Re: [PATCH v4 3/3] iio: ak8975: add ak09911 and ak09912 support

[Jonathan Cameron <jic23@kernel.org>]

On 21/11/14 18:45, Gwendal Grignou wrote:
> Add 2 new definition entries to support ak0991x compass.
> Add a more advanced function to check we are dealing with the
> expected device.
> Remove standalone driver for ak09911.
> 
> Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Convention puts the author sign off first

reviewed-by, tested-by, acked-by, sign-offs of people along the chain afterwards
and whoever applied the patches sign off last.

Anyhow, reordered and applied to the togreg branch of iio.git -
initially pushed out as testing for the autobuilders to play with it.

Thanks

Jonathan
> ---
>  drivers/iio/magnetometer/Kconfig   |  15 +-
>  drivers/iio/magnetometer/Makefile  |   1 -
>  drivers/iio/magnetometer/ak09911.c | 326 -------------------------------------
>  drivers/iio/magnetometer/ak8975.c  | 195 ++++++++++++++++++++--
>  4 files changed, 184 insertions(+), 353 deletions(-)
>  delete mode 100644 drivers/iio/magnetometer/ak09911.c
> 
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index b2dba9e..4c7a4c5 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -6,26 +6,21 @@
>  menu "Magnetometer sensors"
>  
>  config AK8975
> -	tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
> +	tristate "Asahi Kasei AK 3-Axis Magnetometer"
>  	depends on I2C
>  	depends on GPIOLIB
>  	help
> -	  Say yes here to build support for Asahi Kasei AK8975 3-Axis
> -	  Magnetometer. This driver can also support AK8963, if i2c
> -	  device name is identified as ak8963.
> +	  Say yes here to build support for Asahi Kasei AK8975, AK8963,
> +	  AK09911 or AK09912 3-Axis Magnetometer.
>  
>  	  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
> +	select AK8975
>  	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.
> +	  Deprecated: AK09911 is now supported by AK8975 driver.
>  
>  config MAG3110
>  	tristate "Freescale MAG3110 3-Axis Magnetometer"
> diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
> index b91315e..0f5d3c9 100644
> --- a/drivers/iio/magnetometer/Makefile
> +++ b/drivers/iio/magnetometer/Makefile
> @@ -3,7 +3,6 @@
>  #
>  
>  # 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
> deleted file mode 100644
> index b2bc942..0000000
> --- a/drivers/iio/magnetometer/ak09911.c
> +++ /dev/null
> @@ -1,326 +0,0 @@
> -/*
> - * 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->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");
> diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
> index 58c9a78..55d4732 100644
> --- a/drivers/iio/magnetometer/ak8975.c
> +++ b/drivers/iio/magnetometer/ak8975.c
> @@ -81,6 +81,58 @@
>  #define AK8975_MAX_REGS			AK8975_REG_ASAZ
>  
>  /*
> + * AK09912 Register definitions
> + */
> +#define AK09912_REG_WIA1		0x00
> +#define AK09912_REG_WIA2		0x01
> +#define AK09912_DEVICE_ID		0x04
> +#define AK09911_DEVICE_ID		0x05
> +
> +#define AK09911_REG_INFO1		0x02
> +#define AK09911_REG_INFO2		0x03
> +
> +#define AK09912_REG_ST1			0x10
> +
> +#define AK09912_REG_ST1_DRDY_SHIFT	0
> +#define AK09912_REG_ST1_DRDY_MASK	(1 << AK09912_REG_ST1_DRDY_SHIFT)
> +
> +#define AK09912_REG_HXL			0x11
> +#define AK09912_REG_HXH			0x12
> +#define AK09912_REG_HYL			0x13
> +#define AK09912_REG_HYH			0x14
> +#define AK09912_REG_HZL			0x15
> +#define AK09912_REG_HZH			0x16
> +#define AK09912_REG_TMPS		0x17
> +
> +#define AK09912_REG_ST2			0x18
> +#define AK09912_REG_ST2_HOFL_SHIFT	3
