1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for keys on TCA6416 I2C IO expander
4  *
5  * Copyright (C) 2010 Texas Instruments
6  *
7  * Author : Sriramakrishnan.A.G. <srk@ti.com>
8  */
9 
10 #include <linux/types.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/delay.h>
14 #include <linux/slab.h>
15 #include <linux/interrupt.h>
16 #include <linux/workqueue.h>
17 #include <linux/gpio.h>
18 #include <linux/i2c.h>
19 #include <linux/input.h>
20 #include <linux/tca6416_keypad.h>
21 
22 #define TCA6416_INPUT          0
23 #define TCA6416_OUTPUT         1
24 #define TCA6416_INVERT         2
25 #define TCA6416_DIRECTION      3
26 
27 static const struct i2c_device_id tca6416_id[] = {
28 	{ "tca6416-keys", 16, },
29 	{ "tca6408-keys", 8, },
30 	{ }
31 };
32 MODULE_DEVICE_TABLE(i2c, tca6416_id);
33 
34 struct tca6416_drv_data {
35 	struct input_dev *input;
36 	struct tca6416_button data[];
37 };
38 
39 struct tca6416_keypad_chip {
40 	uint16_t reg_output;
41 	uint16_t reg_direction;
42 	uint16_t reg_input;
43 
44 	struct i2c_client *client;
45 	struct input_dev *input;
46 	struct delayed_work dwork;
47 	int io_size;
48 	int irqnum;
49 	u16 pinmask;
50 	bool use_polling;
51 	struct tca6416_button buttons[];
52 };
53 
54 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
55 {
56 	int error;
57 
58 	error = chip->io_size > 8 ?
59 		i2c_smbus_write_word_data(chip->client, reg << 1, val) :
60 		i2c_smbus_write_byte_data(chip->client, reg, val);
61 	if (error < 0) {
62 		dev_err(&chip->client->dev,
63 			"%s failed, reg: %d, val: %d, error: %d\n",
64 			__func__, reg, val, error);
65 		return error;
66 	}
67 
68 	return 0;
69 }
70 
71 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
72 {
73 	int retval;
74 
75 	retval = chip->io_size > 8 ?
76 		 i2c_smbus_read_word_data(chip->client, reg << 1) :
77 		 i2c_smbus_read_byte_data(chip->client, reg);
78 	if (retval < 0) {
79 		dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
80 			__func__, reg, retval);
81 		return retval;
82 	}
83 
84 	*val = (u16)retval;
85 	return 0;
86 }
87 
88 static void tca6416_keys_scan(struct tca6416_keypad_chip *chip)
89 {
90 	struct input_dev *input = chip->input;
91 	u16 reg_val, val;
92 	int error, i, pin_index;
93 
94 	error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
95 	if (error)
96 		return;
97 
98 	reg_val &= chip->pinmask;
99 
100 	/* Figure out which lines have changed */
101 	val = reg_val ^ chip->reg_input;
102 	chip->reg_input = reg_val;
103 
104 	for (i = 0, pin_index = 0; i < 16; i++) {
105 		if (val & (1 << i)) {
106 			struct tca6416_button *button = &chip->buttons[pin_index];
107 			unsigned int type = button->type ?: EV_KEY;
108 			int state = ((reg_val & (1 << i)) ? 1 : 0)
109 						^ button->active_low;
110 
111 			input_event(input, type, button->code, !!state);
112 			input_sync(input);
113 		}
114 
115 		if (chip->pinmask & (1 << i))
116 			pin_index++;
117 	}
118 }
119 
120 /*
121  * This is threaded IRQ handler and this can (and will) sleep.
122  */
123 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
124 {
125 	struct tca6416_keypad_chip *chip = dev_id;
126 
127 	tca6416_keys_scan(chip);
128 
129 	return IRQ_HANDLED;
130 }
131 
132 static void tca6416_keys_work_func(struct work_struct *work)
133 {
134 	struct tca6416_keypad_chip *chip =
135 		container_of(work, struct tca6416_keypad_chip, dwork.work);
136 
137 	tca6416_keys_scan(chip);
138 	schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
139 }
140 
141 static int tca6416_keys_open(struct input_dev *dev)
142 {
143 	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
144 
145 	/* Get initial device state in case it has switches */
146 	tca6416_keys_scan(chip);
147 
148 	if (chip->use_polling)
149 		schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
150 	else
151 		enable_irq(chip->irqnum);
152 
153 	return 0;
154 }
155 
156 static void tca6416_keys_close(struct input_dev *dev)
157 {
158 	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
159 
160 	if (chip->use_polling)
161 		cancel_delayed_work_sync(&chip->dwork);
162 	else
163 		disable_irq(chip->irqnum);
164 }
165 
166 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
167 {
168 	int error;
169 
170 	error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
171 	if (error)
172 		return error;
173 
174 	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
175 	if (error)
176 		return error;
177 
178 	/* ensure that keypad pins are set to input */
179 	error = tca6416_write_reg(chip, TCA6416_DIRECTION,
180 				  chip->reg_direction | chip->pinmask);
181 	if (error)
182 		return error;
183 
184 	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
185 	if (error)
186 		return error;
187 
188 	error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
189 	if (error)
190 		return error;
191 
192 	chip->reg_input &= chip->pinmask;
193 
