1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for keys on TCA6416 I2C IO expander
4 *
5 * Copyright (C) 2010 Texas Instruments
6 *
7 * Author : Sriramakrishnan.A.G. <srk@ti.com>
8 */
9
10 #include <linux/types.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/delay.h>
14 #include <linux/slab.h>
15 #include <linux/interrupt.h>
16 #include <linux/workqueue.h>
17 #include <linux/i2c.h>
18 #include <linux/input.h>
19 #include <linux/tca6416_keypad.h>
20
21 #define TCA6416_INPUT 0
22 #define TCA6416_OUTPUT 1
23 #define TCA6416_INVERT 2
24 #define TCA6416_DIRECTION 3
25
26 #define TCA6416_POLL_INTERVAL 100 /* msec */
27
28 static const struct i2c_device_id tca6416_id[] = {
29 { "tca6416-keys", 16, },
30 { "tca6408-keys", 8, },
31 { }
32 };
33 MODULE_DEVICE_TABLE(i2c, tca6416_id);
34
35 struct tca6416_keypad_chip {
36 uint16_t reg_output;
37 uint16_t reg_direction;
38 uint16_t reg_input;
39
40 struct i2c_client *client;
41 struct input_dev *input;
42 int io_size;
43 u16 pinmask;
44 bool use_polling;
45 struct tca6416_button buttons[];
46 };
47
tca6416_write_reg(struct tca6416_keypad_chip * chip,int reg,u16 val)48 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
49 {
50 int error;
51
52 error = chip->io_size > 8 ?
53 i2c_smbus_write_word_data(chip->client, reg << 1, val) :
54 i2c_smbus_write_byte_data(chip->client, reg, val);
55 if (error < 0) {
56 dev_err(&chip->client->dev,
57 "%s failed, reg: %d, val: %d, error: %d\n",
58 __func__, reg, val, error);
59 return error;
60 }
61
62 return 0;
63 }
64
tca6416_read_reg(struct tca6416_keypad_chip * chip,int reg,u16 * val)65 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
66 {
67 int retval;
68
69 retval = chip->io_size > 8 ?
70 i2c_smbus_read_word_data(chip->client, reg << 1) :
71 i2c_smbus_read_byte_data(chip->client, reg);
72 if (retval < 0) {
73 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
74 __func__, reg, retval);
75 return retval;
76 }
77
78 *val = (u16)retval;
79 return 0;
80 }
81
tca6416_keys_scan(struct input_dev * input)82 static void tca6416_keys_scan(struct input_dev *input)
83 {
84 struct tca6416_keypad_chip *chip = input_get_drvdata(input);
85 u16 reg_val, val;
86 int error, i, pin_index;
87
88 error = tca6416_read_reg(chip, TCA6416_INPUT, ®_val);
89 if (error)
90 return;
91
92 reg_val &= chip->pinmask;
93
94 /* Figure out which lines have changed */
95 val = reg_val ^ chip->reg_input;
96 chip->reg_input = reg_val;
97
98 for (i = 0, pin_index = 0; i < 16; i++) {
99 if (val & (1 << i)) {
100 struct tca6416_button *button = &chip->buttons[pin_index];
101 unsigned int type = button->type ?: EV_KEY;
102 int state = ((reg_val & (1 << i)) ? 1 : 0)
103 ^ button->active_low;
104
105 input_event(input, type, button->code, !!state);
106 input_sync(input);
107 }
108
109 if (chip->pinmask & (1 << i))
110 pin_index++;
111 }
112 }
113
114 /*
115 * This is threaded IRQ handler and this can (and will) sleep.
