Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 1 | /* |
| 2 | * rotary_encoder.c |
| 3 | * |
| 4 | * (c) 2009 Daniel Mack <daniel@caiaq.de> |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 5 | * Copyright (C) 2011 Johan Hovold <jhovold@gmail.com> |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 6 | * |
| 7 | * state machine code inspired by code from Tim Ruetz |
| 8 | * |
| 9 | * A generic driver for rotary encoders connected to GPIO lines. |
Paul Bolle | 395cf96 | 2011-08-15 02:02:26 +0200 | [diff] [blame] | 10 | * See file:Documentation/input/rotary-encoder.txt for more information |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 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/init.h> |
| 20 | #include <linux/interrupt.h> |
| 21 | #include <linux/input.h> |
| 22 | #include <linux/device.h> |
| 23 | #include <linux/platform_device.h> |
| 24 | #include <linux/gpio.h> |
| 25 | #include <linux/rotary_encoder.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 26 | #include <linux/slab.h> |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 27 | #include <linux/of_platform.h> |
| 28 | #include <linux/of_gpio.h> |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 29 | |
| 30 | #define DRV_NAME "rotary-encoder" |
| 31 | |
| 32 | struct rotary_encoder { |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 33 | struct input_dev *input; |
Dmitry Torokhov | ce91953 | 2012-07-31 22:08:49 -0700 | [diff] [blame] | 34 | const struct rotary_encoder_platform_data *pdata; |
H Hartley Sweeten | bd3ce65 | 2009-04-17 20:12:35 -0700 | [diff] [blame] | 35 | |
| 36 | unsigned int axis; |
| 37 | unsigned int pos; |
| 38 | |
| 39 | unsigned int irq_a; |
| 40 | unsigned int irq_b; |
| 41 | |
| 42 | bool armed; |
| 43 | unsigned char dir; /* 0 - clockwise, 1 - CCW */ |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 44 | |
| 45 | char last_stable; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 46 | }; |
| 47 | |
Dmitry Torokhov | ce91953 | 2012-07-31 22:08:49 -0700 | [diff] [blame] | 48 | static int rotary_encoder_get_state(const struct rotary_encoder_platform_data *pdata) |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 49 | { |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 50 | int a = !!gpio_get_value(pdata->gpio_a); |
| 51 | int b = !!gpio_get_value(pdata->gpio_b); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 52 | |
| 53 | a ^= pdata->inverted_a; |
| 54 | b ^= pdata->inverted_b; |
Johan Hovold | 521a8f5 | 2011-05-11 16:33:50 -0700 | [diff] [blame] | 55 | |
| 56 | return ((a << 1) | b); |
| 57 | } |
| 58 | |
| 59 | static void rotary_encoder_report_event(struct rotary_encoder *encoder) |
| 60 | { |
Dmitry Torokhov | ce91953 | 2012-07-31 22:08:49 -0700 | [diff] [blame] | 61 | const struct rotary_encoder_platform_data *pdata = encoder->pdata; |
Johan Hovold | 521a8f5 | 2011-05-11 16:33:50 -0700 | [diff] [blame] | 62 | |
| 63 | if (pdata->relative_axis) { |
| 64 | input_report_rel(encoder->input, |
| 65 | pdata->axis, encoder->dir ? -1 : 1); |
| 66 | } else { |
| 67 | unsigned int pos = encoder->pos; |
| 68 | |
| 69 | if (encoder->dir) { |
| 70 | /* turning counter-clockwise */ |
| 71 | if (pdata->rollover) |
| 72 | pos += pdata->steps; |
| 73 | if (pos) |
| 74 | pos--; |
| 75 | } else { |
| 76 | /* turning clockwise */ |
| 77 | if (pdata->rollover || pos < pdata->steps) |
| 78 | pos++; |
| 79 | } |
| 80 | |
| 81 | if (pdata->rollover) |
| 82 | pos %= pdata->steps; |
| 83 | |
| 84 | encoder->pos = pos; |
| 85 | input_report_abs(encoder->input, pdata->axis, encoder->pos); |
| 86 | } |
| 87 | |
| 88 | input_sync(encoder->input); |
| 89 | } |
| 90 | |
| 91 | static irqreturn_t rotary_encoder_irq(int irq, void *dev_id) |
| 92 | { |
| 93 | struct rotary_encoder *encoder = dev_id; |
| 94 | int state; |
| 95 | |
