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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Rohm BU21029 touchscreen controller driver | |
4 | * | |
5 | * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/delay.h> | |
13 | #include <linux/gpio/consumer.h> | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/input.h> | |
16 | #include <linux/input/touchscreen.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/irq.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/regulator/consumer.h> | |
21 | #include <linux/timer.h> | |
22 | ||
23 | /* | |
24 | * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only) | |
25 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
26 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
27 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
28 | * | HW_IDH | | |
29 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
30 | * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only) | |
31 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
32 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
33 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
34 | * | HW_IDL | | |
35 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
36 | * HW_IDH: high 8bits of IC's ID | |
37 | * HW_IDL: low 8bits of IC's ID | |
38 | */ | |
39 | #define BU21029_HWID_REG (0x0E << 3) | |
40 | #define SUPPORTED_HWID 0x0229 | |
41 | ||
42 | /* | |
43 | * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20) | |
44 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
45 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
46 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
47 | * | 0 | 0 | CALIB | INTRM | 0 | 0 | 0 | 0 | | |
48 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
49 | * CALIB: 0 = not to use calibration result (*) | |
50 | * 1 = use calibration result | |
51 | * INTRM: 0 = INT output depend on "pen down" (*) | |
52 | * 1 = INT output always "0" | |
53 | */ | |
54 | #define BU21029_CFR0_REG (0x00 << 3) | |
55 | #define CFR0_VALUE 0x00 | |
56 | ||
57 | /* | |
58 | * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6) | |
59 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
60 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
61 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
62 | * | MAV | AVE[2:0] | 0 | SMPL[2:0] | | |
63 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
64 | * MAV: 0 = median average filter off | |
65 | * 1 = median average filter on (*) | |
66 | * AVE: AVE+1 = number of average samples for MAV, | |
67 | * if AVE>SMPL, then AVE=SMPL (=3) | |
68 | * SMPL: SMPL+1 = number of conversion samples for MAV (=7) | |
69 | */ | |
70 | #define BU21029_CFR1_REG (0x01 << 3) | |
71 | #define CFR1_VALUE 0xA6 | |
72 | ||
73 | /* | |
74 | * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04) | |
75 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
76 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
77 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
78 | * | INTVL_TIME[3:0] | TIME_ST_ADC[3:0] | | |
79 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
80 | * INTVL_TIME: waiting time between completion of conversion | |
81 | * and start of next conversion, only usable in | |
82 | * autoscan mode (=20.480ms) | |
83 | * TIME_ST_ADC: waiting time between application of voltage | |
84 | * to panel and start of A/D conversion (=100us) | |
85 | */ | |
86 | #define BU21029_CFR2_REG (0x02 << 3) | |
87 | #define CFR2_VALUE 0xC9 | |
88 | ||
89 | /* | |
90 | * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72) | |
91 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
92 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
93 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
94 | * | RM8 | STRETCH| PU90K | DUAL | PIDAC_OFS[3:0] | | |
95 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
96 | * RM8: 0 = coordinate resolution is 12bit (*) | |
97 | * 1 = coordinate resolution is 8bit | |
98 | * STRETCH: 0 = SCL_STRETCH function off | |
99 | * 1 = SCL_STRETCH function on (*) | |
100 | * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*) | |
101 | * 1 = internal pull-up resistance for touch detection is ~90kohms | |
102 | * DUAL: 0 = dual touch detection off (*) | |
103 | * 1 = dual touch detection on | |
104 | * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary | |
105 | * to change this from initial value | |
106 | */ | |
107 | #define BU21029_CFR3_REG (0x0B << 3) | |
108 | #define CFR3_VALUE 0x42 | |