> +#define AK09912_REG_ST2_HOFL_MASK	(1 << AK09912_REG_ST2_HOFL_SHIFT)
> +
> +#define AK09912_REG_CNTL1		0x30
> +
> +#define AK09912_REG_CNTL2		0x31
> +#define AK09912_REG_CNTL_MODE_POWER_DOWN	0x00
> +#define AK09912_REG_CNTL_MODE_ONCE	0x01
> +#define AK09912_REG_CNTL_MODE_SELF_TEST	0x10
> +#define AK09912_REG_CNTL_MODE_FUSE_ROM	0x1F
> +#define AK09912_REG_CNTL2_MODE_SHIFT	0
> +#define AK09912_REG_CNTL2_MODE_MASK	(0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
> +
> +#define AK09912_REG_CNTL3		0x32
> +
> +#define AK09912_REG_TS1			0x33
> +#define AK09912_REG_TS2			0x34
> +#define AK09912_REG_TS3			0x35
> +#define AK09912_REG_I2CDIS		0x36
> +#define AK09912_REG_TS4			0x37
> +
> +#define AK09912_REG_ASAX		0x60
> +#define AK09912_REG_ASAY		0x61
> +#define AK09912_REG_ASAZ		0x62
> +
> +#define AK09912_MAX_REGS		AK09912_REG_ASAZ
> +
> +/*
>   * Miscellaneous values.
>   */
>  #define AK8975_MAX_CONVERSION_TIMEOUT	500
> @@ -130,22 +182,37 @@ long ak8975_raw_to_gauss(u16 data)
>  }
>  
>  /*
> - * For AK8963, same calculation, but the device is less sensitive:
> + * For AK8963 and AK09911, same calculation, but the device is less sensitive:
>   *
>   * H is in the range of +-8190.  The magnetometer has a range of
>   * +-4912uT.  To go from the raw value to uT is:
>   *
>   * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
>   */
> -long ak8963_raw_to_gauss(u16 data)
> +long ak8963_09911_raw_to_gauss(u16 data)
>  {
>  	return (((long)data + 128) * 6000) / 256;
>  }
>  
> +/*
> + * For AK09912, same calculation, except the device is more sensitive:
> + *
> + * H is in the range of -32752 to 32752.  The magnetometer has a range of
> + * +-4912uT.  To go from the raw value to uT is:
> + *
> + * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
> + */
> +long ak09912_raw_to_gauss(u16 data)
> +{
> +	return (((long)data + 128) * 1500) / 256;
> +}
> +
>  /* Compatible Asahi Kasei Compass parts */
>  enum asahi_compass_chipset {
>  	AK8975,
>  	AK8963,
> +	AK09911,
> +	AK09912,
>  	AK_MAX_TYPE
>  };
>  
> @@ -210,7 +277,7 @@ struct ak_def {
>  	},
>  	{
>  		.type = AK8963,
> -		.raw_to_gauss = ak8963_raw_to_gauss,
> +		.raw_to_gauss = ak8963_09911_raw_to_gauss,
>  		.range = 8190,
>  		.ctrl_regs = {
>  			AK8975_REG_ST1,
> @@ -233,6 +300,56 @@ struct ak_def {
>  			AK8975_REG_HYL,
>  			AK8975_REG_HZL},
>  	},
> +	{
> +		.type = AK09911,
> +		.raw_to_gauss = ak8963_09911_raw_to_gauss,
> +		.range = 8192,
> +		.ctrl_regs = {
> +			AK09912_REG_ST1,
> +			AK09912_REG_ST2,
> +			AK09912_REG_CNTL2,
> +			AK09912_REG_ASAX,
> +			AK09912_MAX_REGS},
> +		.ctrl_masks = {
> +			AK09912_REG_ST1_DRDY_MASK,
> +			AK09912_REG_ST2_HOFL_MASK,
> +			0,
> +			AK09912_REG_CNTL2_MODE_MASK},
> +		.ctrl_modes = {
> +			AK09912_REG_CNTL_MODE_POWER_DOWN,
> +			AK09912_REG_CNTL_MODE_ONCE,
> +			AK09912_REG_CNTL_MODE_SELF_TEST,
> +			AK09912_REG_CNTL_MODE_FUSE_ROM},
> +		.data_regs = {
> +			AK09912_REG_HXL,
> +			AK09912_REG_HYL,
> +			AK09912_REG_HZL},
> +	},
> +	{
> +		.type = AK09912,
> +		.raw_to_gauss = ak09912_raw_to_gauss,
> +		.range = 32752,
> +		.ctrl_regs = {
> +			AK09912_REG_ST1,
> +			AK09912_REG_ST2,
> +			AK09912_REG_CNTL2,
> +			AK09912_REG_ASAX,
> +			AK09912_MAX_REGS},
> +		.ctrl_masks = {
> +			AK09912_REG_ST1_DRDY_MASK,
> +			AK09912_REG_ST2_HOFL_MASK,
> +			0,
> +			AK09912_REG_CNTL2_MODE_MASK},
> +		.ctrl_modes = {
> +			AK09912_REG_CNTL_MODE_POWER_DOWN,
> +			AK09912_REG_CNTL_MODE_ONCE,
