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
60struct 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
68struct mpr121_init_register {
69 int addr;
70 u8 val;
71};
72
73static 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
85static void mpr_touchkey_report(struct input_dev *dev)
86{
87 struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
88 struct input_dev *input = mpr121->input_dev;
89 struct i2c_client *client = mpr121->client;
90 unsigned long bit_changed;
91 unsigned int key_num;
92 int reg;
93
94 reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
95 if (reg < 0) {
96 dev_err(&client->dev, "i2c read error [%d]\n", reg);
97 return;
98 }
99
100 reg <<= 8;
101 reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
102 if (reg < 0) {
103 dev_err(&client->dev, "i2c read error [%d]\n", reg);
104 return;
105 }
106
107 reg &= TOUCH_STATUS_MASK;
108 /* use old press bit to figure out which bit changed */
109 bit_changed = reg ^ mpr121->statusbits;
110 mpr121->statusbits = reg;
111 for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
112 unsigned int key_val, pressed;
113
114 pressed = reg & BIT(key_num);
115 key_val = mpr121->keycodes[key_num];
116
117 input_event(dev: input, EV_MSC, MSC_SCAN, value: key_num);
118 input_report_key(dev: input, code: key_val, value: pressed);
119
120 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
121 pressed ? "pressed" : "released");
122
123 }
124 input_sync(dev: input);
125}
126
127static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
128{
129 struct mpr121_touchkey *mpr121 = dev_id;
130
131 mpr_touchkey_report(dev: mpr121->input_dev);
132
133 return IRQ_HANDLED;
134}
135
136static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
137 struct i2c_client *client, int vdd_uv)
138{
139 const struct mpr121_init_register *reg;
140 unsigned char usl, lsl, tl, eleconf;
141 int i, t, vdd, ret;
142
143 /* Set up touch/release threshold for ele0-ele11 */
144 for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
145 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
146 ret = i2c_smbus_write_byte_data(client, command: t, TOUCH_THRESHOLD);
147 if (ret < 0)
148 goto err_i2c_write;
149 ret = i2c_smbus_write_byte_data(client, command: t + 1,
150 RELEASE_THRESHOLD);
151 if (ret < 0)
152 goto err_i2c_write;
153 }
154
155 /* Set up init register */
156 for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
157 reg = &init_reg_table[i];
158 ret = i2c_smbus_write_byte_data(client, command: reg->addr, value: reg->val);
159 if (ret < 0)
160 goto err_i2c_write;
161 }
162
163
164 /*
165 * Capacitance on sensing input varies and needs to be compensated.
166 * The internal MPR121-auto-configuration can do this if it's
167 * registers are set properly (based on vdd_uv).
168 */
169 vdd = vdd_uv / 1000;
170 usl = ((vdd - 700) * 256) / vdd;
171 lsl = (usl * 65) / 100;
172 tl = (usl * 90) / 100;
173 ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, value: usl);
174 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, value: lsl);
175 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, value: tl);
176
177 /*
178 * Quick charge bit will let the capacitive charge to ready
179 * state quickly, or the buttons may not function after system
180 * boot.
181 */
182 eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
183 ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
184 value: eleconf);
185 if (ret != 0)
186 goto err_i2c_write;
187
188 dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
189
190 return 0;
191
192err_i2c_write:
193 dev_err(&client->dev, "i2c write error: %d\n", ret);
194 return ret;
195}
196
197static int mpr_touchkey_probe(struct i2c_client *client)
198{
199 struct device *dev = &client->dev;
200 int vdd_uv;
201 struct mpr121_touchkey *mpr121;
202 struct input_dev *input_dev;
203 u32 poll_interval = 0;
204 int error;
205 int i;
206
207 vdd_uv = devm_regulator_get_enable_read_voltage(dev, id: "vdd");
208 if (vdd_uv < 0)
209 return dev_err_probe(dev, err: vdd_uv, fmt: "failed to get vdd voltage\n");
210
211 mpr121 = devm_kzalloc(dev, size: sizeof(*mpr121), GFP_KERNEL);
212 if (!mpr121)
213 return -ENOMEM;
214
215 input_dev = devm_input_allocate_device(dev);
216 if (!input_dev)
217 return -ENOMEM;
218
219 mpr121->client = client;
