Re: [PATCH v4] iio: accel: add Freescale MMA7455L/MMA7456L 3-axis accelerometer driver

[Jonathan Cameron <jic23@kernel.org>]

On 01/11/15 18:01, Jonathan Cameron wrote:
> On 31/10/15 12:49, Joachim Eastwood wrote:
>> Add support for Freescale MMA7455L/MMA7456L 3-axis in 10-bit mode for
>> I2C and SPI bus. This rather simple driver that currently doesn't
>> support all the hardware features of MMA7455L/MMA7456L.
>>
>> Tested on Embedded Artist's LPC4357 Dev Kit with MMA7455L on I2C bus.
>>
>> Data sheets for the two devices can be found here:
>> http://cache.freescale.com/files/sensors/doc/data_sheet/MMA7455L.pdf
>> http://cache.freescale.com/files/sensors/doc/data_sheet/MMA7456L.pdf
>>
>> Signed-off-by: Joachim Eastwood <manabian@gmail.com>
> A few really trivial gripes I'll deal with when applying.
> 
> + the s/header/driver thing Martin picked up on.
Forgot the important bit:

Applied to the togreg branch of iio.git - initially pushed out as
testing for the autobuilders to play with it.

Jonathan
> 
> Jonathan
>> ---
>> Hi,
>>
>> This version address the comments from Jonathan Cameron.
>>
>> Changes since v3:
>> * use IIO_CONST_ATTR on sampling_frequency_available
>> * allow changing of rate and scaling while buffer is running
>>
>> Changes since v2:
>> * fix id variable name in MODULE_DEVICE_TABLE
>> * make MMA7455_{I2C,SPI} symbols selectable
>> * rebase on linux-next (tag next-20151020)
>>
>> Changes since v1:
>> * limit retries to 3 in mma7455_drdy
>> * remove mma7455_show_scale_avail
>> * use chan->address instead of chan->scan_index for reg addr
>> * check that val2 is 0 when setting sample freq
>> * use __le16 to hint about endianess in mma7455_trigger_handler
>> * fix endianess in mma7455_read_raw function
>> * add mma7456 id
>> * split it into several source files to support both i2c and spi
>>
>>
>>  drivers/iio/accel/Kconfig        |  29 ++++
>>  drivers/iio/accel/Makefile       |   5 +
>>  drivers/iio/accel/mma7455.h      |  20 +++
>>  drivers/iio/accel/mma7455_core.c | 311 +++++++++++++++++++++++++++++++++++++++
>>  drivers/iio/accel/mma7455_i2c.c  |  57 +++++++
>>  drivers/iio/accel/mma7455_spi.c  |  53 +++++++
>>  6 files changed, 475 insertions(+)
>>  create mode 100644 drivers/iio/accel/mma7455.h
>>  create mode 100644 drivers/iio/accel/mma7455_core.c
>>  create mode 100644 drivers/iio/accel/mma7455_i2c.c
>>  create mode 100644 drivers/iio/accel/mma7455_spi.c
>>
>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>> index 969428dd6329..728a7761aaa6 100644
>> --- a/drivers/iio/accel/Kconfig
>> +++ b/drivers/iio/accel/Kconfig
>> @@ -107,6 +107,35 @@ config KXCJK1013
>>  	  To compile this driver as a module, choose M here: the module will
>>  	  be called kxcjk-1013.
>>  
>> +config MMA7455
>> +	tristate
>> +	select IIO_BUFFER
>> +	select IIO_TRIGGERED_BUFFER
>> +
>> +config MMA7455_I2C
>> +	tristate "Freescale MMA7455L/MMA7456L Accelerometer I2C Driver"
>> +	depends on I2C
>> +	select MMA7455
>> +	select REGMAP_I2C
>> +	help
>> +	  Say yes here to build support for the Freescale MMA7455L and
>> +	  MMA7456L 3-axis accelerometer.
>> +
>> +	  To compile this driver as a module, choose M here: the module
>> +	  will be called mma7455_i2c.
