1/*
2 *  Driver for Freescale's 3-Axis Accelerometer MMA8450
3 *
4 *  Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
5 *
6 *  This program is free software; you can redistribute it and/or modify
7 *  it under the terms of the GNU General Public License as published by
8 *  the Free Software Foundation; either version 2 of the License, or
9 *  (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/delay.h>
25#include <linux/i2c.h>
26#include <linux/input-polldev.h>
27#include <linux/of_device.h>
28
29#define MMA8450_DRV_NAME	"mma8450"
30
31#define MODE_CHANGE_DELAY_MS	100
32#define POLL_INTERVAL		100
33#define POLL_INTERVAL_MAX	500
34
35/* register definitions */
36#define MMA8450_STATUS		0x00
37#define MMA8450_STATUS_ZXYDR	0x08
38
39#define MMA8450_OUT_X8		0x01
40#define MMA8450_OUT_Y8		0x02
41#define MMA8450_OUT_Z8		0x03
42
43#define MMA8450_OUT_X_LSB	0x05
44#define MMA8450_OUT_X_MSB	0x06
45#define MMA8450_OUT_Y_LSB	0x07
46#define MMA8450_OUT_Y_MSB	0x08
47#define MMA8450_OUT_Z_LSB	0x09
48#define MMA8450_OUT_Z_MSB	0x0a
49
50#define MMA8450_XYZ_DATA_CFG	0x16
51
52#define MMA8450_CTRL_REG1	0x38
53#define MMA8450_CTRL_REG2	0x39
54
55/* mma8450 status */
56struct mma8450 {
57	struct i2c_client	*client;
58	struct input_polled_dev	*idev;
59};
60
61static int mma8450_read(struct mma8450 *m, unsigned off)
62{
63	struct i2c_client *c = m->client;
64	int ret;
65
66	ret = i2c_smbus_read_byte_data(c, off);
67	if (ret < 0)
68		dev_err(&c->dev,
69			"failed to read register 0x%02x, error %d\n",
70			off, ret);
71
72	return ret;
73}
74
75static int mma8450_write(struct mma8450 *m, unsigned off, u8 v)
76{
77	struct i2c_client *c = m->client;
78	int error;
79
80	error = i2c_smbus_write_byte_data(c, off, v);
81	if (error < 0) {
82		dev_err(&c->dev,
83			"failed to write to register 0x%02x, error %d\n",
84			off, error);
85		return error;
86	}
87
88	return 0;
89}
90
91static int mma8450_read_block(struct mma8450 *m, unsigned off,
92			      u8 *buf, size_t size)
93{
94	struct i2c_client *c = m->client;
95	int err;
96
97	err = i2c_smbus_read_i2c_block_data(c, off, size, buf);
98	if (err < 0) {
99		dev_err(&c->dev,
100			"failed to read block data at 0x%02x, error %d\n",
101			MMA8450_OUT_X_LSB, err);
102		return err;
103	}
104
105	return 0;
106}
107
108static void mma8450_poll(struct input_polled_dev *dev)
109{
110	struct mma8450 *m = dev->private;
111	int x, y, z;
112	int ret;
113	u8 buf[6];
114
115	ret = mma8450_read(m, MMA8450_STATUS);
116	if (ret < 0)
117		return;
118
119	if (!(ret & MMA8450_STATUS_ZXYDR))
120		return;
121
122	ret = mma8450_read_block(m, MMA8450_OUT_X_LSB, buf, sizeof(buf));
123	if (ret < 0)
124		return;
125
126	x = ((int)(s8)buf[1] << 4) | (buf[0] & 0xf);
127	y = ((int)(s8)buf[3] << 4) | (buf[2] & 0xf);
128	z = ((int)(s8)buf[5] << 4) | (buf[4] & 0xf);
129
130	input_report_abs(dev->input, ABS_X, x);
131	input_report_abs(dev->input, ABS_Y, y);
132	input_report_abs(dev->input, ABS_Z, z);
133	input_sync(dev->input);
134}
135
136/* Initialize the MMA8450 chip */
137static void mma8450_open(struct input_polled_dev *dev)
138{
139	struct mma8450 *m = dev->private;
140	int err;
141
142	/* enable all events from X/Y/Z, no FIFO */
143	err = mma8450_write(m, MMA8450_XYZ_DATA_CFG, 0x07);
144	if (err)
145		return;
146
147	/*
148	 * Sleep mode poll rate - 50Hz
149	 * System output data rate - 400Hz
150	 * Full scale selection - Active, +/- 2G
151	 */
152	err = mma8450_write(m, MMA8450_CTRL_REG1, 0x01);
153	if (err < 0)
154		return;
155
156	msleep(MODE_CHANGE_DELAY_MS);
157}
158
159static void mma8450_close(struct input_polled_dev *dev)
160{
161	struct mma8450 *m = dev->private;
162
163	mma8450_write(m, MMA8450_CTRL_REG1, 0x00);
164	mma8450_write(m, MMA8450_CTRL_REG2, 0x01);
165}
166
167/*
168 * I2C init/probing/exit functions
169 */
170static int mma8450_probe(struct i2c_client *c,
171			 const struct i2c_device_id *id)
172{
173	struct input_polled_dev *idev;
174	struct mma8450 *m;
175	int err;
176
177	m = devm_kzalloc(&c->dev, sizeof(*m), GFP_KERNEL);
178	if (!m)
179		return -ENOMEM;
180
181	idev = devm_input_allocate_polled_device(&c->dev);
182	if (!idev)
183		return -ENOMEM;
184
185	m->client = c;
186	m->idev = idev;
187
188	idev->private		= m;
189	idev->input->name	= MMA8450_DRV_NAME;
190	idev->input->id.bustype	= BUS_I2C;
191	idev->poll		= mma8450_poll;
192	idev->poll_interval	= POLL_INTERVAL;
193	idev->poll_interval_max	= POLL_INTERVAL_MAX;
194	idev->open		= mma8450_open;
195	idev->close		= mma8450_close;
196
197	__set_bit(EV_ABS, idev->input->evbit);
198	input_set_abs_params(idev->input, ABS_X, -2048, 2047, 32, 32);
199	input_set_abs_params(idev->input, ABS_Y, -2048, 2047, 32, 32);
200	input_set_abs_params(idev->input, ABS_Z, -2048, 2047, 32, 32);
201
202	err = input_register_polled_device(idev);
203	if (err) {
204		dev_err(&c->dev, "failed to register polled input device\n");
205		return err;
206	}
207
208	i2c_set_clientdata(c, m);
209
210	return 0;
211}
212
213static const struct i2c_device_id mma8450_id[] = {
214	{ MMA8450_DRV_NAME, 0 },
215	{ },
216};
217MODULE_DEVICE_TABLE(i2c, mma8450_id);
218
219static const struct of_device_id mma8450_dt_ids[] = {
220	{ .compatible = "fsl,mma8450", },
221	{ /* sentinel */ }
222};
223MODULE_DEVICE_TABLE(of, mma8450_dt_ids);
224
225static struct i2c_driver mma8450_driver = {
226	.driver = {
227		.name	= MMA8450_DRV_NAME,
228		.of_match_table = mma8450_dt_ids,
229	},
230	.probe		= mma8450_probe,
231	.id_table	= mma8450_id,
232};
233
234module_i2c_driver(mma8450_driver);
235
236MODULE_AUTHOR("Freescale Semiconductor, Inc.");
237MODULE_DESCRIPTION("MMA8450 3-Axis Accelerometer Driver");
238MODULE_LICENSE("GPL");
239