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(client: keypad_data->client, command: reg, value: 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(client: keypad_data->client, command: 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, val: &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(dev: input, EV_MSC, MSC_SCAN, value: code);
189 input_report_key(dev: input, code: keymap[code], value: state);
190
191 } while (1);
192
193 input_sync(dev: 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, val: &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, val: 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, val: reg);
245 error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, val: reg >> 8);
246 error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, val: reg >> 16);
247
248 /* Enable column debouncing */
249 error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, val: reg);
250 error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, val: reg >> 8);
251 error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, val: 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(adap: 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: &rows, cols: &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(count: cols);
293
294 /* Allocate memory for keypad_data and input device */
295 keypad_data = devm_kzalloc(dev, size: 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, val: &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_dev: 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, propname: "keypad,autorepeat"))
327 __set_bit(EV_REP, input->evbit);
328
329 input_set_capability(dev: input, EV_MSC, MSC_SCAN);
330
331 error = devm_request_threaded_irq(dev, irq: client->irq,
332 NULL, thread_fn: tca8418_irq_handler,
333 IRQF_SHARED | IRQF_ONESHOT,
334 devname: client->name, dev_id: 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};
376module_i2c_driver(tca8418_keypad_driver);
377
378MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
379MODULE_DESCRIPTION("Keypad driver for TCA8418");
380MODULE_LICENSE("GPL");
381

source code of linux/drivers/input/keyboard/tca8418_keypad.c