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 #define TCA6416_POLL_INTERVAL	100 /* msec */
28 
29 static const struct i2c_device_id tca6416_id[] = {
30 	{ "tca6416-keys", 16, },
31 	{ "tca6408-keys", 8, },
32 	{ }
33 };
34 MODULE_DEVICE_TABLE(i2c, tca6416_id);
35 
36 struct tca6416_drv_data {
37 	struct input_dev *input;
38 	struct tca6416_button data[];
39 };
40 
41 struct tca6416_keypad_chip {
42 	uint16_t reg_output;
43 	uint16_t reg_direction;
44 	uint16_t reg_input;
45 
46 	struct i2c_client *client;
47 	struct input_dev *input;
48 	int io_size;
49 	int irqnum;
50 	u16 pinmask;
51 	bool use_polling;
52 	struct tca6416_button buttons[];
53 };
54 
55 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
56 {
57 	int error;
58 
59 	error = chip->io_size > 8 ?
60 		i2c_smbus_write_word_data(chip->client, reg << 1, val) :
61 		i2c_smbus_write_byte_data(chip->client, reg, val);
62 	if (error < 0) {
63 		dev_err(&chip->client->dev,
64 			"%s failed, reg: %d, val: %d, error: %d\n",
65 			__func__, reg, val, error);
66 		return error;
67 	}
68 
69 	return 0;
70 }
71 
72 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
73 {
74 	int retval;
75 
76 	retval = chip->io_size > 8 ?
77 		 i2c_smbus_read_word_data(chip->client, reg << 1) :
78 		 i2c_smbus_read_byte_data(chip->client, reg);
79 	if (retval < 0) {
80 		dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
81 			__func__, reg, retval);
82 		return retval;
83 	}
84 
85 	*val = (u16)retval;
86 	return 0;
87 }
88 
89 static void tca6416_keys_scan(struct input_dev *input)
90 {
91 	struct tca6416_keypad_chip *chip = input_get_drvdata(input);
92 	u16 reg_val, val;
93 	int error, i, pin_index;
94 
95 	error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
96 	if (error)
97 		return;
98 
99 	reg_val &= chip->pinmask;
100 
101 	/* Figure out which lines have changed */
102 	val = reg_val ^ chip->reg_input;
103 	chip->reg_input = reg_val;
104 
105 	for (i = 0, pin_index = 0; i < 16; i++) {
106 		if (val & (1 << i)) {
107 			struct tca6416_button *button = &chip->buttons[pin_index];
108 			unsigned int type = button->type ?: EV_KEY;
109 			int state = ((reg_val & (1 << i)) ? 1 : 0)
110 						^ button->active_low;
111 
112 			input_event(input, type, button->code, !!state);
113 			input_sync(input);
114 		}
115 
116 		if (chip->pinmask & (1 << i))
117 			pin_index++;
118 	}
119 }
120 
121 /*
122  * This is threaded IRQ handler and this can (and will) sleep.
123  */
124 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
125 {
126 	tca6416_keys_scan(dev_id);
127 
128 	return IRQ_HANDLED;
129 }
130 
131 static int tca6416_keys_open(struct input_dev *dev)
132 {
133 	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
134 
135 	if (!chip->use_polling) {
136 		/* Get initial device state in case it has switches */
137 		tca6416_keys_scan(dev);
138 		enable_irq(chip->client->irq);
139 	}
140 
141 	return 0;
142 }
143 
144 static void tca6416_keys_close(struct input_dev *dev)
145 {
146 	struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
147 
148 	if (!chip->use_polling)
149 		disable_irq(chip->client->irq);
150 }
151 
152 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
153 {
154 	int error;
155 
156 	error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
157 	if (error)
158 		return error;
159 
160 	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
161 	if (error)
162 		return error;
163 
164 	/* ensure that keypad pins are set to input */
165 	error = tca6416_write_reg(chip, TCA6416_DIRECTION,
166 				  chip->reg_direction | chip->pinmask);
167 	if (error)
168 		return error;
169 
170 	error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
171 	if (error)
172 		return error;
173 
