mma7660.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Freescale MMA7660FC 3-Axis Accelerometer
  4 *
  5 * Copyright (c) 2016, Intel Corporation.
  6 *
  7 * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
  8 */
  9
 10#include <linux/i2c.h>
 11#include <linux/mod_devicetable.h>
 12#include <linux/module.h>
 13#include <linux/iio/iio.h>
 14#include <linux/iio/sysfs.h>
 15
 16#define MMA7660_DRIVER_NAME	"mma7660"
 17
 18#define MMA7660_REG_XOUT	0x00
 19#define MMA7660_REG_YOUT	0x01
 20#define MMA7660_REG_ZOUT	0x02
 21#define MMA7660_REG_OUT_BIT_ALERT	BIT(6)
 22
 23#define MMA7660_REG_MODE	0x07
 24#define MMA7660_REG_MODE_BIT_MODE	BIT(0)
 25#define MMA7660_REG_MODE_BIT_TON	BIT(2)
 26
 27#define MMA7660_I2C_READ_RETRIES	5
 28
 29/*
 30 * The accelerometer has one measurement range:
 31 *
 32 * -1.5g - +1.5g (6-bit, signed)
 33 *
 34 * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1)	= 0.467142857
 35 */
 36
 37#define MMA7660_SCALE_AVAIL	"0.467142857"
 38
 39static const int mma7660_nscale = 467142857;
 40
 41enum mma7660_mode {
 42	MMA7660_MODE_STANDBY,
 43	MMA7660_MODE_ACTIVE
 44};
 45
 46struct mma7660_data {
 47	struct i2c_client *client;
 48	struct mutex lock;
 49	enum mma7660_mode mode;
 50	struct iio_mount_matrix orientation;
 51};
 52
 53static const struct iio_mount_matrix *
 54mma7660_get_mount_matrix(const struct iio_dev *indio_dev,
 55			const struct iio_chan_spec *chan)
 56{
 57	struct mma7660_data *data = iio_priv(indio_dev);
 58
 59	return &data->orientation;
 60}
 61
 62static const struct iio_chan_spec_ext_info mma7660_ext_info[] = {
 63	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, mma7660_get_mount_matrix),
 64	{ }
 65};
 66
 67static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
 68
 69static struct attribute *mma7660_attributes[] = {
 70	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
 71	NULL,
 72};
 73
 74static const struct attribute_group mma7660_attribute_group = {
 75	.attrs = mma7660_attributes
 76};
 77
 78#define MMA7660_CHANNEL(reg, axis) {	\
 79	.type = IIO_ACCEL,	\
 80	.address = reg,	\
 81	.modified = 1,	\
 82	.channel2 = IIO_MOD_##axis,	\
 83	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 84	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
 85	.ext_info = mma7660_ext_info,				\
 86}
 87
 88static const struct iio_chan_spec mma7660_channels[] = {
 89	MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
 90	MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
 91	MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
 92};
 93
 94static int mma7660_set_mode(struct mma7660_data *data,
 95				enum mma7660_mode mode)
 96{
 97	int ret;
 98	struct i2c_client *client = data->client;
 99
100	if (mode == data->mode)
101		return 0;
102
103	ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
104	if (ret < 0) {
105		dev_err(&client->dev, "failed to read sensor mode\n");
106		return ret;
107	}
108
109	if (mode == MMA7660_MODE_ACTIVE) {
110		ret &= ~MMA7660_REG_MODE_BIT_TON;
111		ret |= MMA7660_REG_MODE_BIT_MODE;
112	} else {
113		ret &= ~MMA7660_REG_MODE_BIT_TON;
114		ret &= ~MMA7660_REG_MODE_BIT_MODE;
115	}
116
117	ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
118	if (ret < 0) {
119		dev_err(&client->dev, "failed to change sensor mode\n");
120		return ret;
121	}
122
123	data->mode = mode;
124
125	return ret;
126}
127
128static int mma7660_read_accel(struct mma7660_data *data, u8 address)
129{
130	int ret, retries = MMA7660_I2C_READ_RETRIES;
131	struct i2c_client *client = data->client;
132
133	/*
134	 * Read data. If the Alert bit is set, the register was read at
135	 * the same time as the device was attempting to update the content.
136	 * The solution is to read the register again. Do this only
137	 * MMA7660_I2C_READ_RETRIES times to avoid spending too much time
138	 * in the kernel.