>> +
>> +config MMA7455_SPI
>> +	tristate "Freescale MMA7455L/MMA7456L Accelerometer SPI Driver"
>> +	depends on SPI_MASTER
>> +	select MMA7455
>> +	select REGMAP_SPI
>> +	help
>> +	  Say yes here to build support for the Freescale MMA7455L and
>> +	  MMA7456L 3-axis accelerometer.
>> +
>> +	  To compile this driver as a module, choose M here: the module
>> +	  will be called mma7455_spi.
>> +
>>  config MMA8452
>>  	tristate "Freescale MMA8452Q and similar Accelerometers Driver"
>>  	depends on I2C
>> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
>> index 7925f166e6e9..7ea21f8b7d98 100644
>> --- a/drivers/iio/accel/Makefile
>> +++ b/drivers/iio/accel/Makefile
>> @@ -10,6 +10,11 @@ obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
>>  obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
>>  obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
>>  obj-$(CONFIG_KXSD9)	+= kxsd9.o
>> +
>> +obj-$(CONFIG_MMA7455)		+= mma7455_core.o
>> +obj-$(CONFIG_MMA7455_I2C)	+= mma7455_i2c.o
>> +obj-$(CONFIG_MMA7455_SPI)	+= mma7455_spi.o
>> +
>>  obj-$(CONFIG_MMA8452)	+= mma8452.o
>>  
>>  obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o
>> diff --git a/drivers/iio/accel/mma7455.h b/drivers/iio/accel/mma7455.h
>> new file mode 100644
>> index 000000000000..8fae9345da88
>> --- /dev/null
>> +++ b/drivers/iio/accel/mma7455.h
>> @@ -0,0 +1,20 @@
>> +/*
>> + * IIO accel header for Freescale MMA7455L 3-axis 10-bit accelerometer
>> + * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
> and another one...
>> + *
>> + */
>> +
>> +#ifndef __MMA7455_H
>> +#define __MMA7455_H
>> +
>> +extern const struct regmap_config mma7455_core_regmap;
>> +
>> +int mma7455_core_probe(struct device *dev, struct regmap *regmap,
>> +		       const char *name);
>> +int mma7455_core_remove(struct device *dev);
>> +
>> +#endif
>> diff --git a/drivers/iio/accel/mma7455_core.c b/drivers/iio/accel/mma7455_core.c
>> new file mode 100644
>> index 000000000000..c633cc2c0789
>> --- /dev/null
>> +++ b/drivers/iio/accel/mma7455_core.c
>> @@ -0,0 +1,311 @@
>> +/*
>> + * IIO accel core driver for Freescale MMA7455L 3-axis 10-bit accelerometer
>> + * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * UNSUPPORTED hardware features:
>> + *  - 8-bit mode with different scales
>> + *  - INT1/INT2 interrupts
>> + *  - Offset calibration
>> + *  - Events
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/trigger.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/iio/triggered_buffer.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "mma7455.h"
>> +
>> +#define MMA7455_REG_XOUTL		0x00
>> +#define MMA7455_REG_XOUTH		0x01
>> +#define MMA7455_REG_YOUTL		0x02
>> +#define MMA7455_REG_YOUTH		0x03
>> +#define MMA7455_REG_ZOUTL		0x04
>> +#define MMA7455_REG_ZOUTH		0x05
>> +#define MMA7455_REG_STATUS		0x09
>> +#define  MMA7455_STATUS_DRDY		BIT(0)
>> +#define MMA7455_REG_WHOAMI		0x0f
>> +#define  MMA7455_WHOAMI_ID		0x55
>> +#define MMA7455_REG_MCTL		0x16
>> +#define  MMA7455_MCTL_MODE_STANDBY	0x00
>> +#define  MMA7455_MCTL_MODE_MEASURE	0x01
>> +#define MMA7455_REG_CTL1		0x18
>> +#define  MMA7455_CTL1_DFBW_MASK		BIT(7)
>> +#define  MMA7455_CTL1_DFBW_125HZ	BIT(7)
>> +#define  MMA7455_CTL1_DFBW_62_5HZ	0
>> +#define MMA7455_REG_TW			0x1e
>> +
>> +/*
>> + * When MMA7455 is used in 10-bit it has a fullscale of -8g
>> + * corresponding to raw value -512. The userspace interface
>> + * uses m/s^2 and we declare micro units.
