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. | |
5fb94e9c | 10 | * See file:Documentation/input/devices/rotary-encoder.rst 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> | |
77a8f0ad | 23 | #include <linux/gpio/consumer.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
2e45e539 | 25 | #include <linux/of.h> |
47ec6e5a | 26 | #include <linux/pm.h> |
a9e340dc | 27 | #include <linux/property.h> |
73969ff0 DM |
28 | |
29 | #define DRV_NAME "rotary-encoder" | |
30 | ||
d205a218 UKK |
31 | enum rotary_encoder_encoding { |
32 | ROTENC_GRAY, | |
33 | ROTENC_BINARY, | |
34 | }; | |
35 | ||
73969ff0 | 36 | struct rotary_encoder { |
73969ff0 | 37 | struct input_dev *input; |
a9e340dc | 38 | |
dee520e3 | 39 | struct mutex access_mutex; |
bd3ce655 | 40 | |
a9e340dc DT |
41 | u32 steps; |
42 | u32 axis; | |
43 | bool relative_axis; | |
44 | bool rollover; | |
d205a218 | 45 | enum rotary_encoder_encoding encoding; |
a9e340dc | 46 | |
bd3ce655 HS |
47 | unsigned int pos; |
48 | ||
7dde4e74 | 49 | struct gpio_descs *gpios; |
77a8f0ad | 50 | |
7dde4e74 | 51 | unsigned int *irq; |
bd3ce655 HS |
52 | |
53 | bool armed; | |
7dde4e74 | 54 | signed char dir; /* 1 - clockwise, -1 - CCW */ |
e70bdd41 | 55 | |
d96caf8c | 56 | unsigned int last_stable; |
73969ff0 DM |
57 | }; |
58 | ||
d96caf8c | 59 | static unsigned int rotary_encoder_get_state(struct rotary_encoder *encoder) |
73969ff0 | 60 | { |
7dde4e74 | 61 | int i; |
d96caf8c | 62 | unsigned int ret = 0; |
73969ff0 | 63 | |
7dde4e74 UKK |
64 | for (i = 0; i < encoder->gpios->ndescs; ++i) { |
65 | int val = gpiod_get_value_cansleep(encoder->gpios->desc[i]); | |
d205a218 | 66 | |
7dde4e74 | 67 | /* convert from gray encoding to normal */ |
d205a218 | 68 | if (encoder->encoding == ROTENC_GRAY && ret & 1) |
7dde4e74 UKK |
69 | val = !val; |
70 | ||
71 | ret = ret << 1 | val; | |
72 | } | |
73 | ||
74 | return ret & 3; | |
521a8f5c | 75 | } |
73969ff0 | 76 | |
521a8f5c JH |
77 | static void rotary_encoder_report_event(struct rotary_encoder *encoder) |
78 | { | |
a9e340dc | 79 | if (encoder->relative_axis) { |
521a8f5c | 80 | input_report_rel(encoder->input, |
7dde4e74 | 81 | encoder->axis, encoder->dir); |
521a8f5c JH |
82 | } else { |
83 | unsigned int pos = encoder->pos; | |
84 | ||
7dde4e74 | 85 | if (encoder->dir < 0) { |
521a8f5c | 86 | /* turning counter-clockwise */ |
a9e340dc DT |
87 | if (encoder->rollover) |
88 | pos += encoder->steps; | |
521a8f5c JH |
89 | if (pos) |
90 | pos--; | |
91 | } else { | |
92 | /* turning clockwise */ | |
a9e340dc | 93 | if (encoder->rollover || pos < encoder->steps) |
521a8f5c | 94 | pos++; |
73969ff0 | 95 | } |
73969ff0 | 96 | |
a9e340dc DT |
97 | if (encoder->rollover) |
98 | pos %= encoder->steps; | |
521a8f5c JH |
99 | |
100 | encoder->pos = pos; | |
a9e340dc | 101 | input_report_abs(encoder->input, encoder->axis, encoder->pos); |
521a8f5c JH |
102 | } |
103 | ||
104 | input_sync(encoder->input); | |
105 | } | |
106 | ||
107 | static irqreturn_t rotary_encoder_irq(int irq, void *dev_id) | |
108 | { | |
109 | struct rotary_encoder *encoder = dev_id; | |
d96caf8c | 110 | unsigned int state; |
521a8f5c | 111 | |
dee520e3 TT |
112 | mutex_lock(&encoder->access_mutex); |
