Subject: Re: [PATCH v2] iio: accel: Add support for Freescale MMA7660FC
To: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
References: <1461914611-9155-1-git-send-email-constantin.musca@intel.com>
 <alpine.DEB.2.02.1604290949190.23132@pmeerw.net>
Cc: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de,
        linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
        daniel.baluta@intel.com
From: Constantin Musca <constantin.musca@intel.com>
Message-ID: <5723530E.5000303@intel.com>
Date: Fri, 29 Apr 2016 15:26:54 +0300
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Thanks. Please see patch v3.

Constantin

On 29.04.2016 11:05, Peter Meerwald-Stadler wrote:
> On Fri, 29 Apr 2016, Constantin Musca wrote:
>
>> Minimal implementation of an IIO driver for the Freescale
>> MMA7660FC 3-axis accelerometer. Datasheet:
>> http://www.freescale.com.cn/files/sensors/doc/data_sheet/MMA7660FC.pdf
> comments below
>   
>> Includes:
>> - ACPI support;
>> - read_raw for x,y,z axes;
>> - reading and setting the scale (range) parameter.
>> - power management
>>
>> Signed-off-by: Constantin Musca <constantin.musca@intel.com>
>> ---
>>   drivers/iio/accel/Kconfig   |  10 ++
>>   drivers/iio/accel/Makefile  |   2 +
>>   drivers/iio/accel/mma7660.c | 275 ++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 287 insertions(+)
>>   create mode 100644 drivers/iio/accel/mma7660.c
>>
>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>> index e4a758c..2e6a0e6 100644
>> --- a/drivers/iio/accel/Kconfig
>> +++ b/drivers/iio/accel/Kconfig
>> @@ -54,6 +54,16 @@ config HID_SENSOR_ACCEL_3D
>>   	  To compile this driver as a module, choose M here: the
>>   	  module will be called hid-sensor-accel-3d.
>>   
>> +config MMA7660
>> +	tristate "Freescale MMA7660FC 3-Axis Accelerometer Driver"
>> +	depends on I2C
>> +	help
>> +	  Say yes here to get support for the Freescale MMA7660FC 3-Axis
>> +	  accelerometer.
>> +
>> +	  Choosing M will build the driver as a module. If so, the module
>> +	  will be called mma7660.
>> +
>>   config IIO_ST_ACCEL_3AXIS
>>   	tristate "STMicroelectronics accelerometers 3-Axis Driver"
>>   	depends on (I2C || SPI_MASTER) && SYSFS
>> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
>> index 71b6794..ba1165f 100644
>> --- a/drivers/iio/accel/Makefile
>> +++ b/drivers/iio/accel/Makefile
>> @@ -15,6 +15,8 @@ obj-$(CONFIG_MMA7455)		+= mma7455_core.o
>>   obj-$(CONFIG_MMA7455_I2C)	+= mma7455_i2c.o
>>   obj-$(CONFIG_MMA7455_SPI)	+= mma7455_spi.o
>>   
>> +obj-$(CONFIG_MMA7660)	+= mma7660.o
>> +
>>   obj-$(CONFIG_MMA8452)	+= mma8452.o
>>   
>>   obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o
>> diff --git a/drivers/iio/accel/mma7660.c b/drivers/iio/accel/mma7660.c
>> new file mode 100644
>> index 0000000..9aad91d
>> --- /dev/null
>> +++ b/drivers/iio/accel/mma7660.c
>> @@ -0,0 +1,275 @@
>> +/**
>> + * 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_MODE_STANDBY	0
>> +#define MMA7660_MODE_ACTIVE		1
> those two could be an enum?
>
>> +
>> +#define MMA7660_I2C_READ_RETRIES	5
>> +
>> +/*
>> + * The accelerometer has one measurement range:
>> + *
>> + * -1.5g - +1.5g (6-bit, signed)
>> + *
>> + * scale1 = (1.5 + 1.5) * 9.81 / (2^6 - 1)     = 0.467142857
> why named scale1?
>
>> + */
>> +
>> +#define MMA7660_SCALE_AVAIL	"0.467142857"
>> +
>> +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),
>> +};
>> +
>> +struct mma7660_data {
>> +	struct i2c_client *client;
>> +	struct mutex lock;
>> +	u8 mode;
> use enum here
>
>> +};
>> +
>> +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, u8 mode)
>> +{
>> +	int ret;
>> +	struct i2c_client *client = data->client;
>> +
>> +	if (mode > 1)
>> +		return -EINVAL;
> check can probably be dropped
>
>> +
>> +	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 change sensor mode\n");
> to read
>
>> +		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;
>> +
>> +	if (address > 2)
>> +		return -EINVAL;
> check needed?
>
>> +
>> +	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 READ_RETRIES were 1, this would always fail, no matter what
> OUT_BIT_ALERT is
>
>> +
>> +	if (retries == 0) {
>> +		dev_err(&client->dev, "all register read retries failed");
>> +		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;
>> +
>> +	if (chan->type != IIO_ACCEL)
>> +		return -EINVAL;
> check needed?
>
>> +
>> +	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;
> nscale is NANO, not MICRO?
>
>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct iio_info mma7660_info = {
>> +	.driver_module	= THIS_MODULE,
>> +	.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 = iio_device_alloc(sizeof(*data));
> devm_
>
>> +	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 = -1;
> MODE_STANDBY probably
>
>> +
>> +	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},
> really uppercase?
>
>> +	{}
>> +};
>> +
>> +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,
>> +		.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");
>>