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/mod_devicetable.h> 12 #include <linux/regulator/consumer.h> 13 #include <asm/unaligned.h> 14 15 #define SDP500_CRC8_POLYNOMIAL 0x31 /* x8+x5+x4+1 (normalized to 0x31) */ 16 #define SDP500_READ_SIZE 3 17 18 #define SDP500_I2C_START_MEAS 0xF1 19 20 struct sdp500_data { 21 struct device *dev; 22 }; 23 24 DECLARE_CRC8_TABLE(sdp500_crc8_table); 25 26 static int sdp500_start_measurement(struct sdp500_data *data) 27 { 28 struct i2c_client *client = to_i2c_client(data->dev); 29 30 return i2c_smbus_write_byte(client, SDP500_I2C_START_MEAS); 31 } 32 33 static const struct iio_chan_spec sdp500_channels[] = { 34 { 35 .type = IIO_PRESSURE, 36 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 37 BIT(IIO_CHAN_INFO_SCALE), 38 }, 39 }; 40 41 static int sdp500_read_raw(struct iio_dev *indio_dev, 42 struct iio_chan_spec const *chan, 43 int *val, int *val2, long mask) 44 { 45 int ret; 46 u8 rxbuf[SDP500_READ_SIZE]; 47 u8 received_crc, calculated_crc; 48 struct sdp500_data *data = iio_priv(indio_dev); 49 struct i2c_client *client = to_i2c_client(data->dev); 50 51 switch (mask) { 52 case IIO_CHAN_INFO_RAW: 53 ret = i2c_master_recv(client, rxbuf, SDP500_READ_SIZE); 54 if (ret < 0) { 55 dev_err(data->dev, "Failed to receive data"); 56 return ret; 57 } 58 if (ret != SDP500_READ_SIZE) { 59 dev_err(data->dev, "Data is received wrongly"); 60 return -EIO; 61 } 62 63 received_crc = rxbuf[2]; 64 calculated_crc = crc8(sdp500_crc8_table, rxbuf, 65 sizeof(rxbuf) - 1, 0x00); 66 if (received_crc != calculated_crc) { 67 dev_err(data->dev, 68 "calculated crc = 0x%.2X, received 0x%.2X", 69 calculated_crc, received_crc); 70 return -EIO; 71 } 72 73 *val = get_unaligned_be16(rxbuf); 74 return IIO_VAL_INT; 75 case IIO_CHAN_INFO_SCALE: 76 *val = 1; 77 *val2 = 60; 78 79 return IIO_VAL_FRACTIONAL; 80 default: 81 return -EINVAL; 82 } 83 } 84 85 static const struct iio_info sdp500_info = { 86 .read_raw = &sdp500_read_raw, 87 }; 88 89 static int sdp500_probe(struct i2c_client *client) 90 { 91 struct iio_dev *indio_dev; 92 struct sdp500_data *data; 93 struct device *dev = &client->dev; 94 int ret; 95 u8 rxbuf[SDP500_READ_SIZE]; 96 97 ret = devm_regulator_get_enable(dev, "vdd"); 98 if (ret) 99 return dev_err_probe(dev, ret, 100 "Failed to get and enable regulator\n"); 101 102 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 103 if (!indio_dev) 104 return -ENOMEM; 105 106 /* has to be done before the first i2c communication */ 107 crc8_populate_msb(sdp500_crc8_table, SDP500_CRC8_POLYNOMIAL); 108 109 data = iio_priv(indio_dev); 110 data->dev = dev; 111 112 indio_dev->name = "sdp500"; 113 indio_dev->channels = sdp500_channels; 114 indio_dev->info = &sdp500_info; 115 indio_dev->modes = INDIO_DIRECT_MODE; 116 indio_dev->num_channels = ARRAY_SIZE(sdp500_channels); 117 118 ret = sdp500_start_measurement(data); 119 if (ret) 120 return dev_err_probe(dev, ret, "Failed to start measurement"); 121 122 /* First measurement is not correct, read it out to get rid of it */ 123 i2c_master_recv(client, rxbuf, SDP500_READ_SIZE); 124 125 ret = devm_iio_device_register(dev, indio_dev); 126 if (ret) 127 return dev_err_probe(dev, ret, "Failed to register indio_dev"); 128 129 return 0; 130 } 131 132 static const struct i2c_device_id sdp500_id[] = { 133 { "sdp500" }, 134 { } 135 }; 136 MODULE_DEVICE_TABLE(i2c, sdp500_id); 137 138 static const struct of_device_id sdp500_of_match[] = { 139 { .compatible = "sensirion,sdp500" }, 140 { } 141 }; 142 MODULE_DEVICE_TABLE(of, sdp500_of_match); 143 144 static struct i2c_driver sdp500_driver = { 145 .driver = { 146 .name = "sensirion,sdp500", 147 .of_match_table = sdp500_of_match, 148 }, 149 .probe = sdp500_probe, 150 .id_table = sdp500_id, 151 }; 152 module_i2c_driver(sdp500_driver); 153 154 MODULE_AUTHOR("Thomas Sioutas <thomas.sioutas@prodrive-technologies.com>"); 155 MODULE_DESCRIPTION("Driver for Sensirion SDP500 differential pressure sensor"); 156 MODULE_LICENSE("GPL"); 157