Re: [PATCH v3] iio: AK09911 : 3 axis compass support

[Jonathan Cameron <jic23@kernel.org>]

On 11/06/14 23:06, Srinivas Pandruvada wrote:
> Added IIO magnetometer driver for AK09911. In functionality is resembles
> AK8975 or AK8963. But there are several differences, so instead of
> modifying existing AK8975 driver and keep it clean, implemented as
> a separate driver.
> The key differences are:
> - Register map is different and have different indexes
> - AK09911 is a very compact interface with no DRDY pin. So no support
>   of interrupt or GPIO poll
> - Even for polled mode no mention on ST2 register, which is required in
> ak8975 driver
> - mode values are different for fuse access
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Applied to the togreg branch of iio.git. I'll initially push this out
as testing.  If either Lars, or Peter want another look
(or to give an acked-by / reviewed-by then it'll sit in testing briefly
so feel free to shout!)

Jonathan
> ---
>   drivers/iio/magnetometer/Kconfig   |  10 ++
>   drivers/iio/magnetometer/Makefile  |   1 +
>   drivers/iio/magnetometer/ak09911.c | 327 +++++++++++++++++++++++++++++++++++++
>   3 files changed, 338 insertions(+)
>   create mode 100644 drivers/iio/magnetometer/ak09911.c
>
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index 05a364c54..b2dba9e 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -17,6 +17,16 @@ config AK8975
>   	  To compile this driver as a module, choose M here: the module
>   	  will be called ak8975.
>
> +config AK09911
> +	tristate "Asahi Kasei AK09911 3-axis Compass"
> +	depends on I2C
> +	help
> +	  Say yes here to build support for Asahi Kasei AK09911 3-Axis
> +	  Magnetometer.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called ak09911.
> +
>   config MAG3110
>   	tristate "Freescale MAG3110 3-Axis Magnetometer"
>   	depends on I2C
> diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
> index 0f5d3c9..b91315e 100644
> --- a/drivers/iio/magnetometer/Makefile
> +++ b/drivers/iio/magnetometer/Makefile
> @@ -3,6 +3,7 @@
>   #
>
>   # When adding new entries keep the list in alphabetical order
> +obj-$(CONFIG_AK09911)	+= ak09911.o
>   obj-$(CONFIG_AK8975)	+= ak8975.o
>   obj-$(CONFIG_MAG3110)	+= mag3110.o
>   obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
> diff --git a/drivers/iio/magnetometer/ak09911.c b/drivers/iio/magnetometer/ak09911.c
> new file mode 100644
> index 0000000..62f980c
> --- /dev/null
> +++ b/drivers/iio/magnetometer/ak09911.c
> @@ -0,0 +1,327 @@
> +/*
> + * AK09911 3-axis compass driver
> + * Copyright (c) 2014, Intel Corporation.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/types.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/acpi.h>
> +#include <linux/iio/iio.h>
> +
> +#define AK09911_REG_WIA1		0x00
> +#define AK09911_REG_WIA2		0x01
> +#define AK09911_WIA1_VALUE		0x48
> +#define AK09911_WIA2_VALUE		0x05
> +
> +#define AK09911_REG_ST1			0x10
> +#define AK09911_REG_HXL			0x11
> +#define AK09911_REG_HXH			0x12
> +#define AK09911_REG_HYL			0x13
> +#define AK09911_REG_HYH			0x14
> +#define AK09911_REG_HZL			0x15
> +#define AK09911_REG_HZH			0x16
> +
> +#define AK09911_REG_ASAX		0x60
> +#define AK09911_REG_ASAY		0x61
> +#define AK09911_REG_ASAZ		0x62
> +
> +#define AK09911_REG_CNTL1		0x30
> +#define AK09911_REG_CNTL2		0x31
> +#define AK09911_REG_CNTL3		0x32
> +
> +#define AK09911_MODE_SNG_MEASURE	0x01
> +#define AK09911_MODE_SELF_TEST		0x10
> +#define AK09911_MODE_FUSE_ACCESS	0x1F
