xref: /linux/drivers/input/misc/mma8450.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
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 */
56 struct mma8450 {
57 	struct i2c_client	*client;
58 	struct input_polled_dev	*idev;
59 };
60 
61 static 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 
75 static 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 
91 static 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 
108 static 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 = ((buf[1] << 4) & 0xff0) | (buf[0] & 0xf);
127 	y = ((buf[3] << 4) & 0xff0) | (buf[2] & 0xf);
128 	z = ((buf[5] << 4) & 0xff0) | (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 */
137 static 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 
159 static 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  */
170 static 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 = kzalloc(sizeof(struct mma8450), GFP_KERNEL);
178 	idev = input_allocate_polled_device();
179 	if (!m || !idev) {
180 		err = -ENOMEM;
181 		goto err_free_mem;
182 	}
183 
184 	m->client = c;
185 	m->idev = idev;
186 
187 	idev->private		= m;
188 	idev->input->name	= MMA8450_DRV_NAME;
189 	idev->input->id.bustype	= BUS_I2C;
190 	idev->poll		= mma8450_poll;
191 	idev->poll_interval	= POLL_INTERVAL;
192 	idev->poll_interval_max	= POLL_INTERVAL_MAX;
193 	idev->open		= mma8450_open;
194 	idev->close		= mma8450_close;
195 
196 	__set_bit(EV_ABS, idev->input->evbit);
197 	input_set_abs_params(idev->input, ABS_X, -2048, 2047, 32, 32);
198 	input_set_abs_params(idev->input, ABS_Y, -2048, 2047, 32, 32);
199 	input_set_abs_params(idev->input, ABS_Z, -2048, 2047, 32, 32);
200 
201 	err = input_register_polled_device(idev);
202 	if (err) {
203 		dev_err(&c->dev, "failed to register polled input device\n");
204 		goto err_free_mem;
205 	}
206 
207 	return 0;
208 
209 err_free_mem:
210 	input_free_polled_device(idev);
211 	kfree(m);
212 	return err;
213 }
214 
215 static int mma8450_remove(struct i2c_client *c)
216 {
217 	struct mma8450 *m = i2c_get_clientdata(c);
218 	struct input_polled_dev *idev = m->idev;
219 
220 	input_unregister_polled_device(idev);
221 	input_free_polled_device(idev);
222 	kfree(m);
223 
224 	return 0;
225 }
226 
227 static const struct i2c_device_id mma8450_id[] = {
228 	{ MMA8450_DRV_NAME, 0 },
229 	{ },
230 };
231 MODULE_DEVICE_TABLE(i2c, mma8450_id);
232 
233 static const struct of_device_id mma8450_dt_ids[] = {
234 	{ .compatible = "fsl,mma8450", },
235 	{ /* sentinel */ }
236 };
237 MODULE_DEVICE_TABLE(of, mma8450_dt_ids);
238 
239 static struct i2c_driver mma8450_driver = {
240 	.driver = {
241 		.name	= MMA8450_DRV_NAME,
242 		.owner	= THIS_MODULE,
243 		.of_match_table = mma8450_dt_ids,
244 	},
245 	.probe		= mma8450_probe,
246 	.remove		= mma8450_remove,
247 	.id_table	= mma8450_id,
248 };
249 
250 module_i2c_driver(mma8450_driver);
251 
252 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
253 MODULE_DESCRIPTION("MMA8450 3-Axis Accelerometer Driver");
254 MODULE_LICENSE("GPL");
255