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 
112 struct 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  */
122 static 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  */
141 static 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 
159 static 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 		/* Read for next loop */
192 		error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
193 	} while (1);
194 
195 	input_sync(input);
196 }
197 
198 /*
199  * Threaded IRQ handler and this can (and will) sleep.
200  */
201 static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
202 {
203 	struct tca8418_keypad *keypad_data = dev_id;
204 	u8 reg;
205 	int error;
206 
207 	error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
208 	if (error) {
209 		dev_err(&keypad_data->client->dev,
210 			"unable to read REG_INT_STAT\n");
211 		return IRQ_NONE;
212 	}
213 
214 	if (!reg)
215 		return IRQ_NONE;
216 
217 	if (reg & INT_STAT_OVR_FLOW_INT)
218 		dev_warn(&keypad_data->client->dev, "overflow occurred\n");
219 
220 	if (reg & INT_STAT_K_INT)
221 		tca8418_read_keypad(keypad_data);
222 
223 	/* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
224 	reg = 0xff;
225 	error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
226 	if (error)
227 		dev_err(&keypad_data->client->dev,
228 			"unable to clear REG_INT_STAT\n");
229 
230 	return IRQ_HANDLED;
231 }
232 
233 /*
234  * Configure the TCA8418 for keypad operation
235  */
236 static int tca8418_configure(struct tca8418_keypad *keypad_data,
237 			     u32 rows, u32 cols)
238 {
239 	int reg, error;
240 
241 	/* Write config register, if this fails assume device not present */
242 	error = tca8418_write_byte(keypad_data, REG_CFG,
243 				CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
244 	if (error < 0)
245 		return -ENODEV;
246 
247 
248 	/* Assemble a mask for row and column registers */
249 	reg  =  ~(~0 << rows);
250 	reg += (~(~0 << cols)) << 8;
251 
252 	/* Set registers to keypad mode */
253 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
254 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
255 	error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);
256 
257 	/* Enable column debouncing */
258 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
259 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
260 	error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);
261 
262 	return error;
263 }
264 
265 static int tca8418_keypad_probe(struct i2c_client *client,
266 				const struct i2c_device_id *id)
267 {
268 	struct device *dev = &client->dev;
269 	struct tca8418_keypad *keypad_data;
270 	struct input_dev *input;
271 	u32 rows = 0, cols = 0;
272 	int error, row_shift, max_keys;
273 
274 	/* Check i2c driver capabilities */
275 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
276 		dev_err(dev, "%s adapter not supported\n",
277 			dev_driver_string(&client->adapter->dev));
278 		return -ENODEV;
279 	}
280 
281 	error = matrix_keypad_parse_properties(dev, &rows, &cols);
282 	if (error)
283 		return error;
284 
285 	if (!rows || rows > TCA8418_MAX_ROWS) {
286 		dev_err(dev, "invalid rows\n");
287 		return -EINVAL;
288 	}
289 
290 	if (!cols || cols > TCA8418_MAX_COLS) {
291 		dev_err(dev, "invalid columns\n");
292 		return -EINVAL;
293 	}
294 
295 	row_shift = get_count_order(cols);
296 	max_keys = rows << row_shift;
297 
298 	/* Allocate memory for keypad_data and input device */
299 	keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
300 	if (!keypad_data)
301 		return -ENOMEM;
302 
303 	keypad_data->client = client;
304 	keypad_data->row_shift = row_shift;
305 
306 	/* Initialize the chip or fail if chip isn't present */
307 	error = tca8418_configure(keypad_data, rows, cols);
308 	if (error < 0)
309 		return error;
310 
311 	/* Configure input device */
312 	input = devm_input_allocate_device(dev);
313 	if (!input)
314 		return -ENOMEM;
315 
316 	keypad_data->input = input;
317 
318 	input->name = client->name;
319 	input->id.bustype = BUS_I2C;
320 	input->id.vendor  = 0x0001;
321 	input->id.product = 0x001;
322 	input->id.version = 0x0001;
323 
324 	error = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL, input);
325 	if (error) {
326 		dev_err(dev, "Failed to build keymap\n");
327 		return error;
328 	}
329 
330 	if (device_property_read_bool(dev, "keypad,autorepeat"))
331 		__set_bit(EV_REP, input->evbit);
332 
333 	input_set_capability(input, EV_MSC, MSC_SCAN);
334 
335 	error = devm_request_threaded_irq(dev, client->irq,
336 					  NULL, tca8418_irq_handler,
337 					  IRQF_SHARED | IRQF_ONESHOT,
338 					  client->name, keypad_data);
339 	if (error) {
340 		dev_err(dev, "Unable to claim irq %d; error %d\n",
341 			client->irq, error);
342 		return error;
343 	}
344 
345 	error = input_register_device(input);
346 	if (error) {
347 		dev_err(dev, "Unable to register input device, error: %d\n",
348 			error);
349 		return error;
350 	}
351 
352 	return 0;
353 }
354 
355 static const struct i2c_device_id tca8418_id[] = {
356 	{ "tca8418", 8418, },
357 	{ }
358 };
359 MODULE_DEVICE_TABLE(i2c, tca8418_id);
360 
361 static const struct of_device_id tca8418_dt_ids[] = {
362 	{ .compatible = "ti,tca8418", },
363 	{ }
364 };
365 MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
366 
367 static struct i2c_driver tca8418_keypad_driver = {
368 	.driver = {
369 		.name	= "tca8418_keypad",
370 		.of_match_table = tca8418_dt_ids,
371 	},
372 	.probe		= tca8418_keypad_probe,
373 	.id_table	= tca8418_id,
374 };
375 
376 static int __init tca8418_keypad_init(void)
377 {
378 	return i2c_add_driver(&tca8418_keypad_driver);
379 }
380 subsys_initcall(tca8418_keypad_init);
381 
382 static void __exit tca8418_keypad_exit(void)
383 {
384 	i2c_del_driver(&tca8418_keypad_driver);
385 }
386 module_exit(tca8418_keypad_exit);
387 
388 MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
389 MODULE_DESCRIPTION("Keypad driver for TCA8418");
390 MODULE_LICENSE("GPL");
391