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