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/i2c.h>
18#include <linux/input.h>
19#include <linux/tca6416_keypad.h>
20
21#define TCA6416_INPUT          0
22#define TCA6416_OUTPUT         1
23#define TCA6416_INVERT         2
24#define TCA6416_DIRECTION      3
25
26#define TCA6416_POLL_INTERVAL	100 /* msec */
27
28static const struct i2c_device_id tca6416_id[] = {
29	{ "tca6416-keys", 16, },
30	{ "tca6408-keys", 8, },
31	{ }
32};
33MODULE_DEVICE_TABLE(i2c, tca6416_id);
34
35struct tca6416_drv_data {
36	struct input_dev *input;
37	struct tca6416_button data[];
38};
39
40struct tca6416_keypad_chip {
41	uint16_t reg_output;
42	uint16_t reg_direction;
43	uint16_t reg_input;
44
45	struct i2c_client *client;
46	struct input_dev *input;
47	int io_size;
48	int irqnum;
49	u16 pinmask;
50	bool use_polling;
51	struct tca6416_button buttons[];
52};
53
54static 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
71static 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
88static void tca6416_keys_scan(struct input_dev *input)
89{
90	struct tca6416_keypad_chip *chip = input_get_drvdata(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 */
123static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
124{
125	tca6416_keys_scan(dev_id);
126
127	return IRQ_HANDLED;
128}
129
130static int tca6416_keys_open(struct input_dev *dev)
131{
132	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
133
134	if (!chip->use_polling) {
135		/* Get initial device state in case it has switches */
136		tca6416_keys_scan(dev);
137		enable_irq(chip->client->irq);
138	}
139
140	return 0;
141}
142
143static void tca6416_keys_close(struct input_dev *dev)
144{
145	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
146
147	if (!chip->use_polling)
148		disable_irq(chip->client->irq);
149}
150
151static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
152{
153	int error;
154
155	error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
156	if (error)
157		return error;
158
159	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
160	if (error)
161		return error;
162
163	/* ensure that keypad pins are set to input */
164	error = tca6416_write_reg(chip, TCA6416_DIRECTION,
165				  chip->reg_direction | chip->pinmask);
166	if (error)
167		return error;
168
169	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
170	if (error)
171		return error;
172
173	error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
174	if (error)
175		return error;
176
177	chip->reg_input &= chip->pinmask;
178
179	return 0;
180}
181
182static int tca6416_keypad_probe(struct i2c_client *client)
183{
184	const struct i2c_device_id *id = i2c_client_get_device_id(client);
185	struct tca6416_keys_platform_data *pdata;
186	struct tca6416_keypad_chip *chip;
187	struct input_dev *input;
188	int error;
189	int i;
190
191	/* Check functionality */
192	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
193		dev_err(&client->dev, "%s adapter not supported\n",
194			dev_driver_string(&client->adapter->dev));
195		return -ENODEV;
196	}
197
198	pdata = dev_get_platdata(&client->dev);
199	if (!pdata) {
200		dev_dbg(&client->dev, "no platform data\n");
201		return -EINVAL;
202	}
203
204	chip = devm_kzalloc(&client->dev,
205			    struct_size(chip, buttons, pdata->nbuttons),
206			    GFP_KERNEL);
207	if (!chip)
208		return -ENOMEM;
209
210	input = devm_input_allocate_device(&client->dev);
211	if (!input)
212		return -ENOMEM;
213
214	chip->client = client;
215	chip->input = input;
216	chip->io_size = id->driver_data;
217	chip->pinmask = pdata->pinmask;
218	chip->use_polling = pdata->use_polling;
219
220	input->phys = "tca6416-keys/input0";
221	input->name = client->name;
222
223	input->open = tca6416_keys_open;
224	input->close = tca6416_keys_close;
225
226	input->id.bustype = BUS_HOST;
227	input->id.vendor = 0x0001;
228	input->id.product = 0x0001;
229	input->id.version = 0x0100;
230
231	/* Enable auto repeat feature of Linux input subsystem */
232	if (pdata->rep)
233		__set_bit(EV_REP, input->evbit);
234
235	for (i = 0; i < pdata->nbuttons; i++) {
236		unsigned int type;
237
238		chip->buttons[i] = pdata->buttons[i];
239		type = (pdata->buttons[i].type) ?: EV_KEY;
240		input_set_capability(input, type, pdata->buttons[i].code);
241	}
242
243	input_set_drvdata(input, chip);
244
245	/*
246	 * Initialize cached registers from their original values.
247	 * we can't share this chip with another i2c master.
248	 */
249	error = tca6416_setup_registers(chip);
250	if (error)
251		return error;
252
253	if (chip->use_polling) {
254		error = input_setup_polling(input, tca6416_keys_scan);
255		if (error) {
256			dev_err(&client->dev, "Failed to setup polling\n");
257			return error;
258		}
259
260		input_set_poll_interval(input, TCA6416_POLL_INTERVAL);
261	} else {
262		error = devm_request_threaded_irq(&client->dev, client->irq,
263						  NULL, tca6416_keys_isr,
264						  IRQF_TRIGGER_FALLING |
265							IRQF_ONESHOT |
266							IRQF_NO_AUTOEN,
267						  "tca6416-keypad", input);
268		if (error) {
269			dev_dbg(&client->dev,
270				"Unable to claim irq %d; error %d\n",
271				client->irq, error);
272			return error;
273		}
274	}
275
276	error = input_register_device(input);
277	if (error) {
278		dev_dbg(&client->dev,
279			"Unable to register input device, error: %d\n", error);
280		return error;
281	}
282
283	i2c_set_clientdata(client, chip);
284
285	return 0;
286}
287
288static struct i2c_driver tca6416_keypad_driver = {
289	.driver = {
290		.name	= "tca6416-keypad",
291	},
292	.probe		= tca6416_keypad_probe,
293	.id_table	= tca6416_id,
294};
295
296static int __init tca6416_keypad_init(void)
297{
298	return i2c_add_driver(&tca6416_keypad_driver);
299}
300
301subsys_initcall(tca6416_keypad_init);
302
303static void __exit tca6416_keypad_exit(void)
304{
305	i2c_del_driver(&tca6416_keypad_driver);
306}
307module_exit(tca6416_keypad_exit);
308
309MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
310MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
311MODULE_LICENSE("GPL");
312