1/*
2 * Input driver for Microchip CAP11xx based capacitive touch sensors
3 *
4 * (c) 2014 Daniel Mack <linux@zonque.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/interrupt.h>
14#include <linux/input.h>
15#include <linux/of_irq.h>
16#include <linux/regmap.h>
17#include <linux/i2c.h>
18#include <linux/gpio/consumer.h>
19
20#define CAP11XX_REG_MAIN_CONTROL	0x00
21#define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT	(6)
22#define CAP11XX_REG_MAIN_CONTROL_GAIN_MASK	(0xc0)
23#define CAP11XX_REG_MAIN_CONTROL_DLSEEP		BIT(4)
24#define CAP11XX_REG_GENERAL_STATUS	0x02
25#define CAP11XX_REG_SENSOR_INPUT	0x03
26#define CAP11XX_REG_NOISE_FLAG_STATUS	0x0a
27#define CAP11XX_REG_SENOR_DELTA(X)	(0x10 + (X))
28#define CAP11XX_REG_SENSITIVITY_CONTROL	0x1f
29#define CAP11XX_REG_CONFIG		0x20
30#define CAP11XX_REG_SENSOR_ENABLE	0x21
31#define CAP11XX_REG_SENSOR_CONFIG	0x22
32#define CAP11XX_REG_SENSOR_CONFIG2	0x23
33#define CAP11XX_REG_SAMPLING_CONFIG	0x24
34#define CAP11XX_REG_CALIBRATION		0x26
35#define CAP11XX_REG_INT_ENABLE		0x27
36#define CAP11XX_REG_REPEAT_RATE		0x28
37#define CAP11XX_REG_MT_CONFIG		0x2a
38#define CAP11XX_REG_MT_PATTERN_CONFIG	0x2b
39#define CAP11XX_REG_MT_PATTERN		0x2d
40#define CAP11XX_REG_RECALIB_CONFIG	0x2f
41#define CAP11XX_REG_SENSOR_THRESH(X)	(0x30 + (X))
42#define CAP11XX_REG_SENSOR_NOISE_THRESH	0x38
43#define CAP11XX_REG_STANDBY_CHANNEL	0x40
44#define CAP11XX_REG_STANDBY_CONFIG	0x41
45#define CAP11XX_REG_STANDBY_SENSITIVITY	0x42
46#define CAP11XX_REG_STANDBY_THRESH	0x43
47#define CAP11XX_REG_CONFIG2		0x44
48#define CAP11XX_REG_CONFIG2_ALT_POL	BIT(6)
49#define CAP11XX_REG_SENSOR_BASE_CNT(X)	(0x50 + (X))
50#define CAP11XX_REG_SENSOR_CALIB	(0xb1 + (X))
51#define CAP11XX_REG_SENSOR_CALIB_LSB1	0xb9
52#define CAP11XX_REG_SENSOR_CALIB_LSB2	0xba
53#define CAP11XX_REG_PRODUCT_ID		0xfd
54#define CAP11XX_REG_MANUFACTURER_ID	0xfe
55#define CAP11XX_REG_REVISION		0xff
56
57#define CAP11XX_MANUFACTURER_ID	0x5d
58
59struct cap11xx_priv {
60	struct regmap *regmap;
61	struct input_dev *idev;
62
63	/* config */
64	u32 keycodes[];
65};
66
67struct cap11xx_hw_model {
68	u8 product_id;
69	unsigned int num_channels;
70};
71
72enum {
73	CAP1106,
74	CAP1126,
75	CAP1188,
76};
77
78static const struct cap11xx_hw_model cap11xx_devices[] = {
79	[CAP1106] = { .product_id = 0x55, .num_channels = 6 },
80	[CAP1126] = { .product_id = 0x53, .num_channels = 6 },
81	[CAP1188] = { .product_id = 0x50, .num_channels = 8 },
82};
83
84static const struct reg_default cap11xx_reg_defaults[] = {
