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
29static const struct i2c_device_id tca6416_id[] = {
30 { "tca6416-keys", 16, },
31 { "tca6408-keys", 8, },
32 { }
33};
34MODULE_DEVICE_TABLE(i2c, tca6416_id);
35
36struct tca6416_drv_data {
37 struct input_dev *input;
38 struct tca6416_button data[];
39};
40
41struct 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
55static 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(client: chip->client, command: reg << 1, value: val) :
61 i2c_smbus_write_byte_data(client: chip->client, command: reg, value: 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
72static 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(client: chip->client, command: reg << 1) :
78 i2c_smbus_read_byte_data(client: chip->client, command: 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
89static void tca6416_keys_scan(struct input_dev *input)
90{
91 struct tca6416_keypad_chip *chip = input_get_drvdata(dev: input);
92 u16 reg_val, val;
93 int error, i, pin_index;
94
95 error = tca6416_read_reg(chip, TCA6416_INPUT, val: &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(dev: input, type, code: button->code, value: !!state);
113 input_sync(dev: 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 */
124static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
125{
126 tca6416_keys_scan(input: dev_id);
127
128 return IRQ_HANDLED;
129}
130
131static 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(input: dev);
138 enable_irq(irq: chip->client->irq);
139 }
140
141 return 0;
142}
143
144static 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(irq: chip->client->irq);
150}
151
152static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
153{
154 int error;
155
156 error = tca6416_read_reg(chip, TCA6416_OUTPUT, val: &chip->reg_output);
157 if (error)
158 return error;
159
160 error = tca6416_read_reg(chip, TCA6416_DIRECTION, val: &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 val: chip->reg_direction | chip->pinmask);
167 if (error)
168 return error;
169
170 error = tca6416_read_reg(chip, TCA6416_DIRECTION, val: &chip->reg_direction);
171 if (error)
172 return error;
173
174 error = tca6416_read_reg(chip, TCA6416_INPUT, val: &chip->reg_input);
175 if (error)
176 return error;
177
178 chip->reg_input &= chip->pinmask;
179
180 return 0;
181}
182
183static 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(adap: 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(dev: &client->dev);
200 if (!pdata) {
201 dev_dbg(&client->dev, "no platform data\n");
202 return -EINVAL;
203 }
204
205 chip = devm_kzalloc(dev: &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(dev: input, type, code: pdata->buttons[i].code);
242 }
243
244 input_set_drvdata(dev: input, data: 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(dev: input, poll_fn: 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(dev: input, TCA6416_POLL_INTERVAL);
262 } else {
263 error = devm_request_threaded_irq(dev: &client->dev, irq: client->irq,
264 NULL, thread_fn: tca6416_keys_isr,
265 IRQF_TRIGGER_FALLING |
266 IRQF_ONESHOT |
267 IRQF_NO_AUTOEN,
268 devname: "tca6416-keypad", dev_id: 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, data: chip);
285
286 return 0;
287}
288
289static 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
297static int __init tca6416_keypad_init(void)
298{
299 return i2c_add_driver(&tca6416_keypad_driver);
300}
301
302subsys_initcall(tca6416_keypad_init);
303
304static void __exit tca6416_keypad_exit(void)
305{
306 i2c_del_driver(driver: &tca6416_keypad_driver);
307}
308module_exit(tca6416_keypad_exit);
309
310MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
311MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
312MODULE_LICENSE("GPL");
313

source code of linux/drivers/input/keyboard/tca6416-keypad.c