Commit | Line | Data |
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73969ff0 DM |
1 | /* |
2 | * rotary_encoder.c | |
3 | * | |
4 | * (c) 2009 Daniel Mack <daniel@caiaq.de> | |
e70bdd41 | 5 | * Copyright (C) 2011 Johan Hovold <jhovold@gmail.com> |
73969ff0 DM |
6 | * |
7 | * state machine code inspired by code from Tim Ruetz | |
8 | * | |
9 | * A generic driver for rotary encoders connected to GPIO lines. | |
395cf969 | 10 | * See file:Documentation/input/rotary-encoder.txt for more information |
73969ff0 DM |
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> | |
73969ff0 DM |
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> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
2e45e539 | 26 | #include <linux/of.h> |
80c99bcd DM |
27 | #include <linux/of_platform.h> |
28 | #include <linux/of_gpio.h> | |
47ec6e5a | 29 | #include <linux/pm.h> |
73969ff0 DM |
30 | |
31 | #define DRV_NAME "rotary-encoder" | |
32 | ||
33 | struct rotary_encoder { | |
73969ff0 | 34 | struct input_dev *input; |
ce919537 | 35 | const struct rotary_encoder_platform_data *pdata; |
bd3ce655 HS |
36 | |
37 | unsigned int axis; | |
38 | unsigned int pos; | |
39 | ||
40 | unsigned int irq_a; | |
41 | unsigned int irq_b; | |
42 | ||
43 | bool armed; | |
44 | unsigned char dir; /* 0 - clockwise, 1 - CCW */ | |
e70bdd41 JH |
45 | |
46 | char last_stable; | |
73969ff0 DM |
47 | }; |
48 | ||
ce919537 | 49 | static int rotary_encoder_get_state(const struct rotary_encoder_platform_data *pdata) |
73969ff0 | 50 | { |
73969ff0 DM |
51 | int a = !!gpio_get_value(pdata->gpio_a); |
52 | int b = !!gpio_get_value(pdata->gpio_b); | |
73969ff0 DM |
53 | |
54 | a ^= pdata->inverted_a; | |
55 | b ^= pdata->inverted_b; | |
73969ff0 | 56 | |
521a8f5c JH |
57 | return ((a << 1) | b); |
58 | } | |
73969ff0 | 59 | |
521a8f5c JH |
60 | static void rotary_encoder_report_event(struct rotary_encoder *encoder) |
61 | { | |
ce919537 | 62 | const struct rotary_encoder_platform_data *pdata = encoder->pdata; |
73969ff0 | 63 | |
521a8f5c JH |
64 | if (pdata->relative_axis) { |
65 | input_report_rel(encoder->input, | |
66 | pdata->axis, encoder->dir ? -1 : 1); | |
67 | } else { | |
68 | unsigned int pos = encoder->pos; | |
69 | ||
70 | if (encoder->dir) { | |
71 | /* turning counter-clockwise */ | |
bd3ce655 | 72 | if (pdata->rollover) |
521a8f5c JH |
73 | pos += pdata->steps; |
74 | if (pos) | |
75 | pos--; | |
76 | } else { | |
77 | /* turning clockwise */ | |
78 | if (pdata->rollover || pos < pdata->steps) | |
79 | pos++; | |
73969ff0 | 80 | } |
73969ff0 | 81 | |
521a8f5c JH |
82 | if (pdata->rollover) |
83 | pos %= pdata->steps; | |
84 | ||
85 | encoder->pos = pos; | |
86 | input_report_abs(encoder->input, pdata->axis, encoder->pos); | |
87 | } | |
88 | ||
89 | input_sync(encoder->input); | |
90 | } | |
91 | ||
92 | static irqreturn_t rotary_encoder_irq(int irq, void *dev_id) | |
93 | { | |
94 | struct rotary_encoder *encoder = dev_id; | |
95 | int state; | |
96 | ||
97 | state = rotary_encoder_get_state(encoder->pdata); | |
98 | ||
99 | switch (state) { | |
100 | case 0x0: | |
101 | if (encoder->armed) { | |
102 | rotary_encoder_report_event(encoder); | |
103 | encoder->armed = false; | |
104 | } | |
73969ff0 DM |
105 | break; |
106 | ||
107 | case 0x1: | |
108 | case 0x2: | |
109 | if (encoder->armed) | |
110 | encoder->dir = state - 1; | |
111 | break; | |
112 | ||
113 | case 0x3: | |
bd3ce655 | 114 | encoder->armed = true; |
73969ff0 DM |
115 | break; |
116 | } | |
117 | ||
118 | return IRQ_HANDLED; | |
119 | } | |
120 | ||
e70bdd41 JH |
121 | static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id) |
122 | { | |
123 | struct rotary_encoder *encoder = dev_id; | |
124 | int state; | |
125 | ||
126 | state = rotary_encoder_get_state(encoder->pdata); | |
