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