1/*
2 * Driver for keys on TCA6416 I2C IO expander
3 *
4 * Copyright (C) 2010 Texas Instruments
5 *
6 * Author : Sriramakrishnan.A.G. <srk@ti.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/types.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/delay.h>
17#include <linux/slab.h>
18#include <linux/interrupt.h>
19#include <linux/workqueue.h>
20#include <linux/gpio.h>
21#include <linux/i2c.h>
22#include <linux/input.h>
23#include <linux/tca6416_keypad.h>
24
25#define TCA6416_INPUT 0
26#define TCA6416_OUTPUT 1
27#define TCA6416_INVERT 2
28#define TCA6416_DIRECTION 3
29
30static const struct i2c_device_id tca6416_id[] = {
31 { "tca6416-keys", 16, },
32 { "tca6408-keys", 8, },
33 { }
34};
35MODULE_DEVICE_TABLE(i2c, tca6416_id);
36
37struct tca6416_drv_data {
38 struct input_dev *input;
39 struct tca6416_button data[0];
40};
41
42struct tca6416_keypad_chip {
43 uint16_t reg_output;
44 uint16_t reg_direction;
45 uint16_t reg_input;
46
47 struct i2c_client *client;
48 struct input_dev *input;
49 struct delayed_work dwork;
50 int io_size;
51 int irqnum;
52 u16 pinmask;
53 bool use_polling;
54 struct tca6416_button buttons[0];
55};
56
57static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
58{
59 int error;
60
61 error = chip->io_size > 8 ?
62 i2c_smbus_write_word_data(chip->client, reg << 1, val) :
63 i2c_smbus_write_byte_data(chip->client, reg, val);
64 if (error < 0) {
65 dev_err(&chip->client->dev,
66 "%s failed, reg: %d, val: %d, error: %d\n",
67 __func__, reg, val, error);
68 return error;
69 }
70
71 return 0;
72}
73
74static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
75{
76 int retval;
77
78 retval = chip->io_size > 8 ?
79 i2c_smbus_read_word_data(chip->client, reg << 1) :
80 i2c_smbus_read_byte_data(chip->client, reg);
81 if (retval < 0) {
82 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
83 __func__, reg, retval);
84 return retval;
85 }
86
87 *val = (u16)retval;
88 return 0;
89}
90
91static void tca6416_keys_scan(struct tca6416_keypad_chip *chip)
92{
93 struct input_dev *input = chip->input;
94 u16 reg_val, val;
95 int error, i, pin_index;
96
97 error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
98 if (error)
99 return;
100
101 reg_val &= chip->pinmask;
102
103 /* Figure out which lines have changed */
104 val = reg_val ^ chip->reg_input;
105 chip->reg_input = reg_val;
106
107 for (i = 0, pin_index = 0; i < 16; i++) {
108 if (val & (1 << i)) {
109 struct tca6416_button *button = &chip->buttons[pin_index];
110 unsigned int type = button->type ?: EV_KEY;
111 int state = ((reg_val & (1 << i)) ? 1 : 0)
112 ^ button->active_low;
113
114 input_event(input, type, button->code, !!state);
115 input_sync(input);
116 }
117
118 if (chip->pinmask & (1 << i))
119 pin_index++;
120 }
121}
122
123/*
124 * This is threaded IRQ handler and this can (and will) sleep.
125 */
126static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
127{
128 struct tca6416_keypad_chip *chip = dev_id;
129
130 tca6416_keys_scan(chip);
131
132 return IRQ_HANDLED;
133}
134
135static void tca6416_keys_work_func(struct work_struct *work)
136{
137 struct tca6416_keypad_chip *chip =
138 container_of(work, struct tca6416_keypad_chip, dwork.work);
139
140 tca6416_keys_scan(chip);
141 schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
142}
143
144static int tca6416_keys_open(struct input_dev *dev)
145{
146 struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
147
148 /* Get initial device state in case it has switches */
149 tca6416_keys_scan(chip);
150
151 if (chip->use_polling)
152 schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
153 else
154 enable_irq(chip->irqnum);
155
156 return 0;
157}
158
159static void tca6416_keys_close(struct input_dev *dev)
160{
161 struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
162
163 if (chip->use_polling)
164 cancel_delayed_work_sync(&chip->dwork);
165 else
166 disable_irq(chip->irqnum);
167}
168
169static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
170{
171 int error;
172
173 error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
174 if (error)
175 return error;
176
177 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
178 if (error)
179 return error;
180
181 /* ensure that keypad pins are set to input */
182 error = tca6416_write_reg(chip, TCA6416_DIRECTION,
183 chip->reg_direction | chip->pinmask);
184 if (error)
185 return error;
186
187 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
188 if (error)
189 return error;
190
191 error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
192 if (error)
193 return error;
194
195 chip->reg_input &= chip->pinmask;
196
197 return 0;
