1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * IIO driver for the 3-axis accelerometer Domintech DMARD09. 4 * 5 * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl> 6 */ 7 8 #include <asm/unaligned.h> 9 #include <linux/module.h> 10 #include <linux/i2c.h> 11 #include <linux/iio/iio.h> 12 13 #define DMARD09_DRV_NAME "dmard09" 14 15 #define DMARD09_REG_CHIPID 0x18 16 #define DMARD09_REG_STAT 0x0A 17 #define DMARD09_REG_X 0x0C 18 #define DMARD09_REG_Y 0x0E 19 #define DMARD09_REG_Z 0x10 20 #define DMARD09_CHIPID 0x95 21 22 #define DMARD09_BUF_LEN 8 23 #define DMARD09_AXIS_X 0 24 #define DMARD09_AXIS_Y 1 25 #define DMARD09_AXIS_Z 2 26 #define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2) 27 #define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2) 28 #define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2) 29 30 struct dmard09_data { 31 struct i2c_client *client; 32 }; 33 34 #define DMARD09_CHANNEL(_axis, offset) { \ 35 .type = IIO_ACCEL, \ 36 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 37 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 38 .modified = 1, \ 39 .address = offset, \ 40 .channel2 = IIO_MOD_##_axis, \ 41 } 42 43 static const struct iio_chan_spec dmard09_channels[] = { 44 DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET), 45 DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET), 46 DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET), 47 }; 48 49 static int dmard09_read_raw(struct iio_dev *indio_dev, 50 struct iio_chan_spec const *chan, 51 int *val, int *val2, long mask) 52 { 53 struct dmard09_data *data = iio_priv(indio_dev); 54 u8 buf[DMARD09_BUF_LEN]; 55 int ret; 56 s16 accel; 57 58 switch (mask) { 59 case IIO_CHAN_INFO_RAW: 60 /* 61 * Read from the DMAR09_REG_STAT register, since the chip 62 * caches reads from the individual X, Y, Z registers. 63 */ 64 ret = i2c_smbus_read_i2c_block_data(data->client, 65 DMARD09_REG_STAT, 66 DMARD09_BUF_LEN, buf); 67 if (ret < 0) { 68 dev_err(&data->client->dev, "Error reading reg %d\n", 69 DMARD09_REG_STAT); 70 return ret; 71 } 72 73 accel = get_unaligned_le16(&buf[chan->address]); 74 75 /* Remove lower 3 bits and sign extend */ 76 accel <<= 4; 77 accel >>= 7; 78 79 *val = accel; 80 81 return IIO_VAL_INT; 82 default: 83 return -EINVAL; 84 } 85 } 86 87 static const struct iio_info dmard09_info = { 88 .read_raw = dmard09_read_raw, 89 }; 90 91 static int dmard09_probe(struct i2c_client *client, 92 const struct i2c_device_id *id) 93 { 94 int ret; 95 struct iio_dev *indio_dev; 96 struct dmard09_data *data; 97 98 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 99 if (!indio_dev) { 100 dev_err(&client->dev, "iio allocation failed\n"); 101 return -ENOMEM; 102 } 103 104 data = iio_priv(indio_dev); 105 data->client = client; 106 107 ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID); 108 if (ret < 0) { 109 dev_err(&client->dev, "Error reading chip id %d\n", ret); 110 return ret; 111 } 112 113 if (ret != DMARD09_CHIPID) { 114 dev_err(&client->dev, "Invalid chip id %d\n", ret); 115 return -ENODEV; 116 } 117 118 i2c_set_clientdata(client, indio_dev); 119 indio_dev->name = DMARD09_DRV_NAME; 120 indio_dev->modes = INDIO_DIRECT_MODE; 121 indio_dev->channels = dmard09_channels; 122 indio_dev->num_channels = ARRAY_SIZE(dmard09_channels); 123 indio_dev->info = &dmard09_info; 124 125 return devm_iio_device_register(&client->dev, indio_dev); 126 } 127 128 static const struct i2c_device_id dmard09_id[] = { 129 { "dmard09", 0 }, 130 { }, 131 }; 132 133 MODULE_DEVICE_TABLE(i2c, dmard09_id); 134 135 static struct i2c_driver dmard09_driver = { 136 .driver = { 137 .name = DMARD09_DRV_NAME 138 }, 139 .probe = dmard09_probe, 140 .id_table = dmard09_id, 141 }; 142 143 module_i2c_driver(dmard09_driver); 144 145 MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>"); 146 MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver"); 147 MODULE_LICENSE("GPL"); 148