85	{ CAP11XX_REG_MAIN_CONTROL,		0x00 },
86	{ CAP11XX_REG_GENERAL_STATUS,		0x00 },
87	{ CAP11XX_REG_SENSOR_INPUT,		0x00 },
88	{ CAP11XX_REG_NOISE_FLAG_STATUS,	0x00 },
89	{ CAP11XX_REG_SENSITIVITY_CONTROL,	0x2f },
90	{ CAP11XX_REG_CONFIG,			0x20 },
91	{ CAP11XX_REG_SENSOR_ENABLE,		0x3f },
92	{ CAP11XX_REG_SENSOR_CONFIG,		0xa4 },
93	{ CAP11XX_REG_SENSOR_CONFIG2,		0x07 },
94	{ CAP11XX_REG_SAMPLING_CONFIG,		0x39 },
95	{ CAP11XX_REG_CALIBRATION,		0x00 },
96	{ CAP11XX_REG_INT_ENABLE,		0x3f },
97	{ CAP11XX_REG_REPEAT_RATE,		0x3f },
98	{ CAP11XX_REG_MT_CONFIG,		0x80 },
99	{ CAP11XX_REG_MT_PATTERN_CONFIG,	0x00 },
100	{ CAP11XX_REG_MT_PATTERN,		0x3f },
101	{ CAP11XX_REG_RECALIB_CONFIG,		0x8a },
102	{ CAP11XX_REG_SENSOR_THRESH(0),		0x40 },
103	{ CAP11XX_REG_SENSOR_THRESH(1),		0x40 },
104	{ CAP11XX_REG_SENSOR_THRESH(2),		0x40 },
105	{ CAP11XX_REG_SENSOR_THRESH(3),		0x40 },
106	{ CAP11XX_REG_SENSOR_THRESH(4),		0x40 },
107	{ CAP11XX_REG_SENSOR_THRESH(5),		0x40 },
108	{ CAP11XX_REG_SENSOR_NOISE_THRESH,	0x01 },
109	{ CAP11XX_REG_STANDBY_CHANNEL,		0x00 },
110	{ CAP11XX_REG_STANDBY_CONFIG,		0x39 },
111	{ CAP11XX_REG_STANDBY_SENSITIVITY,	0x02 },
112	{ CAP11XX_REG_STANDBY_THRESH,		0x40 },
113	{ CAP11XX_REG_CONFIG2,			0x40 },
114	{ CAP11XX_REG_SENSOR_CALIB_LSB1,	0x00 },
115	{ CAP11XX_REG_SENSOR_CALIB_LSB2,	0x00 },
116};
117
118static bool cap11xx_volatile_reg(struct device *dev, unsigned int reg)
119{
120	switch (reg) {
121	case CAP11XX_REG_MAIN_CONTROL:
122	case CAP11XX_REG_SENSOR_INPUT:
123	case CAP11XX_REG_SENOR_DELTA(0):
124	case CAP11XX_REG_SENOR_DELTA(1):
125	case CAP11XX_REG_SENOR_DELTA(2):
126	case CAP11XX_REG_SENOR_DELTA(3):
127	case CAP11XX_REG_SENOR_DELTA(4):
128	case CAP11XX_REG_SENOR_DELTA(5):
129	case CAP11XX_REG_PRODUCT_ID:
130	case CAP11XX_REG_MANUFACTURER_ID:
131	case CAP11XX_REG_REVISION:
132		return true;
133	}
134
135	return false;
136}
137
138static const struct regmap_config cap11xx_regmap_config = {
139	.reg_bits = 8,
140	.val_bits = 8,
141
142	.max_register = CAP11XX_REG_REVISION,
143	.reg_defaults = cap11xx_reg_defaults,
144
145	.num_reg_defaults = ARRAY_SIZE(cap11xx_reg_defaults),
146	.cache_type = REGCACHE_RBTREE,
147	.volatile_reg = cap11xx_volatile_reg,
148};
149
150static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
151{
152	struct cap11xx_priv *priv = data;
153	unsigned int status;
154	int ret, i;
155
156	/*
157	 * Deassert interrupt. This needs to be done before reading the status
158	 * registers, which will not carry valid values otherwise.
