mpr121_touchkey.c

  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(input, EV_MSC, MSC_SCAN, key_num);
118		input_report_key(input, key_val, 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(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(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, t, TOUCH_THRESHOLD);
147		if (ret < 0)
148			goto err_i2c_write;
149		ret = i2c_smbus_write_byte_data(client, 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, reg->addr, 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, usl);
174	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
175	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, 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					 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, "vdd");
208	if (vdd_uv < 0)
209		return dev_err_probe(dev, vdd_uv, "failed to get vdd voltage\n");
210
211	mpr121 = devm_kzalloc(dev, 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, "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, "linux,keycodes",
228					       mpr121->keycodes,
229					       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, "autorepeat"))
240		__set_bit(EV_REP, input_dev->evbit);
241	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
242	input_set_drvdata(input_dev, 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(input_dev, EV_KEY, 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, "poll-interval", &poll_interval);
258
259	if (client->irq) {
260		error = devm_request_threaded_irq(dev, client->irq, NULL,
261						  mpr_touchkey_interrupt,
262						  IRQF_TRIGGER_FALLING |
263						  IRQF_ONESHOT,
264						  dev->driver->name, 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(input_dev, 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(input_dev, poll_interval);
283		input_set_min_poll_interval(input_dev,
284					    MPR121_MIN_POLL_INTERVAL);
285		input_set_max_poll_interval(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, mpr121);
298	device_init_wakeup(dev,
299			device_property_read_bool(dev, "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(&client->dev))
309		enable_irq_wake(client->irq);
310
311	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 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(&client->dev))
322		disable_irq_wake(client->irq);
323
324	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
325				  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");