198}
199
200static int tca6416_keypad_probe(struct i2c_client *client,
201 const struct i2c_device_id *id)
202{
203 struct tca6416_keys_platform_data *pdata;
204 struct tca6416_keypad_chip *chip;
205 struct input_dev *input;
206 int error;
207 int i;
208
209 /* Check functionality */
210 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
211 dev_err(&client->dev, "%s adapter not supported\n",
212 dev_driver_string(&client->adapter->dev));
213 return -ENODEV;
214 }
215
216 pdata = dev_get_platdata(&client->dev);
217 if (!pdata) {
218 dev_dbg(&client->dev, "no platform data\n");
219 return -EINVAL;
220 }
221
222 chip = kzalloc(struct_size(chip, buttons, pdata->nbuttons), GFP_KERNEL);
223 input = input_allocate_device();
224 if (!chip || !input) {
225 error = -ENOMEM;
226 goto fail1;
227 }
228
229 chip->client = client;
230 chip->input = input;
231 chip->io_size = id->driver_data;
232 chip->pinmask = pdata->pinmask;
233 chip->use_polling = pdata->use_polling;
234
235 INIT_DELAYED_WORK(&chip->dwork, tca6416_keys_work_func);
236
237 input->phys = "tca6416-keys/input0";
238 input->name = client->name;
239 input->dev.parent = &client->dev;
240
241 input->open = tca6416_keys_open;
242 input->close = tca6416_keys_close;
243
244 input->id.bustype = BUS_HOST;
245 input->id.vendor = 0x0001;
246 input->id.product = 0x0001;
247 input->id.version = 0x0100;
248
249 /* Enable auto repeat feature of Linux input subsystem */
250 if (pdata->rep)
251 __set_bit(EV_REP, input->evbit);
252
253 for (i = 0; i < pdata->nbuttons; i++) {
254 unsigned int type;
255
256 chip->buttons[i] = pdata->buttons[i];
257 type = (pdata->buttons[i].type) ?: EV_KEY;
258 input_set_capability(input, type, pdata->buttons[i].code);
259 }
260
261 input_set_drvdata(input, chip);
262
263 /*
264 * Initialize cached registers from their original values.
265 * we can't share this chip with another i2c master.
266 */
267 error = tca6416_setup_registers(chip);
268 if (error)
269 goto fail1;
270
271 if (!chip->use_polling) {
272 if (pdata->irq_is_gpio)
273 chip->irqnum = gpio_to_irq(client->irq);
274 else
275 chip->irqnum = client->irq;
276
277 error = request_threaded_irq(chip->irqnum, NULL,
278 tca6416_keys_isr,
279 IRQF_TRIGGER_FALLING |
280 IRQF_ONESHOT,
281 "tca6416-keypad", chip);
282 if (error) {
283 dev_dbg(&client->dev,
284 "Unable to claim irq %d; error %d\n",
285 chip->irqnum, error);
286 goto fail1;
287 }
288 disable_irq(chip->irqnum);
289 }
290
291 error = input_register_device(input);
292 if (error) {
293 dev_dbg(&client->dev,
294 "Unable to register input device, error: %d\n", error);
295 goto fail2;
296 }
297
298 i2c_set_clientdata(client, chip);
299 device_init_wakeup(&client->dev, 1);
300
301 return 0;
302
303fail2:
304 if (!chip->use_polling) {
305 free_irq(chip->irqnum, chip);
306 enable_irq(chip->irqnum);
307 }
308fail1:
309 input_free_device(input);
310 kfree(chip);
311 return error;
312}
313
314static int tca6416_keypad_remove(struct i2c_client *client)
315{
316 struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
317
318 if (!chip->use_polling) {
319 free_irq(chip->irqnum, chip);
320 enable_irq(chip->irqnum);
321 }
322
323 input_unregister_device(chip->input);
324 kfree(chip);
325
326 return 0;
327}
328
329#ifdef CONFIG_PM_SLEEP
330static int tca6416_keypad_suspend(struct device *dev)
331{
332 struct i2c_client *client = to_i2c_client(dev);
333 struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
334
335 if (device_may_wakeup(dev))
336 enable_irq_wake(chip->irqnum);
337
338 return 0;
339}
340
341static int tca6416_keypad_resume(struct device *dev)
342{
343 struct i2c_client *client = to_i2c_client(dev);
344 struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
345
346 if (device_may_wakeup(dev))
347 disable_irq_wake(chip->irqnum);
348
349 return 0;
350}
351#endif
352
353static SIMPLE_DEV_PM_OPS(tca6416_keypad_dev_pm_ops,
354 tca6416_keypad_suspend, tca6416_keypad_resume);
355
356static struct i2c_driver tca6416_keypad_driver = {
357 .driver = {
358 .name = "tca6416-keypad",
359 .pm = &tca6416_keypad_dev_pm_ops,
360 },
361 .probe = tca6416_keypad_probe,
362 .remove = tca6416_keypad_remove,
363 .id_table = tca6416_id,
364};
365
366static int __init tca6416_keypad_init(void)
367{
368 return i2c_add_driver(&tca6416_keypad_driver);
369}
370
371subsys_initcall(tca6416_keypad_init);
372
373static void __exit tca6416_keypad_exit(void)
374{
375 i2c_del_driver(&tca6416_keypad_driver);
376}
377module_exit(tca6416_keypad_exit);
378
379MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
380MODULE_DESCRIPTION("Keypad driver over tca6146 IO expander");
381MODULE_LICENSE("GPL");
382