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