tca8418_keypad.c revision 91c5d67f17784078169bdcce4c21df82ac6c234c 
1/*
2 * Driver for TCA8418 I2C keyboard
3 *
4 * Copyright (C) 2011 Fuel7, Inc.  All rights reserved.
5 *
6 * Author: Kyle Manna <kyle.manna@fuel7.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public
10 * License v2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public
18 * License along with this program; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 021110-1307, USA.
21 *
22 * If you can't comply with GPLv2, alternative licensing terms may be
23 * arranged. Please contact Fuel7, Inc. (http://fuel7.com/) for proprietary
24 * alternative licensing inquiries.
25 */
26
27#include <linux/types.h>
28#include <linux/module.h>
29#include <linux/init.h>
30#include <linux/delay.h>
31#include <linux/slab.h>
32#include <linux/interrupt.h>
33#include <linux/workqueue.h>
34#include <linux/gpio.h>
35#include <linux/i2c.h>
36#include <linux/input.h>
37#include <linux/input/tca8418_keypad.h>
38#include <linux/of.h>
39
40/* TCA8418 hardware limits */
41#define TCA8418_MAX_ROWS	8
42#define TCA8418_MAX_COLS	10
43
44/* TCA8418 register offsets */
45#define REG_CFG			0x01
46#define REG_INT_STAT		0x02
47#define REG_KEY_LCK_EC		0x03
48#define REG_KEY_EVENT_A		0x04
49#define REG_KEY_EVENT_B		0x05
50#define REG_KEY_EVENT_C		0x06
51#define REG_KEY_EVENT_D		0x07
52#define REG_KEY_EVENT_E		0x08
53#define REG_KEY_EVENT_F		0x09
54#define REG_KEY_EVENT_G		0x0A
55#define REG_KEY_EVENT_H		0x0B
56#define REG_KEY_EVENT_I		0x0C
57#define REG_KEY_EVENT_J		0x0D
58#define REG_KP_LCK_TIMER	0x0E
59#define REG_UNLOCK1		0x0F
60#define REG_UNLOCK2		0x10
61#define REG_GPIO_INT_STAT1	0x11
62#define REG_GPIO_INT_STAT2	0x12
63#define REG_GPIO_INT_STAT3	0x13
64#define REG_GPIO_DAT_STAT1	0x14
65#define REG_GPIO_DAT_STAT2	0x15
66#define REG_GPIO_DAT_STAT3	0x16
67#define REG_GPIO_DAT_OUT1	0x17
68#define REG_GPIO_DAT_OUT2	0x18
69#define REG_GPIO_DAT_OUT3	0x19
70#define REG_GPIO_INT_EN1	0x1A
71#define REG_GPIO_INT_EN2	0x1B
72#define REG_GPIO_INT_EN3	0x1C
73#define REG_KP_GPIO1		0x1D
74#define REG_KP_GPIO2		0x1E
75#define REG_KP_GPIO3		0x1F
76#define REG_GPI_EM1		0x20
77#define REG_GPI_EM2		0x21
78#define REG_GPI_EM3		0x22
79#define REG_GPIO_DIR1		0x23
80#define REG_GPIO_DIR2		0x24
81#define REG_GPIO_DIR3		0x25
82#define REG_GPIO_INT_LVL1	0x26
83#define REG_GPIO_INT_LVL2	0x27
84#define REG_GPIO_INT_LVL3	0x28
85#define REG_DEBOUNCE_DIS1	0x29
86#define REG_DEBOUNCE_DIS2	0x2A
87#define REG_DEBOUNCE_DIS3	0x2B
88#define REG_GPIO_PULL1		0x2C
89#define REG_GPIO_PULL2		0x2D
90#define REG_GPIO_PULL3		0x2E
91
92/* TCA8418 bit definitions */
93#define CFG_AI			BIT(7)
94#define CFG_GPI_E_CFG		BIT(6)
95#define CFG_OVR_FLOW_M		BIT(5)
96#define CFG_INT_CFG		BIT(4)
97#define CFG_OVR_FLOW_IEN	BIT(3)
98#define CFG_K_LCK_IEN		BIT(2)
99#define CFG_GPI_IEN		BIT(1)
100#define CFG_KE_IEN		BIT(0)
101
102#define INT_STAT_CAD_INT	BIT(4)
103#define INT_STAT_OVR_FLOW_INT	BIT(3)
104#define INT_STAT_K_LCK_INT	BIT(2)
105#define INT_STAT_GPI_INT	BIT(1)
106#define INT_STAT_K_INT		BIT(0)
107
108/* TCA8418 register masks */
109#define KEY_LCK_EC_KEC		0x7
110#define KEY_EVENT_CODE		0x7f
111#define KEY_EVENT_VALUE		0x80
112
113struct tca8418_keypad {
114	unsigned int irq;
115	unsigned int row_shift;
116
117	struct i2c_client *client;
118	struct input_dev *input;
119
120	/* Flexible array member, must be at end of struct */
121	unsigned short keymap[];
122};
123
124/*
125 * Write a byte to the TCA8418
126 */
127static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
128			      int reg, u8 val)
129{
130	int error;
131
132	error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
133	if (error < 0) {
134		dev_err(&keypad_data->client->dev,
135			"%s failed, reg: %d, val: %d, error: %d\n",
136			__func__, reg, val, error);
137		return error;
138	}
139
140	return 0;
141}
142
143/*
144 * Read a byte from the TCA8418
145 */
146static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
147			     int reg, u8 *val)
148{
149	int error;
150
151	error = i2c_smbus_read_byte_data(keypad_data->client, reg);
