xref: /openbmc/linux/drivers/iio/accel/mma7660.c (revision 6aa7de05)
1 /**
2  * Freescale MMA7660FC 3-Axis Accelerometer
3  *
4  * Copyright (c) 2016, Intel Corporation.
5  *
6  * This file is subject to the terms and conditions of version 2 of
7  * the GNU General Public License. See the file COPYING in the main
8  * directory of this archive for more details.
9  *
10  * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
11  */
12 
13 #include <linux/acpi.h>
14 #include <linux/i2c.h>
15 #include <linux/module.h>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
18 
19 #define MMA7660_DRIVER_NAME	"mma7660"
20 
21 #define MMA7660_REG_XOUT	0x00
22 #define MMA7660_REG_YOUT	0x01
23 #define MMA7660_REG_ZOUT	0x02
24 #define MMA7660_REG_OUT_BIT_ALERT	BIT(6)
25 
26 #define MMA7660_REG_MODE	0x07
27 #define MMA7660_REG_MODE_BIT_MODE	BIT(0)
28 #define MMA7660_REG_MODE_BIT_TON	BIT(2)
29 
30 #define MMA7660_I2C_READ_RETRIES	5
31 
32 /*
33  * The accelerometer has one measurement range:
34  *
35  * -1.5g - +1.5g (6-bit, signed)
36  *
37  * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1)	= 0.467142857
38  */
39 
40 #define MMA7660_SCALE_AVAIL	"0.467142857"
41 
42 static const int mma7660_nscale = 467142857;
43 
44 #define MMA7660_CHANNEL(reg, axis) {	\
45 	.type = IIO_ACCEL,	\
46 	.address = reg,	\
47 	.modified = 1,	\
48 	.channel2 = IIO_MOD_##axis,	\
49 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
50 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
51 }
52 
53 static const struct iio_chan_spec mma7660_channels[] = {
54 	MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
55 	MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
56 	MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
57 };
58 
59 enum mma7660_mode {
60 	MMA7660_MODE_STANDBY,
61 	MMA7660_MODE_ACTIVE
62 };
63 
64 struct mma7660_data {
65 	struct i2c_client *client;
66 	struct mutex lock;
67 	enum mma7660_mode mode;
68 };
69 
70 static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
71 
72 static struct attribute *mma7660_attributes[] = {
73 	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
74 	NULL,
75 };
76 
77 static const struct attribute_group mma7660_attribute_group = {
78 	.attrs = mma7660_attributes
79 };
80 
81 static int mma7660_set_mode(struct mma7660_data *data,
82 				enum mma7660_mode mode)
83 {
84 	int ret;
85 	struct i2c_client *client = data->client;
86 
87 	if (mode == data->mode)
88 		return 0;
89 
90 	ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
91 	if (ret < 0) {
92 		dev_err(&client->dev, "failed to read sensor mode\n");
93 		return ret;
94 	}
95 
96 	if (mode == MMA7660_MODE_ACTIVE) {
97 		ret &= ~MMA7660_REG_MODE_BIT_TON;
98 		ret |= MMA7660_REG_MODE_BIT_MODE;
99 	} else {
100 		ret &= ~MMA7660_REG_MODE_BIT_TON;
101 		ret &= ~MMA7660_REG_MODE_BIT_MODE;
102 	}
103 
104 	ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
105 	if (ret < 0) {
106 		dev_err(&client->dev, "failed to change sensor mode\n");
107 		return ret;
108 	}
109 
110 	data->mode = mode;
111 
112 	return ret;
113 }
114 
115 static int mma7660_read_accel(struct mma7660_data *data, u8 address)
116 {
117 	int ret, retries = MMA7660_I2C_READ_RETRIES;
118 	struct i2c_client *client = data->client;
119 
120 	/*
121 	 * Read data. If the Alert bit is set, the register was read at
122 	 * the same time as the device was attempting to update the content.
123 	 * The solution is to read the register again. Do this only
124 	 * MMA7660_I2C_READ_RETRIES times to avoid spending too much time
125 	 * in the kernel.
