![Hans de Goede](/assets/img/avatar_default.png)
The initial commit adding support for the mxc6225 assumed the mxc6225 has a chip-id of 0xe5 based on testing on a single Allwinner A23 tablet with a mxc6225. Testing on a bunch of other Allwinner tablets have shown that the chip-id for the mxc6225 is not constant. A datasheet for the MXC6255 which I've found online says that bits 7 and 6 of the chip-id register are undefined (for the mxc6255), testing on 5 different tablets with a mxc6225 has found the following ids: 0x25, 0x45, 0x65, 0x85, 0xe5. So it seems that for the mxc6225 bits 7, 6 and 5 of the chip-id register are undefined. This commit adjusts the chip-id check so that the mxc6255 driver properly recognizes the mxc6225 in all these tablets. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
201 lines
4.6 KiB
C
201 lines
4.6 KiB
C
/*
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* MXC6255 - MEMSIC orientation sensing accelerometer
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*
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* Copyright (c) 2015, Intel Corporation.
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* IIO driver for MXC6255 (7-bit I2C slave address 0x15).
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/iio/iio.h>
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#include <linux/delay.h>
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#include <linux/acpi.h>
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#include <linux/regmap.h>
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#include <linux/iio/sysfs.h>
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#define MXC6255_DRV_NAME "mxc6255"
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#define MXC6255_REGMAP_NAME "mxc6255_regmap"
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#define MXC6255_REG_XOUT 0x00
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#define MXC6255_REG_YOUT 0x01
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#define MXC6255_REG_CHIP_ID 0x08
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#define MXC6255_CHIP_ID 0x05
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/*
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* MXC6255 has only one measurement range: +/- 2G.
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* The acceleration output is an 8-bit value.
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*
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* Scale is calculated as follows:
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* (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
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*
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* Scale value for +/- 2G measurement range
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*/
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#define MXC6255_SCALE 153829
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enum mxc6255_axis {
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AXIS_X,
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AXIS_Y,
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};
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struct mxc6255_data {
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struct i2c_client *client;
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struct regmap *regmap;
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};
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static int mxc6255_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct mxc6255_data *data = iio_priv(indio_dev);
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unsigned int reg;
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = regmap_read(data->regmap, chan->address, ®);
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if (ret < 0) {
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dev_err(&data->client->dev,
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"Error reading reg %lu\n", chan->address);
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return ret;
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}
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*val = sign_extend32(reg, 7);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = 0;
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*val2 = MXC6255_SCALE;
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return IIO_VAL_INT_PLUS_MICRO;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info mxc6255_info = {
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.driver_module = THIS_MODULE,
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.read_raw = mxc6255_read_raw,
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};
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#define MXC6255_CHANNEL(_axis, reg) { \
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.type = IIO_ACCEL, \
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.modified = 1, \
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.channel2 = IIO_MOD_##_axis, \
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.address = reg, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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static const struct iio_chan_spec mxc6255_channels[] = {
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MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
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MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
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};
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static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
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{
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switch (reg) {
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case MXC6255_REG_XOUT:
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case MXC6255_REG_YOUT:
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case MXC6255_REG_CHIP_ID:
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return true;
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default:
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return false;
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}
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}
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static const struct regmap_config mxc6255_regmap_config = {
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.name = MXC6255_REGMAP_NAME,
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.reg_bits = 8,
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.val_bits = 8,
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.readable_reg = mxc6255_is_readable_reg,
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};
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static int mxc6255_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct mxc6255_data *data;
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struct iio_dev *indio_dev;
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struct regmap *regmap;
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unsigned int chip_id;
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int ret;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
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if (IS_ERR(regmap)) {
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dev_err(&client->dev, "Error initializing regmap\n");
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return PTR_ERR(regmap);
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}
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client = client;
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data->regmap = regmap;
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indio_dev->name = MXC6255_DRV_NAME;
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indio_dev->dev.parent = &client->dev;
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indio_dev->channels = mxc6255_channels;
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indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &mxc6255_info;
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ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
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if (ret < 0) {
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dev_err(&client->dev, "Error reading chip id %d\n", ret);
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return ret;
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}
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if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
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dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
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return -ENODEV;
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}
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dev_dbg(&client->dev, "Chip id %x\n", chip_id);
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ret = devm_iio_device_register(&client->dev, indio_dev);
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if (ret < 0) {
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dev_err(&client->dev, "Could not register IIO device\n");
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return ret;
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}
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return 0;
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}
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static const struct acpi_device_id mxc6255_acpi_match[] = {
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{"MXC6225", 0},
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{"MXC6255", 0},
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
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static const struct i2c_device_id mxc6255_id[] = {
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{"mxc6225", 0},
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{"mxc6255", 0},
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, mxc6255_id);
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static struct i2c_driver mxc6255_driver = {
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.driver = {
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.name = MXC6255_DRV_NAME,
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.acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
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},
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.probe = mxc6255_probe,
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.id_table = mxc6255_id,
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};
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module_i2c_driver(mxc6255_driver);
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MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
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MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
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MODULE_LICENSE("GPL v2");
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