127 | ||
128 | switch (state) { | |
129 | case 0x00: | |
130 | case 0x03: | |
131 | if (state != encoder->last_stable) { | |
132 | rotary_encoder_report_event(encoder); | |
133 | encoder->last_stable = state; | |
134 | } | |
135 | break; | |
136 | ||
137 | case 0x01: | |
138 | case 0x02: | |
139 | encoder->dir = (encoder->last_stable + state) & 0x01; | |
140 | break; | |
141 | } | |
142 | ||
143 | return IRQ_HANDLED; | |
144 | } | |
145 | ||
3a341a4c EG |
146 | static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id) |
147 | { | |
148 | struct rotary_encoder *encoder = dev_id; | |
149 | unsigned char sum; | |
150 | int state; | |
151 | ||
152 | state = rotary_encoder_get_state(encoder->pdata); | |
153 | ||
154 | /* | |
155 | * We encode the previous and the current state using a byte. | |
156 | * The previous state in the MSB nibble, the current state in the LSB | |
157 | * nibble. Then use a table to decide the direction of the turn. | |
158 | */ | |
159 | sum = (encoder->last_stable << 4) + state; | |
160 | switch (sum) { | |
161 | case 0x31: | |
162 | case 0x10: | |
163 | case 0x02: | |
164 | case 0x23: | |
165 | encoder->dir = 0; /* clockwise */ | |
166 | break; | |
167 | ||
168 | case 0x13: | |
169 | case 0x01: | |
170 | case 0x20: | |
171 | case 0x32: | |
172 | encoder->dir = 1; /* counter-clockwise */ | |
173 | break; | |
174 | ||
175 | default: | |
176 | /* | |
177 | * Ignore all other values. This covers the case when the | |
178 | * state didn't change (a spurious interrupt) and the | |
179 | * cases where the state changed by two steps, making it | |
180 | * impossible to tell the direction. | |
181 | * | |
182 | * In either case, don't report any event and save the | |
183 | * state for later. | |
184 | */ | |
185 | goto out; | |
186 | } | |
187 | ||
188 | rotary_encoder_report_event(encoder); | |
189 | ||
190 | out: | |
191 | encoder->last_stable = state; | |
192 | return IRQ_HANDLED; | |
193 | } | |
194 | ||
80c99bcd | 195 | #ifdef CONFIG_OF |
5f155ee1 | 196 | static const struct of_device_id rotary_encoder_of_match[] = { |
80c99bcd DM |
197 | { .compatible = "rotary-encoder", }, |
198 | { }, | |
199 | }; | |
200 | MODULE_DEVICE_TABLE(of, rotary_encoder_of_match); | |
201 | ||
5298cc4c | 202 | static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct device *dev) |
80c99bcd DM |
203 | { |
204 | const struct of_device_id *of_id = | |
205 | of_match_device(rotary_encoder_of_match, dev); | |
206 | struct device_node *np = dev->of_node; | |
207 | struct rotary_encoder_platform_data *pdata; | |
208 | enum of_gpio_flags flags; | |
3a341a4c | 209 | int error; |
80c99bcd DM |
210 | |
211 | if (!of_id || !np) | |
212 | return NULL; | |
213 | ||
214 | pdata = kzalloc(sizeof(struct rotary_encoder_platform_data), | |
215 | GFP_KERNEL); | |
216 | if (!pdata) | |
217 | return ERR_PTR(-ENOMEM); | |
218 | ||
219 | of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps); | |
220 | of_property_read_u32(np, "linux,axis", &pdata->axis); | |
221 | ||
222 | pdata->gpio_a = of_get_gpio_flags(np, 0, &flags); | |
223 | pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW; | |
224 | ||
225 | pdata->gpio_b = of_get_gpio_flags(np, 1, &flags); | |
226 | pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW; | |
227 | ||
648b15cb BG |
228 | pdata->relative_axis = |
229 | of_property_read_bool(np, "rotary-encoder,relative-axis"); | |
230 | pdata->rollover = of_property_read_bool(np, "rotary-encoder,rollover"); | |
3a341a4c EG |
231 | |
232 | error = of_property_read_u32(np, "rotary-encoder,steps-per-period", | |
233 | &pdata->steps_per_period); | |
234 | if (error) { | |
235 | /* | |
236 | * The 'half-period' property has been deprecated, you must use | |
237 | * 'steps-per-period' and set an appropriate value, but we still | |