> +#define AK09911_MODE_POWERDOWN		0x00
> +#define AK09911_RESET_DATA		0x01
> +
> +#define AK09911_REG_CNTL1		0x30
> +#define AK09911_REG_CNTL2		0x31
> +#define AK09911_REG_CNTL3		0x32
> +
> +#define AK09911_RAW_TO_GAUSS(asa)	((((asa) + 128) * 6000) / 256)
> +
> +#define AK09911_MAX_CONVERSION_TIMEOUT_MS	500
> +#define AK09911_CONVERSION_DONE_POLL_TIME_MS	10
> +
> +struct ak09911_data {
> +	struct i2c_client	*client;
> +	struct mutex		lock;
> +	u8			asa[3];
> +	long			raw_to_gauss[3];
> +};
> +
> +static const int ak09911_index_to_reg[] = {
> +	AK09911_REG_HXL, AK09911_REG_HYL, AK09911_REG_HZL,
> +};
> +
> +static int ak09911_set_mode(struct i2c_client *client, u8 mode)
> +{
> +	int ret;
> +
> +	switch (mode) {
> +	case AK09911_MODE_SNG_MEASURE:
> +	case AK09911_MODE_SELF_TEST:
> +	case AK09911_MODE_FUSE_ACCESS:
> +	case AK09911_MODE_POWERDOWN:
> +		ret = i2c_smbus_write_byte_data(client,
> +						AK09911_REG_CNTL2, mode);
> +		if (ret < 0) {
> +			dev_err(&client->dev, "set_mode error\n");
> +			return ret;
> +		}
> +		/* After mode change wait atleast 100us */
> +		usleep_range(100, 500);
> +		break;
> +	default:
> +		dev_err(&client->dev,
> +			"%s: Unknown mode(%d).", __func__, mode);
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +/* Get Sensitivity Adjustment value */
> +static int ak09911_get_asa(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct ak09911_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = ak09911_set_mode(client, AK09911_MODE_FUSE_ACCESS);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Get asa data and store in the device data. */
> +	ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_ASAX,
> +					    3, data->asa);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Not able to read asa data\n");
> +		return ret;
> +	}
> +
> +	ret = ak09911_set_mode(client,  AK09911_MODE_POWERDOWN);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->raw_to_gauss[0] = AK09911_RAW_TO_GAUSS(data->asa[0]);
> +	data->raw_to_gauss[1] = AK09911_RAW_TO_GAUSS(data->asa[1]);
> +	data->raw_to_gauss[2] = AK09911_RAW_TO_GAUSS(data->asa[2]);
> +
> +	return 0;
> +}
> +
> +static int ak09911_verify_chip_id(struct i2c_client *client)
> +{
> +	u8 wia_val[2];
> +	int ret;
> +
> +	ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_WIA1,
> +					    2, wia_val);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Error reading WIA\n");
> +		return ret;
> +	}
> +
> +	dev_dbg(&client->dev, "WIA %02x %02x\n", wia_val[0], wia_val[1]);
> +
> +	if (wia_val[0] != AK09911_WIA1_VALUE ||
> +		wia_val[1] != AK09911_WIA2_VALUE) {
> +		dev_err(&client->dev, "Device ak09911 not found\n");
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static int wait_conversion_complete_polled(struct ak09911_data *data)
> +{
> +	struct i2c_client *client = data->client;
> +	u8 read_status;
> +	u32 timeout_ms = AK09911_MAX_CONVERSION_TIMEOUT_MS;
> +	int ret;
> +
> +	/* Wait for the conversion to complete. */
> +	while (timeout_ms) {
> +		msleep_interruptible(AK09911_CONVERSION_DONE_POLL_TIME_MS);
> +		ret = i2c_smbus_read_byte_data(client, AK09911_REG_ST1);
> +		if (ret < 0) {
> +			dev_err(&client->dev, "Error in reading ST1\n");
> +			return ret;
> +		}
> +		read_status = ret & 0x01;
> +		if (read_status)
> +			break;
> +		timeout_ms -= AK09911_CONVERSION_DONE_POLL_TIME_MS;
> +	}
> +	if (!timeout_ms) {
> +		dev_err(&client->dev, "Conversion timeout happened\n");
> +		return -EIO;
> +	}
> +
> +	return read_status;