139	 */
140	do {
141		ret = i2c_smbus_read_byte_data(client, address);
142		if (ret < 0) {
143			dev_err(&client->dev, "register read failed\n");
144			return ret;
145		}
146	} while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);
147
148	if (ret & MMA7660_REG_OUT_BIT_ALERT) {
149		dev_err(&client->dev, "all register read retries failed\n");
150		return -ETIMEDOUT;
151	}
152
153	return ret;
154}
155
156static int mma7660_read_raw(struct iio_dev *indio_dev,
157				struct iio_chan_spec const *chan,
158				int *val, int *val2, long mask)
159{
160	struct mma7660_data *data = iio_priv(indio_dev);
161	int ret;
162
163	switch (mask) {
164	case IIO_CHAN_INFO_RAW:
165		mutex_lock(&data->lock);
166		ret = mma7660_read_accel(data, chan->address);
167		mutex_unlock(&data->lock);
168		if (ret < 0)
169			return ret;
170		*val = sign_extend32(ret, 5);
171		return IIO_VAL_INT;
172	case IIO_CHAN_INFO_SCALE:
173		*val = 0;
174		*val2 = mma7660_nscale;
175		return IIO_VAL_INT_PLUS_NANO;
176	default:
177		return -EINVAL;
178	}
179
180	return -EINVAL;
181}
182
183static const struct iio_info mma7660_info = {
184	.read_raw		= mma7660_read_raw,
185	.attrs			= &mma7660_attribute_group,
186};
187
188static int mma7660_probe(struct i2c_client *client)
189{
190	int ret;
191	struct iio_dev *indio_dev;
192	struct mma7660_data *data;
193
194	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
195	if (!indio_dev)
196		return -ENOMEM;
197
198	data = iio_priv(indio_dev);
199	data->client = client;
200	i2c_set_clientdata(client, indio_dev);
201	mutex_init(&data->lock);
202	data->mode = MMA7660_MODE_STANDBY;
203
204	ret = iio_read_mount_matrix(&client->dev, &data->orientation);
205	if (ret)
206		return ret;
207
208	indio_dev->info = &mma7660_info;
209	indio_dev->name = MMA7660_DRIVER_NAME;
210	indio_dev->modes = INDIO_DIRECT_MODE;
211	indio_dev->channels = mma7660_channels;
212	indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);
213
214	ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
215	if (ret < 0)
216		return ret;
217
218	ret = iio_device_register(indio_dev);
219	if (ret < 0) {
220		dev_err(&client->dev, "device_register failed\n");
221		mma7660_set_mode(data, MMA7660_MODE_STANDBY);
222	}
223
224	return ret;
225}
226
227static void mma7660_remove(struct i2c_client *client)
228{
229	struct iio_dev *indio_dev = i2c_get_clientdata(client);
230	int ret;
231
232	iio_device_unregister(indio_dev);
233
234	ret = mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
235	if (ret)
236		dev_warn(&client->dev, "Failed to put device in stand-by mode (%pe), ignoring\n",
237			 ERR_PTR(ret));
238}
239
240static int mma7660_suspend(struct device *dev)
241{
242	struct mma7660_data *data;
243
244	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
245
246	return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
247}
248
249static int mma7660_resume(struct device *dev)
250{
251	struct mma7660_data *data;
252
253	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
254
255	return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
256}
257
258static DEFINE_SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend,
259				mma7660_resume);
260
261static const struct i2c_device_id mma7660_i2c_id[] = {
262	{ "mma7660" },
263	{ }
264};
265MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id);
266
267static const struct of_device_id mma7660_of_match[] = {
268	{ .compatible = "fsl,mma7660" },
269	{ }
270};
271MODULE_DEVICE_TABLE(of, mma7660_of_match);
272
273static const struct acpi_device_id mma7660_acpi_id[] = {
274	{"MMA7660", 0},
275	{ }
276};
277
278MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
279
280static struct i2c_driver mma7660_driver = {
281	.driver = {
282		.name = "mma7660",
283		.pm = pm_sleep_ptr(&mma7660_pm_ops),
284		.of_match_table = mma7660_of_match,
285		.acpi_match_table = mma7660_acpi_id,
286	},
287	.probe		= mma7660_probe,
288	.remove		= mma7660_remove,
289	.id_table	= mma7660_i2c_id,
290};
291
292module_i2c_driver(mma7660_driver);
293
294MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
295MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
296MODULE_LICENSE("GPL v2");