| 96 | state = rotary_encoder_get_state(encoder->pdata); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 97 | |
| 98 | switch (state) { |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 99 | case 0x0: |
Johan Hovold | 521a8f5 | 2011-05-11 16:33:50 -0700 | [diff] [blame] | 100 | if (encoder->armed) { |
| 101 | rotary_encoder_report_event(encoder); |
| 102 | encoder->armed = false; |
H Hartley Sweeten | bd3ce65 | 2009-04-17 20:12:35 -0700 | [diff] [blame] | 103 | } |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 104 | break; |
| 105 | |
| 106 | case 0x1: |
| 107 | case 0x2: |
| 108 | if (encoder->armed) |
| 109 | encoder->dir = state - 1; |
| 110 | break; |
| 111 | |
| 112 | case 0x3: |
H Hartley Sweeten | bd3ce65 | 2009-04-17 20:12:35 -0700 | [diff] [blame] | 113 | encoder->armed = true; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 114 | break; |
| 115 | } |
| 116 | |
| 117 | return IRQ_HANDLED; |
| 118 | } |
| 119 | |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 120 | static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id) |
| 121 | { |
| 122 | struct rotary_encoder *encoder = dev_id; |
| 123 | int state; |
| 124 | |
| 125 | state = rotary_encoder_get_state(encoder->pdata); |
| 126 | |
| 127 | switch (state) { |
| 128 | case 0x00: |
| 129 | case 0x03: |
| 130 | if (state != encoder->last_stable) { |
| 131 | rotary_encoder_report_event(encoder); |
| 132 | encoder->last_stable = state; |
| 133 | } |
| 134 | break; |
| 135 | |
| 136 | case 0x01: |
| 137 | case 0x02: |
| 138 | encoder->dir = (encoder->last_stable + state) & 0x01; |
| 139 | break; |
| 140 | } |
| 141 | |
| 142 | return IRQ_HANDLED; |
| 143 | } |
| 144 | |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 145 | #ifdef CONFIG_OF |
| 146 | static struct of_device_id rotary_encoder_of_match[] = { |
| 147 | { .compatible = "rotary-encoder", }, |
| 148 | { }, |
| 149 | }; |
| 150 | MODULE_DEVICE_TABLE(of, rotary_encoder_of_match); |
| 151 | |
Bill Pemberton | 5298cc4 | 2012-11-23 21:38:25 -0800 | [diff] [blame] | 152 | static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct device *dev) |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 153 | { |
| 154 | const struct of_device_id *of_id = |
| 155 | of_match_device(rotary_encoder_of_match, dev); |
| 156 | struct device_node *np = dev->of_node; |
| 157 | struct rotary_encoder_platform_data *pdata; |
| 158 | enum of_gpio_flags flags; |
| 159 | |
| 160 | if (!of_id || !np) |
| 161 | return NULL; |
| 162 | |
| 163 | pdata = kzalloc(sizeof(struct rotary_encoder_platform_data), |
| 164 | GFP_KERNEL); |
| 165 | if (!pdata) |
| 166 | return ERR_PTR(-ENOMEM); |
| 167 | |
| 168 | of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps); |
| 169 | of_property_read_u32(np, "linux,axis", &pdata->axis); |
| 170 | |
| 171 | pdata->gpio_a = of_get_gpio_flags(np, 0, &flags); |
| 172 | pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW; |
| 173 | |
| 174 | pdata->gpio_b = of_get_gpio_flags(np, 1, &flags); |
| 175 | pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW; |
| 176 | |
| 177 | pdata->relative_axis = !!of_get_property(np, |
| 178 | "rotary-encoder,relative-axis", NULL); |
| 179 | pdata->rollover = !!of_get_property(np, |
| 180 | "rotary-encoder,rollover", NULL); |
| 181 | pdata->half_period = !!of_get_property(np, |
| 182 | "rotary-encoder,half-period", NULL); |
| 183 | |
| 184 | return pdata; |
| 185 | } |
| 186 | #else |
| 187 | static inline struct rotary_encoder_platform_data * |
| 188 | rotary_encoder_parse_dt(struct device *dev) |
| 189 | { |
| 190 | return NULL; |
| 191 | } |
| 192 | #endif |
| 193 | |
Bill Pemberton | 5298cc4 | 2012-11-23 21:38:25 -0800 | [diff] [blame] | 194 | static int rotary_encoder_probe(struct platform_device *pdev) |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 195 | { |
Dmitry Torokhov | ce91953 | 2012-07-31 22:08:49 -0700 | [diff] [blame] | 196 | struct device *dev = &pdev->dev; |