> +}
> +
> +static int ak09911_read_axis(struct iio_dev *indio_dev, int index, int *val)
> +{
> +	struct ak09911_data *data = iio_priv(indio_dev);
> +	struct i2c_client *client = data->client;
> +	int ret;
> +
> +	mutex_lock(&data->lock);
> +
> +	ret = ak09911_set_mode(client, AK09911_MODE_SNG_MEASURE);
> +	if (ret < 0)
> +		goto fn_exit;
> +
> +	ret = wait_conversion_complete_polled(data);
> +	if (ret < 0)
> +		goto fn_exit;
> +
> +	/* Read data */
> +	ret = i2c_smbus_read_word_data(client, ak09911_index_to_reg[index]);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Read axis data fails\n");
> +		goto fn_exit;
> +	}
> +
> +	mutex_unlock(&data->lock);
> +
> +	/* Clamp to valid range. */
> +	*val = sign_extend32(clamp_t(s16, ret, -8192, 8191), 13);
> +
> +	return IIO_VAL_INT;
> +
> +fn_exit:
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int ak09911_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int *val, int *val2,
> +			    long mask)
> +{
> +	struct ak09911_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		return ak09911_read_axis(indio_dev, chan->address, val);
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 0;
> +		*val2 = data->raw_to_gauss[chan->address];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +#define AK09911_CHANNEL(axis, index)					\
> +	{								\
> +		.type = IIO_MAGN,					\
> +		.modified = 1,						\
> +		.channel2 = IIO_MOD_##axis,				\
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
> +			     BIT(IIO_CHAN_INFO_SCALE),			\
> +		.address = index,					\
> +	}
> +
> +static const struct iio_chan_spec ak09911_channels[] = {
> +	AK09911_CHANNEL(X, 0), AK09911_CHANNEL(Y, 1), AK09911_CHANNEL(Z, 2),
> +};
> +
> +static const struct iio_info ak09911_info = {
> +	.read_raw = &ak09911_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static const struct acpi_device_id ak_acpi_match[] = {
> +	{"AK009911", 0},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
> +
> +static int ak09911_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct iio_dev *indio_dev;
> +	struct ak09911_data *data;
> +	const char *name;
> +	int ret;
> +
> +	ret = ak09911_verify_chip_id(client);
> +	if (ret) {
> +		dev_err(&client->dev, "AK00911 not detected\n");
> +		return -ENODEV;
> +	}
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (indio_dev == NULL)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	data->client = client;
> +	mutex_init(&data->lock);
> +
> +	ret = ak09911_get_asa(client);
> +	if (ret)
> +		return ret;
> +
> +	if (id)
> +		name = id->name;
> +	else if (ACPI_HANDLE(&client->dev))
> +		name = dev_name(&client->dev);
> +	else
> +		return -ENODEV;
> +
> +	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->channels = ak09911_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ak09911_channels);
> +	indio_dev->info = &ak09911_info;
> +	indio_dev->name = id->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->name = name;
> +
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static const struct i2c_device_id ak09911_id[] = {
> +	{"ak09911", 0},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, ak09911_id);
> +
> +static struct i2c_driver ak09911_driver = {
> +	.driver = {
> +		.name	= "ak09911",
> +		.acpi_match_table = ACPI_PTR(ak_acpi_match),
> +	},
> +	.probe		= ak09911_probe,
> +	.id_table	= ak09911_id,
> +};
> +module_i2c_driver(ak09911_driver);
> +
> +MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("AK09911 Compass driver");
>