Re: [PATCH 2/4] iio: accel: kxcjk-1013: Move ACPI ROTM parsing to new acpi-helpers.h

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 4/20/24 1:13 PM, Jonathan Cameron wrote:
> On Wed, 17 Apr 2024 18:46:14 +0200
> Hans de Goede <hdegoede@redhat.com> wrote:
> 
>> The ACPI "ROTM" rotation matrix parsing code atm is already duplicated
>> between bmc150-accel-core.c and kxcjk-1013.c and a third user of this is
>> coming.
>>
>> Move the ROTM parsing from kxcjk-1013.c, which has slightly better error
>> logging (and otherwise is 100% identical), into a new acpi-helpers.h file
>> so that it can be shared.
>>
>> Other then moving the code the only 2 other changes are:
>>
>> 1. Rename the function to acpi_read_mount_matrix() to make clear this
>>    is a generic ACPI mount matrix read function.
>> 2. Add a "char *acpi_method" parameter since some bmc150 dual-accel setups
>>    (360° hinges with 1 accel in kbd/base + 1 in display half) declare both
>>    accels in a single ACPI device with 2 different method names for
>>    the 2 matrices.
>>
>> Cc: Sean Rhodes <sean@starlabs.systems>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> 
> Tempted to ask you to rename this to
> acpi_non_standard_microsoft_extension_that_they_never_agreed_with_aswg_read_mount_matrix()
> but meh, I'll cope with a reference to:
> https://learn.microsoft.com/en-us/windows-hardware/drivers/sensors/sensors-acpi-entries
> and a comment saying this is not part of the ACPI standard.

Ok, so I'll add a comment like this for v2:

> 
> I'm not grumpy at all about companies who add non standard stuff without
> at least reserving the ID space.
> 
> Why isn't it a _DSM (Device Specific Method) with a microsoft defined UUID? Harrumph.
> 
> +CC Rafael and linux-acpi as whilst this remains in IIO, it is named such that it
> ends up in the acpi_* namespace.  They may not care, but best to check!
> 
> Jonathan
> 
> 
>> ---
>>  drivers/iio/accel/acpi-helpers.h | 76 ++++++++++++++++++++++++++++++++
>>  drivers/iio/accel/kxcjk-1013.c   | 71 ++---------------------------
>>  2 files changed, 79 insertions(+), 68 deletions(-)
>>  create mode 100644 drivers/iio/accel/acpi-helpers.h
>>
>> diff --git a/drivers/iio/accel/acpi-helpers.h b/drivers/iio/accel/acpi-helpers.h
>> new file mode 100644
>> index 000000000000..a4357925bf07
>> --- /dev/null
>> +++ b/drivers/iio/accel/acpi-helpers.h
>> @@ -0,0 +1,76 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/* ACPI helper functions for parsing ACPI rotation matrices */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/dev_printk.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/sprintf.h>
>> +
>> +#ifdef CONFIG_ACPI
>> +static inline bool acpi_read_mount_matrix(struct device *dev,
>> +					  struct iio_mount_matrix *orientation,
>> +					  char *acpi_method)
>> +{
>> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	struct acpi_device *adev = ACPI_COMPANION(dev);
>> +	char *str;
>> +	union acpi_object *obj, *elements;
>> +	acpi_status status;
>> +	int i, j, val[3];
>> +	bool ret = false;
>> +
>> +	if (!adev || !acpi_has_method(adev->handle, acpi_method))
>> +		return false;
>> +
>> +	status = acpi_evaluate_object(adev->handle, acpi_method, NULL, &buffer);
>> +	if (ACPI_FAILURE(status)) {
>> +		dev_err(dev, "Failed to get ACPI mount matrix: %d\n", status);
>> +		return false;
>> +	}
>> +
>> +	obj = buffer.pointer;
>> +	if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {
>> +		dev_err(dev, "Unknown ACPI mount matrix package format\n");
>> +		goto out_free_buffer;
>> +	}
>> +
>> +	elements = obj->package.elements;
>> +	for (i = 0; i < 3; i++) {
>> +		if (elements[i].type != ACPI_TYPE_STRING) {
>> +			dev_err(dev, "Unknown ACPI mount matrix element format\n");
>> +			goto out_free_buffer;
>> +		}
>> +
>> +		str = elements[i].string.pointer;
>> +		if (sscanf(str, "%d %d %d", &val[0], &val[1], &val[2]) != 3) {
>> +			dev_err(dev, "Incorrect ACPI mount matrix string format\n");
>> +			goto out_free_buffer;
>> +		}
>> +
>> +		for (j = 0; j < 3; j++) {
>> +			switch (val[j]) {
>> +			case -1: str = "-1"; break;
>> +			case 0:  str = "0";  break;
>> +			case 1:  str = "1";  break;
>> +			default:
>> +				dev_err(dev, "Invalid value in ACPI mount matrix: %d\n", val[j]);
>> +				goto out_free_buffer;
>> +			}
>> +			orientation->rotation[i * 3 + j] = str;
>> +		}
>> +	}
>> +
>> +	ret = true;
>> +
>> +out_free_buffer:
>> +	kfree(buffer.pointer);
>> +	return ret;
>> +}
>> +#else
>> +static inline bool acpi_read_mount_matrix(struct device *dev,
>> +					  struct iio_mount_matrix *orientation,
>> +					  char *acpi_method)
>> +{
>> +	return false;
>> +}
>> +#endif
>> diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
>> index bb1660667bb0..7e19278491dc 100644
>> --- a/drivers/iio/accel/kxcjk-1013.c
>> +++ b/drivers/iio/accel/kxcjk-1013.c
>> @@ -24,6 +24,8 @@
>>  #include <linux/iio/triggered_buffer.h>
>>  #include <linux/iio/accel/kxcjk_1013.h>
>>  
>> +#include "acpi-helpers.h"
>> +
>>  #define KXCJK1013_DRV_NAME "kxcjk1013"
>>  #define KXCJK1013_IRQ_NAME "kxcjk1013_event"
>>  
>> @@ -636,73 +638,6 @@ static int kxcjk1013_set_power_state(struct kxcjk1013_data *data, bool on)
>>  	return 0;
>>  }
>>  
>> -#ifdef CONFIG_ACPI
>> -static bool kxj1009_apply_acpi_orientation(struct device *dev,
>> -					   struct iio_mount_matrix *orientation)
>> -{
>> -	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>> -	struct acpi_device *adev = ACPI_COMPANION(dev);
>> -	char *str;
>> -	union acpi_object *obj, *elements;
>> -	acpi_status status;
>> -	int i, j, val[3];
>> -	bool ret = false;
>> -
>> -	if (!adev || !acpi_has_method(adev->handle, "ROTM"))
>> -		return false;
>> -
>> -	status = acpi_evaluate_object(adev->handle, "ROTM", NULL, &buffer);
>> -	if (ACPI_FAILURE(status)) {
>> -		dev_err(dev, "Failed to get ACPI mount matrix: %d\n", status);
>> -		return false;
>> -	}
>> -
>> -	obj = buffer.pointer;
>> -	if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {
>> -		dev_err(dev, "Unknown ACPI mount matrix package format\n");
>> -		goto out_free_buffer;
>> -	}
>> -
>> -	elements = obj->package.elements;
>> -	for (i = 0; i < 3; i++) {
>> -		if (elements[i].type != ACPI_TYPE_STRING) {
>> -			dev_err(dev, "Unknown ACPI mount matrix element format\n");
>> -			goto out_free_buffer;
>> -		}
>> -
>> -		str = elements[i].string.pointer;
>> -		if (sscanf(str, "%d %d %d", &val[0], &val[1], &val[2]) != 3) {
>> -			dev_err(dev, "Incorrect ACPI mount matrix string format\n");
>> -			goto out_free_buffer;
>> -		}
>> -
>> -		for (j = 0; j < 3; j++) {
>> -			switch (val[j]) {
>> -			case -1: str = "-1"; break;
>> -			case 0:  str = "0";  break;
>> -			case 1:  str = "1";  break;
>> -			default:
>> -				dev_err(dev, "Invalid value in ACPI mount matrix: %d\n", val[j]);
>> -				goto out_free_buffer;
>> -			}
>> -			orientation->rotation[i * 3 + j] = str;
>> -		}
>> -	}
>> -
>> -	ret = true;
>> -
>> -out_free_buffer:
>> -	kfree(buffer.pointer);
>> -	return ret;
>> -}
>> -#else
>> -static bool kxj1009_apply_acpi_orientation(struct device *dev,
>> -					  struct iio_mount_matrix *orientation)
>> -{
>> -	return false;
>> -}
>> -#endif
>> -
>>  static int kxcjk1013_chip_update_thresholds(struct kxcjk1013_data *data)
>>  {
>>  	int ret;
>> @@ -1533,7 +1468,7 @@ static int kxcjk1013_probe(struct i2c_client *client)
>>  	} else {
>>  		data->active_high_intr = true; /* default polarity */
>>  
>> -		if (!kxj1009_apply_acpi_orientation(&client->dev, &data->orientation)) {
>> +		if (!acpi_read_mount_matrix(&client->dev, &data->orientation, "ROTM")) {
>>  			ret = iio_read_mount_matrix(&client->dev, &data->orientation);
>>  			if (ret)
>>  				return ret;
>