113 | ||
77a8f0ad | 114 | state = rotary_encoder_get_state(encoder); |
521a8f5c JH |
115 | |
116 | switch (state) { | |
117 | case 0x0: | |
118 | if (encoder->armed) { | |
119 | rotary_encoder_report_event(encoder); | |
120 | encoder->armed = false; | |
121 | } | |
73969ff0 DM |
122 | break; |
123 | ||
124 | case 0x1: | |
7dde4e74 | 125 | case 0x3: |
73969ff0 | 126 | if (encoder->armed) |
7dde4e74 | 127 | encoder->dir = 2 - state; |
73969ff0 DM |
128 | break; |
129 | ||
7dde4e74 | 130 | case 0x2: |
bd3ce655 | 131 | encoder->armed = true; |
73969ff0 DM |
132 | break; |
133 | } | |
134 | ||
dee520e3 TT |
135 | mutex_unlock(&encoder->access_mutex); |
136 | ||
73969ff0 DM |
137 | return IRQ_HANDLED; |
138 | } | |
139 | ||
e70bdd41 JH |
140 | static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id) |
141 | { | |
142 | struct rotary_encoder *encoder = dev_id; | |
7dde4e74 | 143 | unsigned int state; |
e70bdd41 | 144 | |
dee520e3 TT |
145 | mutex_lock(&encoder->access_mutex); |
146 | ||
77a8f0ad | 147 | state = rotary_encoder_get_state(encoder); |
e70bdd41 | 148 | |
7dde4e74 UKK |
149 | if (state & 1) { |
150 | encoder->dir = ((encoder->last_stable - state + 1) % 4) - 1; | |
151 | } else { | |
e70bdd41 JH |
152 | if (state != encoder->last_stable) { |
153 | rotary_encoder_report_event(encoder); | |
154 | encoder->last_stable = state; | |
155 | } | |
e70bdd41 JH |
156 | } |
157 | ||
dee520e3 TT |
158 | mutex_unlock(&encoder->access_mutex); |
159 | ||
e70bdd41 JH |
160 | return IRQ_HANDLED; |
161 | } | |
162 | ||
3a341a4c EG |
163 | static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id) |
164 | { | |
165 | struct rotary_encoder *encoder = dev_id; | |
7dde4e74 | 166 | unsigned int state; |
3a341a4c | 167 | |
dee520e3 TT |
168 | mutex_lock(&encoder->access_mutex); |
169 | ||
77a8f0ad | 170 | state = rotary_encoder_get_state(encoder); |
3a341a4c | 171 | |
7dde4e74 UKK |
172 | if ((encoder->last_stable + 1) % 4 == state) |
173 | encoder->dir = 1; | |
174 | else if (encoder->last_stable == (state + 1) % 4) | |
175 | encoder->dir = -1; | |
176 | else | |
3a341a4c | 177 | goto out; |
3a341a4c EG |
178 | |
179 | rotary_encoder_report_event(encoder); | |
180 | ||
181 | out: | |
182 | encoder->last_stable = state; | |
dee520e3 TT |
183 | mutex_unlock(&encoder->access_mutex); |
184 | ||
3a341a4c EG |
185 | return IRQ_HANDLED; |
186 | } | |
187 | ||
5298cc4c | 188 | static int rotary_encoder_probe(struct platform_device *pdev) |
73969ff0 | 189 | { |
ce919537 | 190 | struct device *dev = &pdev->dev; |
73969ff0 DM |
191 | struct rotary_encoder *encoder; |
192 | struct input_dev *input; | |
e70bdd41 | 193 | irq_handler_t handler; |
a9e340dc | 194 | u32 steps_per_period; |
7dde4e74 | 195 | unsigned int i; |
73969ff0 DM |
196 | int err; |
197 | ||
d9202af2 TT |
198 | encoder = devm_kzalloc(dev, sizeof(struct rotary_encoder), GFP_KERNEL); |
199 | if (!encoder) | |
200 | return -ENOMEM; | |
201 | ||
77a8f0ad | 202 | mutex_init(&encoder->access_mutex); |
a9e340dc DT |
203 | |
204 | device_property_read_u32(dev, "rotary-encoder,steps", &encoder->steps); | |
205 | ||
206 | err = device_property_read_u32(dev, "rotary-encoder,steps-per-period", | |
