Re: [PATCH] iio: Add Freescale MMA8452Q 3-axis accelerometer driver

[Jonathan Cameron <jic23@kernel.org>]

On 02/05/14 09:51, Peter Meerwald wrote:
> 3-axis accelerometer sensor (2/4/8 g) with 12-bit resolution
> and I2C interface
>
> many extra features are unsupported (freefall detection, orientation
> change, autosleep)
>
> datasheet is here:
> http://cache.freescale.com/files/sensors/doc/data_sheet/MMA8452Q.pdf
>
> v2: (thanks to Jonathan Cameron)
> * use ARRAY_SIZE()
>
> Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Fair enough on your responses in the cover letter.
Applied to the togreg branch of iio.git

Thanks,

Jonathan
> ---
>   drivers/iio/accel/Kconfig   |  12 ++
>   drivers/iio/accel/Makefile  |   1 +
>   drivers/iio/accel/mma8452.c | 439 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 452 insertions(+)
>   create mode 100644 drivers/iio/accel/mma8452.c
>
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index e23e5085..1e120fa 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -65,4 +65,16 @@ config KXSD9
>   	  Say yes here to build support for the Kionix KXSD9 accelerometer.
>   	  Currently this only supports the device via an SPI interface.
>
> +config MMA8452
> +	tristate "Freescale MMA8452Q Accelerometer Driver"
> +	depends on I2C
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	help
> +	  Say yes here to build support for the Freescale MMA8452Q 3-axis
> +	  accelerometer.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called mma8452.
> +
>   endmenu
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index c48d15f..dc0e379 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -6,6 +6,7 @@
>   obj-$(CONFIG_BMA180) += bma180.o
>   obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
>   obj-$(CONFIG_KXSD9)	+= kxsd9.o
> +obj-$(CONFIG_MMA8452)	+= mma8452.o
>
>   obj-$(CONFIG_IIO_ST_ACCEL_3AXIS) += st_accel.o
>   st_accel-y := st_accel_core.o
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> new file mode 100644
> index 0000000..17aeea1
> --- /dev/null
> +++ b/drivers/iio/accel/mma8452.c
> @@ -0,0 +1,439 @@
> +/*
> + * mma8452.c - Support for Freescale MMA8452Q 3-axis 12-bit accelerometer
> + *
> + * Copyright 2014 Peter Meerwald <pmeerw@pmeerw.net>
> + *
> + * 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.
> + *
> + * 7-bit I2C slave address 0x1c/0x1d (pin selectable)
> + *
> + * TODO: interrupt, thresholding, orientation / freefall events, autosleep
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/delay.h>
> +
> +#define MMA8452_STATUS 0x00
> +#define MMA8452_OUT_X 0x01 /* MSB first, 12-bit  */
> +#define MMA8452_OUT_Y 0x03
> +#define MMA8452_OUT_Z 0x05
> +#define MMA8452_WHO_AM_I 0x0d
> +#define MMA8452_DATA_CFG 0x0e
> +#define MMA8452_OFF_X 0x2f
> +#define MMA8452_OFF_Y 0x30
> +#define MMA8452_OFF_Z 0x31
> +#define MMA8452_CTRL_REG1 0x2a
> +#define MMA8452_CTRL_REG2 0x2b
> +
> +#define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
> +
> +#define MMA8452_CTRL_DR_MASK (BIT(5) | BIT(4) | BIT(3))
> +#define MMA8452_CTRL_DR_SHIFT 3
> +#define MMA8452_CTRL_DR_DEFAULT 0x4 /* 50 Hz sample frequency */
> +#define MMA8452_CTRL_ACTIVE BIT(0)
> +
> +#define MMA8452_DATA_CFG_FS_MASK (BIT(1) | BIT(0))
> +#define MMA8452_DATA_CFG_FS_2G 0
> +#define MMA8452_DATA_CFG_FS_4G 1
> +#define MMA8452_DATA_CFG_FS_8G 2
> +
> +#define MMA8452_DEVICE_ID 0x2a
> +
> +struct mma8452_data {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	u8 ctrl_reg1;
> +	u8 data_cfg;
> +};
> +
> +static int mma8452_drdy(struct mma8452_data *data)
> +{
> +	int tries = 150;
> +
> +	while (tries-- > 0) {
> +		int ret = i2c_smbus_read_byte_data(data->client,
> +			MMA8452_STATUS);
> +		if (ret < 0)
> +			return ret;
> +		if ((ret & MMA8452_STATUS_DRDY) == MMA8452_STATUS_DRDY)
> +			return 0;
> +		msleep(20);
> +	}
> +
> +	dev_err(&data->client->dev, "data not ready\n");
> +	return -EIO;
> +}
> +
> +static int mma8452_read(struct mma8452_data *data, __be16 buf[3])
> +{
> +	int ret = mma8452_drdy(data);
> +	if (ret < 0)
> +		return ret;
> +	return i2c_smbus_read_i2c_block_data(data->client,
> +		MMA8452_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
> +}
> +
> +static ssize_t mma8452_show_int_plus_micros(char *buf,
> +	const int (*vals)[2], int n)
> +{
> +	size_t len = 0;
> +
> +	while (n-- > 0)
> +		len += scnprintf(buf + len, PAGE_SIZE - len,
> +			"%d.%06d ", vals[n][0], vals[n][1]);
> +
