Re: [PATCH v6] HID: i2c-hid: Refactor _DSM helper and add i2c-hid-acpi-prp0001 driver

[Jiri Kosina]

On Wed, 24 Jun 2026, 谢致邦 (XIE Zhibang) wrote:

> Move the _DSM call that gets the HID descriptor address from
> i2c-hid-acpi.c into i2c-hid-acpi.h as a static inline so both the ACPI
> and the new PRP0001 driver can use it. While refactoring, move the
> blacklist check and the _DSM call to the top of probe() to avoid a
> pointless alloc when the device is blacklisted or does not implement the
> _DSM.
> 
> Some devices, for example the Lenovo KaiTian N60d and Inspur CP300L3,
> are declared with _HID "PRP0001" and _DSD compatible "hid-over-i2c" but
> lack "hid-descr-addr" from the _DSD and provide the HID descriptor
> address only through an ACPI _DSM. The OF driver fails to probe them
> because it requires hid-descr-addr. Add a new driver that handles these
> devices by calling the shared _DSM helper.
> 
> Fixes: b33752c30023 ("HID: i2c-hid: Reorganize so ACPI and OF are separate modules")
> Signed-off-by: 谢致邦 (XIE Zhibang) <Yeking@xxxxxxxxx>
> ---
> v2: Name the unused parameter and document why
> acpi_device_fix_up_power() is skipped.
> v3: Add a dev_warn() asking users to contact vendors for firmware
> updates, and use existing locals in devm_kzalloc() and
> acpi_device_fix_up_power().
> v4: Double the power-up delay from 250ms to 500ms.
> v5: Document why of_match_ptr() on the of_match_table is safe when
> CONFIG_OF=n.
> v6: Increase power-up delay from 500ms to 750ms. During cold boot on low
> battery, 500ms causes non-fatal I2C transfer errors (-ENXIO). 750ms
> fixes them.

Thanks for all the effort you've put into this.

[ ... snip ... ]
> --- a/drivers/hid/i2c-hid/Kconfig
> +++ b/drivers/hid/i2c-hid/Kconfig
> @@ -22,6 +22,24 @@ config I2C_HID_ACPI
>  	  will be called i2c-hid-acpi.  It will also build/depend on the
>  	  module i2c-hid.
>  
> +config I2C_HID_ACPI_PRP0001
> +	tristate "Driver for PRP0001 devices missing hid-descr-addr"
> +	depends on ACPI
> +	depends on DRM || !DRM
> +	select I2C_HID_CORE
> +	help
> +	  Say Y here if you want support for I2C HID touchpads that
> +	  are declared with _HID "PRP0001" and _DSD compatible
> +	  "hid-over-i2c" but lack the "hid-descr-addr" property from
> +	  the _DSD. The HID descriptor address is instead provided
> +	  through an ACPI _DSM. Known affected devices include the
> +	  Lenovo KaiTian N60d and Inspur CP300L3.
> +
> +	  If unsure, say N.
> +
> +	  This support is also available as a module. If so, the
> +	  module will be called i2c-hid-acpi-prp0001.

The only question I have -- do we really want to have this build-time 
selectable by the endusers? It's unlikely that the description will make 
sense to most of the people, being very low-level technical, and they'd be 
unsure what to chose.

Is there a reason not to include it alwyas under the I2C_HID_CORE 
umbrella?

Thanks,

-- 
Jiri Kosina
SUSE Labs