1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Touchkey driver for Freescale MPR121 Controllor
4 *
5 * Copyright (C) 2011 Freescale Semiconductor, Inc.
6 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
7 *
8 * Based on mcs_touchkey.c
9 */
10
11 #include <linux/bitops.h>
12 #include <linux/delay.h>
13 #include <linux/i2c.h>
14 #include <linux/input.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/property.h>
19 #include <linux/regulator/consumer.h>
20 #include <linux/slab.h>
21
22 /* Register definitions */
23 #define ELE_TOUCH_STATUS_0_ADDR 0x0
24 #define ELE_TOUCH_STATUS_1_ADDR 0X1
25 #define MHD_RISING_ADDR 0x2b
26 #define NHD_RISING_ADDR 0x2c
27 #define NCL_RISING_ADDR 0x2d
28 #define FDL_RISING_ADDR 0x2e
29 #define MHD_FALLING_ADDR 0x2f
30 #define NHD_FALLING_ADDR 0x30
31 #define NCL_FALLING_ADDR 0x31
32 #define FDL_FALLING_ADDR 0x32
33 #define ELE0_TOUCH_THRESHOLD_ADDR 0x41
34 #define ELE0_RELEASE_THRESHOLD_ADDR 0x42
35 #define AFE_CONF_ADDR 0x5c
36 #define FILTER_CONF_ADDR 0x5d
37
38 /*
39 * ELECTRODE_CONF_ADDR: This register configures the number of
40 * enabled capacitance sensing inputs and its run/suspend mode.
41 */
42 #define ELECTRODE_CONF_ADDR 0x5e
43 #define ELECTRODE_CONF_QUICK_CHARGE 0x80
44 #define AUTO_CONFIG_CTRL_ADDR 0x7b
45 #define AUTO_CONFIG_USL_ADDR 0x7d
46 #define AUTO_CONFIG_LSL_ADDR 0x7e
47 #define AUTO_CONFIG_TL_ADDR 0x7f
48
49 /* Threshold of touch/release trigger */
50 #define TOUCH_THRESHOLD 0x08
51 #define RELEASE_THRESHOLD 0x05
52 /* Masks for touch and release triggers */
53 #define TOUCH_STATUS_MASK 0xfff
54 /* MPR121 has 12 keys */
55 #define MPR121_MAX_KEY_COUNT 12
56
57 #define MPR121_MIN_POLL_INTERVAL 10
58 #define MPR121_MAX_POLL_INTERVAL 200
59
60 struct mpr121_touchkey {
61 struct i2c_client *client;
62 struct input_dev *input_dev;
63 unsigned int statusbits;
64 unsigned int keycount;
65 u32 keycodes[MPR121_MAX_KEY_COUNT];
66 };
67
68 struct mpr121_init_register {
69 int addr;
70 u8 val;
71 };
72
73 static const struct mpr121_init_register init_reg_table[] = {
74 { MHD_RISING_ADDR, 0x1 },
75 { NHD_RISING_ADDR, 0x1 },
76 { MHD_FALLING_ADDR, 0x1 },
77 { NHD_FALLING_ADDR, 0x1 },
78 { NCL_FALLING_ADDR, 0xff },
79 { FDL_FALLING_ADDR, 0x02 },
80 { FILTER_CONF_ADDR, 0x04 },
81 { AFE_CONF_ADDR, 0x0b },
82 { AUTO_CONFIG_CTRL_ADDR, 0x0b },
83 };
84
mpr121_vdd_supply_disable(void * data)85 static void mpr121_vdd_supply_disable(void *data)
86 {
87 struct regulator *vdd_supply = data;
88
89 regulator_disable(vdd_supply);
90 }
91
mpr121_vdd_supply_init(struct device * dev)92 static struct regulator *mpr121_vdd_supply_init(struct device *dev)
93 {
94 struct regulator *vdd_supply;
95 int err;
96
97 vdd_supply = devm_regulator_get(dev, "vdd");
98 if (IS_ERR(vdd_supply)) {
99 dev_err(dev, "failed to get vdd regulator: %ld\n",
100 PTR_ERR(vdd_supply));
101 return vdd_supply;
102 }
103
104 err = regulator_enable(vdd_supply);
105 if (err) {
106 dev_err(dev, "failed to enable vdd regulator: %d\n", err);
107 return ERR_PTR(err);
108 }
109
110 err = devm_add_action(dev, mpr121_vdd_supply_disable, vdd_supply);
111 if (err) {
112 regulator_disable(vdd_supply);
113 dev_err(dev, "failed to add disable regulator action: %d\n",