| 197 | const struct rotary_encoder_platform_data *pdata = dev_get_platdata(dev); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 198 | struct rotary_encoder *encoder; |
| 199 | struct input_dev *input; |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 200 | irq_handler_t handler; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 201 | int err; |
| 202 | |
H Hartley Sweeten | 06ee3d3 | 2009-10-05 21:43:42 -0700 | [diff] [blame] | 203 | if (!pdata) { |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 204 | pdata = rotary_encoder_parse_dt(dev); |
| 205 | if (IS_ERR(pdata)) |
| 206 | return PTR_ERR(pdata); |
| 207 | |
| 208 | if (!pdata) { |
| 209 | dev_err(dev, "missing platform data\n"); |
| 210 | return -EINVAL; |
| 211 | } |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 212 | } |
| 213 | |
| 214 | encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL); |
| 215 | input = input_allocate_device(); |
| 216 | if (!encoder || !input) { |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 217 | err = -ENOMEM; |
| 218 | goto exit_free_mem; |
| 219 | } |
| 220 | |
| 221 | encoder->input = input; |
| 222 | encoder->pdata = pdata; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 223 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 224 | input->name = pdev->name; |
| 225 | input->id.bustype = BUS_HOST; |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 226 | input->dev.parent = dev; |
H Hartley Sweeten | bd3ce65 | 2009-04-17 20:12:35 -0700 | [diff] [blame] | 227 | |
| 228 | if (pdata->relative_axis) { |
| 229 | input->evbit[0] = BIT_MASK(EV_REL); |
| 230 | input->relbit[0] = BIT_MASK(pdata->axis); |
| 231 | } else { |
| 232 | input->evbit[0] = BIT_MASK(EV_ABS); |
| 233 | input_set_abs_params(encoder->input, |
| 234 | pdata->axis, 0, pdata->steps, 0, 1); |
| 235 | } |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 236 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 237 | /* request the GPIOs */ |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 238 | err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev)); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 239 | if (err) { |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 240 | dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a); |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 241 | goto exit_free_mem; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 242 | } |
| 243 | |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 244 | err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev)); |
Andrew Clayton | 5deeac9 | 2010-02-10 23:18:05 -0800 | [diff] [blame] | 245 | if (err) { |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 246 | dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b); |
Andrew Clayton | 5deeac9 | 2010-02-10 23:18:05 -0800 | [diff] [blame] | 247 | goto exit_free_gpio_a; |
| 248 | } |
| 249 | |
Daniel Mack | a78769b | 2012-07-31 22:08:47 -0700 | [diff] [blame] | 250 | encoder->irq_a = gpio_to_irq(pdata->gpio_a); |
| 251 | encoder->irq_b = gpio_to_irq(pdata->gpio_b); |
| 252 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 253 | /* request the IRQs */ |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 254 | if (pdata->half_period) { |
| 255 | handler = &rotary_encoder_half_period_irq; |
| 256 | encoder->last_stable = rotary_encoder_get_state(pdata); |
| 257 | } else { |
| 258 | handler = &rotary_encoder_irq; |
| 259 | } |
| 260 | |
| 261 | err = request_irq(encoder->irq_a, handler, |
Alexander Stein | e0d5f4c | 2011-02-02 22:59:54 -0800 | [diff] [blame] | 262 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 263 | DRV_NAME, encoder); |
| 264 | if (err) { |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 265 | dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 266 | goto exit_free_gpio_b; |