> +	/* replace trailing space by newline */
> +	buf[len - 1] = '\n';
> +
> +	return len;
> +}
> +
> +static int mma8452_get_int_plus_micros_index(const int (*vals)[2], int n,
> +					int val, int val2)
> +{
> +	while (n-- > 0)
> +		if (val == vals[n][0] && val2 == vals[n][1])
> +			return n;
> +
> +	return -EINVAL;
> +}
> +
> +static const int mma8452_samp_freq[8][2] = {
> +	{800, 0}, {400, 0}, {200, 0}, {100, 0}, {50, 0}, {12, 500000},
> +	{6, 250000}, {1, 560000}
> +};
> +
> +static const int mma8452_scales[3][2] = {
> +	{0, 977}, {0, 1953}, {0, 3906}
> +};
> +
> +static ssize_t mma8452_show_samp_freq_avail(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	return mma8452_show_int_plus_micros(buf, mma8452_samp_freq,
> +		ARRAY_SIZE(mma8452_samp_freq));
> +}
> +
> +static ssize_t mma8452_show_scale_avail(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	return mma8452_show_int_plus_micros(buf, mma8452_scales,
> +		ARRAY_SIZE(mma8452_scales));
> +}
> +
> +static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma8452_show_samp_freq_avail);
> +static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
> +	mma8452_show_scale_avail, NULL, 0);
> +
> +static int mma8452_get_samp_freq_index(struct mma8452_data *data,
> +	int val, int val2)
> +{
> +	return mma8452_get_int_plus_micros_index(mma8452_samp_freq,
> +		ARRAY_SIZE(mma8452_samp_freq), val, val2);
> +}
> +
> +static int mma8452_get_scale_index(struct mma8452_data *data,
> +	int val, int val2)
> +{
> +	return mma8452_get_int_plus_micros_index(mma8452_scales,
> +		ARRAY_SIZE(mma8452_scales), val, val2);
> +}
> +
> +static int mma8452_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int *val, int *val2, long mask)
> +{
> +	struct mma8452_data *data = iio_priv(indio_dev);
> +	__be16 buffer[3];
> +	int i, ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (iio_buffer_enabled(indio_dev))
> +			return -EBUSY;
> +
> +		mutex_lock(&data->lock);
> +		ret = mma8452_read(data, buffer);
> +		mutex_unlock(&data->lock);
> +		if (ret < 0)
> +			return ret;
> +		*val = sign_extend32(
> +			be16_to_cpu(buffer[chan->scan_index]) >> 4, 11);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		i = data->data_cfg & MMA8452_DATA_CFG_FS_MASK;
> +		*val = mma8452_scales[i][0];
> +		*val2 = mma8452_scales[i][1];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		i = (data->ctrl_reg1 & MMA8452_CTRL_DR_MASK) >>
> +			MMA8452_CTRL_DR_SHIFT;
> +		*val = mma8452_samp_freq[i][0];
> +		*val2 = mma8452_samp_freq[i][1];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		ret = i2c_smbus_read_byte_data(data->client, MMA8452_OFF_X +
> +			chan->scan_index);
> +		if (ret < 0)
> +			return ret;
> +		*val = sign_extend32(ret, 7);
> +		return IIO_VAL_INT;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int mma8452_standby(struct mma8452_data *data)
> +{
> +	return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
> +		data->ctrl_reg1 & ~MMA8452_CTRL_ACTIVE);
> +}
> +
> +static int mma8452_active(struct mma8452_data *data)
> +{
> +	return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
> +		data->ctrl_reg1);
> +}
> +
> +static int mma8452_change_config(struct mma8452_data *data, u8 reg, u8 val)
> +{
> +	int ret;
> +
> +	mutex_lock(&data->lock);
> +
> +	/* config can only be changed when in standby */
> +	ret = mma8452_standby(data);
> +	if (ret < 0)
> +		goto fail;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, reg, val);
> +	if (ret < 0)
> +		goto fail;
> +
> +	ret = mma8452_active(data);
> +	if (ret < 0)
> +		goto fail;
> +
> +	ret = 0;
> +fail:
> +	mutex_unlock(&data->lock);
> +	return ret;
> +}
> +
> +static int mma8452_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int val, int val2, long mask)
> +{
> +	struct mma8452_data *data = iio_priv(indio_dev);
> +	int i;
> +
> +	if (iio_buffer_enabled(indio_dev))
> +		return -EBUSY;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		i = mma8452_get_samp_freq_index(data, val, val2);
> +		if (i < 0)
> +			return -EINVAL;
> +
> +		data->ctrl_reg1 &= ~MMA8452_CTRL_DR_MASK;
> +		data->ctrl_reg1 |= i << MMA8452_CTRL_DR_SHIFT;
> +		return mma8452_change_config(data, MMA8452_CTRL_REG1,
> +			data->ctrl_reg1);
> +	case IIO_CHAN_INFO_SCALE:
> +		i = mma8452_get_scale_index(data, val, val2);
> +		if (i < 0)
> +			return -EINVAL;
> +		data->data_cfg &= ~MMA8452_DATA_CFG_FS_MASK;
> +		data->data_cfg |= i;
> +		return mma8452_change_config(data, MMA8452_DATA_CFG,
