1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * TM2 touchkey device driver
4  *
5  * Copyright 2005 Phil Blundell
6  * Copyright 2016 Samsung Electronics Co., Ltd.
7  *
8  * Author: Beomho Seo <beomho.seo@samsung.com>
9  * Author: Jaechul Lee <jcsing.lee@samsung.com>
10  */
11 
12 #include <linux/bitops.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/i2c.h>
16 #include <linux/input.h>
17 #include <linux/interrupt.h>
18 #include <linux/irq.h>
19 #include <linux/leds.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/pm.h>
23 #include <linux/regulator/consumer.h>
24 
25 #define TM2_TOUCHKEY_DEV_NAME		"tm2-touchkey"
26 
27 #define ARIES_TOUCHKEY_CMD_LED_ON	0x1
28 #define ARIES_TOUCHKEY_CMD_LED_OFF	0x2
29 #define TM2_TOUCHKEY_CMD_LED_ON		0x10
30 #define TM2_TOUCHKEY_CMD_LED_OFF	0x20
31 #define TM2_TOUCHKEY_BIT_PRESS_EV	BIT(3)
32 #define TM2_TOUCHKEY_BIT_KEYCODE	GENMASK(2, 0)
33 #define TM2_TOUCHKEY_LED_VOLTAGE_MIN	2500000
34 #define TM2_TOUCHKEY_LED_VOLTAGE_MAX	3300000
35 
36 struct touchkey_variant {
37 	u8 keycode_reg;
38 	u8 base_reg;
39 	u8 cmd_led_on;
40 	u8 cmd_led_off;
41 	bool no_reg;
42 	bool fixed_regulator;
43 };
44 
45 struct tm2_touchkey_data {
46 	struct i2c_client *client;
47 	struct input_dev *input_dev;
48 	struct led_classdev led_dev;
49 	struct regulator *vdd;
50 	struct regulator_bulk_data regulators[3];
51 	const struct touchkey_variant *variant;
52 	u32 keycodes[4];
53 	int num_keycodes;
54 };
55 
56 static const struct touchkey_variant tm2_touchkey_variant = {
57 	.keycode_reg = 0x03,
58 	.base_reg = 0x00,
59 	.cmd_led_on = TM2_TOUCHKEY_CMD_LED_ON,
60 	.cmd_led_off = TM2_TOUCHKEY_CMD_LED_OFF,
61 };
62 
63 static const struct touchkey_variant midas_touchkey_variant = {
64 	.keycode_reg = 0x00,
65 	.base_reg = 0x00,
66 	.cmd_led_on = TM2_TOUCHKEY_CMD_LED_ON,
67 	.cmd_led_off = TM2_TOUCHKEY_CMD_LED_OFF,
68 };
69 
70 static struct touchkey_variant aries_touchkey_variant = {
71 	.no_reg = true,
72 	.fixed_regulator = true,
73 	.cmd_led_on = ARIES_TOUCHKEY_CMD_LED_ON,
74 	.cmd_led_off = ARIES_TOUCHKEY_CMD_LED_OFF,
75 };
76 
77 static const struct touchkey_variant tc360_touchkey_variant = {
78 	.keycode_reg = 0x00,
79 	.base_reg = 0x00,
80 	.fixed_regulator = true,
81 	.cmd_led_on = TM2_TOUCHKEY_CMD_LED_ON,
82 	.cmd_led_off = TM2_TOUCHKEY_CMD_LED_OFF,
83 };
84 
85 static int tm2_touchkey_led_brightness_set(struct led_classdev *led_dev,
86 					    enum led_brightness brightness)
87 {
88 	struct tm2_touchkey_data *touchkey =
89 		container_of(led_dev, struct tm2_touchkey_data, led_dev);
90 	u32 volt;
91 	u8 data;
92 
93 	if (brightness == LED_OFF) {
94 		volt = TM2_TOUCHKEY_LED_VOLTAGE_MIN;
95 		data = touchkey->variant->cmd_led_off;
96 	} else {
97 		volt = TM2_TOUCHKEY_LED_VOLTAGE_MAX;
98 		data = touchkey->variant->cmd_led_on;
99 	}
100 
101 	if (!touchkey->variant->fixed_regulator)
102 		regulator_set_voltage(touchkey->vdd, volt, volt);
103 
104 	return touchkey->variant->no_reg ?
