1/*
2 * Input driver for Microchip CAP11xx based capacitive touch sensors
3 *
4 * (c) 2014 Daniel Mack <linux@zonque.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/interrupt.h>
14#include <linux/input.h>
15#include <linux/leds.h>
16#include <linux/of_irq.h>
17#include <linux/regmap.h>
18#include <linux/i2c.h>
19#include <linux/gpio/consumer.h>
20
21#define CAP11XX_REG_MAIN_CONTROL 0x00
22#define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT (6)
23#define CAP11XX_REG_MAIN_CONTROL_GAIN_MASK (0xc0)
24#define CAP11XX_REG_MAIN_CONTROL_DLSEEP BIT(4)
25#define CAP11XX_REG_GENERAL_STATUS 0x02
26#define CAP11XX_REG_SENSOR_INPUT 0x03
27#define CAP11XX_REG_NOISE_FLAG_STATUS 0x0a
28#define CAP11XX_REG_SENOR_DELTA(X) (0x10 + (X))
29#define CAP11XX_REG_SENSITIVITY_CONTROL 0x1f
30#define CAP11XX_REG_CONFIG 0x20
31#define CAP11XX_REG_SENSOR_ENABLE 0x21
32#define CAP11XX_REG_SENSOR_CONFIG 0x22
33#define CAP11XX_REG_SENSOR_CONFIG2 0x23
34#define CAP11XX_REG_SAMPLING_CONFIG 0x24
35#define CAP11XX_REG_CALIBRATION 0x26
36#define CAP11XX_REG_INT_ENABLE 0x27
37#define CAP11XX_REG_REPEAT_RATE 0x28
38#define CAP11XX_REG_MT_CONFIG 0x2a
39#define CAP11XX_REG_MT_PATTERN_CONFIG 0x2b
40#define CAP11XX_REG_MT_PATTERN 0x2d
41#define CAP11XX_REG_RECALIB_CONFIG 0x2f
42#define CAP11XX_REG_SENSOR_THRESH(X) (0x30 + (X))
43#define CAP11XX_REG_SENSOR_NOISE_THRESH 0x38
44#define CAP11XX_REG_STANDBY_CHANNEL 0x40
45#define CAP11XX_REG_STANDBY_CONFIG 0x41
46#define CAP11XX_REG_STANDBY_SENSITIVITY 0x42
47#define CAP11XX_REG_STANDBY_THRESH 0x43
48#define CAP11XX_REG_CONFIG2 0x44
49#define CAP11XX_REG_CONFIG2_ALT_POL BIT(6)
50#define CAP11XX_REG_SENSOR_BASE_CNT(X) (0x50 + (X))
51#define CAP11XX_REG_LED_POLARITY 0x73
52#define CAP11XX_REG_LED_OUTPUT_CONTROL 0x74
53
54#define CAP11XX_REG_LED_DUTY_CYCLE_1 0x90
55#define CAP11XX_REG_LED_DUTY_CYCLE_2 0x91
56#define CAP11XX_REG_LED_DUTY_CYCLE_3 0x92
57#define CAP11XX_REG_LED_DUTY_CYCLE_4 0x93
58
59#define CAP11XX_REG_LED_DUTY_MIN_MASK (0x0f)
60#define CAP11XX_REG_LED_DUTY_MIN_MASK_SHIFT (0)
61#define CAP11XX_REG_LED_DUTY_MAX_MASK (0xf0)
62#define CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT (4)
63#define CAP11XX_REG_LED_DUTY_MAX_VALUE (15)
64
65#define CAP11XX_REG_SENSOR_CALIB (0xb1 + (X))
66#define CAP11XX_REG_SENSOR_CALIB_LSB1 0xb9
67#define CAP11XX_REG_SENSOR_CALIB_LSB2 0xba
68#define CAP11XX_REG_PRODUCT_ID 0xfd
69#define CAP11XX_REG_MANUFACTURER_ID 0xfe
70#define CAP11XX_REG_REVISION 0xff
71