238 | * need to parse it to maintain compatibility. | |
239 | */ | |
240 | if (of_property_read_bool(np, "rotary-encoder,half-period")) { | |
241 | pdata->steps_per_period = 2; | |
242 | } else { | |
243 | /* Fallback to one step per period behavior */ | |
244 | pdata->steps_per_period = 1; | |
245 | } | |
246 | } | |
247 | ||
648b15cb | 248 | pdata->wakeup_source = of_property_read_bool(np, "wakeup-source"); |
80c99bcd DM |
249 | |
250 | return pdata; | |
251 | } | |
252 | #else | |
253 | static inline struct rotary_encoder_platform_data * | |
254 | rotary_encoder_parse_dt(struct device *dev) | |
255 | { | |
256 | return NULL; | |
257 | } | |
258 | #endif | |
259 | ||
5298cc4c | 260 | static int rotary_encoder_probe(struct platform_device *pdev) |
73969ff0 | 261 | { |
ce919537 DT |
262 | struct device *dev = &pdev->dev; |
263 | const struct rotary_encoder_platform_data *pdata = dev_get_platdata(dev); | |
73969ff0 DM |
264 | struct rotary_encoder *encoder; |
265 | struct input_dev *input; | |
e70bdd41 | 266 | irq_handler_t handler; |
73969ff0 DM |
267 | int err; |
268 | ||
06ee3d3c | 269 | if (!pdata) { |
80c99bcd DM |
270 | pdata = rotary_encoder_parse_dt(dev); |
271 | if (IS_ERR(pdata)) | |
272 | return PTR_ERR(pdata); | |
273 | ||
274 | if (!pdata) { | |
275 | dev_err(dev, "missing platform data\n"); | |
276 | return -EINVAL; | |
277 | } | |
73969ff0 DM |
278 | } |
279 | ||
280 | encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL); | |
281 | input = input_allocate_device(); | |
282 | if (!encoder || !input) { | |
73969ff0 DM |
283 | err = -ENOMEM; |
284 | goto exit_free_mem; | |
285 | } | |
286 | ||
287 | encoder->input = input; | |
288 | encoder->pdata = pdata; | |
73969ff0 | 289 | |
73969ff0 DM |
290 | input->name = pdev->name; |
291 | input->id.bustype = BUS_HOST; | |
80c99bcd | 292 | input->dev.parent = dev; |
bd3ce655 HS |
293 | |
294 | if (pdata->relative_axis) { | |
295 | input->evbit[0] = BIT_MASK(EV_REL); | |
296 | input->relbit[0] = BIT_MASK(pdata->axis); | |
297 | } else { | |
298 | input->evbit[0] = BIT_MASK(EV_ABS); | |
299 | input_set_abs_params(encoder->input, | |
300 | pdata->axis, 0, pdata->steps, 0, 1); | |
301 | } | |
73969ff0 | 302 | |
73969ff0 | 303 | /* request the GPIOs */ |
429a34d7 | 304 | err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev)); |
73969ff0 | 305 | if (err) { |
429a34d7 | 306 | dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a); |
80c99bcd | 307 | goto exit_free_mem; |
73969ff0 DM |
308 | } |
309 | ||
429a34d7 | 310 | err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev)); |
5deeac99 | 311 | if (err) { |
429a34d7 | 312 | dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b); |
5deeac99 AC |
313 | goto exit_free_gpio_a; |
314 | } | |
315 | ||
a78769b8 DM |
316 | encoder->irq_a = gpio_to_irq(pdata->gpio_a); |
317 | encoder->irq_b = gpio_to_irq(pdata->gpio_b); | |
318 | ||
3a341a4c EG |
319 | switch (pdata->steps_per_period) { |
320 | case 4: | |
321 | handler = &rotary_encoder_quarter_period_irq; | |
322 | encoder->last_stable = rotary_encoder_get_state(pdata); | |
323 | break; | |
324 | case 2: | |
e70bdd41 JH |
325 | handler = &rotary_encoder_half_period_irq; |
326 | encoder->last_stable = rotary_encoder_get_state(pdata); | |
3a341a4c EG |
327 | break; |
328 | case 1: | |
e70bdd41 | 329 | handler = &rotary_encoder_irq; |
3a341a4c EG |
330 | break; |
331 | default: | |
332 | dev_err(dev, "'%d' is not a valid steps-per-period value\n", | |
333 | pdata->steps_per_period); | |
334 | err = -EINVAL; | |
335 | goto exit_free_gpio_b; | |
e70bdd41 JH |
336 | } |
337 | ||
338 | err = request_irq(encoder->irq_a, handler, | |
e0d5f4c3 | 339 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, |
73969ff0 DM |
340 | DRV_NAME, encoder); |
