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	struct i2c_client *client;
115	struct input_dev *input;
116
117	unsigned int row_shift;
118};
119
120/*
121 * Write a byte to the TCA8418
122 */
123static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
124			      int reg, u8 val)
125{
126	int error;
127
128	error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
129	if (error < 0) {
130		dev_err(&keypad_data->client->dev,
131			"%s failed, reg: %d, val: %d, error: %d\n",
132			__func__, reg, val, error);
133		return error;
134	}
135
136	return 0;
137}
138
139/*
140 * Read a byte from the TCA8418
141 */
142static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
143			     int reg, u8 *val)
144{
145	int error;
146
147	error = i2c_smbus_read_byte_data(keypad_data->client, reg);
148	if (error < 0) {
149		dev_err(&keypad_data->client->dev,
150				"%s failed, reg: %d, error: %d\n",
151				__func__, reg, error);
152		return error;
153	}
154
155	*val = (u8)error;
156
157	return 0;
158}
159
160static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
161{
162	struct input_dev *input = keypad_data->input;
163	unsigned short *keymap = input->keycode;
164	int error, col, row;
165	u8 reg, state, code;
166
167	/* Initial read of the key event FIFO */
168	error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
169
170	/* Assume that key code 0 signifies empty FIFO */
171	while (error >= 0 && reg > 0) {
172		state = reg & KEY_EVENT_VALUE;
173		code  = reg & KEY_EVENT_CODE;
174
175		row = code / TCA8418_MAX_COLS;
176		col = code % TCA8418_MAX_COLS;
177
178		row = (col) ? row : row - 1;
179		col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;
180
181		code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
182		input_event(input, EV_MSC, MSC_SCAN, code);
183		input_report_key(input, keymap[code], state);
184
185		/* Read for next loop */
186		error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
187	}
188
189	if (error < 0)
190		dev_err(&keypad_data->client->dev,
191			"unable to read REG_KEY_EVENT_A\n");
192
193	input_sync(input);
194}
195
196/*
197 * Threaded IRQ handler and this can (and will) sleep.
198 */
199static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
200{
201	struct tca8418_keypad *keypad_data = dev_id;
202	u8 reg;
203	int error;
204
205	error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
206	if (error) {
207		dev_err(&keypad_data->client->dev,
208			"unable to read REG_INT_STAT\n");
209		return IRQ_NONE;
210	}
211
212	if (!reg)
213		return IRQ_NONE;
214
215	if (reg & INT_STAT_OVR_FLOW_INT)
216		dev_warn(&keypad_data->client->dev, "overflow occurred\n");
217
218	if (reg & INT_STAT_K_INT)
219		tca8418_read_keypad(keypad_data);
220
221	/* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
222	reg = 0xff;
223	error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
224	if (error)
225		dev_err(&keypad_data->client->dev,
226			"unable to clear REG_INT_STAT\n");
227
228	return IRQ_HANDLED;
229}
230
231/*
232 * Configure the TCA8418 for keypad operation
233 */
234static int tca8418_configure(struct tca8418_keypad *keypad_data,
235			     u32 rows, u32 cols)
236{
237	int reg, error;
238
239	/* Write config register, if this fails assume device not present */
240	error = tca8418_write_byte(keypad_data, REG_CFG,
241				CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
242	if (error < 0)
243		return -ENODEV;
244
245
246	/* Assemble a mask for row and column registers */
247	reg  =  ~(~0 << rows);
248	reg += (~(~0 << cols)) << 8;
249
250	/* Set registers to keypad mode */
251	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
252	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
253	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);
254
255	/* Enable column debouncing */
256	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
257	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
258	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);
259
260	return error;
261}
262
263static int tca8418_keypad_probe(struct i2c_client *client,
