Re: [PATCH bugfix for 5.10 2/2] iio: accel: kxcjk1013: Add support for KIOX010A ACPI DSM for setting tablet-mode

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 10 Nov 2020 14:38:35 +0100
Hans de Goede <hdegoede@redhat.com> wrote:

> Some 360 degree hinges (yoga) style 2-in-1 devices use 2 KXCJ91008-s
> to allow the OS to determine the angle between the display and the base
> of the device, so that the OS can determine if the 2-in-1 is in laptop
> or in tablet-mode.
> 
> On Windows both accelerometers are read by a special HingeAngleService
> process; and this process calls a DSM (Device Specific Method) on the
> ACPI KIOX010A device node for the sensor in the display, to let the
> embedded-controller (EC) know about the mode so that it can disable the
> kbd and touchpad to avoid spurious input while folded into tablet-mode.
> 
> This notifying of the EC is problematic because sometimes the EC comes up
> thinking that device is in tablet-mode and the kbd and touchpad do not
> work. This happens for example on Irbis NB111 devices after a suspend /
> resume cycle (after a complete battery drain / hard reset without having
> booted Windows at least once). Other 2-in-1s which are likely affected
> too are e.g. the Teclast F5 and F6 series.
> 
> The kxcjk-1013 driver may seem like a strange place to deal with this,
> but since it is *the* driver for the ACPI KIOX010A device, it is also
> the driver which has access to the ACPI handle needed by the DSM.
> 
> Add support for calling the DSM and on probe unconditionally tell the
> EC that the device is laptop mode, fixing the kbd and touchpad sometimes
> not working.
> 
> Reported-and-tested-by: russianneuromancer <russianneuromancer@ya.ru>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Hi Hans,

*Mutters darkly about crazy firmware hacks*

I'm fine taking this but I assume we want to backport and for that I'm
after a fixes tag.

Thanks,

Jonathan
 
> ---
>  drivers/iio/accel/kxcjk-1013.c | 36 ++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
> index abeb0d254046..560a3373ff20 100644
> --- a/drivers/iio/accel/kxcjk-1013.c
> +++ b/drivers/iio/accel/kxcjk-1013.c
> @@ -129,6 +129,7 @@ enum kx_chipset {
>  enum kx_acpi_type {
>  	ACPI_GENERIC,
>  	ACPI_SMO8500,
> +	ACPI_KIOX010A,
>  };
>  
>  struct kxcjk1013_data {
> @@ -275,6 +276,32 @@ static const struct {
>  			      {19163, 1, 0},
>  			      {38326, 0, 1} };
>  
> +#ifdef CONFIG_ACPI
> +enum kiox010a_fn_index {
> +	KIOX010A_SET_LAPTOP_MODE = 1,
> +	KIOX010A_SET_TABLET_MODE = 2,
> +};
> +
> +static int kiox010a_dsm(struct device *dev, int fn_index)
> +{
> +	acpi_handle handle = ACPI_HANDLE(dev);
> +	guid_t kiox010a_dsm_guid;
> +	union acpi_object *obj;
> +
> +	if (!handle)
> +		return -ENODEV;
> +
> +	guid_parse("1f339696-d475-4e26-8cad-2e9f8e6d7a91", &kiox010a_dsm_guid);
> +
> +	obj = acpi_evaluate_dsm(handle, &kiox010a_dsm_guid, 1, fn_index, NULL);
> +	if (!obj)
> +		return -EIO;
> +
> +	ACPI_FREE(obj);
> +	return 0;
> +}
> +#endif
> +
>  static int kxcjk1013_set_mode(struct kxcjk1013_data *data,
>  			      enum kxcjk1013_mode mode)
>  {
> @@ -352,6 +379,13 @@ static int kxcjk1013_chip_init(struct kxcjk1013_data *data)
>  {
>  	int ret;
>  
> +#ifdef CONFIG_ACPI
> +	if (data->acpi_type == ACPI_KIOX010A) {
> +		/* Make sure the kbd and touchpad on 2-in-1s using 2 KXCJ91008-s work */
> +		kiox010a_dsm(&data->client->dev, KIOX010A_SET_LAPTOP_MODE);
> +	}
> +#endif
> +
>  	ret = i2c_smbus_read_byte_data(data->client, KXCJK1013_REG_WHO_AM_I);
>  	if (ret < 0) {
>  		dev_err(&data->client->dev, "Error reading who_am_i\n");
> @@ -1262,6 +1296,8 @@ static const char *kxcjk1013_match_acpi_device(struct device *dev,
>  
>  	if (strcmp(id->id, "SMO8500") == 0)
>  		*acpi_type = ACPI_SMO8500;
> +	else if (strcmp(id->id, "KIOX010A") == 0)
> +		*acpi_type = ACPI_KIOX010A;
>  
>  	*chipset = (enum kx_chipset)id->driver_data;
>