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 struct mpr121_touchkey {
58 struct i2c_client *client;
59 struct input_dev *input_dev;
60 unsigned int statusbits;
61 unsigned int keycount;
62 u32 keycodes[MPR121_MAX_KEY_COUNT];
63 };
64
65 struct mpr121_init_register {
66 int addr;
67 u8 val;
68 };
69
70 static const struct mpr121_init_register init_reg_table[] = {
71 { MHD_RISING_ADDR, 0x1 },
72 { NHD_RISING_ADDR, 0x1 },
73 { MHD_FALLING_ADDR, 0x1 },
74 { NHD_FALLING_ADDR, 0x1 },
75 { NCL_FALLING_ADDR, 0xff },
76 { FDL_FALLING_ADDR, 0x02 },
77 { FILTER_CONF_ADDR, 0x04 },
78 { AFE_CONF_ADDR, 0x0b },
79 { AUTO_CONFIG_CTRL_ADDR, 0x0b },
80 };
81
mpr121_vdd_supply_disable(void * data)82 static void mpr121_vdd_supply_disable(void *data)
83 {
84 struct regulator *vdd_supply = data;
85
86 regulator_disable(vdd_supply);
87 }
88
mpr121_vdd_supply_init(struct device * dev)89 static struct regulator *mpr121_vdd_supply_init(struct device *dev)
90 {
91 struct regulator *vdd_supply;
92 int err;
93
94 vdd_supply = devm_regulator_get(dev, "vdd");
95 if (IS_ERR(vdd_supply)) {
96 dev_err(dev, "failed to get vdd regulator: %ld\n",
97 PTR_ERR(vdd_supply));
98 return vdd_supply;
99 }
100
101 err = regulator_enable(vdd_supply);
102 if (err) {
103 dev_err(dev, "failed to enable vdd regulator: %d\n", err);
104 return ERR_PTR(err);
105 }
106
107 err = devm_add_action(dev, mpr121_vdd_supply_disable, vdd_supply);
108 if (err) {
109 regulator_disable(vdd_supply);
110 dev_err(dev, "failed to add disable regulator action: %d\n",
111 err);
112 return ERR_PTR(err);
113 }
114
115 return vdd_supply;
116 }
117
mpr_touchkey_interrupt(int irq,void * dev_id)118 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
119 {
120 struct mpr121_touchkey *mpr121 = dev_id;
121 struct i2c_client *client = mpr121->client;
122 struct input_dev *input = mpr121->input_dev;
123 unsigned long bit_changed;
124 unsigned int key_num;
125 int reg;
126
127 reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
128 if (reg < 0) {
129 dev_err(&client->dev, "i2c read error [%d]\n", reg);
130 goto out;
131 }
132
133 reg <<= 8;
134 reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
135 if (reg < 0) {
136 dev_err(&client->dev, "i2c read error [%d]\n", reg);
137 goto out;
138 }
139
140 reg &= TOUCH_STATUS_MASK;
141 /* use old press bit to figure out which bit changed */
142 bit_changed = reg ^ mpr121->statusbits;
143 mpr121->statusbits = reg;
144 for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
145 unsigned int key_val, pressed;
146
147 pressed = reg & BIT(key_num);
148 key_val = mpr121->keycodes[key_num];
149
150 input_event(input, EV_MSC, MSC_SCAN, key_num);
151 input_report_key(input, key_val, pressed);
152
153 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
154 pressed ? "pressed" : "released");
155
156 }
157 input_sync(input);
158
159 out:
160 return IRQ_HANDLED;
161 }
162
mpr121_phys_init(struct mpr121_touchkey * mpr121,struct i2c_client * client,int vdd_uv)163 static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
164 struct i2c_client *client, int vdd_uv)
165 {
166 const struct mpr121_init_register *reg;
167 unsigned char usl, lsl, tl, eleconf;
168 int i, t, vdd, ret;
169
170 /* Set up touch/release threshold for ele0-ele11 */
171 for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
172 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
173 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
174 if (ret < 0)
175 goto err_i2c_write;
176 ret = i2c_smbus_write_byte_data(client, t + 1,
177 RELEASE_THRESHOLD);
178 if (ret < 0)
179 goto err_i2c_write;
180 }
181
182 /* Set up init register */
183 for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
184 reg = &init_reg_table[i];
185 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
186 if (ret < 0)
187 goto err_i2c_write;
188 }
189
190
191 /*
192 * Capacitance on sensing input varies and needs to be compensated.
193 * The internal MPR121-auto-configuration can do this if it's
194 * registers are set properly (based on vdd_uv).