105 		i2c_smbus_write_byte(touchkey->client, data) :
106 		i2c_smbus_write_byte_data(touchkey->client,
107 					  touchkey->variant->base_reg, data);
108 }
109 
110 static int tm2_touchkey_power_enable(struct tm2_touchkey_data *touchkey)
111 {
112 	int error;
113 
114 	error = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
115 				      touchkey->regulators);
116 	if (error)
117 		return error;
118 
119 	/* waiting for device initialization, at least 150ms */
120 	msleep(150);
121 
122 	return 0;
123 }
124 
125 static void tm2_touchkey_power_disable(void *data)
126 {
127 	struct tm2_touchkey_data *touchkey = data;
128 
129 	regulator_bulk_disable(ARRAY_SIZE(touchkey->regulators),
130 			       touchkey->regulators);
131 }
132 
133 static irqreturn_t tm2_touchkey_irq_handler(int irq, void *devid)
134 {
135 	struct tm2_touchkey_data *touchkey = devid;
136 	int data;
137 	int index;
138 	int i;
139 
140 	if (touchkey->variant->no_reg)
141 		data = i2c_smbus_read_byte(touchkey->client);
142 	else
143 		data = i2c_smbus_read_byte_data(touchkey->client,
144 						touchkey->variant->keycode_reg);
145 	if (data < 0) {
146 		dev_err(&touchkey->client->dev,
147 			"failed to read i2c data: %d\n", data);
148 		goto out;
149 	}
150 
151 	index = (data & TM2_TOUCHKEY_BIT_KEYCODE) - 1;
152 	if (index < 0 || index >= touchkey->num_keycodes) {
153 		dev_warn(&touchkey->client->dev,
154 			 "invalid keycode index %d\n", index);
155 		goto out;
156 	}
157 
158 	input_event(touchkey->input_dev, EV_MSC, MSC_SCAN, index);
159 
160 	if (data & TM2_TOUCHKEY_BIT_PRESS_EV) {
161 		for (i = 0; i < touchkey->num_keycodes; i++)
162 			input_report_key(touchkey->input_dev,
163 					 touchkey->keycodes[i], 0);
164 	} else {
165 		input_report_key(touchkey->input_dev,
166 				 touchkey->keycodes[index], 1);
167 	}
168 
169 	input_sync(touchkey->input_dev);
170 
171 out:
172 	if (touchkey->variant->fixed_regulator &&
173 				data & TM2_TOUCHKEY_BIT_PRESS_EV) {
174 		/* touch turns backlight on, so make sure we're in sync */
175 		if (touchkey->led_dev.brightness == LED_OFF)
176 			tm2_touchkey_led_brightness_set(&touchkey->led_dev,
177 							LED_OFF);
178 	}
179 
180 	return IRQ_HANDLED;
181 }
182 
183 static int tm2_touchkey_probe(struct i2c_client *client)
184 {
185 	struct device_node *np = client->dev.of_node;
186 	struct tm2_touchkey_data *touchkey;
187 	int error;
188 	int i;
189 
190 	if (!i2c_check_functionality(client->adapter,
191 			I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA)) {
192 		dev_err(&client->dev, "incompatible I2C adapter\n");
193 		return -EIO;
194 	}
195 
196 	touchkey = devm_kzalloc(&client->dev, sizeof(*touchkey), GFP_KERNEL);
197 	if (!touchkey)
198 		return -ENOMEM;
199 
200 	touchkey->client = client;
201 	i2c_set_clientdata(client, touchkey);
202 
203 	touchkey->variant = of_device_get_match_data(&client->dev);
204 
205 	touchkey->regulators[0].supply = "vcc";
206 	touchkey->regulators[1].supply = "vdd";
207 	touchkey->regulators[2].supply = "vddio";
208 	error = devm_regulator_bulk_get(&client->dev,
209 					ARRAY_SIZE(touchkey->regulators),
210 					touchkey->regulators);
211 	if (error) {
212 		dev_err(&client->dev, "failed to get regulators: %d\n", error);
213 		return error;
214 	}
215 
216 	/* Save VDD for easy access */
217 	touchkey->vdd = touchkey->regulators[1].consumer;
218 
219 	touchkey->num_keycodes = of_property_read_variable_u32_array(np,
220 					"linux,keycodes", touchkey->keycodes, 0,
221 					ARRAY_SIZE(touchkey->keycodes));
222 	if (touchkey->num_keycodes <= 0) {
223 		/* default keycodes */
224 		touchkey->keycodes[0] = KEY_PHONE;
225 		touchkey->keycodes[1] = KEY_BACK;
226 		touchkey->num_keycodes = 2;
227 	}
228 
229 	error = tm2_touchkey_power_enable(touchkey);
230 	if (error) {
231 		dev_err(&client->dev, "failed to power up device: %d\n", error);
232 		return error;
233 	}
234 
235 	error = devm_add_action_or_reset(&client->dev,
236 					 tm2_touchkey_power_disable, touchkey);
237 	if (error) {
