Re: [PATCH v2] iio: accel: Add support for Sensortek STK8BA50

[Jonathan Cameron <jic23@kernel.org>]

On 18/05/15 12:49, Tiberiu Breana wrote:
> Minimal implementation of an IIO driver for the Sensortek
> STK8BA50 3-axis accelerometer. Datasheet:
> http://szgsensor.com/uploads/soft/141229/STK8BA50%D2%E5%BC%CE.pdf
> 
> Includes:
> - ACPI support;
> - read_raw for x,y,z axes;
> - reading and setting the scale (range) parameter.
> - power management
> 
> Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com>
Just one little left over check that no longer has any meaning
(I've dropped it)

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

Peter if you get in fairly fast, please do have a final look
and I can back it out or add your reviewed by as relevant!

Jonathan
> ---
> Change log:
> 
> v2:
> - addressed Peter & Jon's comments
> - changed the way read_accel reads data
> - renamed set_mode to set_power and changed its implementation
> ---
>  drivers/iio/accel/Kconfig    |  10 ++
>  drivers/iio/accel/Makefile   |   1 +
>  drivers/iio/accel/stk8ba50.c | 305 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 316 insertions(+)
>  create mode 100644 drivers/iio/accel/stk8ba50.c
> 
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index 8bd8ccb..00e7bcb 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -147,4 +147,14 @@ config STK8312
>  	  Choosing M will build the driver as a module. If so, the module
>  	  will be called stk8312.
>  
> +config STK8BA50
> +	tristate "Sensortek STK8BA50 3-Axis Accelerometer Driver"
> +	depends on I2C
> +	help
> +	  Say yes here to get support for the Sensortek STK8BA50 3-axis
> +	  accelerometer.
> +
> +	  Choosing M will build the driver as a module. If so, the module
> +	  will be called stk8ba50.
> +
>  endmenu
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index 8b327c1..ebd2675 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_MMA9551)		+= mma9551.o
>  obj-$(CONFIG_MMA9553)		+= mma9553.o
>  
>  obj-$(CONFIG_STK8312)		+= stk8312.o
> +obj-$(CONFIG_STK8BA50)		+= stk8ba50.o
>  
>  obj-$(CONFIG_IIO_SSP_SENSORS_COMMONS) += ssp_accel_sensor.o
>  
> diff --git a/drivers/iio/accel/stk8ba50.c b/drivers/iio/accel/stk8ba50.c
> new file mode 100644
> index 0000000..8ac2a3b
> --- /dev/null
> +++ b/drivers/iio/accel/stk8ba50.c
> @@ -0,0 +1,305 @@
> +/**
> + * Sensortek STK8BA50 3-Axis Accelerometer
> + *
> + * Copyright (c) 2015, 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.
> + *
> + * STK8BA50 7-bit I2C address: 0x18.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define STK8BA50_REG_XOUT			0x02
> +#define STK8BA50_REG_YOUT			0x04
> +#define STK8BA50_REG_ZOUT			0x06
> +#define STK8BA50_REG_RANGE			0x0F
> +#define STK8BA50_REG_POWMODE			0x11
> +#define STK8BA50_REG_SWRST			0x14
> +
> +#define STK8BA50_MODE_NORMAL			0
> +#define STK8BA50_MODE_SUSPEND			1
> +#define STK8BA50_MODE_POWERBIT			BIT(7)
> +#define STK8BA50_DATA_SHIFT			6
> +#define STK8BA50_RESET_CMD			0xB6
> +
> +#define STK8BA50_DRIVER_NAME			"stk8ba50"
> +
> +#define STK8BA50_SCALE_AVAIL			"0.0384 0.0767 0.1534 0.3069"
> +
> +/*
> + * The accelerometer has four measurement ranges:
> + * +/-2g; +/-4g; +/-8g; +/-16g
> + *
> + * Acceleration values are 10-bit, 2's complement.
> + * Scales are calculated as following:
> + *
> + * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
> + * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
> + * etc.
> + *
> + * Scales are stored in this format:
> + * { <register value>, <scale value> }
> + *
> + * Locally, the range is stored as a table index.
> + */
> +static const int stk8ba50_scale_table[][2] = {
> +	{3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
> +};
> +
> +struct stk8ba50_data {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	int range;
> +};
> +
> +#define STK8BA50_ACCEL_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 stk8ba50_channels[] = {
> +	STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_XOUT, X),
> +	STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_YOUT, Y),
> +	STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_ZOUT, Z),
> +};
> +
> +static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
> +
> +static struct attribute *stk8ba50_attributes[] = {
> +	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group stk8ba50_attribute_group = {
> +	.attrs = stk8ba50_attributes
> +};
> +
> +static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
> +{
> +	int ret;
> +	struct i2c_client *client = data->client;
> +
> +	ret = i2c_smbus_read_word_data(client, reg);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "register read failed\n");