174 	error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
175 	if (error)
176 		return error;
177 
178 	chip->reg_input &= chip->pinmask;
179 
180 	return 0;
181 }
182 
183 static int tca6416_keypad_probe(struct i2c_client *client)
184 {
185 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
186 	struct tca6416_keys_platform_data *pdata;
187 	struct tca6416_keypad_chip *chip;
188 	struct input_dev *input;
189 	int error;
190 	int i;
191 
192 	/* Check functionality */
193 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
194 		dev_err(&client->dev, "%s adapter not supported\n",
195 			dev_driver_string(&client->adapter->dev));
196 		return -ENODEV;
197 	}
198 
199 	pdata = dev_get_platdata(&client->dev);
200 	if (!pdata) {
201 		dev_dbg(&client->dev, "no platform data\n");
202 		return -EINVAL;
203 	}
204 
205 	chip = devm_kzalloc(&client->dev,
206 			    struct_size(chip, buttons, pdata->nbuttons),
207 			    GFP_KERNEL);
208 	if (!chip)
209 		return -ENOMEM;
210 
211 	input = devm_input_allocate_device(&client->dev);
212 	if (!input)
213 		return -ENOMEM;
214 
215 	chip->client = client;
216 	chip->input = input;
217 	chip->io_size = id->driver_data;
218 	chip->pinmask = pdata->pinmask;
219 	chip->use_polling = pdata->use_polling;
220 
221 	input->phys = "tca6416-keys/input0";
222 	input->name = client->name;
223 
224 	input->open = tca6416_keys_open;
225 	input->close = tca6416_keys_close;
226 
227 	input->id.bustype = BUS_HOST;
228 	input->id.vendor = 0x0001;
229 	input->id.product = 0x0001;
230 	input->id.version = 0x0100;
231 
232 	/* Enable auto repeat feature of Linux input subsystem */
233 	if (pdata->rep)
234 		__set_bit(EV_REP, input->evbit);
235 
236 	for (i = 0; i < pdata->nbuttons; i++) {
237 		unsigned int type;
238 
239 		chip->buttons[i] = pdata->buttons[i];
240 		type = (pdata->buttons[i].type) ?: EV_KEY;
241 		input_set_capability(input, type, pdata->buttons[i].code);
242 	}
243 
244 	input_set_drvdata(input, chip);
245 
246 	/*
247 	 * Initialize cached registers from their original values.
248 	 * we can't share this chip with another i2c master.
249 	 */
250 	error = tca6416_setup_registers(chip);
251 	if (error)
252 		return error;
253 
254 	if (chip->use_polling) {
255 		error = input_setup_polling(input, tca6416_keys_scan);
256 		if (error) {
257 			dev_err(&client->dev, "Failed to setup polling\n");
258 			return error;
259 		}
260 
261 		input_set_poll_interval(input, TCA6416_POLL_INTERVAL);
262 	} else {
263 		error = devm_request_threaded_irq(&client->dev, client->irq,
264 						  NULL, tca6416_keys_isr,
265 						  IRQF_TRIGGER_FALLING |
266 							IRQF_ONESHOT |
267 							IRQF_NO_AUTOEN,
268 						  "tca6416-keypad", input);
269 		if (error) {
270 			dev_dbg(&client->dev,
271 				"Unable to claim irq %d; error %d\n",
272 				client->irq, error);
273 			return error;
274 		}
275 	}
276 
277 	error = input_register_device(input);
278 	if (error) {
279 		dev_dbg(&client->dev,
280 			"Unable to register input device, error: %d\n", error);
281 		return error;
282 	}
283 
284 	i2c_set_clientdata(client, chip);
285 
286 	return 0;
287 }
288 
289 static struct i2c_driver tca6416_keypad_driver = {
290 	.driver = {
291 		.name	= "tca6416-keypad",
292 	},
293 	.probe		= tca6416_keypad_probe,
294 	.id_table	= tca6416_id,
295 };
296 
297 static int __init tca6416_keypad_init(void)
298 {
299 	return i2c_add_driver(&tca6416_keypad_driver);
300 }
301 
302 subsys_initcall(tca6416_keypad_init);
303 
304 static void __exit tca6416_keypad_exit(void)
305 {
306 	i2c_del_driver(&tca6416_keypad_driver);
307 }
308 module_exit(tca6416_keypad_exit);
309 
310 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
311 MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
312 MODULE_LICENSE("GPL");
313