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 	} while (1);
192 
193 	input_sync(input);
194 }
195 
196 /*
197  * Threaded IRQ handler and this can (and will) sleep.
198  */
199 static 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  */
234 static 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 
262 static 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 
356 static const struct i2c_device_id tca8418_id[] = {
357 	{ "tca8418", 8418, },
358 	{ }
359 };
360 MODULE_DEVICE_TABLE(i2c, tca8418_id);
361 
362 static const struct of_device_id tca8418_dt_ids[] = {
363 	{ .compatible = "ti,tca8418", },
364 	{ }
365 };
366 MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
367 
368 static struct i2c_driver tca8418_keypad_driver = {
369 	.driver = {
370 		.name	= "tca8418_keypad",
371 		.of_match_table = tca8418_dt_ids,
372 	},
373 	.probe_new	= tca8418_keypad_probe,
374 	.id_table	= tca8418_id,
375 };
376 
377 static int __init tca8418_keypad_init(void)
378 {
379 	return i2c_add_driver(&tca8418_keypad_driver);
380 }
381 subsys_initcall(tca8418_keypad_init);
382 
383 static void __exit tca8418_keypad_exit(void)
384 {
385 	i2c_del_driver(&tca8418_keypad_driver);
386 }
387 module_exit(tca8418_keypad_exit);
388 
389 MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
390 MODULE_DESCRIPTION("Keypad driver for TCA8418");
391 MODULE_LICENSE("GPL");
392