195 */
196 vdd = vdd_uv / 1000;
197 usl = ((vdd - 700) * 256) / vdd;
198 lsl = (usl * 65) / 100;
199 tl = (usl * 90) / 100;
200 ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
201 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
202 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
203
204 /*
205 * Quick charge bit will let the capacitive charge to ready
206 * state quickly, or the buttons may not function after system
207 * boot.
208 */
209 eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
210 ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
211 eleconf);
212 if (ret != 0)
213 goto err_i2c_write;
214
215 dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
216
217 return 0;
218
219 err_i2c_write:
220 dev_err(&client->dev, "i2c write error: %d\n", ret);
221 return ret;
222 }
223
mpr_touchkey_probe(struct i2c_client * client,const struct i2c_device_id * id)224 static int mpr_touchkey_probe(struct i2c_client *client,
225 const struct i2c_device_id *id)
226 {
227 struct device *dev = &client->dev;
228 struct regulator *vdd_supply;
229 int vdd_uv;
230 struct mpr121_touchkey *mpr121;
231 struct input_dev *input_dev;
232 int error;
233 int i;
234
235 if (!client->irq) {
236 dev_err(dev, "irq number should not be zero\n");
237 return -EINVAL;
238 }
239
240 vdd_supply = mpr121_vdd_supply_init(dev);
241 if (IS_ERR(vdd_supply))
242 return PTR_ERR(vdd_supply);
243
244 vdd_uv = regulator_get_voltage(vdd_supply);
245
246 mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
247 if (!mpr121)
248 return -ENOMEM;
249
250 input_dev = devm_input_allocate_device(dev);
251 if (!input_dev)
252 return -ENOMEM;
253
254 mpr121->client = client;
255 mpr121->input_dev = input_dev;
256 mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
257 if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
258 dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
259 return -EINVAL;
260 }
261
262 error = device_property_read_u32_array(dev, "linux,keycodes",
263 mpr121->keycodes,
264 mpr121->keycount);
265 if (error) {
266 dev_err(dev,
267 "failed to read linux,keycode property: %d\n", error);
268 return error;
269 }
270
271 input_dev->name = "Freescale MPR121 Touchkey";
272 input_dev->id.bustype = BUS_I2C;
273 input_dev->dev.parent = dev;
274 if (device_property_read_bool(dev, "autorepeat"))
275 __set_bit(EV_REP, input_dev->evbit);
276 input_set_capability(input_dev, EV_MSC, MSC_SCAN);
277
278 input_dev->keycode = mpr121->keycodes;
279 input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
280 input_dev->keycodemax = mpr121->keycount;
281
282 for (i = 0; i < mpr121->keycount; i++)
283 input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);
284
285 error = mpr121_phys_init(mpr121, client, vdd_uv);
286 if (error) {
287 dev_err(dev, "Failed to init register\n");
288 return error;
289 }
290
291 error = devm_request_threaded_irq(dev, client->irq, NULL,
292 mpr_touchkey_interrupt,
293 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
294 dev->driver->name, mpr121);
295 if (error) {
296 dev_err(dev, "Failed to register interrupt\n");
297 return error;
298 }
299
300 error = input_register_device(input_dev);
301 if (error)
302 return error;
303
304 i2c_set_clientdata(client, mpr121);
305 device_init_wakeup(dev,
306 device_property_read_bool(dev, "wakeup-source"));
307
308 return 0;
309 }
310
mpr_suspend(struct device * dev)311 static int __maybe_unused mpr_suspend(struct device *dev)
312 {
313 struct i2c_client *client = to_i2c_client(dev);
314
315 if (device_may_wakeup(&client->dev))
316 enable_irq_wake(client->irq);
317
318 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
319
320 return 0;
321 }
322
mpr_resume(struct device * dev)323 static int __maybe_unused mpr_resume(struct device *dev)
324 {
325 struct i2c_client *client = to_i2c_client(dev);
326 struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
327
328 if (device_may_wakeup(&client->dev))
329 disable_irq_wake(client->irq);
330
331 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
332 mpr121->keycount);
333
334 return 0;
335 }
336
337 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
338
339 static const struct i2c_device_id mpr121_id[] = {
340 { "mpr121_touchkey", 0 },
341 { }
342 };
343 MODULE_DEVICE_TABLE(i2c, mpr121_id);
344
345 #ifdef CONFIG_OF
346 static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
347 { .compatible = "fsl,mpr121-touchkey" },
348 { },
349 };
350 MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
351 #endif
352
353 static struct i2c_driver mpr_touchkey_driver = {
354 .driver = {
355 .name = "mpr121",
356 .pm = &mpr121_touchkey_pm_ops,
357 .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
358 },
359 .id_table = mpr121_id,
360 .probe = mpr_touchkey_probe,
361 };
362
363 module_i2c_driver(mpr_touchkey_driver);
364
365 MODULE_LICENSE("GPL");
366 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
367 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
368