> +		return ret;
> +	}
> +
> +	return sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
> +}
> +
> +static int stk8ba50_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct stk8ba50_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&data->lock);
> +		*val = stk8ba50_read_accel(data, chan->address);
> +		mutex_unlock(&data->lock);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 0;
> +		*val2 = stk8ba50_scale_table[data->range][1];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int stk8ba50_write_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int val, int val2, long mask)
> +{
> +	int ret;
> +	int i;
> +	int index = -1;
> +	struct stk8ba50_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		if (val != 0)
> +			return -EINVAL;
> +
> +		for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
> +			if (val2 == stk8ba50_scale_table[i][1]) {
> +				index = i;
> +				break;
> +			}
> +		if (index < 0)
> +			return -EINVAL;
> +
> +		ret = i2c_smbus_write_byte_data(data->client,
> +				STK8BA50_REG_RANGE,
> +				stk8ba50_scale_table[index][0]);
> +		if (ret < 0)
> +			dev_err(&data->client->dev,
> +					"failed to set measurement range\n");
> +		else
> +			data->range = index;
> +
> +		return ret;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info stk8ba50_info = {
> +	.driver_module		= THIS_MODULE,
> +	.read_raw		= stk8ba50_read_raw,
> +	.write_raw		= stk8ba50_write_raw,
> +	.attrs			= &stk8ba50_attribute_group,
> +};
> +
> +static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
> +{
> +	int ret;
> +	u8 masked_reg;
> +	struct i2c_client *client = data->client;
> +
Bool > 1?  A left over it appears...  I'll clear this out.
> +	if (mode > 1)
> +		return -EINVAL;
> +
> +	ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
> +	if (ret < 0)
> +		goto exit_err;
> +
> +	if (mode)
> +		masked_reg = ret | STK8BA50_MODE_POWERBIT;
> +	else
> +		masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
> +
> +	ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
> +					masked_reg);
> +	if (ret < 0)
> +		goto exit_err;
> +
> +	return ret;
> +
> +exit_err:
> +	dev_err(&client->dev, "failed to change sensor mode\n");
> +	return ret;
> +}
> +
> +static int stk8ba50_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	int ret;
> +	struct iio_dev *indio_dev;
> +	struct stk8ba50_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);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &stk8ba50_info;
> +	indio_dev->name = STK8BA50_DRIVER_NAME;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = stk8ba50_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
> +
> +	/* Reset all registers on startup */
> +	ret = i2c_smbus_write_byte_data(client,
> +			STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to reset sensor\n");
> +		return ret;
> +	}
> +
> +	/* The default range is +/-2g */
> +	data->range = 0;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "device_register failed\n");
> +		stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
> +	}
> +
> +	return ret;
> +}
> +
> +static int stk8ba50_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	return stk8ba50_set_power(iio_priv(indio_dev), STK8BA50_MODE_SUSPEND);
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int stk8ba50_suspend(struct device *dev)
> +{
> +	struct stk8ba50_data *data;
> +
> +	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +
> +	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
> +}
> +
> +static int stk8ba50_resume(struct device *dev)
> +{
> +	struct stk8ba50_data *data;
> +
> +	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +
> +	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
> +
> +#define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
> +#else
> +#define STK8BA50_PM_OPS NULL
> +#endif
> +
> +static const struct i2c_device_id stk8ba50_i2c_id[] = {
> +	{"stk8ba50", 0},
> +	{}
> +};
> +
> +static const struct acpi_device_id stk8ba50_acpi_id[] = {
> +	{"STK8BA50", 0},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
> +
> +static struct i2c_driver stk8ba50_driver = {
> +	.driver = {
> +		.name = "stk8ba50",
> +		.pm = STK8BA50_PM_OPS,
> +		.acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
> +	},
> +	.probe =            stk8ba50_probe,
> +	.remove =           stk8ba50_remove,
> +	.id_table =         stk8ba50_i2c_id,
> +};
> +
> +module_i2c_driver(stk8ba50_driver);
> +
> +MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
> +MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
> +MODULE_LICENSE("GPL v2");
>