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