72#define CAP11XX_MANUFACTURER_ID 0x5d
73
74#ifdef CONFIG_LEDS_CLASS
75struct cap11xx_led {
76 struct cap11xx_priv *priv;
77 struct led_classdev cdev;
78 u32 reg;
79};
80#endif
81
82struct cap11xx_priv {
83 struct regmap *regmap;
84 struct input_dev *idev;
85
86 struct cap11xx_led *leds;
87 int num_leds;
88
89 /* config */
90 u32 keycodes[];
91};
92
93struct cap11xx_hw_model {
94 u8 product_id;
95 unsigned int num_channels;
96 unsigned int num_leds;
97};
98
99enum {
100 CAP1106,
101 CAP1126,
102 CAP1188,
103};
104
105static const struct cap11xx_hw_model cap11xx_devices[] = {
106 [CAP1106] = { .product_id = 0x55, .num_channels = 6, .num_leds = 0 },
107 [CAP1126] = { .product_id = 0x53, .num_channels = 6, .num_leds = 2 },
108 [CAP1188] = { .product_id = 0x50, .num_channels = 8, .num_leds = 8 },
109};
110
111static const struct reg_default cap11xx_reg_defaults[] = {
112 { CAP11XX_REG_MAIN_CONTROL, 0x00 },
113 { CAP11XX_REG_GENERAL_STATUS, 0x00 },
114 { CAP11XX_REG_SENSOR_INPUT, 0x00 },
115 { CAP11XX_REG_NOISE_FLAG_STATUS, 0x00 },
116 { CAP11XX_REG_SENSITIVITY_CONTROL, 0x2f },
117 { CAP11XX_REG_CONFIG, 0x20 },
118 { CAP11XX_REG_SENSOR_ENABLE, 0x3f },
119 { CAP11XX_REG_SENSOR_CONFIG, 0xa4 },
120 { CAP11XX_REG_SENSOR_CONFIG2, 0x07 },
121 { CAP11XX_REG_SAMPLING_CONFIG, 0x39 },
122 { CAP11XX_REG_CALIBRATION, 0x00 },
123 { CAP11XX_REG_INT_ENABLE, 0x3f },
124 { CAP11XX_REG_REPEAT_RATE, 0x3f },
125 { CAP11XX_REG_MT_CONFIG, 0x80 },
126 { CAP11XX_REG_MT_PATTERN_CONFIG, 0x00 },
127 { CAP11XX_REG_MT_PATTERN, 0x3f },
128 { CAP11XX_REG_RECALIB_CONFIG, 0x8a },
129 { CAP11XX_REG_SENSOR_THRESH(0), 0x40 },
130 { CAP11XX_REG_SENSOR_THRESH(1), 0x40 },
131 { CAP11XX_REG_SENSOR_THRESH(2), 0x40 },
132 { CAP11XX_REG_SENSOR_THRESH(3), 0x40 },
133 { CAP11XX_REG_SENSOR_THRESH(4), 0x40 },
134 { CAP11XX_REG_SENSOR_THRESH(5), 0x40 },
135 { CAP11XX_REG_SENSOR_NOISE_THRESH, 0x01 },
136 { CAP11XX_REG_STANDBY_CHANNEL, 0x00 },
137 { CAP11XX_REG_STANDBY_CONFIG, 0x39 },
138 { CAP11XX_REG_STANDBY_SENSITIVITY, 0x02 },
139 { CAP11XX_REG_STANDBY_THRESH, 0x40 },
140 { CAP11XX_REG_CONFIG2, 0x40 },
141 { CAP11XX_REG_LED_POLARITY, 0x00 },
142 { CAP11XX_REG_SENSOR_CALIB_LSB1, 0x00 },
143 { CAP11XX_REG_SENSOR_CALIB_LSB2, 0x00 },
144};
145
146static bool cap11xx_volatile_reg(struct device *dev, unsigned int reg)
147{
148 switch (reg) {
149 case CAP11XX_REG_MAIN_CONTROL:
150 case CAP11XX_REG_SENSOR_INPUT:
151 case CAP11XX_REG_SENOR_DELTA(0):
152 case CAP11XX_REG_SENOR_DELTA(1):
