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/acpi.h> 16 #include <linux/regmap.h> 17 #include <linux/iio/sysfs.h> 18 19 #define MXC6255_DRV_NAME "mxc6255" 20 #define MXC6255_REGMAP_NAME "mxc6255_regmap" 21 22 #define MXC6255_REG_XOUT 0x00 23 #define MXC6255_REG_YOUT 0x01 24 #define MXC6255_REG_CHIP_ID 0x08 25 26 #define MXC6255_CHIP_ID 0x05 27 28 /* 29 * MXC6255 has only one measurement range: +/- 2G. 30 * The acceleration output is an 8-bit value. 31 * 32 * Scale is calculated as follows: 33 * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829 34 * 35 * Scale value for +/- 2G measurement range 36 */ 37 #define MXC6255_SCALE 153829 38 39 enum mxc6255_axis { 40 AXIS_X, 41 AXIS_Y, 42 }; 43 44 struct mxc6255_data { 45 struct i2c_client *client; 46 struct regmap *regmap; 47 }; 48 49 static int mxc6255_read_raw(struct iio_dev *indio_dev, 50 struct iio_chan_spec const *chan, 51 int *val, int *val2, long mask) 52 { 53 struct mxc6255_data *data = iio_priv(indio_dev); 54 unsigned int reg; 55 int ret; 56 57 switch (mask) { 58 case IIO_CHAN_INFO_RAW: 59 ret = regmap_read(data->regmap, chan->address, ®); 60 if (ret < 0) { 61 dev_err(&data->client->dev, 62 "Error reading reg %lu\n", chan->address); 63 return ret; 64 } 65 66 *val = sign_extend32(reg, 7); 67 return IIO_VAL_INT; 68 case IIO_CHAN_INFO_SCALE: 69 *val = 0; 70 *val2 = MXC6255_SCALE; 71 return IIO_VAL_INT_PLUS_MICRO; 72 default: 73 return -EINVAL; 74 } 75 } 76 77 static const struct iio_info mxc6255_info = { 78 .read_raw = mxc6255_read_raw, 79 }; 80 81 #define MXC6255_CHANNEL(_axis, reg) { \ 82 .type = IIO_ACCEL, \ 83 .modified = 1, \ 84 .channel2 = IIO_MOD_##_axis, \ 85 .address = reg, \ 86 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 87 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 88 } 89 90 static const struct iio_chan_spec mxc6255_channels[] = { 91 MXC6255_CHANNEL(X, MXC6255_REG_XOUT), 92 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT), 93 }; 94 95 static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg) 96 { 97 switch (reg) { 98 case MXC6255_REG_XOUT: 99 case MXC6255_REG_YOUT: 100 case MXC6255_REG_CHIP_ID: 101 return true; 102 default: 103 return false; 104 } 105 } 106 107 static const struct regmap_config mxc6255_regmap_config = { 108 .name = MXC6255_REGMAP_NAME, 109 110 .reg_bits = 8, 111 .val_bits = 8, 112 113 .readable_reg = mxc6255_is_readable_reg, 114 }; 115 116 static int mxc6255_probe(struct i2c_client *client) 117 { 118 struct mxc6255_data *data; 119 struct iio_dev *indio_dev; 120 struct regmap *regmap; 121 unsigned int chip_id; 122 int ret; 123 124 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 125 if (!indio_dev) 126 return -ENOMEM; 127 128 regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config); 129 if (IS_ERR(regmap)) { 130 dev_err(&client->dev, "Error initializing regmap\n"); 131 return PTR_ERR(regmap); 132 } 133 134 data = iio_priv(indio_dev); 135 i2c_set_clientdata(client, indio_dev); 136 data->client = client; 137 data->regmap = regmap; 138 139 indio_dev->name = MXC6255_DRV_NAME; 140 indio_dev->channels = mxc6255_channels; 141 indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels); 142 indio_dev->modes = INDIO_DIRECT_MODE; 143 indio_dev->info = &mxc6255_info; 144 145 ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id); 146 if (ret < 0) { 147 dev_err(&client->dev, "Error reading chip id %d\n", ret); 148 return ret; 149 } 150 151 if ((chip_id & 0x1f) != MXC6255_CHIP_ID) { 152 dev_err(&client->dev, "Invalid chip id %x\n", chip_id); 153 return -ENODEV; 154 } 155 156 dev_dbg(&client->dev, "Chip id %x\n", chip_id); 157 158 ret = devm_iio_device_register(&client->dev, indio_dev); 159 if (ret < 0) { 160 dev_err(&client->dev, "Could not register IIO device\n"); 161 return ret; 162 } 163 164 return 0; 165 } 166 167 static const struct acpi_device_id mxc6255_acpi_match[] = { 168 {"MXC6225", 0}, 169 {"MXC6255", 0}, 170 { } 171 }; 172 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match); 173 174 static const struct i2c_device_id mxc6255_id[] = { 175 {"mxc6225", 0}, 176 {"mxc6255", 0}, 177 { } 178 }; 179 MODULE_DEVICE_TABLE(i2c, mxc6255_id); 180 181 static struct i2c_driver mxc6255_driver = { 182 .driver = { 183 .name = MXC6255_DRV_NAME, 184 .acpi_match_table = ACPI_PTR(mxc6255_acpi_match), 185 }, 186 .probe_new = mxc6255_probe, 187 .id_table = mxc6255_id, 188 }; 189 190 module_i2c_driver(mxc6255_driver); 191 192 MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>"); 193 MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver"); 194 MODULE_LICENSE("GPL v2"); 195