152	if (error < 0) {
153		dev_err(&keypad_data->client->dev,
154				"%s failed, reg: %d, error: %d\n",
155				__func__, reg, error);
156		return error;
157	}
158
159	*val = (u8)error;
160
161	return 0;
162}
163
164static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
165{
166	int error, col, row;
167	u8 reg, state, code;
168
169	/* Initial read of the key event FIFO */
170	error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
171
172	/* Assume that key code 0 signifies empty FIFO */
173	while (error >= 0 && reg > 0) {
174		state = reg & KEY_EVENT_VALUE;
175		code  = reg & KEY_EVENT_CODE;
176
177		row = code / TCA8418_MAX_COLS;
178		col = code % TCA8418_MAX_COLS;
179
180		row = (col) ? row : row - 1;
181		col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;
182
183		code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
184		input_event(keypad_data->input, EV_MSC, MSC_SCAN, code);
185		input_report_key(keypad_data->input,
186				keypad_data->keymap[code], state);
187
188		/* Read for next loop */
189		error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
190	}
191
192	if (error < 0)
193		dev_err(&keypad_data->client->dev,
194			"unable to read REG_KEY_EVENT_A\n");
195
196	input_sync(keypad_data->input);
197}
198
199/*
200 * Threaded IRQ handler and this can (and will) sleep.
201 */
202static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
203{
204	struct tca8418_keypad *keypad_data = dev_id;
205	u8 reg;
206	int error;
207
208	error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
209	if (error) {
210		dev_err(&keypad_data->client->dev,
211			"unable to read REG_INT_STAT\n");
212		return IRQ_NONE;
213	}
214
215	if (!reg)
216		return IRQ_NONE;
217
218	if (reg & INT_STAT_OVR_FLOW_INT)
219		dev_warn(&keypad_data->client->dev, "overflow occurred\n");
220
221	if (reg & INT_STAT_K_INT)
222		tca8418_read_keypad(keypad_data);
223
224	/* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
225	reg = 0xff;
226	error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
227	if (error)
228		dev_err(&keypad_data->client->dev,
229			"unable to clear REG_INT_STAT\n");
230
231	return IRQ_HANDLED;
232}
233
234/*
235 * Configure the TCA8418 for keypad operation
236 */
237static int tca8418_configure(struct tca8418_keypad *keypad_data,
238			     u32 rows, u32 cols)
239{
240	int reg, error;
241
242	/* Write config register, if this fails assume device not present */
243	error = tca8418_write_byte(keypad_data, REG_CFG,
244				CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
245	if (error < 0)
246		return -ENODEV;
247
248
249	/* Assemble a mask for row and column registers */
250	reg  =  ~(~0 << rows);
251	reg += (~(~0 << cols)) << 8;
252
253	/* Set registers to keypad mode */
254	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
255	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
256	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);
257
258	/* Enable column debouncing */
259	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
260	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
261	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);
262
263	return error;
264}
265
266static int tca8418_keypad_probe(struct i2c_client *client,
267					  const struct i2c_device_id *id)
268{
269	struct device *dev = &client->dev;
270	const struct tca8418_keypad_platform_data *pdata =
271						dev_get_platdata(dev);
272	struct tca8418_keypad *keypad_data;
273	struct input_dev *input;
274	const struct matrix_keymap_data *keymap_data = NULL;
275	u32 rows = 0, cols = 0;
276	bool rep = false;
277	bool irq_is_gpio = false;
278	int error, row_shift, max_keys;
279
280	/* Copy the platform data */
281	if (pdata) {
282		if (!pdata->keymap_data) {
283			dev_err(dev, "no keymap data defined\n");
284			return -EINVAL;
285		}
286		keymap_data = pdata->keymap_data;
287		rows = pdata->rows;
288		cols = pdata->cols;
289		rep  = pdata->rep;
290		irq_is_gpio = pdata->irq_is_gpio;
291	} else {
292		struct device_node *np = dev->of_node;