153 case CAP11XX_REG_SENOR_DELTA(2):
154 case CAP11XX_REG_SENOR_DELTA(3):
155 case CAP11XX_REG_SENOR_DELTA(4):
156 case CAP11XX_REG_SENOR_DELTA(5):
157 case CAP11XX_REG_PRODUCT_ID:
158 case CAP11XX_REG_MANUFACTURER_ID:
159 case CAP11XX_REG_REVISION:
160 return true;
161 }
162
163 return false;
164}
165
166static const struct regmap_config cap11xx_regmap_config = {
167 .reg_bits = 8,
168 .val_bits = 8,
169
170 .max_register = CAP11XX_REG_REVISION,
171 .reg_defaults = cap11xx_reg_defaults,
172
173 .num_reg_defaults = ARRAY_SIZE(cap11xx_reg_defaults),
174 .cache_type = REGCACHE_RBTREE,
175 .volatile_reg = cap11xx_volatile_reg,
176};
177
178static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
179{
180 struct cap11xx_priv *priv = data;
181 unsigned int status;
182 int ret, i;
183
184 /*
185 * Deassert interrupt. This needs to be done before reading the status
186 * registers, which will not carry valid values otherwise.
187 */
188 ret = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL, 1, 0);
189 if (ret < 0)
190 goto out;
191
192 ret = regmap_read(priv->regmap, CAP11XX_REG_SENSOR_INPUT, &status);
193 if (ret < 0)
194 goto out;
195
196 for (i = 0; i < priv->idev->keycodemax; i++)
197 input_report_key(priv->idev, priv->keycodes[i],
198 status & (1 << i));
199
200 input_sync(priv->idev);
201
202out:
203 return IRQ_HANDLED;
204}
205
206static int cap11xx_set_sleep(struct cap11xx_priv *priv, bool sleep)
207{
208 /*
209 * DLSEEP mode will turn off all LEDS, prevent this
210 */
211 if (IS_ENABLED(CONFIG_LEDS_CLASS) && priv->num_leds)
212 return 0;
213
214 return regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
215 CAP11XX_REG_MAIN_CONTROL_DLSEEP,
216 sleep ? CAP11XX_REG_MAIN_CONTROL_DLSEEP : 0);
217}
218
219static int cap11xx_input_open(struct input_dev *idev)
220{
221 struct cap11xx_priv *priv = input_get_drvdata(idev);
222
223 return cap11xx_set_sleep(priv, false);
224}
225
226static void cap11xx_input_close(struct input_dev *idev)
227{
228 struct cap11xx_priv *priv = input_get_drvdata(idev);
229
230 cap11xx_set_sleep(priv, true);
231}
232
233#ifdef CONFIG_LEDS_CLASS
234static int cap11xx_led_set(struct led_classdev *cdev,
235 enum led_brightness value)
236{
237 struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
238 struct cap11xx_priv *priv = led->priv;
239
240 /*
241 * All LEDs share the same duty cycle as this is a HW
242 * limitation. Brightness levels per LED are either
243 * 0 (OFF) and 1 (ON).
