1/*
2 * LM8333 keypad driver
3 * Copyright (C) 2012 Wolfram Sang, Pengutronix <kernel@pengutronix.de>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License.
8 */
9
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/irq.h>
13#include <linux/i2c.h>
14#include <linux/interrupt.h>
15#include <linux/input/matrix_keypad.h>
16#include <linux/input/lm8333.h>
17
18#define LM8333_FIFO_READ		0x20
19#define LM8333_DEBOUNCE			0x22
20#define LM8333_READ_INT			0xD0
21#define LM8333_ACTIVE			0xE4
22#define LM8333_READ_ERROR		0xF0
23
24#define LM8333_KEYPAD_IRQ		(1 << 0)
25#define LM8333_ERROR_IRQ		(1 << 3)
26
27#define LM8333_ERROR_KEYOVR		0x04
28#define LM8333_ERROR_FIFOOVR		0x40
29
30#define LM8333_FIFO_TRANSFER_SIZE	16
31
32#define LM8333_NUM_ROWS		8
33#define LM8333_NUM_COLS		16
34#define LM8333_ROW_SHIFT	4
35
36struct lm8333 {
37	struct i2c_client *client;
38	struct input_dev *input;
39	unsigned short keycodes[LM8333_NUM_ROWS << LM8333_ROW_SHIFT];
40};
41
42/* The accessors try twice because the first access may be needed for wakeup */
43#define LM8333_READ_RETRIES 2
44
45int lm8333_read8(struct lm8333 *lm8333, u8 cmd)
46{
47	int retries = 0, ret;
48
49	do {
50		ret = i2c_smbus_read_byte_data(lm8333->client, cmd);
51	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
52
53	return ret;
54}
55
56int lm8333_write8(struct lm8333 *lm8333, u8 cmd, u8 val)
57{
58	int retries = 0, ret;
59
60	do {
61		ret = i2c_smbus_write_byte_data(lm8333->client, cmd, val);
62	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
63
64	return ret;
65}
66
67int lm8333_read_block(struct lm8333 *lm8333, u8 cmd, u8 len, u8 *buf)
68{
69	int retries = 0, ret;
70
71	do {
72		ret = i2c_smbus_read_i2c_block_data(lm8333->client,
73						    cmd, len, buf);
74	} while (ret < 0 && retries++ < LM8333_READ_RETRIES);
75
76	return ret;
77}
78
79static void lm8333_key_handler(struct lm8333 *lm8333)
80{
81	struct input_dev *input = lm8333->input;
82	u8 keys[LM8333_FIFO_TRANSFER_SIZE];
83	u8 code, pressed;
84	int i, ret;
85
86	ret = lm8333_read_block(lm8333, LM8333_FIFO_READ,
87				LM8333_FIFO_TRANSFER_SIZE, keys);
88	if (ret != LM8333_FIFO_TRANSFER_SIZE) {
89		dev_err(&lm8333->client->dev,
90			"Error %d while reading FIFO\n", ret);
91		return;
92	}
93
94	for (i = 0; i < LM8333_FIFO_TRANSFER_SIZE && keys[i]; i++) {
95		pressed = keys[i] & 0x80;
96		code = keys[i] & 0x7f;
97
98		input_event(input, EV_MSC, MSC_SCAN, code);
99		input_report_key(input, lm8333->keycodes[code], pressed);
100	}
101
102	input_sync(input);
103}
104
105static irqreturn_t lm8333_irq_thread(int irq, void *data)
106{
107	struct lm8333 *lm8333 = data;
108	u8 status = lm8333_read8(lm8333, LM8333_READ_INT);
109
110	if (!status)
111		return IRQ_NONE;
112
113	if (status & LM8333_ERROR_IRQ) {
114		u8 err = lm8333_read8(lm8333, LM8333_READ_ERROR);
115
116		if (err & (LM8333_ERROR_KEYOVR | LM8333_ERROR_FIFOOVR)) {
117			u8 dummy[LM8333_FIFO_TRANSFER_SIZE];
118
119			lm8333_read_block(lm8333, LM8333_FIFO_READ,
120					LM8333_FIFO_TRANSFER_SIZE, dummy);
121		}
122		dev_err(&lm8333->client->dev, "Got error %02x\n", err);
123	}
124
125	if (status & LM8333_KEYPAD_IRQ)
126		lm8333_key_handler(lm8333);
127
128	return IRQ_HANDLED;
129}
130
131static int lm8333_probe(struct i2c_client *client,
132				  const struct i2c_device_id *id)
133{
134	const struct lm8333_platform_data *pdata =
135			dev_get_platdata(&client->dev);
136	struct lm8333 *lm8333;
137	struct input_dev *input;
138	int err, active_time;
139
140	if (!pdata)
141		return -EINVAL;
142
143	active_time = pdata->active_time ?: 500;
144	if (active_time / 3 <= pdata->debounce_time / 3) {
145		dev_err(&client->dev, "Active time not big enough!\n");
146		return -EINVAL;
147	}
148
149	lm8333 = kzalloc(sizeof(*lm8333), GFP_KERNEL);
150	input = input_allocate_device();
151	if (!lm8333 || !input) {
152		err = -ENOMEM;
153		goto free_mem;
154	}
155
156	lm8333->client = client;
157	lm8333->input = input;
158
159	input->name = client->name;
160	input->dev.parent = &client->dev;
161	input->id.bustype = BUS_I2C;
162
163	input_set_capability(input, EV_MSC, MSC_SCAN);
164
165	err = matrix_keypad_build_keymap(pdata->matrix_data, NULL,
166					 LM8333_NUM_ROWS, LM8333_NUM_COLS,
167					 lm8333->keycodes, input);
168	if (err)
169		goto free_mem;
170
171	if (pdata->debounce_time) {
172		err = lm8333_write8(lm8333, LM8333_DEBOUNCE,
173				    pdata->debounce_time / 3);
174		if (err)
175			dev_warn(&client->dev, "Unable to set debounce time\n");
176	}
177
178	if (pdata->active_time) {
179		err = lm8333_write8(lm8333, LM8333_ACTIVE,
180				    pdata->active_time / 3);
181		if (err)
182			dev_warn(&client->dev, "Unable to set active time\n");
183	}
184
185	err = request_threaded_irq(client->irq, NULL, lm8333_irq_thread,
186				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
187				   "lm8333", lm8333);
188	if (err)
189		goto free_mem;
190
191	err = input_register_device(input);
192	if (err)
193		goto free_irq;
194
195	i2c_set_clientdata(client, lm8333);
196	return 0;
197
198 free_irq:
199	free_irq(client->irq, lm8333);
200 free_mem:
201	input_free_device(input);
202	kfree(lm8333);
203	return err;
204}
205
206static int lm8333_remove(struct i2c_client *client)
207{
208	struct lm8333 *lm8333 = i2c_get_clientdata(client);
209
210	free_irq(client->irq, lm8333);
211	input_unregister_device(lm8333->input);
212	kfree(lm8333);
213
214	return 0;
215}
216
217static const struct i2c_device_id lm8333_id[] = {
218	{ "lm8333", 0 },
219	{ }
220};
221MODULE_DEVICE_TABLE(i2c, lm8333_id);
222
223static struct i2c_driver lm8333_driver = {
224	.driver = {
225		.name		= "lm8333",
226	},
227	.probe		= lm8333_probe,
228	.remove		= lm8333_remove,
229	.id_table	= lm8333_id,
230};
231module_i2c_driver(lm8333_driver);
232
233MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
234MODULE_DESCRIPTION("LM8333 keyboard driver");
235MODULE_LICENSE("GPL v2");
236