> +			data->data_cfg);
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		if (val < -128 || val > 127)
> +			return -EINVAL;
> +		return mma8452_change_config(data, MMA8452_OFF_X +
> +			chan->scan_index, val);
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static irqreturn_t mma8452_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct mma8452_data *data = iio_priv(indio_dev);
> +	u8 buffer[16]; /* 3 16-bit channels + padding + ts */
> +	int ret;
> +
> +	ret = mma8452_read(data, (__be16 *) buffer);
> +	if (ret < 0)
> +		goto done;
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> +		iio_get_time_ns());
> +
> +done:
> +	iio_trigger_notify_done(indio_dev->trig);
> +	return IRQ_HANDLED;
> +}
> +
> +#define MMA8452_CHANNEL(axis, idx) { \
> +	.type = IIO_ACCEL, \
> +	.modified = 1, \
> +	.channel2 = IIO_MOD_##axis, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +		BIT(IIO_CHAN_INFO_CALIBBIAS), \
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
> +		BIT(IIO_CHAN_INFO_SCALE), \
> +	.scan_index = idx, \
> +	.scan_type = { \
> +		.sign = 's', \
> +		.realbits = 12, \
> +		.storagebits = 16, \
> +		.shift = 4, \
> +		.endianness = IIO_BE, \
> +	}, \
> +}
> +
> +static const struct iio_chan_spec mma8452_channels[] = {
> +	MMA8452_CHANNEL(X, 0),
> +	MMA8452_CHANNEL(Y, 1),
> +	MMA8452_CHANNEL(Z, 2),
> +	IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> +static struct attribute *mma8452_attributes[] = {
> +	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
> +	&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group mma8452_group = {
> +	.attrs = mma8452_attributes,
> +};
> +
> +static const struct iio_info mma8452_info = {
> +	.attrs = &mma8452_group,
> +	.read_raw = &mma8452_read_raw,
> +	.write_raw = &mma8452_write_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static const unsigned long mma8452_scan_masks[] = {0x7, 0};
> +
> +static int mma8452_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct mma8452_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
> +	if (ret < 0)
> +		return ret;
> +	if (ret != MMA8452_DEVICE_ID)
> +		return -ENODEV;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	data->client = client;
> +	mutex_init(&data->lock);
> +
> +	i2c_set_clientdata(client, indio_dev);
> +	indio_dev->info = &mma8452_info;
> +	indio_dev->name = id->name;
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = mma8452_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
> +	indio_dev->available_scan_masks = mma8452_scan_masks;
> +
> +	data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
> +		(MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
> +	ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
> +		data->ctrl_reg1);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->data_cfg = MMA8452_DATA_CFG_FS_2G;
> +	ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
> +		data->data_cfg);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = iio_triggered_buffer_setup(indio_dev, NULL,
> +		mma8452_trigger_handler, NULL);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0)
> +		goto buffer_cleanup;
> +	return 0;
> +
> +buffer_cleanup:
> +	iio_triggered_buffer_cleanup(indio_dev);
> +	return ret;
> +}
> +
> +static int mma8452_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
> +	mma8452_standby(iio_priv(indio_dev));
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int mma8452_suspend(struct device *dev)
> +{
> +	return mma8452_standby(iio_priv(i2c_get_clientdata(
> +		to_i2c_client(dev))));
> +}
> +
> +static int mma8452_resume(struct device *dev)
> +{
> +	return mma8452_active(iio_priv(i2c_get_clientdata(
> +		to_i2c_client(dev))));
> +}
> +
> +static SIMPLE_DEV_PM_OPS(mma8452_pm_ops, mma8452_suspend, mma8452_resume);
> +#define MMA8452_PM_OPS (&mma8452_pm_ops)
> +#else
> +#define MMA8452_PM_OPS NULL
> +#endif
> +
> +static const struct i2c_device_id mma8452_id[] = {
> +	{ "mma8452", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, mma8452_id);
> +
> +static struct i2c_driver mma8452_driver = {
> +	.driver = {
> +		.name	= "mma8452",
> +		.pm	= MMA8452_PM_OPS,
> +	},
> +	.probe = mma8452_probe,
> +	.remove = mma8452_remove,
> +	.id_table = mma8452_id,
> +};
> +module_i2c_driver(mma8452_driver);
> +
> +MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
> +MODULE_DESCRIPTION("Freescale MMA8452 accelerometer driver");
> +MODULE_LICENSE("GPL");
>