126 	 */
127 	do {
128 		ret = i2c_smbus_read_byte_data(client, address);
129 		if (ret < 0) {
130 			dev_err(&client->dev, "register read failed\n");
131 			return ret;
132 		}
133 	} while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);
134 
135 	if (ret & MMA7660_REG_OUT_BIT_ALERT) {
136 		dev_err(&client->dev, "all register read retries failed\n");
137 		return -ETIMEDOUT;
138 	}
139 
140 	return ret;
141 }
142 
143 static int mma7660_read_raw(struct iio_dev *indio_dev,
144 				struct iio_chan_spec const *chan,
145 				int *val, int *val2, long mask)
146 {
147 	struct mma7660_data *data = iio_priv(indio_dev);
148 	int ret;
149 
150 	switch (mask) {
151 	case IIO_CHAN_INFO_RAW:
152 		mutex_lock(&data->lock);
153 		ret = mma7660_read_accel(data, chan->address);
154 		mutex_unlock(&data->lock);
155 		if (ret < 0)
156 			return ret;
157 		*val = sign_extend32(ret, 5);
158 		return IIO_VAL_INT;
159 	case IIO_CHAN_INFO_SCALE:
160 		*val = 0;
161 		*val2 = mma7660_nscale;
162 		return IIO_VAL_INT_PLUS_NANO;
163 	default:
164 		return -EINVAL;
165 	}
166 
167 	return -EINVAL;
168 }
169 
170 static const struct iio_info mma7660_info = {
171 	.driver_module	= THIS_MODULE,
172 	.read_raw		= mma7660_read_raw,
173 	.attrs			= &mma7660_attribute_group,
174 };
175 
176 static int mma7660_probe(struct i2c_client *client,
177 			const struct i2c_device_id *id)
178 {
179 	int ret;
180 	struct iio_dev *indio_dev;
181 	struct mma7660_data *data;
182 
183 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
184 	if (!indio_dev) {
185 		dev_err(&client->dev, "iio allocation failed!\n");
186 		return -ENOMEM;
187 	}
188 
189 	data = iio_priv(indio_dev);
190 	data->client = client;
191 	i2c_set_clientdata(client, indio_dev);
192 	mutex_init(&data->lock);
193 	data->mode = MMA7660_MODE_STANDBY;
194 
195 	indio_dev->dev.parent = &client->dev;
196 	indio_dev->info = &mma7660_info;
197 	indio_dev->name = MMA7660_DRIVER_NAME;
198 	indio_dev->modes = INDIO_DIRECT_MODE;
199 	indio_dev->channels = mma7660_channels;
200 	indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);
201 
202 	ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
203 	if (ret < 0)
204 		return ret;
205 
206 	ret = iio_device_register(indio_dev);
207 	if (ret < 0) {
208 		dev_err(&client->dev, "device_register failed\n");
209 		mma7660_set_mode(data, MMA7660_MODE_STANDBY);
210 	}
211 
212 	return ret;
213 }
214 
215 static int mma7660_remove(struct i2c_client *client)
216 {
217 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
218 
219 	iio_device_unregister(indio_dev);
220 
221 	return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
222 }
223 
224 #ifdef CONFIG_PM_SLEEP
225 static int mma7660_suspend(struct device *dev)
226 {
227 	struct mma7660_data *data;
228 
229 	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
230 
231 	return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
232 }
233 
234 static int mma7660_resume(struct device *dev)
235 {
236 	struct mma7660_data *data;
237 
238 	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
239 
240 	return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
241 }
242 
243 static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);
244 
245 #define MMA7660_PM_OPS (&mma7660_pm_ops)
246 #else
247 #define MMA7660_PM_OPS NULL
248 #endif
249 
250 static const struct i2c_device_id mma7660_i2c_id[] = {
251 	{"mma7660", 0},
252 	{}
253 };
254 MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id);
255 
256 static const struct of_device_id mma7660_of_match[] = {
257 	{ .compatible = "fsl,mma7660" },
258 	{ }
259 };
260 MODULE_DEVICE_TABLE(of, mma7660_of_match);
261 
262 static const struct acpi_device_id mma7660_acpi_id[] = {
263 	{"MMA7660", 0},
264 	{}
265 };
266 
267 MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
268 
269 static struct i2c_driver mma7660_driver = {
270 	.driver = {
271 		.name = "mma7660",
272 		.pm = MMA7660_PM_OPS,
273 		.of_match_table = mma7660_of_match,
274 		.acpi_match_table = ACPI_PTR(mma7660_acpi_id),
275 	},
276 	.probe		= mma7660_probe,
277 	.remove		= mma7660_remove,
278 	.id_table	= mma7660_i2c_id,
279 };
280 
281 module_i2c_driver(mma7660_driver);
282 
283 MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
284 MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
285 MODULE_LICENSE("GPL v2");
286