244 */
245 return regmap_update_bits(priv->regmap,
246 CAP11XX_REG_LED_OUTPUT_CONTROL,
247 BIT(led->reg),
248 value ? BIT(led->reg) : 0);
249}
250
251static int cap11xx_init_leds(struct device *dev,
252 struct cap11xx_priv *priv, int num_leds)
253{
254 struct device_node *node = dev->of_node, *child;
255 struct cap11xx_led *led;
256 int cnt = of_get_child_count(node);
257 int error;
258
259 if (!num_leds || !cnt)
260 return 0;
261
262 if (cnt > num_leds)
263 return -EINVAL;
264
265 led = devm_kcalloc(dev, cnt, sizeof(struct cap11xx_led), GFP_KERNEL);
266 if (!led)
267 return -ENOMEM;
268
269 priv->leds = led;
270
271 error = regmap_update_bits(priv->regmap,
272 CAP11XX_REG_LED_OUTPUT_CONTROL, 0xff, 0);
273 if (error)
274 return error;
275
276 error = regmap_update_bits(priv->regmap, CAP11XX_REG_LED_DUTY_CYCLE_4,
277 CAP11XX_REG_LED_DUTY_MAX_MASK,
278 CAP11XX_REG_LED_DUTY_MAX_VALUE <<
279 CAP11XX_REG_LED_DUTY_MAX_MASK_SHIFT);
280 if (error)
281 return error;
282
283 for_each_child_of_node(node, child) {
284 u32 reg;
285
286 led->cdev.name =
287 of_get_property(child, "label", NULL) ? : child->name;
288 led->cdev.default_trigger =
289 of_get_property(child, "linux,default-trigger", NULL);
290 led->cdev.flags = 0;
291 led->cdev.brightness_set_blocking = cap11xx_led_set;
292 led->cdev.max_brightness = 1;
293 led->cdev.brightness = LED_OFF;
294
295 error = of_property_read_u32(child, "reg", &reg);
296 if (error != 0 || reg >= num_leds) {
297 of_node_put(child);
298 return -EINVAL;
299 }
300
301 led->reg = reg;
302 led->priv = priv;
303
304 error = devm_led_classdev_register(dev, &led->cdev);
305 if (error) {
306 of_node_put(child);
307 return error;
308 }
309
310 priv->num_leds++;
311 led++;
312 }
313
314 return 0;
315}
316#else
317static int cap11xx_init_leds(struct device *dev,
318 struct cap11xx_priv *priv, int num_leds)
319{
320 return 0;
321}
322#endif
323
324static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
325 const struct i2c_device_id *id)
326{
327 struct device *dev = &i2c_client->dev;
328 struct cap11xx_priv *priv;
329 struct device_node *node;
330 const struct cap11xx_hw_model *cap;
331 int i, error, irq, gain = 0;
332 unsigned int val, rev;
333 u32 gain32;
334
335 if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
336 dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
337 return -EINVAL;
338 }
339
340 cap = &cap11xx_devices[id->driver_data];
341 if (!cap || !cap->num_channels) {
342 dev_err(dev, "Invalid device configuration\n");
343 return -EINVAL;
344 }
345
346 priv = devm_kzalloc(dev,
347 struct_size(priv, keycodes, cap->num_channels),
348 GFP_KERNEL);
349 if (!priv)
350 return -ENOMEM;
351
352 priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
353 if (IS_ERR(priv->regmap))
354 return PTR_ERR(priv->regmap);
355
356 error = regmap_read(priv->regmap, CAP11XX_REG_PRODUCT_ID, &val);
357 if (error)
358 return error;
359
360 if (val != cap->product_id) {
361 dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
362 val, cap->product_id);
363 return -ENXIO;
364 }
365
366 error = regmap_read(priv->regmap, CAP11XX_REG_MANUFACTURER_ID, &val);
367 if (error)
368 return error;
369
370 if (val != CAP11XX_MANUFACTURER_ID) {
371 dev_err(dev, "Manufacturer ID: Got 0x%02x, expected 0x%02x\n",
372 val, CAP11XX_MANUFACTURER_ID);
373 return -ENXIO;
374 }
375
376 error = regmap_read(priv->regmap, CAP11XX_REG_REVISION, &rev);
377 if (error < 0)
378 return error;
379
380 dev_info(dev, "CAP11XX detected, revision 0x%02x\n", rev);
