1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MXC6255 - MEMSIC orientation sensing accelerometer 4 * 5 * Copyright (c) 2015, Intel Corporation. 6 * 7 * IIO driver for MXC6255 (7-bit I2C slave address 0x15). 8 */ 9 10 #include <linux/module.h> 11 #include <linux/i2c.h> 12 #include <linux/init.h> 13 #include <linux/iio/iio.h> 14 #include <linux/delay.h> 15 #include <linux/mod_devicetable.h> 16 #include <linux/regmap.h> 17 #include <linux/iio/sysfs.h> 18 19 #define MXC6255_DRV_NAME "mxc6255" 20 21 #define MXC6255_REG_XOUT 0x00 22 #define MXC6255_REG_YOUT 0x01 23 #define MXC6255_REG_CHIP_ID 0x08 24 25 #define MXC6255_CHIP_ID 0x05 26 27 /* 28 * MXC6255 has only one measurement range: +/- 2G. 29 * The acceleration output is an 8-bit value. 30 * 31 * Scale is calculated as follows: 32 * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829 33 * 34 * Scale value for +/- 2G measurement range 35 */ 36 #define MXC6255_SCALE 153829 37 38 enum mxc6255_axis { 39 AXIS_X, 40 AXIS_Y, 41 }; 42 43 struct mxc6255_data { 44 struct i2c_client *client; 45 struct regmap *regmap; 46 }; 47 48 static int mxc6255_read_raw(struct iio_dev *indio_dev, 49 struct iio_chan_spec const *chan, 50 int *val, int *val2, long mask) 51 { 52 struct mxc6255_data *data = iio_priv(indio_dev); 53 unsigned int reg; 54 int ret; 55 56 switch (mask) { 57 case IIO_CHAN_INFO_RAW: 58 ret = regmap_read(data->regmap, chan->address, ®); 59 if (ret < 0) { 60 dev_err(&data->client->dev, 61 "Error reading reg %lu\n", chan->address); 62 return ret; 63 } 64 65 *val = sign_extend32(reg, 7); 66 return IIO_VAL_INT; 67 case IIO_CHAN_INFO_SCALE: 68 *val = 0; 69 *val2 = MXC6255_SCALE; 70 return IIO_VAL_INT_PLUS_MICRO; 71 default: 72 return -EINVAL; 73 } 74 } 75 76 static const struct iio_info mxc6255_info = { 77 .read_raw = mxc6255_read_raw, 78 }; 79 80 #define MXC6255_CHANNEL(_axis, reg) { \ 81 .type = IIO_ACCEL, \ 82 .modified = 1, \ 83 .channel2 = IIO_MOD_##_axis, \ 84 .address = reg, \ 85 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 86 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 87 } 88 89 static const struct iio_chan_spec mxc6255_channels[] = { 90 MXC6255_CHANNEL(X, MXC6255_REG_XOUT), 91 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT), 92 }; 93 94 static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg) 95 { 96 switch (reg) { 97 case MXC6255_REG_XOUT: 98 case MXC6255_REG_YOUT: 99 case MXC6255_REG_CHIP_ID: 100 return true; 101 default: 102 return false; 103 } 104 } 105 106 static const struct regmap_config mxc6255_regmap_config = { 107 .name = "mxc6255_regmap", 108 109 .reg_bits = 8, 110 .val_bits = 8, 111 112 .readable_reg = mxc6255_is_readable_reg, 113 }; 114 115 static int mxc6255_probe(struct i2c_client *client) 116 { 117 struct mxc6255_data *data; 118 struct iio_dev *indio_dev; 119 struct regmap *regmap; 120 unsigned int chip_id; 121 int ret; 122 123 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 124 if (!indio_dev) 125 return -ENOMEM; 126 127 regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config); 128 if (IS_ERR(regmap)) { 129 dev_err(&client->dev, "Error initializing regmap\n"); 130 return PTR_ERR(regmap); 131 } 132 133 data = iio_priv(indio_dev); 134 i2c_set_clientdata(client, indio_dev); 135 data->client = client; 136 data->regmap = regmap; 137 138 indio_dev->name = MXC6255_DRV_NAME; 139 indio_dev->channels = mxc6255_channels; 140 indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels); 141 indio_dev->modes = INDIO_DIRECT_MODE; 142 indio_dev->info = &mxc6255_info; 143 144 ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id); 145 if (ret < 0) { 146 dev_err(&client->dev, "Error reading chip id %d\n", ret); 147 return ret; 148 } 149 150 if ((chip_id & 0x1f) != MXC6255_CHIP_ID) { 151 dev_err(&client->dev, "Invalid chip id %x\n", chip_id); 152 return -ENODEV; 153 } 154 155 dev_dbg(&client->dev, "Chip id %x\n", chip_id); 156 157 ret = devm_iio_device_register(&client->dev, indio_dev); 158 if (ret < 0) { 159 dev_err(&client->dev, "Could not register IIO device\n"); 160 return ret; 161 } 162 163 return 0; 164 } 165 166 static const struct acpi_device_id mxc6255_acpi_match[] = { 167 {"MXC6225", 0}, 168 {"MXC6255", 0}, 169 { } 170 }; 171 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match); 172 173 static const struct i2c_device_id mxc6255_id[] = { 174 { "mxc6225" }, 175 { "mxc6255" }, 176 { } 177 }; 178 MODULE_DEVICE_TABLE(i2c, mxc6255_id); 179 180 static struct i2c_driver mxc6255_driver = { 181 .driver = { 182 .name = MXC6255_DRV_NAME, 183 .acpi_match_table = mxc6255_acpi_match, 184 }, 185 .probe = mxc6255_probe, 186 .id_table = mxc6255_id, 187 }; 188 189 module_i2c_driver(mxc6255_driver); 190 191 MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>"); 192 MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver"); 193 MODULE_LICENSE("GPL v2"); 194