116 */
tca6416_keys_isr(int irq,void * dev_id)117 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
118 {
119 tca6416_keys_scan(dev_id);
120
121 return IRQ_HANDLED;
122 }
123
tca6416_keys_open(struct input_dev * dev)124 static int tca6416_keys_open(struct input_dev *dev)
125 {
126 struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
127
128 if (!chip->use_polling) {
129 /* Get initial device state in case it has switches */
130 tca6416_keys_scan(dev);
131 enable_irq(chip->client->irq);
132 }
133
134 return 0;
135 }
136
tca6416_keys_close(struct input_dev * dev)137 static void tca6416_keys_close(struct input_dev *dev)
138 {
139 struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
140
141 if (!chip->use_polling)
142 disable_irq(chip->client->irq);
143 }
144
tca6416_setup_registers(struct tca6416_keypad_chip * chip)145 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
146 {
147 int error;
148
149 error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
150 if (error)
151 return error;
152
153 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
154 if (error)
155 return error;
156
157 /* ensure that keypad pins are set to input */
158 error = tca6416_write_reg(chip, TCA6416_DIRECTION,
159 chip->reg_direction | chip->pinmask);
160 if (error)
161 return error;
162
163 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
164 if (error)
165 return error;
166
167 error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
168 if (error)
169 return error;
170
171 chip->reg_input &= chip->pinmask;
172
173 return 0;
174 }
175
tca6416_keypad_probe(struct i2c_client * client)176 static int tca6416_keypad_probe(struct i2c_client *client)
177 {
178 const struct i2c_device_id *id = i2c_client_get_device_id(client);
179 struct tca6416_keys_platform_data *pdata;
180 struct tca6416_keypad_chip *chip;
181 struct input_dev *input;
182 int error;
183 int i;
184
185 /* Check functionality */
186 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
187 dev_err(&client->dev, "%s adapter not supported\n",
188 dev_driver_string(&client->adapter->dev));
189 return -ENODEV;
190 }
191
192 pdata = dev_get_platdata(&client->dev);
193 if (!pdata) {
194 dev_dbg(&client->dev, "no platform data\n");
195 return -EINVAL;
196 }
197
198 chip = devm_kzalloc(&client->dev,
199 struct_size(chip, buttons, pdata->nbuttons),
200 GFP_KERNEL);
201 if (!chip)
202 return -ENOMEM;
203
204 input = devm_input_allocate_device(&client->dev);
205 if (!input)
206 return -ENOMEM;
207
208 chip->client = client;
209 chip->input = input;
210 chip->io_size = id->driver_data;
211 chip->pinmask = pdata->pinmask;
212 chip->use_polling = pdata->use_polling;
213
214 input->phys = "tca6416-keys/input0";
215 input->name = client->name;
216
217 input->open = tca6416_keys_open;
218 input->close = tca6416_keys_close;
219
220 input->id.bustype = BUS_HOST;
221 input->id.vendor = 0x0001;
222 input->id.product = 0x0001;
223 input->id.version = 0x0100;
224
225 /* Enable auto repeat feature of Linux input subsystem */
226 if (pdata->rep)
227 __set_bit(EV_REP, input->evbit);
228
229 for (i = 0; i < pdata->nbuttons; i++) {
230 unsigned int type;
231
232 chip->buttons[i] = pdata->buttons[i];
233 type = (pdata->buttons[i].type) ?: EV_KEY;
234 input_set_capability(input, type, pdata->buttons[i].code);
235 }
236
237 input_set_drvdata(input, chip);
238
239 /*
240 * Initialize cached registers from their original values.
241 * we can't share this chip with another i2c master.
242 */
243 error = tca6416_setup_registers(chip);
244 if (error)
245 return error;
246
247 if (chip->use_polling) {
248 error = input_setup_polling(input, tca6416_keys_scan);
249 if (error) {
250 dev_err(&client->dev, "Failed to setup polling\n");
251 return error;
252 }
253
254 input_set_poll_interval(input, TCA6416_POLL_INTERVAL);
255 } else {
256 error = devm_request_threaded_irq(&client->dev, client->irq,
257 NULL, tca6416_keys_isr,
258 IRQF_TRIGGER_FALLING |
259 IRQF_ONESHOT |
260 IRQF_NO_AUTOEN,
261 "tca6416-keypad", input);
262 if (error) {
263 dev_dbg(&client->dev,
264 "Unable to claim irq %d; error %d\n",
265 client->irq, error);
266 return error;
267 }
268 }
269
270 error = input_register_device(input);
271 if (error) {
272 dev_dbg(&client->dev,
273 "Unable to register input device, error: %d\n", error);
274 return error;
275 }
276
277 i2c_set_clientdata(client, chip);
278
279 return 0;
280 }
281
282 static struct i2c_driver tca6416_keypad_driver = {
283 .driver = {
284 .name = "tca6416-keypad",
285 },
286 .probe = tca6416_keypad_probe,
287 .id_table = tca6416_id,
288 };
289
tca6416_keypad_init(void)290 static int __init tca6416_keypad_init(void)
291 {
292 return i2c_add_driver(&tca6416_keypad_driver);
293 }
294
295 subsys_initcall(tca6416_keypad_init);
296
tca6416_keypad_exit(void)297 static void __exit tca6416_keypad_exit(void)
298 {
299 i2c_del_driver(&tca6416_keypad_driver);
300 }
301 module_exit(tca6416_keypad_exit);
302
303 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
304 MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
305 MODULE_LICENSE("GPL");
306