381 node = dev->of_node;
382
383 if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
384 if (is_power_of_2(gain32) && gain32 <= 8)
385 gain = ilog2(gain32);
386 else
387 dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
388 }
389
390 if (of_property_read_bool(node, "microchip,irq-active-high")) {
391 error = regmap_update_bits(priv->regmap, CAP11XX_REG_CONFIG2,
392 CAP11XX_REG_CONFIG2_ALT_POL, 0);
393 if (error)
394 return error;
395 }
396
397 /* Provide some useful defaults */
398 for (i = 0; i < cap->num_channels; i++)
399 priv->keycodes[i] = KEY_A + i;
400
401 of_property_read_u32_array(node, "linux,keycodes",
402 priv->keycodes, cap->num_channels);
403
404 error = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
405 CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
406 gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
407 if (error)
408 return error;
409
410 /* Disable autorepeat. The Linux input system has its own handling. */
411 error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
412 if (error)
413 return error;
414
415 priv->idev = devm_input_allocate_device(dev);
416 if (!priv->idev)
417 return -ENOMEM;
418
419 priv->idev->name = "CAP11XX capacitive touch sensor";
420 priv->idev->id.bustype = BUS_I2C;
421 priv->idev->evbit[0] = BIT_MASK(EV_KEY);
422
423 if (of_property_read_bool(node, "autorepeat"))
424 __set_bit(EV_REP, priv->idev->evbit);
425
426 for (i = 0; i < cap->num_channels; i++)
427 __set_bit(priv->keycodes[i], priv->idev->keybit);
428
429 __clear_bit(KEY_RESERVED, priv->idev->keybit);
430
431 priv->idev->keycode = priv->keycodes;
432 priv->idev->keycodesize = sizeof(priv->keycodes[0]);
433 priv->idev->keycodemax = cap->num_channels;
434
435 priv->idev->id.vendor = CAP11XX_MANUFACTURER_ID;
436 priv->idev->id.product = cap->product_id;
437 priv->idev->id.version = rev;
438
439 priv->idev->open = cap11xx_input_open;
440 priv->idev->close = cap11xx_input_close;
441
442 error = cap11xx_init_leds(dev, priv, cap->num_leds);
443 if (error)
444 return error;
445
446 input_set_drvdata(priv->idev, priv);
447
448 /*
449 * Put the device in deep sleep mode for now.
450 * ->open() will bring it back once the it is actually needed.
451 */
452 cap11xx_set_sleep(priv, true);
453
454 error = input_register_device(priv->idev);
455 if (error)
456 return error;
457
458 irq = irq_of_parse_and_map(node, 0);
459 if (!irq) {
460 dev_err(dev, "Unable to parse or map IRQ\n");
461 return -ENXIO;
462 }
463
464 error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
465 IRQF_ONESHOT, dev_name(dev), priv);
466 if (error)
467 return error;
468
469 return 0;
470}
471
472static const struct of_device_id cap11xx_dt_ids[] = {
473 { .compatible = "microchip,cap1106", },
474 { .compatible = "microchip,cap1126", },
475 { .compatible = "microchip,cap1188", },
476 {}
477};
478MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);
479
480static const struct i2c_device_id cap11xx_i2c_ids[] = {
481 { "cap1106", CAP1106 },
482 { "cap1126", CAP1126 },
483 { "cap1188", CAP1188 },
484 {}
485};
486MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);
487
488static struct i2c_driver cap11xx_i2c_driver = {
489 .driver = {
490 .name = "cap11xx",
491 .of_match_table = cap11xx_dt_ids,
492 },
493 .id_table = cap11xx_i2c_ids,
494 .probe = cap11xx_i2c_probe,
495};
496
497module_i2c_driver(cap11xx_i2c_driver);
498
499MODULE_DESCRIPTION("Microchip CAP11XX driver");
500MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
501MODULE_LICENSE("GPL v2");
502