159	 */
160	ret = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL, 1, 0);
161	if (ret < 0)
162		goto out;
163
164	ret = regmap_read(priv->regmap, CAP11XX_REG_SENSOR_INPUT, &status);
165	if (ret < 0)
166		goto out;
167
168	for (i = 0; i < priv->idev->keycodemax; i++)
169		input_report_key(priv->idev, priv->keycodes[i],
170				 status & (1 << i));
171
172	input_sync(priv->idev);
173
174out:
175	return IRQ_HANDLED;
176}
177
178static int cap11xx_set_sleep(struct cap11xx_priv *priv, bool sleep)
179{
180	return regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
181				  CAP11XX_REG_MAIN_CONTROL_DLSEEP,
182				  sleep ? CAP11XX_REG_MAIN_CONTROL_DLSEEP : 0);
183}
184
185static int cap11xx_input_open(struct input_dev *idev)
186{
187	struct cap11xx_priv *priv = input_get_drvdata(idev);
188
189	return cap11xx_set_sleep(priv, false);
190}
191
192static void cap11xx_input_close(struct input_dev *idev)
193{
194	struct cap11xx_priv *priv = input_get_drvdata(idev);
195
196	cap11xx_set_sleep(priv, true);
197}
198
199static int cap11xx_i2c_probe(struct i2c_client *i2c_client,
200			     const struct i2c_device_id *id)
201{
202	struct device *dev = &i2c_client->dev;
203	struct cap11xx_priv *priv;
204	struct device_node *node;
205	const struct cap11xx_hw_model *cap;
206	int i, error, irq, gain = 0;
207	unsigned int val, rev;
208	u32 gain32;
209
210	if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
211		dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
212		return -EINVAL;
213	}
214
215	cap = &cap11xx_devices[id->driver_data];
216	if (!cap || !cap->num_channels) {
217		dev_err(dev, "Invalid device configuration\n");
218		return -EINVAL;
219	}
220
221	priv = devm_kzalloc(dev,
222			    sizeof(*priv) +
223				cap->num_channels * sizeof(priv->keycodes[0]),
224			    GFP_KERNEL);
225	if (!priv)
226		return -ENOMEM;
227
228	priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
229	if (IS_ERR(priv->regmap))
230		return PTR_ERR(priv->regmap);
231
232	error = regmap_read(priv->regmap, CAP11XX_REG_PRODUCT_ID, &val);
233	if (error)
234		return error;
235
236	if (val != cap->product_id) {
237		dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
238			val, cap->product_id);
239		return -ENXIO;
240	}
241
242	error = regmap_read(priv->regmap, CAP11XX_REG_MANUFACTURER_ID, &val);
243	if (error)
244		return error;
245
246	if (val != CAP11XX_MANUFACTURER_ID) {
247		dev_err(dev, "Manufacturer ID: Got 0x%02x, expected 0x%02x\n",
248			val, CAP11XX_MANUFACTURER_ID);
249		return -ENXIO;
250	}
251
252	error = regmap_read(priv->regmap, CAP11XX_REG_REVISION, &rev);
253	if (error < 0)
254		return error;
255
256	dev_info(dev, "CAP11XX detected, revision 0x%02x\n", rev);
257	i2c_set_clientdata(i2c_client, priv);
258	node = dev->of_node;
259
260	if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
261		if (is_power_of_2(gain32) && gain32 <= 8)
262			gain = ilog2(gain32);
263		else
264			dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
265	}
266
267	if (of_property_read_bool(node, "microchip,irq-active-high")) {
268		error = regmap_update_bits(priv->regmap, CAP11XX_REG_CONFIG2,