114 err);
115 return ERR_PTR(err);
116 }
117
118 return vdd_supply;
119 }
120
mpr_touchkey_report(struct input_dev * dev)121 static void mpr_touchkey_report(struct input_dev *dev)
122 {
123 struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
124 struct input_dev *input = mpr121->input_dev;
125 struct i2c_client *client = mpr121->client;
126 unsigned long bit_changed;
127 unsigned int key_num;
128 int reg;
129
130 reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
131 if (reg < 0) {
132 dev_err(&client->dev, "i2c read error [%d]\n", reg);
133 return;
134 }
135
136 reg <<= 8;
137 reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
138 if (reg < 0) {
139 dev_err(&client->dev, "i2c read error [%d]\n", reg);
140 return;
141 }
142
143 reg &= TOUCH_STATUS_MASK;
144 /* use old press bit to figure out which bit changed */
145 bit_changed = reg ^ mpr121->statusbits;
146 mpr121->statusbits = reg;
147 for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
148 unsigned int key_val, pressed;
149
150 pressed = reg & BIT(key_num);
151 key_val = mpr121->keycodes[key_num];
152
153 input_event(input, EV_MSC, MSC_SCAN, key_num);
154 input_report_key(input, key_val, pressed);
155
156 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
157 pressed ? "pressed" : "released");
158
159 }
160 input_sync(input);
161 }
162
mpr_touchkey_interrupt(int irq,void * dev_id)163 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
164 {
165 struct mpr121_touchkey *mpr121 = dev_id;
166
167 mpr_touchkey_report(mpr121->input_dev);
168
169 return IRQ_HANDLED;
170 }
171
mpr121_phys_init(struct mpr121_touchkey * mpr121,struct i2c_client * client,int vdd_uv)172 static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
173 struct i2c_client *client, int vdd_uv)
174 {
175 const struct mpr121_init_register *reg;
176 unsigned char usl, lsl, tl, eleconf;
177 int i, t, vdd, ret;
178
179 /* Set up touch/release threshold for ele0-ele11 */
180 for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
181 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
182 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
183 if (ret < 0)
184 goto err_i2c_write;
185 ret = i2c_smbus_write_byte_data(client, t + 1,
186 RELEASE_THRESHOLD);
187 if (ret < 0)
188 goto err_i2c_write;
189 }
190
191 /* Set up init register */
192 for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
193 reg = &init_reg_table[i];
194 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
195 if (ret < 0)
196 goto err_i2c_write;
197 }
198
199
200 /*
201 * Capacitance on sensing input varies and needs to be compensated.
202 * The internal MPR121-auto-configuration can do this if it's
203 * registers are set properly (based on vdd_uv).
204 */
205 vdd = vdd_uv / 1000;
206 usl = ((vdd - 700) * 256) / vdd;
207 lsl = (usl * 65) / 100;
208 tl = (usl * 90) / 100;
209 ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
210 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
211 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
212
213 /*
214 * Quick charge bit will let the capacitive charge to ready
215 * state quickly, or the buttons may not function after system
216 * boot.
