1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for Sensirion sdp500 and sdp510 pressure sensors
4 *
5 * Datasheet: https://sensirion.com/resource/datasheet/sdp600
6 */
7
8 #include <linux/i2c.h>
9 #include <linux/crc8.h>
10 #include <linux/iio/iio.h>
11 #include <linux/regulator/consumer.h>
12 #include <linux/unaligned.h>
13
14 #define SDP500_CRC8_POLYNOMIAL 0x31 /* x8+x5+x4+1 (normalized to 0x31) */
15 #define SDP500_READ_SIZE 3
16
17 #define SDP500_I2C_START_MEAS 0xF1
18
19 struct sdp500_data {
20 struct device *dev;
21 };
22
23 DECLARE_CRC8_TABLE(sdp500_crc8_table);
24
sdp500_start_measurement(struct sdp500_data * data)25 static int sdp500_start_measurement(struct sdp500_data *data)
26 {
27 struct i2c_client *client = to_i2c_client(data->dev);
28
29 return i2c_smbus_write_byte(client, SDP500_I2C_START_MEAS);
30 }
31
32 static const struct iio_chan_spec sdp500_channels[] = {
33 {
34 .type = IIO_PRESSURE,
35 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
36 BIT(IIO_CHAN_INFO_SCALE),
37 },
38 };
39
sdp500_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)40 static int sdp500_read_raw(struct iio_dev *indio_dev,
41 struct iio_chan_spec const *chan,
42 int *val, int *val2, long mask)
43 {
44 int ret;
45 u8 rxbuf[SDP500_READ_SIZE];
46 u8 received_crc, calculated_crc;
47 struct sdp500_data *data = iio_priv(indio_dev);
48 struct i2c_client *client = to_i2c_client(data->dev);
49
50 switch (mask) {
51 case IIO_CHAN_INFO_RAW:
52 ret = i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
53 if (ret < 0) {
54 dev_err(data->dev, "Failed to receive data");
55 return ret;
56 }
57 if (ret != SDP500_READ_SIZE) {
58 dev_err(data->dev, "Data is received wrongly");
59 return -EIO;
60 }
61
62 received_crc = rxbuf[2];
63 calculated_crc = crc8(sdp500_crc8_table, rxbuf,
64 sizeof(rxbuf) - 1, 0x00);
65 if (received_crc != calculated_crc) {
66 dev_err(data->dev,
67 "calculated crc = 0x%.2X, received 0x%.2X",
68 calculated_crc, received_crc);
69 return -EIO;
70 }
71
72 *val = get_unaligned_be16(rxbuf);
73 return IIO_VAL_INT;
74 case IIO_CHAN_INFO_SCALE:
75 *val = 1;
76 *val2 = 60;
77
78 return IIO_VAL_FRACTIONAL;
79 default:
80 return -EINVAL;
81 }
82 }
83
84 static const struct iio_info sdp500_info = {
85 .read_raw = &sdp500_read_raw,
86 };
87
sdp500_probe(struct i2c_client * client)88 static int sdp500_probe(struct i2c_client *client)
89 {
90 struct iio_dev *indio_dev;
91 struct sdp500_data *data;
92 struct device *dev = &client->dev;
93 int ret;
94 u8 rxbuf[SDP500_READ_SIZE];
95
96 ret = devm_regulator_get_enable(dev, "vdd");
97 if (ret)
98 return dev_err_probe(dev, ret,
99 "Failed to get and enable regulator\n");
100
101 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
102 if (!indio_dev)
103 return -ENOMEM;
104
105 /* has to be done before the first i2c communication */
106 crc8_populate_msb(sdp500_crc8_table, SDP500_CRC8_POLYNOMIAL);
107
108 data = iio_priv(indio_dev);
109 data->dev = dev;
110
111 indio_dev->name = "sdp500";
112 indio_dev->channels = sdp500_channels;
113 indio_dev->info = &sdp500_info;
114 indio_dev->modes = INDIO_DIRECT_MODE;
115 indio_dev->num_channels = ARRAY_SIZE(sdp500_channels);
116
117 ret = sdp500_start_measurement(data);
118 if (ret)
119 return dev_err_probe(dev, ret, "Failed to start measurement");
120
121 /* First measurement is not correct, read it out to get rid of it */
122 i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
123
124 ret = devm_iio_device_register(dev, indio_dev);
125 if (ret)
126 return dev_err_probe(dev, ret, "Failed to register indio_dev");
127
128 return 0;
129 }
130
131 static const struct i2c_device_id sdp500_id[] = {
132 { .name = "sdp500" },
133 { }
134 };
135 MODULE_DEVICE_TABLE(i2c, sdp500_id);
136
137 static const struct of_device_id sdp500_of_match[] = {
138 { .compatible = "sensirion,sdp500" },
139 { }
140 };
141 MODULE_DEVICE_TABLE(of, sdp500_of_match);
142
143 static struct i2c_driver sdp500_driver = {
144 .driver = {
145 .name = "sensirion,sdp500",
146 .of_match_table = sdp500_of_match,
147 },
148 .probe = sdp500_probe,
149 .id_table = sdp500_id,
150 };
151 module_i2c_driver(sdp500_driver);
152
153 MODULE_AUTHOR("Thomas Sioutas <thomas.sioutas@prodrive-technologies.com>");
154 MODULE_DESCRIPTION("Driver for Sensirion SDP500 differential pressure sensor");
155 MODULE_LICENSE("GPL");
156