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Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/accel/mma7660.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/iio/accel/mma7660.c b/drivers/iio/accel/mma7660.c new file mode 100644 index 000000000..f1a13724e --- /dev/null +++ b/drivers/iio/accel/mma7660.c @@ -0,0 +1,284 @@ +/** + * Freescale MMA7660FC 3-Axis Accelerometer + * + * Copyright (c) 2016, Intel Corporation. + * + * This file is subject to the terms and conditions of version 2 of + * the GNU General Public License. See the file COPYING in the main + * directory of this archive for more details. + * + * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c. + */ + +#include <linux/acpi.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define MMA7660_DRIVER_NAME "mma7660" + +#define MMA7660_REG_XOUT 0x00 +#define MMA7660_REG_YOUT 0x01 +#define MMA7660_REG_ZOUT 0x02 +#define MMA7660_REG_OUT_BIT_ALERT BIT(6) + +#define MMA7660_REG_MODE 0x07 +#define MMA7660_REG_MODE_BIT_MODE BIT(0) +#define MMA7660_REG_MODE_BIT_TON BIT(2) + +#define MMA7660_I2C_READ_RETRIES 5 + +/* + * The accelerometer has one measurement range: + * + * -1.5g - +1.5g (6-bit, signed) + * + * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1) = 0.467142857 + */ + +#define MMA7660_SCALE_AVAIL "0.467142857" + +static const int mma7660_nscale = 467142857; + +#define MMA7660_CHANNEL(reg, axis) { \ + .type = IIO_ACCEL, \ + .address = reg, \ + .modified = 1, \ + .channel2 = IIO_MOD_##axis, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +static const struct iio_chan_spec mma7660_channels[] = { + MMA7660_CHANNEL(MMA7660_REG_XOUT, X), + MMA7660_CHANNEL(MMA7660_REG_YOUT, Y), + MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z), +}; + +enum mma7660_mode { + MMA7660_MODE_STANDBY, + MMA7660_MODE_ACTIVE +}; + +struct mma7660_data { + struct i2c_client *client; + struct mutex lock; + enum mma7660_mode mode; +}; + +static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL); + +static struct attribute *mma7660_attributes[] = { + &iio_const_attr_in_accel_scale_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group mma7660_attribute_group = { + .attrs = mma7660_attributes +}; + +static int mma7660_set_mode(struct mma7660_data *data, + enum mma7660_mode mode) +{ + int ret; + struct i2c_client *client = data->client; + + if (mode == data->mode) + return 0; + + ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE); + if (ret < 0) { + dev_err(&client->dev, "failed to read sensor mode\n"); + return ret; + } + + if (mode == MMA7660_MODE_ACTIVE) { + ret &= ~MMA7660_REG_MODE_BIT_TON; + ret |= MMA7660_REG_MODE_BIT_MODE; + } else { + ret &= ~MMA7660_REG_MODE_BIT_TON; + ret &= ~MMA7660_REG_MODE_BIT_MODE; + } + + ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret); + if (ret < 0) { + dev_err(&client->dev, "failed to change sensor mode\n"); + return ret; + } + + data->mode = mode; + + return ret; +} + +static int mma7660_read_accel(struct mma7660_data *data, u8 address) +{ + int ret, retries = MMA7660_I2C_READ_RETRIES; + struct i2c_client *client = data->client; + + /* + * Read data. If the Alert bit is set, the register was read at + * the same time as the device was attempting to update the content. + * The solution is to read the register again. Do this only + * MMA7660_I2C_READ_RETRIES times to avoid spending too much time + * in the kernel. + */ + do { + ret = i2c_smbus_read_byte_data(client, address); + if (ret < 0) { + dev_err(&client->dev, "register read failed\n"); + return ret; + } + } while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT); + + if (ret & MMA7660_REG_OUT_BIT_ALERT) { + dev_err(&client->dev, "all register read retries failed\n"); + return -ETIMEDOUT; + } + + return ret; +} + +static int mma7660_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mma7660_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + ret = mma7660_read_accel(data, chan->address); + mutex_unlock(&data->lock); + if (ret < 0) + return ret; + *val = sign_extend32(ret, 5); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = mma7660_nscale; + return IIO_VAL_INT_PLUS_NANO; + default: + return -EINVAL; + } + + return -EINVAL; +} + +static const struct iio_info mma7660_info = { + .read_raw = mma7660_read_raw, + .attrs = &mma7660_attribute_group, +}; + +static int mma7660_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int ret; + struct iio_dev *indio_dev; + struct mma7660_data *data; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) { + dev_err(&client->dev, "iio allocation failed!\n"); + return -ENOMEM; + } + + data = iio_priv(indio_dev); + data->client = client; + i2c_set_clientdata(client, indio_dev); + mutex_init(&data->lock); + data->mode = MMA7660_MODE_STANDBY; + + indio_dev->dev.parent = &client->dev; + indio_dev->info = &mma7660_info; + indio_dev->name = MMA7660_DRIVER_NAME; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = mma7660_channels; + indio_dev->num_channels = ARRAY_SIZE(mma7660_channels); + + ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE); + if (ret < 0) + return ret; + + ret = iio_device_register(indio_dev); + if (ret < 0) { + dev_err(&client->dev, "device_register failed\n"); + mma7660_set_mode(data, MMA7660_MODE_STANDBY); + } + + return ret; +} + +static int mma7660_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + + iio_device_unregister(indio_dev); + + return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY); +} + +#ifdef CONFIG_PM_SLEEP +static int mma7660_suspend(struct device *dev) +{ + struct mma7660_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return mma7660_set_mode(data, MMA7660_MODE_STANDBY); +} + +static int mma7660_resume(struct device *dev) +{ + struct mma7660_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return mma7660_set_mode(data, MMA7660_MODE_ACTIVE); +} + +static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume); + +#define MMA7660_PM_OPS (&mma7660_pm_ops) +#else +#define MMA7660_PM_OPS NULL +#endif + +static const struct i2c_device_id mma7660_i2c_id[] = { + {"mma7660", 0}, + {} +}; +MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id); + +static const struct of_device_id mma7660_of_match[] = { + { .compatible = "fsl,mma7660" }, + { } +}; +MODULE_DEVICE_TABLE(of, mma7660_of_match); + +static const struct acpi_device_id mma7660_acpi_id[] = { + {"MMA7660", 0}, + {} +}; + +MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id); + +static struct i2c_driver mma7660_driver = { + .driver = { + .name = "mma7660", + .pm = MMA7660_PM_OPS, + .of_match_table = mma7660_of_match, + .acpi_match_table = ACPI_PTR(mma7660_acpi_id), + }, + .probe = mma7660_probe, + .remove = mma7660_remove, + .id_table = mma7660_i2c_id, +}; + +module_i2c_driver(mma7660_driver); + +MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>"); +MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver"); +MODULE_LICENSE("GPL v2"); |