217 */
218 eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
219 ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
220 eleconf);
221 if (ret != 0)
222 goto err_i2c_write;
223
224 dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
225
226 return 0;
227
228 err_i2c_write:
229 dev_err(&client->dev, "i2c write error: %d\n", ret);
230 return ret;
231 }
232
mpr_touchkey_probe(struct i2c_client * client,const struct i2c_device_id * id)233 static int mpr_touchkey_probe(struct i2c_client *client,
234 const struct i2c_device_id *id)
235 {
236 struct device *dev = &client->dev;
237 struct regulator *vdd_supply;
238 int vdd_uv;
239 struct mpr121_touchkey *mpr121;
240 struct input_dev *input_dev;
241 u32 poll_interval = 0;
242 int error;
243 int i;
244
245 vdd_supply = mpr121_vdd_supply_init(dev);
246 if (IS_ERR(vdd_supply))
247 return PTR_ERR(vdd_supply);
248
249 vdd_uv = regulator_get_voltage(vdd_supply);
250
251 mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
252 if (!mpr121)
253 return -ENOMEM;
254
255 input_dev = devm_input_allocate_device(dev);
256 if (!input_dev)
257 return -ENOMEM;
258
259 mpr121->client = client;
260 mpr121->input_dev = input_dev;
261 mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
262 if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
263 dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
264 return -EINVAL;
265 }
266
267 error = device_property_read_u32_array(dev, "linux,keycodes",
268 mpr121->keycodes,
269 mpr121->keycount);
270 if (error) {
271 dev_err(dev,
272 "failed to read linux,keycode property: %d\n", error);
273 return error;
274 }
275
276 input_dev->name = "Freescale MPR121 Touchkey";
277 input_dev->id.bustype = BUS_I2C;
278 input_dev->dev.parent = dev;
279 if (device_property_read_bool(dev, "autorepeat"))
280 __set_bit(EV_REP, input_dev->evbit);
281 input_set_capability(input_dev, EV_MSC, MSC_SCAN);
282 input_set_drvdata(input_dev, mpr121);
283
284 input_dev->keycode = mpr121->keycodes;
285 input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
286 input_dev->keycodemax = mpr121->keycount;
287
288 for (i = 0; i < mpr121->keycount; i++)
289 input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);
290
291 error = mpr121_phys_init(mpr121, client, vdd_uv);
292 if (error) {
293 dev_err(dev, "Failed to init register\n");
294 return error;
295 }
296
297 device_property_read_u32(dev, "poll-interval", &poll_interval);
298
299 if (client->irq) {
300 error = devm_request_threaded_irq(dev, client->irq, NULL,
301 mpr_touchkey_interrupt,
302 IRQF_TRIGGER_FALLING |
303 IRQF_ONESHOT,
304 dev->driver->name, mpr121);
305 if (error) {
306 dev_err(dev, "Failed to register interrupt\n");
307 return error;
308 }
309 } else if (poll_interval) {
310 if (poll_interval < MPR121_MIN_POLL_INTERVAL)
311 return -EINVAL;
312
313 if (poll_interval > MPR121_MAX_POLL_INTERVAL)
314 return -EINVAL;
315
316 error = input_setup_polling(input_dev, mpr_touchkey_report);
317 if (error) {
318 dev_err(dev, "Failed to setup polling\n");
319 return error;
320 }
321
322 input_set_poll_interval(input_dev, poll_interval);
323 input_set_min_poll_interval(input_dev,
324 MPR121_MIN_POLL_INTERVAL);
325 input_set_max_poll_interval(input_dev,
326 MPR121_MAX_POLL_INTERVAL);
327 } else {
328 dev_err(dev,
329 "invalid IRQ number and polling not configured\n");
330 return -EINVAL;
331 }
332
333 error = input_register_device(input_dev);
334 if (error)
335 return error;
336
337 i2c_set_clientdata(client, mpr121);
338 device_init_wakeup(dev,
339 device_property_read_bool(dev, "wakeup-source"));
340
341 return 0;
342 }
343
mpr_suspend(struct device * dev)344 static int __maybe_unused mpr_suspend(struct device *dev)
345 {
346 struct i2c_client *client = to_i2c_client(dev);
347
348 if (device_may_wakeup(&client->dev))
349 enable_irq_wake(client->irq);
350
351 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
352
353 return 0;
354 }
355
mpr_resume(struct device * dev)356 static int __maybe_unused mpr_resume(struct device *dev)
357 {
358 struct i2c_client *client = to_i2c_client(dev);
359 struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
360
361 if (device_may_wakeup(&client->dev))
362 disable_irq_wake(client->irq);
363
364 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
365 mpr121->keycount);
366
367 return 0;
368 }
369
370 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
371
372 static const struct i2c_device_id mpr121_id[] = {
373 { "mpr121_touchkey", 0 },
374 { }
375 };
376 MODULE_DEVICE_TABLE(i2c, mpr121_id);
377
378 #ifdef CONFIG_OF
379 static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
380 { .compatible = "fsl,mpr121-touchkey" },
381 { },
382 };
383 MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
384 #endif
385
386 static struct i2c_driver mpr_touchkey_driver = {
387 .driver = {
388 .name = "mpr121",
389 .pm = &mpr121_touchkey_pm_ops,
390 .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
391 },
392 .id_table = mpr121_id,
393 .probe = mpr_touchkey_probe,
394 };
395
396 module_i2c_driver(mpr_touchkey_driver);
397
398 MODULE_LICENSE("GPL");
399 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
400 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
401