1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * LM8333 keypad driver
4 * Copyright (C) 2012 Wolfram Sang, Pengutronix <kernel@pengutronix.de>
5 */
6
7#include <linux/i2c.h>
8#include <linux/input.h>
9#include <linux/input/matrix_keypad.h>
10#include <linux/input/lm8333.h>
11#include <linux/interrupt.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14
15#define LM8333_FIFO_READ		0x20
16#define LM8333_DEBOUNCE			0x22
17#define LM8333_READ_INT			0xD0
18#define LM8333_ACTIVE			0xE4
19#define LM8333_READ_ERROR		0xF0
20
21#define LM8333_KEYPAD_IRQ		(1 << 0)
22#define LM8333_ERROR_IRQ		(1 << 3)
23
24#define LM8333_ERROR_KEYOVR		0x04
25#define LM8333_ERROR_FIFOOVR		0x40
26
27#define LM8333_FIFO_TRANSFER_SIZE	16
28
29#define LM8333_NUM_ROWS		8
30#define LM8333_NUM_COLS		16
31#define LM8333_ROW_SHIFT	4
32
33struct lm8333 {
34	struct i2c_client *client;
35	struct input_dev *input;
36	unsigned short keycodes[LM8333_NUM_ROWS << LM8333_ROW_SHIFT];
37};
38
39/* The accessors try twice because the first access may be needed for wakeup */
40#define LM8333_READ_RETRIES 2
41
42int lm8333_read8(struct lm8333 *lm8333, u8 cmd)
43{
44	int retries = 0, ret;
45
46	do {
47		ret = i2c_smbus_read_byte_data(lm8333->client, cmd);
48	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
49
50	return ret;
51}
52
53int lm8333_write8(struct lm8333 *lm8333, u8 cmd, u8 val)
54{
55	int retries = 0, ret;
56
57	do {
58		ret = i2c_smbus_write_byte_data(lm8333->client, cmd, val);
59	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
60
61	return ret;
62}
63
64int lm8333_read_block(struct lm8333 *lm8333, u8 cmd, u8 len, u8 *buf)
65{
66	int retries = 0, ret;
67
68	do {
69		ret = i2c_smbus_read_i2c_block_data(lm8333->client,
70						    cmd, len, buf);
71	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
72
73	return ret;
74}
75
76static void lm8333_key_handler(struct lm8333 *lm8333)
77{
78	struct input_dev *input = lm8333->input;
79	u8 keys[LM8333_FIFO_TRANSFER_SIZE];
80	u8 code, pressed;
81	int i, ret;
82
83	ret = lm8333_read_block(lm8333, LM8333_FIFO_READ,
84				LM8333_FIFO_TRANSFER_SIZE, keys);
85	if (ret != LM8333_FIFO_TRANSFER_SIZE) {
86		dev_err(&lm8333->client->dev,
87			"Error %d while reading FIFO\n", ret);
88		return;
89	}
90
91	for (i = 0; i < LM8333_FIFO_TRANSFER_SIZE && keys[i]; i++) {
92		pressed = keys[i] & 0x80;
93		code = keys[i] & 0x7f;
94
95		input_event(input, EV_MSC, MSC_SCAN, code);
96		input_report_key(input, lm8333->keycodes[code], pressed);
97	}
98
99	input_sync(input);
100}
101
102static irqreturn_t lm8333_irq_thread(int irq, void *data)
103{
104	struct lm8333 *lm8333 = data;
105	u8 status = lm8333_read8(lm8333, LM8333_READ_INT);
106
107	if (!status)
108		return IRQ_NONE;
109
110	if (status & LM8333_ERROR_IRQ) {
111		u8 err = lm8333_read8(lm8333, LM8333_READ_ERROR);
112
113		if (err & (LM8333_ERROR_KEYOVR | LM8333_ERROR_FIFOOVR)) {
114			u8 dummy[LM8333_FIFO_TRANSFER_SIZE];
115
116			lm8333_read_block(lm8333, LM8333_FIFO_READ,
117					LM8333_FIFO_TRANSFER_SIZE, dummy);
118		}
119		dev_err(&lm8333->client->dev, "Got error %02x\n", err);
120	}
121
122	if (status & LM8333_KEYPAD_IRQ)
123		lm8333_key_handler(lm8333);
124
125	return IRQ_HANDLED;
126}
127
128static int lm8333_probe(struct i2c_client *client)
129{
130	const struct lm8333_platform_data *pdata =
131			dev_get_platdata(&client->dev);
132	struct lm8333 *lm8333;
133	struct input_dev *input;
134	int err, active_time;
135
136	if (!pdata)
137		return -EINVAL;
138
139	active_time = pdata->active_time ?: 500;
140	if (active_time / 3 <= pdata->debounce_time / 3) {
141		dev_err(&client->dev, "Active time not big enough!\n");
142		return -EINVAL;
143	}
144
145	lm8333 = devm_kzalloc(&client->dev, sizeof(*lm8333), GFP_KERNEL);
146	if (!lm8333)
147		return -ENOMEM;
148
149	input = devm_input_allocate_device(&client->dev);
150	if (!input)
151		return -ENOMEM;
152
153	lm8333->client = client;
154	lm8333->input = input;
155
156	input->name = client->name;
157	input->id.bustype = BUS_I2C;
158
159	input_set_capability(input, EV_MSC, MSC_SCAN);
160
161	err = matrix_keypad_build_keymap(pdata->matrix_data, NULL,
162					 LM8333_NUM_ROWS, LM8333_NUM_COLS,
163					 lm8333->keycodes, input);
164	if (err)
165		return err;
166
167	if (pdata->debounce_time) {
168		err = lm8333_write8(lm8333, LM8333_DEBOUNCE,
169				    pdata->debounce_time / 3);
170		if (err)
171			dev_warn(&client->dev, "Unable to set debounce time\n");
172	}
173
174	if (pdata->active_time) {
175		err = lm8333_write8(lm8333, LM8333_ACTIVE,
176				    pdata->active_time / 3);
177		if (err)
178			dev_warn(&client->dev, "Unable to set active time\n");
179	}
180
181	err = devm_request_threaded_irq(&client->dev, client->irq,
182					NULL, lm8333_irq_thread,
183					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
184					"lm8333", lm8333);
185	if (err)
186		return err;
187
188	err = input_register_device(input);
189	if (err)
190		return err;
191
192	i2c_set_clientdata(client, lm8333);
193	return 0;
194}
195
196static const struct i2c_device_id lm8333_id[] = {
197	{ "lm8333", 0 },
198	{ }
199};
200MODULE_DEVICE_TABLE(i2c, lm8333_id);
201
202static struct i2c_driver lm8333_driver = {
203	.driver = {
204		.name		= "lm8333",
205	},
206	.probe		= lm8333_probe,
207	.id_table	= lm8333_id,
208};
209module_i2c_driver(lm8333_driver);
210
211MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
212MODULE_DESCRIPTION("LM8333 keyboard driver");
213MODULE_LICENSE("GPL v2");
214