| 267 | } |
| 268 | |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 269 | err = request_irq(encoder->irq_b, handler, |
Alexander Stein | e0d5f4c | 2011-02-02 22:59:54 -0800 | [diff] [blame] | 270 | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 271 | DRV_NAME, encoder); |
| 272 | if (err) { |
Daniel Mack | 429a34d | 2012-07-31 22:08:48 -0700 | [diff] [blame] | 273 | dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 274 | goto exit_free_irq_a; |
| 275 | } |
| 276 | |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 277 | err = input_register_device(input); |
| 278 | if (err) { |
| 279 | dev_err(dev, "failed to register input device\n"); |
| 280 | goto exit_free_irq_b; |
| 281 | } |
| 282 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 283 | platform_set_drvdata(pdev, encoder); |
| 284 | |
| 285 | return 0; |
| 286 | |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 287 | exit_free_irq_b: |
| 288 | free_irq(encoder->irq_b, encoder); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 289 | exit_free_irq_a: |
| 290 | free_irq(encoder->irq_a, encoder); |
| 291 | exit_free_gpio_b: |
| 292 | gpio_free(pdata->gpio_b); |
| 293 | exit_free_gpio_a: |
| 294 | gpio_free(pdata->gpio_a); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 295 | exit_free_mem: |
| 296 | input_free_device(input); |
| 297 | kfree(encoder); |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 298 | if (!dev_get_platdata(&pdev->dev)) |
| 299 | kfree(pdata); |
| 300 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 301 | return err; |
| 302 | } |
| 303 | |
Bill Pemberton | e2619cf | 2012-11-23 21:50:47 -0800 | [diff] [blame] | 304 | static int rotary_encoder_remove(struct platform_device *pdev) |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 305 | { |
| 306 | struct rotary_encoder *encoder = platform_get_drvdata(pdev); |
Dmitry Torokhov | ce91953 | 2012-07-31 22:08:49 -0700 | [diff] [blame] | 307 | const struct rotary_encoder_platform_data *pdata = encoder->pdata; |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 308 | |
| 309 | free_irq(encoder->irq_a, encoder); |
| 310 | free_irq(encoder->irq_b, encoder); |
| 311 | gpio_free(pdata->gpio_a); |
| 312 | gpio_free(pdata->gpio_b); |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 313 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 314 | input_unregister_device(encoder->input); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 315 | kfree(encoder); |
| 316 | |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 317 | if (!dev_get_platdata(&pdev->dev)) |
| 318 | kfree(pdata); |
| 319 | |
| 320 | platform_set_drvdata(pdev, NULL); |
| 321 | |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 322 | return 0; |
| 323 | } |
| 324 | |
| 325 | static struct platform_driver rotary_encoder_driver = { |
| 326 | .probe = rotary_encoder_probe, |
Bill Pemberton | 1cb0aa8 | 2012-11-23 21:27:39 -0800 | [diff] [blame] | 327 | .remove = rotary_encoder_remove, |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 328 | .driver = { |
| 329 | .name = DRV_NAME, |
| 330 | .owner = THIS_MODULE, |
Daniel Mack | 80c99bc | 2012-07-31 22:08:50 -0700 | [diff] [blame] | 331 | .of_match_table = of_match_ptr(rotary_encoder_of_match), |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 332 | } |
| 333 | }; |
JJ Ding | 840a746 | 2011-11-29 11:08:40 -0800 | [diff] [blame] | 334 | module_platform_driver(rotary_encoder_driver); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 335 | |
| 336 | MODULE_ALIAS("platform:" DRV_NAME); |
| 337 | MODULE_DESCRIPTION("GPIO rotary encoder driver"); |
Johan Hovold | e70bdd4 | 2011-05-11 16:35:30 -0700 | [diff] [blame] | 338 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold"); |
Daniel Mack | 73969ff | 2009-03-04 23:27:14 -0800 | [diff] [blame] | 339 | MODULE_LICENSE("GPL v2"); |