238 		dev_err(&client->dev,
239 			"failed to install poweroff handler: %d\n", error);
240 		return error;
241 	}
242 
243 	/* input device */
244 	touchkey->input_dev = devm_input_allocate_device(&client->dev);
245 	if (!touchkey->input_dev) {
246 		dev_err(&client->dev, "failed to allocate input device\n");
247 		return -ENOMEM;
248 	}
249 
250 	touchkey->input_dev->name = TM2_TOUCHKEY_DEV_NAME;
251 	touchkey->input_dev->id.bustype = BUS_I2C;
252 
253 	touchkey->input_dev->keycode = touchkey->keycodes;
254 	touchkey->input_dev->keycodemax = touchkey->num_keycodes;
255 	touchkey->input_dev->keycodesize = sizeof(touchkey->keycodes[0]);
256 
257 	input_set_capability(touchkey->input_dev, EV_MSC, MSC_SCAN);
258 	for (i = 0; i < touchkey->num_keycodes; i++)
259 		input_set_capability(touchkey->input_dev, EV_KEY,
260 				     touchkey->keycodes[i]);
261 
262 	error = input_register_device(touchkey->input_dev);
263 	if (error) {
264 		dev_err(&client->dev,
265 			"failed to register input device: %d\n", error);
266 		return error;
267 	}
268 
269 	error = devm_request_threaded_irq(&client->dev, client->irq,
270 					  NULL, tm2_touchkey_irq_handler,
271 					  IRQF_ONESHOT,
272 					  TM2_TOUCHKEY_DEV_NAME, touchkey);
273 	if (error) {
274 		dev_err(&client->dev,
275 			"failed to request threaded irq: %d\n", error);
276 		return error;
277 	}
278 
279 	/* led device */
280 	touchkey->led_dev.name = TM2_TOUCHKEY_DEV_NAME;
281 	touchkey->led_dev.brightness = LED_ON;
282 	touchkey->led_dev.max_brightness = LED_ON;
283 	touchkey->led_dev.brightness_set_blocking =
284 					tm2_touchkey_led_brightness_set;
285 
286 	error = devm_led_classdev_register(&client->dev, &touchkey->led_dev);
287 	if (error) {
288 		dev_err(&client->dev,
289 			"failed to register touchkey led: %d\n", error);
290 		return error;
291 	}
292 
293 	if (touchkey->variant->fixed_regulator)
294 		tm2_touchkey_led_brightness_set(&touchkey->led_dev, LED_ON);
295 
296 	return 0;
297 }
298 
299 static int tm2_touchkey_suspend(struct device *dev)
300 {
301 	struct i2c_client *client = to_i2c_client(dev);
302 	struct tm2_touchkey_data *touchkey = i2c_get_clientdata(client);
303 
304 	disable_irq(client->irq);
305 	tm2_touchkey_power_disable(touchkey);
306 
307 	return 0;
308 }
309 
310 static int tm2_touchkey_resume(struct device *dev)
311 {
312 	struct i2c_client *client = to_i2c_client(dev);
313 	struct tm2_touchkey_data *touchkey = i2c_get_clientdata(client);
314 	int ret;
315 
316 	enable_irq(client->irq);
317 
318 	ret = tm2_touchkey_power_enable(touchkey);
319 	if (ret)
320 		dev_err(dev, "failed to enable power: %d\n", ret);
321 
322 	return ret;
323 }
324 
325 static DEFINE_SIMPLE_DEV_PM_OPS(tm2_touchkey_pm_ops,
326 				tm2_touchkey_suspend, tm2_touchkey_resume);
327 
328 static const struct i2c_device_id tm2_touchkey_id_table[] = {
329 	{ TM2_TOUCHKEY_DEV_NAME, 0 },
330 	{ },
331 };
332 MODULE_DEVICE_TABLE(i2c, tm2_touchkey_id_table);
333 
334 static const struct of_device_id tm2_touchkey_of_match[] = {
335 	{
336 		.compatible = "cypress,tm2-touchkey",
337 		.data = &tm2_touchkey_variant,
338 	}, {
339 		.compatible = "cypress,midas-touchkey",
340 		.data = &midas_touchkey_variant,
341 	}, {
342 		.compatible = "cypress,aries-touchkey",
343 		.data = &aries_touchkey_variant,
344 	}, {
345 		.compatible = "coreriver,tc360-touchkey",
346 		.data = &tc360_touchkey_variant,
347 	},
348 	{ },
349 };
350 MODULE_DEVICE_TABLE(of, tm2_touchkey_of_match);
351 
352 static struct i2c_driver tm2_touchkey_driver = {
353 	.driver = {
354 		.name = TM2_TOUCHKEY_DEV_NAME,
355 		.pm = pm_sleep_ptr(&tm2_touchkey_pm_ops),
356 		.of_match_table = tm2_touchkey_of_match,
357 	},
358 	.probe = tm2_touchkey_probe,
359 	.id_table = tm2_touchkey_id_table,
360 };
361 module_i2c_driver(tm2_touchkey_driver);
362 
363 MODULE_AUTHOR("Beomho Seo <beomho.seo@samsung.com>");
364 MODULE_AUTHOR("Jaechul Lee <jcsing.lee@samsung.com>");
365 MODULE_DESCRIPTION("Samsung touchkey driver");
366 MODULE_LICENSE("GPL v2");
367