194 	return 0;
195 }
196 
197 static int tca6416_keypad_probe(struct i2c_client *client,
198 				   const struct i2c_device_id *id)
199 {
200 	struct tca6416_keys_platform_data *pdata;
201 	struct tca6416_keypad_chip *chip;
202 	struct input_dev *input;
203 	int error;
204 	int i;
205 
206 	/* Check functionality */
207 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
208 		dev_err(&client->dev, "%s adapter not supported\n",
209 			dev_driver_string(&client->adapter->dev));
210 		return -ENODEV;
211 	}
212 
213 	pdata = dev_get_platdata(&client->dev);
214 	if (!pdata) {
215 		dev_dbg(&client->dev, "no platform data\n");
216 		return -EINVAL;
217 	}
218 
219 	chip = kzalloc(struct_size(chip, buttons, pdata->nbuttons), GFP_KERNEL);
220 	input = input_allocate_device();
221 	if (!chip || !input) {
222 		error = -ENOMEM;
223 		goto fail1;
224 	}
225 
226 	chip->client = client;
227 	chip->input = input;
228 	chip->io_size = id->driver_data;
229 	chip->pinmask = pdata->pinmask;
230 	chip->use_polling = pdata->use_polling;
231 
232 	INIT_DELAYED_WORK(&chip->dwork, tca6416_keys_work_func);
233 
234 	input->phys = "tca6416-keys/input0";
235 	input->name = client->name;
236 	input->dev.parent = &client->dev;
237 
238 	input->open = tca6416_keys_open;
239 	input->close = tca6416_keys_close;
240 
241 	input->id.bustype = BUS_HOST;
242 	input->id.vendor = 0x0001;
243 	input->id.product = 0x0001;
244 	input->id.version = 0x0100;
245 
246 	/* Enable auto repeat feature of Linux input subsystem */
247 	if (pdata->rep)
248 		__set_bit(EV_REP, input->evbit);
249 
250 	for (i = 0; i < pdata->nbuttons; i++) {
251 		unsigned int type;
252 
253 		chip->buttons[i] = pdata->buttons[i];
254 		type = (pdata->buttons[i].type) ?: EV_KEY;
255 		input_set_capability(input, type, pdata->buttons[i].code);
256 	}
257 
258 	input_set_drvdata(input, chip);
259 
260 	/*
261 	 * Initialize cached registers from their original values.
262 	 * we can't share this chip with another i2c master.
263 	 */
264 	error = tca6416_setup_registers(chip);
265 	if (error)
266 		goto fail1;
267 
268 	if (!chip->use_polling) {
269 		if (pdata->irq_is_gpio)
270 			chip->irqnum = gpio_to_irq(client->irq);
271 		else
272 			chip->irqnum = client->irq;
273 
274 		error = request_threaded_irq(chip->irqnum, NULL,
275 					     tca6416_keys_isr,
276 					     IRQF_TRIGGER_FALLING |
277 					     IRQF_ONESHOT | IRQF_NO_AUTOEN,
278 					     "tca6416-keypad", chip);
279 		if (error) {
280 			dev_dbg(&client->dev,
281 				"Unable to claim irq %d; error %d\n",
282 				chip->irqnum, error);
283 			goto fail1;
284 		}
285 	}
286 
287 	error = input_register_device(input);
288 	if (error) {
289 		dev_dbg(&client->dev,
290 			"Unable to register input device, error: %d\n", error);
291 		goto fail2;
292 	}
293 
294 	i2c_set_clientdata(client, chip);
295 	device_init_wakeup(&client->dev, 1);
296 
297 	return 0;
298 
299 fail2:
300 	if (!chip->use_polling) {
301 		free_irq(chip->irqnum, chip);
302 		enable_irq(chip->irqnum);
303 	}
304 fail1:
305 	input_free_device(input);
306 	kfree(chip);
307 	return error;
308 }
309 
310 static void tca6416_keypad_remove(struct i2c_client *client)
311 {
312 	struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
313 
314 	if (!chip->use_polling) {
315 		free_irq(chip->irqnum, chip);
316 		enable_irq(chip->irqnum);
317 	}
318 
319 	input_unregister_device(chip->input);
320 	kfree(chip);
321 }
322 
323 #ifdef CONFIG_PM_SLEEP
324 static int tca6416_keypad_suspend(struct device *dev)
325 {
326 	struct i2c_client *client = to_i2c_client(dev);
327 	struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
328 
329 	if (device_may_wakeup(dev))
330 		enable_irq_wake(chip->irqnum);
331 
332 	return 0;
333 }
334 
335 static int tca6416_keypad_resume(struct device *dev)
336 {
337 	struct i2c_client *client = to_i2c_client(dev);
338 	struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
339 
340 	if (device_may_wakeup(dev))
341 		disable_irq_wake(chip->irqnum);
342 
343 	return 0;
344 }
345 #endif
346 
347 static SIMPLE_DEV_PM_OPS(tca6416_keypad_dev_pm_ops,
348 			 tca6416_keypad_suspend, tca6416_keypad_resume);
349 
350 static struct i2c_driver tca6416_keypad_driver = {
351 	.driver = {
352 		.name	= "tca6416-keypad",
353 		.pm	= &tca6416_keypad_dev_pm_ops,
354 	},
355 	.probe		= tca6416_keypad_probe,
356 	.remove		= tca6416_keypad_remove,
357 	.id_table	= tca6416_id,
358 };
359 
360 static int __init tca6416_keypad_init(void)
361 {
362 	return i2c_add_driver(&tca6416_keypad_driver);
363 }
364 
365 subsys_initcall(tca6416_keypad_init);
366 
367 static void __exit tca6416_keypad_exit(void)
368 {
369 	i2c_del_driver(&tca6416_keypad_driver);
370 }
371 module_exit(tca6416_keypad_exit);
372 
373 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
374 MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
375 MODULE_LICENSE("GPL");
376