109 | ||
110 | /* | |
111 | * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00) | |
112 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
113 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
114 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
115 | * | 0 | PVDD[2:0] | 0 | AVDD[2:0] | | |
116 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
117 | * PVDD: output voltage of panel output regulator (=2.000V) | |
118 | * AVDD: output voltage of analog circuit regulator (=2.000V) | |
119 | */ | |
120 | #define BU21029_LDO_REG (0x0C << 3) | |
121 | #define LDO_VALUE 0x77 | |
122 | ||
123 | /* | |
124 | * Serial Interface Command Byte 1 (CID=1) | |
125 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
126 | * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | | |
127 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
128 | * | 1 | CF | CMSK | PDM | STP | | |
129 | * +--------+--------+--------+--------+--------+--------+--------+--------+ | |
130 | * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan) | |
131 | * CMSK: 0 = executes convert function (*) | |
132 | * 1 = reads the convert result | |
133 | * PDM: 0 = power down after convert function stops (*) | |
134 | * 1 = keep power on after convert function stops | |
135 | * STP: 1 = abort current conversion and power down, set to "0" automatically | |
136 | */ | |
137 | #define BU21029_AUTOSCAN 0x80 | |
138 | ||
139 | /* | |
140 | * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and | |
141 | * conversion time), where tConv4 is calculated by formula: | |
142 | * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3 | |
143 | * see figure 8 in datasheet p15 for details of each field. | |
144 | */ | |
145 | #define PEN_UP_TIMEOUT_MS 50 | |
146 | ||
147 | #define STOP_DELAY_MIN_US 50 | |
148 | #define STOP_DELAY_MAX_US 1000 | |
149 | #define START_DELAY_MS 2 | |
150 | #define BUF_LEN 8 | |
151 | #define SCALE_12BIT (1 << 12) | |
152 | #define MAX_12BIT ((1 << 12) - 1) | |
153 | #define DRIVER_NAME "bu21029" | |
154 | ||
155 | struct bu21029_ts_data { | |
156 | struct i2c_client *client; | |
157 | struct input_dev *in_dev; | |
158 | struct timer_list timer; | |
159 | struct regulator *vdd; | |
160 | struct gpio_desc *reset_gpios; | |
161 | u32 x_plate_ohms; | |
162 | struct touchscreen_properties prop; | |
163 | }; | |
164 | ||
165 | static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf) | |
166 | { | |
167 | u16 x, y, z1, z2; | |
168 | u32 rz; | |
169 | s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE); | |
170 | ||
171 | /* | |
172 | * compose upper 8 and lower 4 bits into a 12bit value: | |
173 | * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | |
174 | * | ByteH | ByteL | | |
175 | * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | |
176 | * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00| | |
177 | * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | |
178 | * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 | | |
179 | * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | |
180 | */ | |
181 | x = (buf[0] << 4) | (buf[1] >> 4); | |
182 | y = (buf[2] << 4) | (buf[3] >> 4); | |
183 | z1 = (buf[4] << 4) | (buf[5] >> 4); | |
184 | z2 = (buf[6] << 4) | (buf[7] >> 4); | |
185 | ||
186 | if (z1 && z2) { | |
187 | /* | |
188 | * calculate Rz (pressure resistance value) by equation: | |
189 | * Rz = Rx * (x/Q) * ((z2/z1) - 1), where | |
190 | * Rx is x-plate resistance, | |
191 | * Q is the touch screen resolution (8bit = 256, 12bit = 4096) | |
192 | * x, z1, z2 are the measured positions. | |
193 | */ | |
194 | rz = z2 - z1; | |
195 | rz *= x; | |
196 | rz *= bu21029->x_plate_ohms; | |
197 | rz /= z1; | |
198 | rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT); | |
199 | if (rz <= max_pressure) { | |
200 | touchscreen_report_pos(bu21029->in_dev, &bu21029->prop, | |
201 | x, y, false); | |
202 | input_report_abs(bu21029->in_dev, ABS_PRESSURE, | |
203 | max_pressure - rz); | |
204 | input_report_key(bu21029->in_dev, BTN_TOUCH, 1); | |
205 | input_sync(bu21029->in_dev); | |
206 | } | |
207 | } | |
208 | } | |
209 | ||
210 | static void bu21029_touch_release(struct timer_list *t) | |
211 | { | |
212 | struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer); | |
213 | ||
214 | input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0); | |
215 | input_report_key(bu21029->in_dev, BTN_TOUCH, 0); | |
216 | input_sync(bu21029->in_dev); | |
217 | } | |
218 | ||