207 | &steps_per_period); | |
208 | if (err) { | |
209 | /* | |
210 | * The 'half-period' property has been deprecated, you must | |
211 | * use 'steps-per-period' and set an appropriate value, but | |
212 | * we still need to parse it to maintain compatibility. If | |
213 | * neither property is present we fall back to the one step | |
214 | * per period behavior. | |
215 | */ | |
216 | steps_per_period = device_property_read_bool(dev, | |
217 | "rotary-encoder,half-period") ? 2 : 1; | |
218 | } | |
219 | ||
220 | encoder->rollover = | |
221 | device_property_read_bool(dev, "rotary-encoder,rollover"); | |
222 | ||
d205a218 UKK |
223 | if (!device_property_present(dev, "rotary-encoder,encoding") || |
224 | !device_property_match_string(dev, "rotary-encoder,encoding", | |
225 | "gray")) { | |
226 | dev_info(dev, "gray"); | |
227 | encoder->encoding = ROTENC_GRAY; | |
228 | } else if (!device_property_match_string(dev, "rotary-encoder,encoding", | |
229 | "binary")) { | |
230 | dev_info(dev, "binary"); | |
231 | encoder->encoding = ROTENC_BINARY; | |
232 | } else { | |
233 | dev_err(dev, "unknown encoding setting\n"); | |
234 | return -EINVAL; | |
235 | } | |
236 | ||
a9e340dc DT |
237 | device_property_read_u32(dev, "linux,axis", &encoder->axis); |
238 | encoder->relative_axis = | |
239 | device_property_read_bool(dev, "rotary-encoder,relative-axis"); | |
77a8f0ad | 240 | |
7dde4e74 UKK |
241 | encoder->gpios = devm_gpiod_get_array(dev, NULL, GPIOD_IN); |
242 | if (IS_ERR(encoder->gpios)) { | |
243 | dev_err(dev, "unable to get gpios\n"); | |
244 | return PTR_ERR(encoder->gpios); | |
77a8f0ad | 245 | } |
7dde4e74 UKK |
246 | if (encoder->gpios->ndescs < 2) { |
247 | dev_err(dev, "not enough gpios found\n"); | |
248 | return -EINVAL; | |
77a8f0ad DT |
249 | } |
250 | ||
d9202af2 TT |
251 | input = devm_input_allocate_device(dev); |
252 | if (!input) | |
253 | return -ENOMEM; | |
73969ff0 DM |
254 | |
255 | encoder->input = input; | |
73969ff0 | 256 | |
73969ff0 DM |
257 | input->name = pdev->name; |
258 | input->id.bustype = BUS_HOST; | |
80c99bcd | 259 | input->dev.parent = dev; |
bd3ce655 | 260 | |
a9e340dc DT |
261 | if (encoder->relative_axis) |
262 | input_set_capability(input, EV_REL, encoder->axis); | |
8631580f | 263 | else |
a9e340dc DT |
264 | input_set_abs_params(input, |
265 | encoder->axis, 0, encoder->steps, 0, 1); | |
73969ff0 | 266 | |
7dde4e74 | 267 | switch (steps_per_period >> (encoder->gpios->ndescs - 2)) { |
3a341a4c EG |
268 | case 4: |
269 | handler = &rotary_encoder_quarter_period_irq; | |
77a8f0ad | 270 | encoder->last_stable = rotary_encoder_get_state(encoder); |
3a341a4c EG |
271 | break; |
272 | case 2: | |
e70bdd41 | 273 | handler = &rotary_encoder_half_period_irq; |
77a8f0ad | 274 | encoder->last_stable = rotary_encoder_get_state(encoder); |
3a341a4c EG |
275 | break; |
276 | case 1: | |
e70bdd41 | 277 | handler = &rotary_encoder_irq; |
3a341a4c EG |
278 | break; |
279 | default: | |
280 | dev_err(dev, "'%d' is not a valid steps-per-period value\n", | |
a9e340dc | 281 | steps_per_period); |
d9202af2 | 282 | return -EINVAL; |
e70bdd41 JH |
283 | } |
284 | ||
7dde4e74 | 285 | encoder->irq = |
a86854d0 KC |
