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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * MXC6255 - MEMSIC orientation sensing accelerometer4 *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#define MXC6255_REGMAP_NAME "mxc6255_regmap"21 22#define MXC6255_REG_XOUT 0x0023#define MXC6255_REG_YOUT 0x0124#define MXC6255_REG_CHIP_ID 0x0825 26#define MXC6255_CHIP_ID 0x0527 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) = 0.15382934 *35 * Scale value for +/- 2G measurement range36 */37#define MXC6255_SCALE 15382938 39enum mxc6255_axis {40 AXIS_X,41 AXIS_Y,42};43 44struct mxc6255_data {45 struct i2c_client *client;46 struct regmap *regmap;47};48 49static 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 77static 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 90static const struct iio_chan_spec mxc6255_channels[] = {91 MXC6255_CHANNEL(X, MXC6255_REG_XOUT),92 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),93};94 95static 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 107static 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 116static 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 167static const struct acpi_device_id mxc6255_acpi_match[] = {168 {"MXC6225", 0},169 {"MXC6255", 0},170 { }171};172MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);173 174static const struct i2c_device_id mxc6255_id[] = {175 { "mxc6225" },176 { "mxc6255" },177 { }178};179MODULE_DEVICE_TABLE(i2c, mxc6255_id);180 181static struct i2c_driver mxc6255_driver = {182 .driver = {183 .name = MXC6255_DRV_NAME,184 .acpi_match_table = mxc6255_acpi_match,185 },186 .probe = mxc6255_probe,187 .id_table = mxc6255_id,188};189 190module_i2c_driver(mxc6255_driver);191 192MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");193MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");194MODULE_LICENSE("GPL v2");195