219 | static irqreturn_t bu21029_touch_soft_irq(int irq, void *data) | |
220 | { | |
221 | struct bu21029_ts_data *bu21029 = data; | |
222 | u8 buf[BUF_LEN]; | |
223 | int error; | |
224 | ||
225 | /* | |
226 | * Read touch data and deassert interrupt (will assert again after | |
227 | * INTVL_TIME + tConv4 for continuous touch) | |
228 | */ | |
229 | error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN, | |
230 | sizeof(buf), buf); | |
231 | if (error < 0) | |
232 | goto out; | |
233 | ||
234 | bu21029_touch_report(bu21029, buf); | |
235 | ||
236 | /* reset timer for pen up detection */ | |
237 | mod_timer(&bu21029->timer, | |
238 | jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS)); | |
239 | ||
240 | out: | |
241 | return IRQ_HANDLED; | |
242 | } | |
243 | ||
244 | static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029) | |
245 | { | |
246 | if (bu21029->reset_gpios) { | |
247 | gpiod_set_value_cansleep(bu21029->reset_gpios, 1); | |
248 | usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US); | |
249 | } | |
250 | } | |
251 | ||
252 | static int bu21029_start_chip(struct input_dev *dev) | |
253 | { | |
254 | struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); | |
255 | struct i2c_client *i2c = bu21029->client; | |
256 | struct { | |
257 | u8 reg; | |
258 | u8 value; | |
259 | } init_table[] = { | |
260 | {BU21029_CFR0_REG, CFR0_VALUE}, | |
261 | {BU21029_CFR1_REG, CFR1_VALUE}, | |
262 | {BU21029_CFR2_REG, CFR2_VALUE}, | |
263 | {BU21029_CFR3_REG, CFR3_VALUE}, | |
264 | {BU21029_LDO_REG, LDO_VALUE} | |
265 | }; | |
266 | int error, i; | |
267 | __be16 hwid; | |
268 | ||
269 | error = regulator_enable(bu21029->vdd); | |
270 | if (error) { | |
271 | dev_err(&i2c->dev, "failed to power up chip: %d", error); | |
272 | return error; | |
273 | } | |
274 | ||
275 | /* take chip out of reset */ | |
276 | if (bu21029->reset_gpios) { | |
277 | gpiod_set_value_cansleep(bu21029->reset_gpios, 0); | |
278 | msleep(START_DELAY_MS); | |
279 | } | |
280 | ||
281 | error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG, | |
282 | sizeof(hwid), (u8 *)&hwid); | |
283 | if (error < 0) { | |
284 | dev_err(&i2c->dev, "failed to read HW ID\n"); | |
285 | goto err_out; | |
286 | } | |
287 | ||
288 | if (be16_to_cpu(hwid) != SUPPORTED_HWID) { | |
289 | dev_err(&i2c->dev, | |
290 | "unsupported HW ID 0x%x\n", be16_to_cpu(hwid)); | |
291 | error = -ENODEV; | |
292 | goto err_out; | |
293 | } | |
294 | ||
295 | for (i = 0; i < ARRAY_SIZE(init_table); ++i) { | |
296 | error = i2c_smbus_write_byte_data(i2c, | |
297 | init_table[i].reg, | |
298 | init_table[i].value); | |
299 | if (error < 0) { | |
300 | dev_err(&i2c->dev, | |
301 | "failed to write %#02x to register %#02x: %d\n", | |
302 | init_table[i].value, init_table[i].reg, | |
303 | error); | |
304 | goto err_out; | |
305 | } | |
306 | } | |
307 | ||
308 | error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN); | |
309 | if (error < 0) { | |
310 | dev_err(&i2c->dev, "failed to start autoscan\n"); | |
311 | goto err_out; | |
312 | } | |
313 | ||
314 | enable_irq(bu21029->client->irq); | |
315 | return 0; | |
316 | ||
317 | err_out: | |
318 | bu21029_put_chip_in_reset(bu21029); | |
319 | regulator_disable(bu21029->vdd); | |
320 | return error; | |
321 | } | |
322 | ||
323 | static void bu21029_stop_chip(struct input_dev *dev) | |
324 | { | |
325 | struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); | |
326 | ||
327 | disable_irq(bu21029->client->irq); | |
328 | del_timer_sync(&bu21029->timer); | |
329 | ||
330 | bu21029_put_chip_in_reset(bu21029); | |
331 | regulator_disable(bu21029->vdd); | |
332 | } | |
333 | ||
334 | static int bu21029_probe(struct i2c_client *client, | |
335 | const struct i2c_device_id *id) | |
336 | { | |
337 | struct bu21029_ts_data *bu21029; | |
338 | struct input_dev *in_dev; | |
339 | int error; | |
340 | ||
341 | if (!i2c_check_functionality(client->adapter, | |
342 | I2C_FUNC_SMBUS_WRITE_BYTE | | |
343 | I2C_FUNC_SMBUS_WRITE_BYTE_DATA | | |
344 | I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { | |
345 | dev_err(&client->dev, | |
346 | "i2c functionality support is not sufficient\n"); | |
347 | return -EIO; | |
348 | } | |
349 | ||
350 | bu21029 = devm_kzalloc(&client->dev, sizeof(*bu21029), GFP_KERNEL); | |
351 | if (!bu21029) | |
352 | return -ENOMEM; | |
353 | ||
354 | error = device_property_read_u32(&client->dev, "rohm,x-plate-ohms", | |
355 | &bu21029->x_plate_ohms); | |
356 | if (error) { | |