293		of_property_read_u32(np, "keypad,num-rows", &rows);
294		of_property_read_u32(np, "keypad,num-columns", &cols);
295		rep = of_property_read_bool(np, "keypad,autorepeat");
296	}
297
298	if (!rows || rows > TCA8418_MAX_ROWS) {
299		dev_err(dev, "invalid rows\n");
300		return -EINVAL;
301	}
302
303	if (!cols || cols > TCA8418_MAX_COLS) {
304		dev_err(dev, "invalid columns\n");
305		return -EINVAL;
306	}
307
308	/* Check i2c driver capabilities */
309	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
310		dev_err(dev, "%s adapter not supported\n",
311			dev_driver_string(&client->adapter->dev));
312		return -ENODEV;
313	}
314
315	row_shift = get_count_order(cols);
316	max_keys = rows << row_shift;
317
318	/* Allocate memory for keypad_data, keymap and input device */
319	keypad_data = kzalloc(sizeof(*keypad_data) +
320			max_keys * sizeof(keypad_data->keymap[0]), GFP_KERNEL);
321	if (!keypad_data)
322		return -ENOMEM;
323
324	keypad_data->client = client;
325	keypad_data->row_shift = row_shift;
326
327	/* Initialize the chip or fail if chip isn't present */
328	error = tca8418_configure(keypad_data, rows, cols);
329	if (error < 0)
330		goto fail1;
331
332	/* Configure input device */
333	input = input_allocate_device();
334	if (!input) {
335		error = -ENOMEM;
336		goto fail1;
337	}
338	keypad_data->input = input;
339
340	input->name = client->name;
341	input->dev.parent = &client->dev;
342
343	input->id.bustype = BUS_I2C;
344	input->id.vendor  = 0x0001;
345	input->id.product = 0x001;
346	input->id.version = 0x0001;
347
348	error = matrix_keypad_build_keymap(keymap_data, NULL, rows, cols,
349					   keypad_data->keymap, input);
350	if (error) {
351		dev_err(dev, "Failed to build keymap\n");
352		goto fail2;
353	}
354
355	if (rep)
356		__set_bit(EV_REP, input->evbit);
357	input_set_capability(input, EV_MSC, MSC_SCAN);
358
359	input_set_drvdata(input, keypad_data);
360
361	if (irq_is_gpio)
362		client->irq = gpio_to_irq(client->irq);
363
364	error = request_threaded_irq(client->irq, NULL, tca8418_irq_handler,
365				     IRQF_TRIGGER_FALLING |
366				     IRQF_SHARED |
367				     IRQF_ONESHOT,
368				     client->name, keypad_data);
369	if (error) {
370		dev_err(dev, "Unable to claim irq %d; error %d\n",
371			client->irq, error);
372		goto fail2;
373	}
374
375	error = input_register_device(input);
376	if (error) {
377		dev_err(dev, "Unable to register input device, error: %d\n",
378			error);
379		goto fail3;
380	}
381
382	i2c_set_clientdata(client, keypad_data);
383	return 0;
384
385fail3:
386	free_irq(client->irq, keypad_data);
387fail2:
388	input_free_device(input);
389fail1:
390	kfree(keypad_data);
391	return error;
392}
393
394static int tca8418_keypad_remove(struct i2c_client *client)
395{
396	struct tca8418_keypad *keypad_data = i2c_get_clientdata(client);
397
398	free_irq(keypad_data->client->irq, keypad_data);
399
400	input_unregister_device(keypad_data->input);
401
402	kfree(keypad_data);
403
404	return 0;
405}
406
407static const struct i2c_device_id tca8418_id[] = {
408	{ TCA8418_NAME, 8418, },
409	{ }
410};
411MODULE_DEVICE_TABLE(i2c, tca8418_id);
412
413#ifdef CONFIG_OF
414static const struct of_device_id tca8418_dt_ids[] __devinitconst = {
415	{ .compatible = "ti,tca8418", },
416	{ }
417};
418MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
419#endif
420
421static struct i2c_driver tca8418_keypad_driver = {
422	.driver = {
423		.name	= TCA8418_NAME,
424		.owner	= THIS_MODULE,
425		.of_match_table = of_match_ptr(tca8418_dt_ids),
426	},
427	.probe		= tca8418_keypad_probe,
428	.remove		= tca8418_keypad_remove,
429	.id_table	= tca8418_id,
430};
431
432static int __init tca8418_keypad_init(void)
433{
434	return i2c_add_driver(&tca8418_keypad_driver);
435}
436subsys_initcall(tca8418_keypad_init);
437
438static void __exit tca8418_keypad_exit(void)
439{
440	i2c_del_driver(&tca8418_keypad_driver);
441}
442module_exit(tca8418_keypad_exit);
443
444MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
445MODULE_DESCRIPTION("Keypad driver for TCA8418");
446MODULE_LICENSE("GPL");
447