> +			AK09912_REG_CNTL_MODE_SELF_TEST,
> +			AK09912_REG_CNTL_MODE_FUSE_ROM},
> +		.data_regs = {
> +			AK09912_REG_HXL,
> +			AK09912_REG_HYL,
> +			AK09912_REG_HZL},
> +	}
>  };
>  
>  /*
> @@ -253,6 +370,52 @@ struct ak8975_data {
>  };
>  
>  /*
> + * Return 0 if the i2c device is the one we expect.
> + * return a negative error number otherwise
> + */
> +static int ak8975_who_i_am(struct i2c_client *client,
> +			   enum asahi_compass_chipset type)
> +{
> +	u8 wia_val[2];
> +	int ret;
> +
> +	/*
> +	 * Signature for each device:
> +	 * Device   |  WIA1      |  WIA2
> +	 * AK09912  |  DEVICE_ID |  AK09912_DEVICE_ID
> +	 * AK09911  |  DEVICE_ID |  AK09911_DEVICE_ID
> +	 * AK8975   |  DEVICE_ID |  NA
> +	 * AK8963   |  DEVICE_ID |  NA
> +	 */
> +	ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1,
> +					    2, wia_val);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Error reading WIA\n");
> +		return ret;
> +	}
> +
> +	if (wia_val[0] != AK8975_DEVICE_ID)
> +		return -ENODEV;
> +
> +	switch (type) {
> +	case AK8975:
> +	case AK8963:
> +		return 0;
> +	case AK09911:
> +		if (wia_val[1] == AK09911_DEVICE_ID)
> +			return 0;
> +		break;
> +	case AK09912:
> +		if (wia_val[1] == AK09912_DEVICE_ID)
> +			return 0;
> +		break;
> +	default:
> +		dev_err(&client->dev, "Type %d unknown\n", type);
> +	}
> +	return -ENODEV;
> +}
> +
> +/*
>   * Helper function to write to CNTL register.
>   */
>  static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode)
> @@ -327,21 +490,8 @@ static int ak8975_setup(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  	struct ak8975_data *data = iio_priv(indio_dev);
> -	u8 device_id;
>  	int ret;
>  
> -	/* Confirm that the device we're talking to is really an AK8975. */
> -	ret = i2c_smbus_read_byte_data(client, AK8975_REG_WIA);
> -	if (ret < 0) {
> -		dev_err(&client->dev, "Error reading WIA\n");
> -		return ret;
> -	}
> -	device_id = ret;
> -	if (device_id != AK8975_DEVICE_ID) {
> -		dev_err(&client->dev, "Device ak8975 not found\n");
> -		return -ENODEV;
> -	}
> -
>  	/* Write the fused rom access mode. */
>  	ret = ak8975_set_mode(data, FUSE_ROM);
>  	if (ret < 0) {
> @@ -552,6 +702,8 @@ static const struct acpi_device_id ak_acpi_match[] = {
>  	{"AK8975", AK8975},
>  	{"AK8963", AK8963},
>  	{"INVN6500", AK8963},
> +	{"AK09911", AK09911},
> +	{"AK09912", AK09912},
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
> @@ -631,6 +783,11 @@ static int ak8975_probe(struct i2c_client *client,
>  	}
>  
>  	data->def = &ak_def_array[chipset];
> +	err = ak8975_who_i_am(client, data->def->type);
> +	if (err < 0) {
> +		dev_err(&client->dev, "Unexpected device\n");
> +		return err;
> +	}
>  	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
>  
>  	/* Perform some basic start-of-day setup of the device. */
> @@ -653,6 +810,8 @@ static int ak8975_probe(struct i2c_client *client,
>  static const struct i2c_device_id ak8975_id[] = {
>  	{"ak8975", AK8975},
>  	{"ak8963", AK8963},
> +	{"ak09911", AK09911},
> +	{"ak09912", AK09912},
>  	{}
>  };
>  
> @@ -663,6 +822,10 @@ static const struct of_device_id ak8975_of_match[] = {
>  	{ .compatible = "ak8975", },
>  	{ .compatible = "asahi-kasei,ak8963", },
>  	{ .compatible = "ak8963", },
> +	{ .compatible = "asahi-kasei,ak09911", },
> +	{ .compatible = "ak09911", },
> +	{ .compatible = "asahi-kasei,ak09912", },
> +	{ .compatible = "ak09912", },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(of, ak8975_of_match);
>