>> + * So scale factor is given by:
>> + *       g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665
>> + */
>> +#define MMA7455_10BIT_SCALE	153229
>> +
>> +struct mma7455_data {
>> +	struct regmap *regmap;
>> +	struct device *dev;
>> +};
>> +
>> +static int mma7455_drdy(struct mma7455_data *mma7455)
>> +{
>> +	unsigned int reg;
>> +	int tries = 3;
>> +	int ret;
>> +
>> +	while (tries-- > 0) {
>> +		ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, &reg);
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (reg & MMA7455_STATUS_DRDY)
>> +			return 0;
>> +
>> +		msleep(20);
>> +	}
>> +
>> +	dev_warn(mma7455->dev, "data not ready\n");
>> +
>> +	return -EIO;
>> +}
>> +
>> +static irqreturn_t mma7455_trigger_handler(int irq, void *p)
>> +{
>> +	struct iio_poll_func *pf = p;
>> +	struct iio_dev *indio_dev = pf->indio_dev;
>> +	struct mma7455_data *mma7455 = iio_priv(indio_dev);
>> +	u8 buf[16]; /* 3 x 16-bit channels + padding + ts */
>> +	int ret;
>> +
>> +	ret = mma7455_drdy(mma7455);
>> +	if (ret)
>> +		goto done;
>> +
>> +	ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf,
>> +			       sizeof(__le16) * 3);
>> +	if (ret)
>> +		goto done;
>> +
>> +	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
>> +
>> +done:
>> +	iio_trigger_notify_done(indio_dev->trig);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int mma7455_read_raw(struct iio_dev *indio_dev,
>> +			    struct iio_chan_spec const *chan,
>> +			    int *val, int *val2, long mask)
>> +{
>> +	struct mma7455_data *mma7455 = iio_priv(indio_dev);
>> +	unsigned int reg;
>> +	__le16 data;
>> +	int ret;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		if (iio_buffer_enabled(indio_dev))
>> +			return -EBUSY;
>> +
>> +		ret = mma7455_drdy(mma7455);
>> +		if (ret)
>> +			return ret;
>> +
>> +		ret = regmap_bulk_read(mma7455->regmap, chan->address, &data,
>> +				       sizeof(data));
>> +		if (ret)
>> +			return ret;
>> +
>> +		*val = sign_extend32(le16_to_cpu(data), 9);
>> +
>> +		return IIO_VAL_INT;
>> +
>> +	case IIO_CHAN_INFO_SCALE:
>> +		*val = 0;
>> +		*val2 = MMA7455_10BIT_SCALE;
>> +
>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, &reg);
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (reg & MMA7455_CTL1_DFBW_MASK)
>> +			*val = 250;
>> +		else
>> +			*val = 125;
>> +
>> +		return IIO_VAL_INT;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int mma7455_write_raw(struct iio_dev *indio_dev,
>> +			     struct iio_chan_spec const *chan,
>> +			     int val, int val2, long mask)
>> +{
>> +	struct mma7455_data *mma7455 = iio_priv(indio_dev);
>> +	int i;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		if (val == 250 && val2 == 0)
>> +			i = MMA7455_CTL1_DFBW_125HZ;
>> +		else if (val == 125 && val2 == 0)
>> +			i = MMA7455_CTL1_DFBW_62_5HZ;
>> +		else
>> +			return -EINVAL;
>> +
>> +		return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1,
>> +					  MMA7455_CTL1_DFBW_MASK, i);
>> +
>> +	case IIO_CHAN_INFO_SCALE:
>> +		/* In 10-bit mode there is only one scale available */
>> +		if (val == 0 && val2 == MMA7455_10BIT_SCALE)
>> +			return 0;
>> +		break;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static IIO_CONST_ATTR(sampling_frequency_available, "125 250");
>> +
>> +static struct attribute *mma7455_attributes[] = {
>> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>> +	NULL
>> +};
>> +
>> +static const struct attribute_group mma7455_group = {
>> +	.attrs = mma7455_attributes,
>> +};
>> +
>> +static const struct iio_info mma7455_info = {
>> +	.attrs = &mma7455_group,
