
131         input->dev.parent = &pdev->dev;
132
133         if (pdata->relative_axis) {
134                 input->evbit[0] = BIT_MASK(EV_REL);
135                 input->relbit[0] = BIT_MASK(pdata->axis);
136         } else {
137                 input->evbit[0] = BIT_MASK(EV_ABS);
138                 input_set_abs_params(encoder->input,
139                                      pdata->axis, 0, pdata->steps, 0, 1);
140         }
141
142         err = input_register_device(input);
143         if (err) {
144                 dev_err(&pdev->dev, "failed to register input device\n");
145                 goto exit_free_mem;
146         }
147
148         /* request the GPIOs */
149         err = gpio_request(pdata->gpio_a, DRV_NAME);
150         if (err) {
151                 dev_err(&pdev->dev, "unable to request GPIO %d\n",
152                         pdata->gpio_a);
153                 goto exit_unregister_input;
154         }
155
156         err = gpio_direction_input(pdata->gpio_a);
157         if (err) {
158                 dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
159                         pdata->gpio_a);
160                 goto exit_unregister_input;
161         }
162
163         err = gpio_request(pdata->gpio_b, DRV_NAME);
164         if (err) {
165                 dev_err(&pdev->dev, "unable to request GPIO %d\n",
166                         pdata->gpio_b);
167                 goto exit_free_gpio_a;
168         }
169
170         err = gpio_direction_input(pdata->gpio_b);
171         if (err) {
172                 dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
173                         pdata->gpio_b);
174                 goto exit_free_gpio_a;
175         }
176
177         /* request the IRQs */
178         err = request_irq(encoder->irq_a, &rotary_encoder_irq,
179                           IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE,
180                           DRV_NAME, encoder);
181         if (err) {
182                 dev_err(&pdev->dev, "unable to request IRQ %d\n",
183                         encoder->irq_a);
184                 goto exit_free_gpio_b;
185         }
186
187         err = request_irq(encoder->irq_b, &rotary_encoder_irq,
188                           IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE,
189                           DRV_NAME, encoder);
190         if (err) {
191                 dev_err(&pdev->dev, "unable to request IRQ %d\n",
192                         encoder->irq_b);
193                 goto exit_free_irq_a;
194         }
195
196         platform_set_drvdata(pdev, encoder);
197
198         return 0;
199
200 exit_free_irq_a:
201         free_irq(encoder->irq_a, encoder);
202 exit_free_gpio_b:
203         gpio_free(pdata->gpio_b);
204 exit_free_gpio_a:
205         gpio_free(pdata->gpio_a);
206 exit_unregister_input:
207         input_unregister_device(input);
208         input = NULL; /* so we don't try to free it */
209 exit_free_mem:
210         input_free_device(input);
211         kfree(encoder);
212         return err;
213 }
214
215 static int __devexit rotary_encoder_remove(struct platform_device *pdev)
216 {
217         struct rotary_encoder *encoder = platform_get_drvdata(pdev);
218         struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
219
220         free_irq(encoder->irq_a, encoder);
221         free_irq(encoder->irq_b, encoder);
222         gpio_free(pdata->gpio_a);
223         gpio_free(pdata->gpio_b);
224         input_unregister_device(encoder->input);
225         platform_set_drvdata(pdev, NULL);
226         kfree(encoder);
227
228         return 0;
229 }
230
231 static struct platform_driver rotary_encoder_driver = {
232         .probe          = rotary_encoder_probe,
233         .remove         = __devexit_p(rotary_encoder_remove),
234         .driver         = {
235                 .name   = DRV_NAME,
236                 .owner  = THIS_MODULE,
237         }
238 };
239
240 static int __init rotary_encoder_init(void)
241 {
242         return platform_driver_register(&rotary_encoder_driver);
243 }
244
245 static void __exit rotary_encoder_exit(void)
246 {
247         platform_driver_unregister(&rotary_encoder_driver);
248 }
249
250 module_init(rotary_encoder_init);
251 module_exit(rotary_encoder_exit);
252
253 MODULE_ALIAS("platform:" DRV_NAME);
254 MODULE_DESCRIPTION("GPIO rotary encoder driver");
255 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
256 MODULE_LICENSE("GPL v2");
257