264					  const struct i2c_device_id *id)
265{
266	struct device *dev = &client->dev;
267	const struct tca8418_keypad_platform_data *pdata =
268						dev_get_platdata(dev);
269	struct tca8418_keypad *keypad_data;
270	struct input_dev *input;
271	const struct matrix_keymap_data *keymap_data = NULL;
272	u32 rows = 0, cols = 0;
273	bool rep = false;
274	bool irq_is_gpio = false;
275	int irq;
276	int error, row_shift, max_keys;
277
278	/* Copy the platform data */
279	if (pdata) {
280		if (!pdata->keymap_data) {
281			dev_err(dev, "no keymap data defined\n");
282			return -EINVAL;
283		}
284		keymap_data = pdata->keymap_data;
285		rows = pdata->rows;
286		cols = pdata->cols;
287		rep  = pdata->rep;
288		irq_is_gpio = pdata->irq_is_gpio;
289	} else {
290		struct device_node *np = dev->of_node;
291		int err;
292
293		err = matrix_keypad_parse_of_params(dev, &rows, &cols);
294		if (err)
295			return err;
296		rep = of_property_read_bool(np, "keypad,autorepeat");
297	}
298
299	if (!rows || rows > TCA8418_MAX_ROWS) {
300		dev_err(dev, "invalid rows\n");
301		return -EINVAL;
302	}
303
304	if (!cols || cols > TCA8418_MAX_COLS) {
305		dev_err(dev, "invalid columns\n");
306		return -EINVAL;
307	}
308
309	/* Check i2c driver capabilities */
310	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
311		dev_err(dev, "%s adapter not supported\n",
312			dev_driver_string(&client->adapter->dev));
313		return -ENODEV;
314	}
315
316	row_shift = get_count_order(cols);
317	max_keys = rows << row_shift;
318
319	/* Allocate memory for keypad_data and input device */
320	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), 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		return error;
331
332	/* Configure input device */
333	input = devm_input_allocate_device(dev);
334	if (!input)
335		return -ENOMEM;
336
337	keypad_data->input = input;
338
339	input->name = client->name;
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(keymap_data, NULL, rows, cols,
346					   NULL, input);
347	if (error) {
348		dev_err(dev, "Failed to build keymap\n");
349		return error;
350	}
351
352	if (rep)
353		__set_bit(EV_REP, input->evbit);
354	input_set_capability(input, EV_MSC, MSC_SCAN);
355
356	input_set_drvdata(input, keypad_data);
357
358	irq = client->irq;
359	if (irq_is_gpio)
360		irq = gpio_to_irq(irq);
361
362	error = devm_request_threaded_irq(dev, irq, NULL, tca8418_irq_handler,
363					  IRQF_TRIGGER_FALLING |
364						IRQF_SHARED |
365						IRQF_ONESHOT,
366					  client->name, keypad_data);
367	if (error) {
368		dev_err(dev, "Unable to claim irq %d; error %d\n",
369			client->irq, error);
370		return error;
371	}
372
373	error = input_register_device(input);
374	if (error) {
375		dev_err(dev, "Unable to register input device, error: %d\n",
376			error);
377		return error;
378	}
379
380	return 0;
381}
382
383static const struct i2c_device_id tca8418_id[] = {
384	{ TCA8418_NAME, 8418, },
385	{ }
386};
387MODULE_DEVICE_TABLE(i2c, tca8418_id);
388
389#ifdef CONFIG_OF
390static const struct of_device_id tca8418_dt_ids[] = {
391	{ .compatible = "ti,tca8418", },
392	{ }
393};
394MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
395
396/*
397 * The device tree based i2c loader looks for
398 * "i2c:" + second_component_of(property("compatible"))
399 * and therefore we need an alias to be found.
400 */
401MODULE_ALIAS("i2c:tca8418");
402#endif
403
404static struct i2c_driver tca8418_keypad_driver = {
405	.driver = {
406		.name	= TCA8418_NAME,
407		.owner	= THIS_MODULE,
408		.of_match_table = of_match_ptr(tca8418_dt_ids),
409	},
410	.probe		= tca8418_keypad_probe,
411	.id_table	= tca8418_id,
412};
413
414static int __init tca8418_keypad_init(void)
415{
416	return i2c_add_driver(&tca8418_keypad_driver);
417}
418subsys_initcall(tca8418_keypad_init);
419
420static void __exit tca8418_keypad_exit(void)
421{
422	i2c_del_driver(&tca8418_keypad_driver);
423}
424module_exit(tca8418_keypad_exit);
425
426MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
427MODULE_DESCRIPTION("Keypad driver for TCA8418");
428MODULE_LICENSE("GPL");
429