357 | dev_err(&client->dev, | |
358 | "invalid 'x-plate-ohms' supplied: %d\n", error); | |
359 | return error; | |
360 | } | |
361 | ||
362 | bu21029->vdd = devm_regulator_get(&client->dev, "vdd"); | |
363 | if (IS_ERR(bu21029->vdd)) { | |
364 | error = PTR_ERR(bu21029->vdd); | |
365 | if (error != -EPROBE_DEFER) | |
366 | dev_err(&client->dev, | |
367 | "failed to acquire 'vdd' supply: %d\n", error); | |
368 | return error; | |
369 | } | |
370 | ||
371 | bu21029->reset_gpios = devm_gpiod_get_optional(&client->dev, | |
372 | "reset", GPIOD_OUT_HIGH); | |
373 | if (IS_ERR(bu21029->reset_gpios)) { | |
374 | error = PTR_ERR(bu21029->reset_gpios); | |
375 | if (error != -EPROBE_DEFER) | |
376 | dev_err(&client->dev, | |
377 | "failed to acquire 'reset' gpio: %d\n", error); | |
378 | return error; | |
379 | } | |
380 | ||
381 | in_dev = devm_input_allocate_device(&client->dev); | |
382 | if (!in_dev) { | |
383 | dev_err(&client->dev, "unable to allocate input device\n"); | |
384 | return -ENOMEM; | |
385 | } | |
386 | ||
387 | bu21029->client = client; | |
388 | bu21029->in_dev = in_dev; | |
389 | timer_setup(&bu21029->timer, bu21029_touch_release, 0); | |
390 | ||
391 | in_dev->name = DRIVER_NAME; | |
392 | in_dev->id.bustype = BUS_I2C; | |
393 | in_dev->open = bu21029_start_chip; | |
394 | in_dev->close = bu21029_stop_chip; | |
395 | ||
396 | input_set_capability(in_dev, EV_KEY, BTN_TOUCH); | |
397 | input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0); | |
398 | input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0); | |
399 | input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); | |
400 | touchscreen_parse_properties(in_dev, false, &bu21029->prop); | |
401 | ||
402 | input_set_drvdata(in_dev, bu21029); | |
403 | ||
404 | irq_set_status_flags(client->irq, IRQ_NOAUTOEN); | |
405 | error = devm_request_threaded_irq(&client->dev, client->irq, | |
406 | NULL, bu21029_touch_soft_irq, | |
407 | IRQF_ONESHOT, DRIVER_NAME, bu21029); | |
408 | if (error) { | |
409 | dev_err(&client->dev, | |
410 | "unable to request touch irq: %d\n", error); | |
411 | return error; | |
412 | } | |
413 | ||
414 | error = input_register_device(in_dev); | |
415 | if (error) { | |
416 | dev_err(&client->dev, | |
417 | "unable to register input device: %d\n", error); | |
418 | return error; | |
419 | } | |
420 | ||
421 | i2c_set_clientdata(client, bu21029); | |
422 | ||
423 | return 0; | |
424 | } | |
425 | ||
426 | static int __maybe_unused bu21029_suspend(struct device *dev) | |
427 | { | |
428 | struct i2c_client *i2c = to_i2c_client(dev); | |
429 | struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); | |
430 | ||
431 | if (!device_may_wakeup(dev)) { | |
432 | mutex_lock(&bu21029->in_dev->mutex); | |
433 | if (bu21029->in_dev->users) | |
434 | bu21029_stop_chip(bu21029->in_dev); | |
435 | mutex_unlock(&bu21029->in_dev->mutex); | |
436 | } | |
437 | ||
438 | return 0; | |
439 | } | |
440 | ||
441 | static int __maybe_unused bu21029_resume(struct device *dev) | |
442 | { | |
443 | struct i2c_client *i2c = to_i2c_client(dev); | |
444 | struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); | |
445 | ||
446 | if (!device_may_wakeup(dev)) { | |
447 | mutex_lock(&bu21029->in_dev->mutex); | |
448 | if (bu21029->in_dev->users) | |
449 | bu21029_start_chip(bu21029->in_dev); | |
450 | mutex_unlock(&bu21029->in_dev->mutex); | |
451 | } | |
452 | ||
453 | return 0; | |
454 | } | |
455 | static SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume); | |
456 | ||
457 | static const struct i2c_device_id bu21029_ids[] = { | |
458 | { DRIVER_NAME, 0 }, | |
459 | { /* sentinel */ } | |
460 | }; | |
461 | MODULE_DEVICE_TABLE(i2c, bu21029_ids); | |
462 | ||
463 | #ifdef CONFIG_OF | |
464 | static const struct of_device_id bu21029_of_ids[] = { | |
465 | { .compatible = "rohm,bu21029" }, | |
466 | { /* sentinel */ } | |
467 | }; | |
468 | MODULE_DEVICE_TABLE(of, bu21029_of_ids); | |
469 | #endif | |
470 | ||
471 | static struct i2c_driver bu21029_driver = { | |
472 | .driver = { | |
473 | .name = DRIVER_NAME, | |
474 | .of_match_table = of_match_ptr(bu21029_of_ids), | |
475 | .pm = &bu21029_pm_ops, | |
476 | }, | |
477 | .id_table = bu21029_ids, | |
478 | .probe = bu21029_probe, | |
479 | }; | |
480 | module_i2c_driver(bu21029_driver); | |
481 | ||
482 | MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>"); | |
483 | MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver"); | |
484 | MODULE_LICENSE("GPL v2"); |