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 mpr121_vdd_supply_disable(void *data)
86{
87	struct regulator *vdd_supply = data;
88
89	regulator_disable(vdd_supply);
90}
91
92static 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
121static 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
163static 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
172static 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
228err_i2c_write:
229	dev_err(&client->dev, "i2c write error: %d\n", ret);
230	return ret;
231}
232
233static 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
344static 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
356static 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
370static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
371
372static const struct i2c_device_id mpr121_id[] = {
373	{ "mpr121_touchkey", 0 },
374	{ }
375};
376MODULE_DEVICE_TABLE(i2c, mpr121_id);
377
378#ifdef CONFIG_OF
379static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
380	{ .compatible = "fsl,mpr121-touchkey" },
381	{ },
382};
383MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
384#endif
385
386static 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
396module_i2c_driver(mpr_touchkey_driver);
397
398MODULE_LICENSE("GPL");
399MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
400MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
401