>> +	.read_raw = mma7455_read_raw,
>> +	.write_raw = mma7455_write_raw,
>> +	.driver_module = THIS_MODULE,
>> +};
>> +
>> +#define MMA7455_CHANNEL(axis, idx) { \
>> +	.type = IIO_ACCEL, \
>> +	.modified = 1, \
>> +	.address = MMA7455_REG_##axis##OUTL,\
>> +	.channel2 = IIO_MOD_##axis, \
>> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
>> +				    BIT(IIO_CHAN_INFO_SCALE), \
>> +	.scan_index = idx, \
>> +	.scan_type = { \
>> +		.sign = 's', \
>> +		.realbits = 10, \
>> +		.storagebits = 16, \
>> +		.endianness = IIO_LE, \
>> +	}, \
>> +}
>> +
>> +static const struct iio_chan_spec mma7455_channels[] = {
>> +	MMA7455_CHANNEL(X, 0),
>> +	MMA7455_CHANNEL(Y, 1),
>> +	MMA7455_CHANNEL(Z, 2),
>> +	IIO_CHAN_SOFT_TIMESTAMP(3),
>> +};
>> +
>> +static const unsigned long mma7455_scan_masks[] = {0x7, 0};
>> +
>> +const struct regmap_config mma7455_core_regmap = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +	.max_register = MMA7455_REG_TW,
>> +};
>> +EXPORT_SYMBOL_GPL(mma7455_core_regmap);
>> +
>> +int mma7455_core_probe(struct device *dev, struct regmap *regmap,
>> +		       const char *name)
>> +{
>> +	struct mma7455_data *mma7455;
>> +	struct iio_dev *indio_dev;
>> +	unsigned int reg;
>> +	int ret;
>> +
>> +	ret = regmap_read(regmap, MMA7455_REG_WHOAMI, &reg);
>> +	if (ret) {
>> +		dev_err(dev, "unable to read reg\n");
>> +		return ret;
>> +	}
>> +
>> +	if (reg != MMA7455_WHOAMI_ID) {
>> +		dev_err(dev, "device id mismatch\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455));
>> +	if (!indio_dev)
>> +		return -ENOMEM;
>> +
>> +	dev_set_drvdata(dev, indio_dev);
>> +	mma7455 = iio_priv(indio_dev);
>> +	mma7455->regmap = regmap;
>> +	mma7455->dev = dev;
>> +
>> +	indio_dev->info = &mma7455_info;
>> +	indio_dev->name = name;
>> +	indio_dev->dev.parent = dev;
>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>> +	indio_dev->channels = mma7455_channels;
>> +	indio_dev->num_channels = ARRAY_SIZE(mma7455_channels);
>> +	indio_dev->available_scan_masks = mma7455_scan_masks;
>> +
>> +	regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
>> +		     MMA7455_MCTL_MODE_MEASURE);
>> +
>> +	ret = iio_triggered_buffer_setup(indio_dev, NULL,
>> +					 mma7455_trigger_handler, NULL);
>> +	if (ret) {
>> +		dev_err(dev, "unable to setup triggered buffer\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = iio_device_register(indio_dev);
>> +	if (ret) {
>> +		dev_err(dev, "unable to register device\n");
>> +		iio_triggered_buffer_cleanup(indio_dev);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(mma7455_core_probe);
>> +
>> +int mma7455_core_remove(struct device *dev)
>> +{
>> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>> +	struct mma7455_data *mma7455 = iio_priv(indio_dev);
>> +
>> +	iio_device_unregister(indio_dev);
>> +	iio_triggered_buffer_cleanup(indio_dev);
>> +
>> +	regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
>> +		     MMA7455_MCTL_MODE_STANDBY);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(mma7455_core_remove);
>> +
>> +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
>> +MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/accel/mma7455_i2c.c b/drivers/iio/accel/mma7455_i2c.c
>> new file mode 100644
>> index 000000000000..ce4ad0d45f98
>> --- /dev/null
>> +++ b/drivers/iio/accel/mma7455_i2c.c
>> @@ -0,0 +1,57 @@
>> +/*
>> + * IIO accel I2C driver for Freescale MMA7455L 3-axis 10-bit accelerometer
>> + * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
> And this one (see below, I review backwards as drivers usually make
> more sense that way around).
