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/delay.h>
28#include <linux/i2c.h>
29#include <linux/init.h>
30#include <linux/input.h>
31#include <linux/input/matrix_keypad.h>
32#include <linux/interrupt.h>
33#include <linux/module.h>
34#include <linux/of.h>
35#include <linux/property.h>
36#include <linux/slab.h>
37#include <linux/types.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
112struct tca8418_keypad {
113	struct i2c_client *client;
114	struct input_dev *input;
115
116	unsigned int row_shift;
117};
118
119/*
120 * Write a byte to the TCA8418
121 */
122static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
123			      int reg, u8 val)
124{
125	int error;
126
127	error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
128	if (error < 0) {
129		dev_err(&keypad_data->client->dev,
130			"%s failed, reg: %d, val: %d, error: %d\n",
131			__func__, reg, val, error);
132		return error;
133	}
134
135	return 0;
136}
137
138/*
139 * Read a byte from the TCA8418
140 */
141static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
142			     int reg, u8 *val)
143{
144	int error;
145
146	error = i2c_smbus_read_byte_data(keypad_data->client, reg);
147	if (error < 0) {
148		dev_err(&keypad_data->client->dev,
149				"%s failed, reg: %d, error: %d\n",
150				__func__, reg, error);
151		return error;
152	}
153
154	*val = (u8)error;
155
156	return 0;
157}
158
159static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
160{
161	struct input_dev *input = keypad_data->input;
162	unsigned short *keymap = input->keycode;
163	int error, col, row;
164	u8 reg, state, code;
165
166	do {
167		error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
168		if (error < 0) {
169			dev_err(&keypad_data->client->dev,
170				"unable to read REG_KEY_EVENT_A\n");
171			break;
172		}
173
174		/* Assume that key code 0 signifies empty FIFO */
175		if (reg <= 0)
176			break;
177
178		state = reg & KEY_EVENT_VALUE;
179		code  = reg & KEY_EVENT_CODE;
180
181		row = code / TCA8418_MAX_COLS;
182		col = code % TCA8418_MAX_COLS;
183
184		row = (col) ? row : row - 1;
185		col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;
186
187		code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
188		input_event(input, EV_MSC, MSC_SCAN, code);
189		input_report_key(input, keymap[code], state);
190
191	} while (1);
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 = 0;
238
239	/* Assemble a mask for row and column registers */
240	reg  =  ~(~0 << rows);
241	reg += (~(~0 << cols)) << 8;
242
243	/* Set registers to keypad mode */
244	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
245	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
246	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);
247
248	/* Enable column debouncing */
249	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
250	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
251	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);
252
253	if (error)
254		return error;
255
256	error = tca8418_write_byte(keypad_data, REG_CFG,
257				CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
258
259	return error;
260}
261
262static int tca8418_keypad_probe(struct i2c_client *client)
263{
264	struct device *dev = &client->dev;
265	struct tca8418_keypad *keypad_data;
266	struct input_dev *input;
267	u32 rows = 0, cols = 0;
268	int error, row_shift;
269	u8 reg;
270
271	/* Check i2c driver capabilities */
272	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
273		dev_err(dev, "%s adapter not supported\n",
274			dev_driver_string(&client->adapter->dev));
275		return -ENODEV;
276	}
277
278	error = matrix_keypad_parse_properties(dev, &rows, &cols);
279	if (error)
280		return error;
281
282	if (!rows || rows > TCA8418_MAX_ROWS) {
283		dev_err(dev, "invalid rows\n");
284		return -EINVAL;
285	}
286
287	if (!cols || cols > TCA8418_MAX_COLS) {
288		dev_err(dev, "invalid columns\n");
289		return -EINVAL;
290	}
291
292	row_shift = get_count_order(cols);
293
294	/* Allocate memory for keypad_data and input device */
295	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
296	if (!keypad_data)
297		return -ENOMEM;
298
299	keypad_data->client = client;
300	keypad_data->row_shift = row_shift;
301
302	/* Read key lock register, if this fails assume device not present */
303	error = tca8418_read_byte(keypad_data, REG_KEY_LCK_EC, &reg);
304	if (error)
305		return -ENODEV;
306
307	/* Configure input device */
308	input = devm_input_allocate_device(dev);
309	if (!input)
310		return -ENOMEM;
311
312	keypad_data->input = input;
313
314	input->name = client->name;
315	input->id.bustype = BUS_I2C;
316	input->id.vendor  = 0x0001;
317	input->id.product = 0x001;
318	input->id.version = 0x0001;
319
320	error = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL, input);
321	if (error) {
322		dev_err(dev, "Failed to build keymap\n");
323		return error;
324	}
325
326	if (device_property_read_bool(dev, "keypad,autorepeat"))
327		__set_bit(EV_REP, input->evbit);
328
329	input_set_capability(input, EV_MSC, MSC_SCAN);
330
331	error = devm_request_threaded_irq(dev, client->irq,
332					  NULL, tca8418_irq_handler,
333					  IRQF_SHARED | IRQF_ONESHOT,
334					  client->name, keypad_data);
335	if (error) {
336		dev_err(dev, "Unable to claim irq %d; error %d\n",
337			client->irq, error);
338		return error;
339	}
340
341	/* Initialize the chip */
342	error = tca8418_configure(keypad_data, rows, cols);
343	if (error < 0)
344		return error;
345
346	error = input_register_device(input);
347	if (error) {
348		dev_err(dev, "Unable to register input device, error: %d\n",
349			error);
350		return error;
351	}
352
353	return 0;
354}
355
356static const struct i2c_device_id tca8418_id[] = {
357	{ "tca8418", 8418, },
358	{ }
359};
360MODULE_DEVICE_TABLE(i2c, tca8418_id);
361
362static const struct of_device_id tca8418_dt_ids[] = {
363	{ .compatible = "ti,tca8418", },
364	{ }
365};
366MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
367
368static struct i2c_driver tca8418_keypad_driver = {
369	.driver = {
370		.name	= "tca8418_keypad",
371		.of_match_table = tca8418_dt_ids,
372	},
373	.probe		= tca8418_keypad_probe,
374	.id_table	= tca8418_id,
375};
376
377static int __init tca8418_keypad_init(void)
378{
379	return i2c_add_driver(&tca8418_keypad_driver);
380}
381subsys_initcall(tca8418_keypad_init);
382
383static void __exit tca8418_keypad_exit(void)
384{
385	i2c_del_driver(&tca8418_keypad_driver);
386}
387module_exit(tca8418_keypad_exit);
388
389MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
390MODULE_DESCRIPTION("Keypad driver for TCA8418");
391MODULE_LICENSE("GPL");
392