220 mpr121->input_dev = input_dev;
221 mpr121->keycount = device_property_count_u32(dev, propname: "linux,keycodes");
222 if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
223 dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
224 return -EINVAL;
225 }
226
227 error = device_property_read_u32_array(dev, propname: "linux,keycodes",
228 val: mpr121->keycodes,
229 nval: mpr121->keycount);
230 if (error) {
231 dev_err(dev,
232 "failed to read linux,keycode property: %d\n", error);
233 return error;
234 }
235
236 input_dev->name = "Freescale MPR121 Touchkey";
237 input_dev->id.bustype = BUS_I2C;
238 input_dev->dev.parent = dev;
239 if (device_property_read_bool(dev, propname: "autorepeat"))
240 __set_bit(EV_REP, input_dev->evbit);
241 input_set_capability(dev: input_dev, EV_MSC, MSC_SCAN);
242 input_set_drvdata(dev: input_dev, data: mpr121);
243
244 input_dev->keycode = mpr121->keycodes;
245 input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
246 input_dev->keycodemax = mpr121->keycount;
247
248 for (i = 0; i < mpr121->keycount; i++)
249 input_set_capability(dev: input_dev, EV_KEY, code: mpr121->keycodes[i]);
250
251 error = mpr121_phys_init(mpr121, client, vdd_uv);
252 if (error) {
253 dev_err(dev, "Failed to init register\n");
254 return error;
255 }
256
257 device_property_read_u32(dev, propname: "poll-interval", val: &poll_interval);
258
259 if (client->irq) {
260 error = devm_request_threaded_irq(dev, irq: client->irq, NULL,
261 thread_fn: mpr_touchkey_interrupt,
262 IRQF_TRIGGER_FALLING |
263 IRQF_ONESHOT,
264 devname: dev->driver->name, dev_id: mpr121);
265 if (error) {
266 dev_err(dev, "Failed to register interrupt\n");
267 return error;
268 }
269 } else if (poll_interval) {
270 if (poll_interval < MPR121_MIN_POLL_INTERVAL)
271 return -EINVAL;
272
273 if (poll_interval > MPR121_MAX_POLL_INTERVAL)
274 return -EINVAL;
275
276 error = input_setup_polling(dev: input_dev, poll_fn: mpr_touchkey_report);
277 if (error) {
278 dev_err(dev, "Failed to setup polling\n");
279 return error;
280 }
281
282 input_set_poll_interval(dev: input_dev, interval: poll_interval);
283 input_set_min_poll_interval(dev: input_dev,
284 MPR121_MIN_POLL_INTERVAL);
285 input_set_max_poll_interval(dev: input_dev,
286 MPR121_MAX_POLL_INTERVAL);
287 } else {
288 dev_err(dev,
289 "invalid IRQ number and polling not configured\n");
290 return -EINVAL;
291 }
292
293 error = input_register_device(input_dev);
294 if (error)
295 return error;
296
297 i2c_set_clientdata(client, data: mpr121);
298 device_init_wakeup(dev,
299 enable: device_property_read_bool(dev, propname: "wakeup-source"));
300
301 return 0;
302}
303
304static int mpr_suspend(struct device *dev)
305{
306 struct i2c_client *client = to_i2c_client(dev);
307
308 if (device_may_wakeup(dev: &client->dev))
309 enable_irq_wake(irq: client->irq);
310
311 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, value: 0x00);
312
313 return 0;
314}
315
316static int mpr_resume(struct device *dev)
317{
318 struct i2c_client *client = to_i2c_client(dev);
319 struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
320
321 if (device_may_wakeup(dev: &client->dev))
322 disable_irq_wake(irq: client->irq);
323
324 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
325 value: mpr121->keycount);
326
327 return 0;
328}
329
330static DEFINE_SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
331
332static const struct i2c_device_id mpr121_id[] = {
333 { "mpr121_touchkey" },
334 { }
335};
336MODULE_DEVICE_TABLE(i2c, mpr121_id);
337
338#ifdef CONFIG_OF
339static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
340 { .compatible = "fsl,mpr121-touchkey" },
341 { },
342};
343MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
344#endif
345
346static struct i2c_driver mpr_touchkey_driver = {
347 .driver = {
348 .name = "mpr121",
349 .pm = pm_sleep_ptr(&mpr121_touchkey_pm_ops),
350 .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
351 },
352 .id_table = mpr121_id,
353 .probe = mpr_touchkey_probe,
354};
355
356module_i2c_driver(mpr_touchkey_driver);
357
358MODULE_LICENSE("GPL");
359MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
360MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
361

source code of linux/drivers/input/keyboard/mpr121_touchkey.c