269					   CAP11XX_REG_CONFIG2_ALT_POL, 0);
270		if (error)
271			return error;
272	}
273
274	/* Provide some useful defaults */
275	for (i = 0; i < cap->num_channels; i++)
276		priv->keycodes[i] = KEY_A + i;
277
278	of_property_read_u32_array(node, "linux,keycodes",
279				   priv->keycodes, cap->num_channels);
280
281	error = regmap_update_bits(priv->regmap, CAP11XX_REG_MAIN_CONTROL,
282				   CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
283				   gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
284	if (error)
285		return error;
286
287	/* Disable autorepeat. The Linux input system has its own handling. */
288	error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
289	if (error)
290		return error;
291
292	priv->idev = devm_input_allocate_device(dev);
293	if (!priv->idev)
294		return -ENOMEM;
295
296	priv->idev->name = "CAP11XX capacitive touch sensor";
297	priv->idev->id.bustype = BUS_I2C;
298	priv->idev->evbit[0] = BIT_MASK(EV_KEY);
299
300	if (of_property_read_bool(node, "autorepeat"))
301		__set_bit(EV_REP, priv->idev->evbit);
302
303	for (i = 0; i < cap->num_channels; i++)
304		__set_bit(priv->keycodes[i], priv->idev->keybit);
305
306	__clear_bit(KEY_RESERVED, priv->idev->keybit);
307
308	priv->idev->keycode = priv->keycodes;
309	priv->idev->keycodesize = sizeof(priv->keycodes[0]);
310	priv->idev->keycodemax = cap->num_channels;
311
312	priv->idev->id.vendor = CAP11XX_MANUFACTURER_ID;
313	priv->idev->id.product = cap->product_id;
314	priv->idev->id.version = rev;
315
316	priv->idev->open = cap11xx_input_open;
317	priv->idev->close = cap11xx_input_close;
318
319	input_set_drvdata(priv->idev, priv);
320
321	/*
322	 * Put the device in deep sleep mode for now.
323	 * ->open() will bring it back once the it is actually needed.
324	 */
325	cap11xx_set_sleep(priv, true);
326
327	error = input_register_device(priv->idev);
328	if (error)
329		return error;
330
331	irq = irq_of_parse_and_map(node, 0);
332	if (!irq) {
333		dev_err(dev, "Unable to parse or map IRQ\n");
334		return -ENXIO;
335	}
336
337	error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
338					  IRQF_ONESHOT, dev_name(dev), priv);
339	if (error)
340		return error;
341
342	return 0;
343}
344
345static const struct of_device_id cap11xx_dt_ids[] = {
346	{ .compatible = "microchip,cap1106", },
347	{ .compatible = "microchip,cap1126", },
348	{ .compatible = "microchip,cap1188", },
349	{}
350};
351MODULE_DEVICE_TABLE(of, cap11xx_dt_ids);
352
353static const struct i2c_device_id cap11xx_i2c_ids[] = {
354	{ "cap1106", CAP1106 },
355	{ "cap1126", CAP1126 },
356	{ "cap1188", CAP1188 },
357	{}
358};
359MODULE_DEVICE_TABLE(i2c, cap11xx_i2c_ids);
360
361static struct i2c_driver cap11xx_i2c_driver = {
362	.driver = {
363		.name	= "cap11xx",
364		.owner	= THIS_MODULE,
365		.of_match_table = cap11xx_dt_ids,
366	},
367	.id_table	= cap11xx_i2c_ids,
368	.probe		= cap11xx_i2c_probe,
369};
370
371module_i2c_driver(cap11xx_i2c_driver);
372
373MODULE_DESCRIPTION("Microchip CAP11XX driver");
374MODULE_AUTHOR("Daniel Mack <linux@zonque.org>");
375MODULE_LICENSE("GPL v2");
376