341 | if (err) { | |
429a34d7 | 342 | dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a); |
73969ff0 DM |
343 | goto exit_free_gpio_b; |
344 | } | |
345 | ||
e70bdd41 | 346 | err = request_irq(encoder->irq_b, handler, |
e0d5f4c3 | 347 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, |
73969ff0 DM |
348 | DRV_NAME, encoder); |
349 | if (err) { | |
429a34d7 | 350 | dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b); |
73969ff0 DM |
351 | goto exit_free_irq_a; |
352 | } | |
353 | ||
80c99bcd DM |
354 | err = input_register_device(input); |
355 | if (err) { | |
356 | dev_err(dev, "failed to register input device\n"); | |
357 | goto exit_free_irq_b; | |
358 | } | |
359 | ||
47ec6e5a SR |
360 | device_init_wakeup(&pdev->dev, pdata->wakeup_source); |
361 | ||
73969ff0 DM |
362 | platform_set_drvdata(pdev, encoder); |
363 | ||
364 | return 0; | |
365 | ||
80c99bcd DM |
366 | exit_free_irq_b: |
367 | free_irq(encoder->irq_b, encoder); | |
73969ff0 DM |
368 | exit_free_irq_a: |
369 | free_irq(encoder->irq_a, encoder); | |
370 | exit_free_gpio_b: | |
371 | gpio_free(pdata->gpio_b); | |
372 | exit_free_gpio_a: | |
373 | gpio_free(pdata->gpio_a); | |
73969ff0 DM |
374 | exit_free_mem: |
375 | input_free_device(input); | |
376 | kfree(encoder); | |
80c99bcd DM |
377 | if (!dev_get_platdata(&pdev->dev)) |
378 | kfree(pdata); | |
379 | ||
73969ff0 DM |
380 | return err; |
381 | } | |
382 | ||
e2619cf7 | 383 | static int rotary_encoder_remove(struct platform_device *pdev) |
73969ff0 DM |
384 | { |
385 | struct rotary_encoder *encoder = platform_get_drvdata(pdev); | |
ce919537 | 386 | const struct rotary_encoder_platform_data *pdata = encoder->pdata; |
73969ff0 | 387 | |
47ec6e5a SR |
388 | device_init_wakeup(&pdev->dev, false); |
389 | ||
73969ff0 DM |
390 | free_irq(encoder->irq_a, encoder); |
391 | free_irq(encoder->irq_b, encoder); | |
392 | gpio_free(pdata->gpio_a); | |
393 | gpio_free(pdata->gpio_b); | |
80c99bcd | 394 | |
73969ff0 | 395 | input_unregister_device(encoder->input); |
73969ff0 DM |
396 | kfree(encoder); |
397 | ||
80c99bcd DM |
398 | if (!dev_get_platdata(&pdev->dev)) |
399 | kfree(pdata); | |
400 | ||
73969ff0 DM |
401 | return 0; |
402 | } | |
403 | ||
47ec6e5a SR |
404 | #ifdef CONFIG_PM_SLEEP |
405 | static int rotary_encoder_suspend(struct device *dev) | |
406 | { | |
407 | struct rotary_encoder *encoder = dev_get_drvdata(dev); | |
408 | ||
409 | if (device_may_wakeup(dev)) { | |
410 | enable_irq_wake(encoder->irq_a); | |
411 | enable_irq_wake(encoder->irq_b); | |
412 | } | |
413 | ||
414 | return 0; | |
415 | } | |
416 | ||
417 | static int rotary_encoder_resume(struct device *dev) | |
418 | { | |
419 | struct rotary_encoder *encoder = dev_get_drvdata(dev); | |
420 | ||
421 | if (device_may_wakeup(dev)) { | |
422 | disable_irq_wake(encoder->irq_a); | |
423 | disable_irq_wake(encoder->irq_b); | |
424 | } | |
425 | ||
426 | return 0; | |
427 | } | |
428 | #endif | |
429 | ||
430 | static SIMPLE_DEV_PM_OPS(rotary_encoder_pm_ops, | |
431 | rotary_encoder_suspend, rotary_encoder_resume); | |
432 | ||
73969ff0 DM |
433 | static struct platform_driver rotary_encoder_driver = { |
434 | .probe = rotary_encoder_probe, | |
1cb0aa88 | 435 | .remove = rotary_encoder_remove, |
73969ff0 DM |
436 | .driver = { |
437 | .name = DRV_NAME, | |
47ec6e5a | 438 | .pm = &rotary_encoder_pm_ops, |
80c99bcd | 439 | .of_match_table = of_match_ptr(rotary_encoder_of_match), |
73969ff0 DM |
440 | } |
441 | }; | |
840a746b | 442 | module_platform_driver(rotary_encoder_driver); |
73969ff0 DM |
443 | |
444 | MODULE_ALIAS("platform:" DRV_NAME); | |
445 | MODULE_DESCRIPTION("GPIO rotary encoder driver"); | |
e70bdd41 | 446 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold"); |
73969ff0 | 447 | MODULE_LICENSE("GPL v2"); |