286 | devm_kcalloc(dev, |
287 | encoder->gpios->ndescs, sizeof(*encoder->irq), | |
7dde4e74 UKK |
288 | GFP_KERNEL); |
289 | if (!encoder->irq) | |
290 | return -ENOMEM; | |
73969ff0 | 291 | |
7dde4e74 UKK |
292 | for (i = 0; i < encoder->gpios->ndescs; ++i) { |
293 | encoder->irq[i] = gpiod_to_irq(encoder->gpios->desc[i]); | |
294 | ||
295 | err = devm_request_threaded_irq(dev, encoder->irq[i], | |
296 | NULL, handler, | |
dee520e3 TT |
297 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | |
298 | IRQF_ONESHOT, | |
299 | DRV_NAME, encoder); | |
7dde4e74 UKK |
300 | if (err) { |
301 | dev_err(dev, "unable to request IRQ %d (gpio#%d)\n", | |
302 | encoder->irq[i], i); | |
303 | return err; | |
304 | } | |
73969ff0 DM |
305 | } |
306 | ||
80c99bcd DM |
307 | err = input_register_device(input); |
308 | if (err) { | |
309 | dev_err(dev, "failed to register input device\n"); | |
d9202af2 | 310 | return err; |
80c99bcd DM |
311 | } |
312 | ||
a9e340dc DT |
313 | device_init_wakeup(dev, |
314 | device_property_read_bool(dev, "wakeup-source")); | |
47ec6e5a | 315 | |
73969ff0 DM |
316 | platform_set_drvdata(pdev, encoder); |
317 | ||
318 | return 0; | |
73969ff0 DM |
319 | } |
320 | ||
6a6f70b3 | 321 | static int __maybe_unused rotary_encoder_suspend(struct device *dev) |
47ec6e5a SR |
322 | { |
323 | struct rotary_encoder *encoder = dev_get_drvdata(dev); | |
7dde4e74 | 324 | unsigned int i; |
47ec6e5a SR |
325 | |
326 | if (device_may_wakeup(dev)) { | |
7dde4e74 UKK |
327 | for (i = 0; i < encoder->gpios->ndescs; ++i) |
328 | enable_irq_wake(encoder->irq[i]); | |
47ec6e5a SR |
329 | } |
330 | ||
331 | return 0; | |
332 | } | |
333 | ||
6a6f70b3 | 334 | static int __maybe_unused rotary_encoder_resume(struct device *dev) |
47ec6e5a SR |
335 | { |
336 | struct rotary_encoder *encoder = dev_get_drvdata(dev); | |
7dde4e74 | 337 | unsigned int i; |
47ec6e5a SR |
338 | |
339 | if (device_may_wakeup(dev)) { | |
7dde4e74 UKK |
340 | for (i = 0; i < encoder->gpios->ndescs; ++i) |
341 | disable_irq_wake(encoder->irq[i]); | |
47ec6e5a SR |
342 | } |
343 | ||
344 | return 0; | |
345 | } | |
47ec6e5a SR |
346 | |
347 | static SIMPLE_DEV_PM_OPS(rotary_encoder_pm_ops, | |
6a6f70b3 | 348 | rotary_encoder_suspend, rotary_encoder_resume); |
47ec6e5a | 349 | |
a9e340dc DT |
350 | #ifdef CONFIG_OF |
351 | static const struct of_device_id rotary_encoder_of_match[] = { | |
352 | { .compatible = "rotary-encoder", }, | |
353 | { }, | |
354 | }; | |
355 | MODULE_DEVICE_TABLE(of, rotary_encoder_of_match); | |
356 | #endif | |
357 | ||
73969ff0 DM |
358 | static struct platform_driver rotary_encoder_driver = { |
359 | .probe = rotary_encoder_probe, | |
73969ff0 DM |
360 | .driver = { |
361 | .name = DRV_NAME, | |
47ec6e5a | 362 | .pm = &rotary_encoder_pm_ops, |
80c99bcd | 363 | .of_match_table = of_match_ptr(rotary_encoder_of_match), |
73969ff0 DM |
364 | } |
365 | }; | |
840a746b | 366 | module_platform_driver(rotary_encoder_driver); |
73969ff0 DM |
367 | |
368 | MODULE_ALIAS("platform:" DRV_NAME); | |
369 | MODULE_DESCRIPTION("GPIO rotary encoder driver"); | |
e70bdd41 | 370 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold"); |
73969ff0 | 371 | MODULE_LICENSE("GPL v2"); |