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "mma7455.h"
>> +
>> +static int mma7455_i2c_probe(struct i2c_client *i2c,
>> +			     const struct i2c_device_id *id)
>> +{
>> +	struct regmap *regmap;
>> +	const char *name = NULL;
>> +
>> +	regmap = devm_regmap_init_i2c(i2c, &mma7455_core_regmap);
>> +	if (IS_ERR(regmap))
>> +		return PTR_ERR(regmap);
>> +
>> +	if (id)
>> +		name = id->name;
>> +
>> +	return mma7455_core_probe(&i2c->dev, regmap, name);
>> +}
>> +
>> +static int mma7455_i2c_remove(struct i2c_client *i2c)
>> +{
>> +	return mma7455_core_remove(&i2c->dev);
>> +}
>> +
>> +static const struct i2c_device_id mma7455_i2c_ids[] = {
>> +	{ "mma7455", 0 },
>> +	{ "mma7456", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, mma7455_i2c_ids);
>> +
>> +static struct i2c_driver mma7455_i2c_driver = {
>> +	.probe = mma7455_i2c_probe,
>> +	.remove = mma7455_i2c_remove,
>> +	.id_table = mma7455_i2c_ids,
>> +	.driver = {
>> +		.name	= "mma7455-i2c",
>> +	},
>> +};
>> +module_i2c_driver(mma7455_i2c_driver);
>> +
>> +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
>> +MODULE_DESCRIPTION("Freescale MMA7455L I2C accelerometer driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/accel/mma7455_spi.c b/drivers/iio/accel/mma7455_spi.c
>> new file mode 100644
>> index 000000000000..5dc0bb75d289
>> --- /dev/null
>> +++ b/drivers/iio/accel/mma7455_spi.c
>> @@ -0,0 +1,53 @@
>> +/*
>> + * IIO accel SPI driver for Freescale MMA7455L 3-axis 10-bit accelerometer
>> + * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
> My quest against blank lines with no purpose continues.  I'll edit this
> one out in the appy.
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/spi/spi.h>
>> +
>> +#include "mma7455.h"
>> +
>> +static int mma7455_spi_probe(struct spi_device *spi)
>> +{
>> +	const struct spi_device_id *id = spi_get_device_id(spi);
>> +	struct regmap *regmap;
>> +
>> +	regmap = devm_regmap_init_spi(spi, &mma7455_core_regmap);
>> +	if (IS_ERR(regmap))
>> +		return PTR_ERR(regmap);
>> +
>> +	return mma7455_core_probe(&spi->dev, regmap, id->name);
>> +}
>> +
>> +static int mma7455_spi_remove(struct spi_device *spi)
>> +{
>> +	return mma7455_core_remove(&spi->dev);
>> +}
>> +
>> +static const struct spi_device_id mma7455_spi_ids[] = {
>> +	{ "mma7455", 0 },
>> +	{ "mma7456", 0 },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(spi, mma7455_spi_ids);
>> +
>> +static struct spi_driver mma7455_spi_driver = {
>> +	.probe = mma7455_spi_probe,
>> +	.remove = mma7455_spi_remove,
>> +	.id_table = mma7455_spi_ids,
>> +	.driver = {
>> +		.name = "mma7455-spi",
>> +	},
>> +};
>> +module_spi_driver(mma7455_spi_driver);
>> +
>> +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
>> +MODULE_DESCRIPTION("Freescale MMA7455L SPI accelerometer driver");
>> +MODULE_LICENSE("GPL v2");
>>
> 
> --
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