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 
113 struct 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  */
123 static 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  */
142 static 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 
160 static 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  */
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;
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 
263 static 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 
383 static const struct i2c_device_id tca8418_id[] = {
384 	{ TCA8418_NAME, 8418, },
385 	{ }
386 };
387 MODULE_DEVICE_TABLE(i2c, tca8418_id);
388 
389 #ifdef CONFIG_OF
390 static const struct of_device_id tca8418_dt_ids[] = {
391 	{ .compatible = "ti,tca8418", },
392 	{ }
393 };
394 MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
395 #endif
396 
397 static struct i2c_driver tca8418_keypad_driver = {
398 	.driver = {
399 		.name	= TCA8418_NAME,
400 		.owner	= THIS_MODULE,
401 		.of_match_table = of_match_ptr(tca8418_dt_ids),
402 	},
403 	.probe		= tca8418_keypad_probe,
404 	.id_table	= tca8418_id,
405 };
406 
407 static int __init tca8418_keypad_init(void)
408 {
409 	return i2c_add_driver(&tca8418_keypad_driver);
410 }
411 subsys_initcall(tca8418_keypad_init);
412 
413 static void __exit tca8418_keypad_exit(void)
414 {
415 	i2c_del_driver(&tca8418_keypad_driver);
416 }
417 module_exit(tca8418_keypad_exit);
418 
419 MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
420 MODULE_DESCRIPTION("Keypad driver for TCA8418");
421 MODULE_LICENSE("GPL");
422