Re: [PATCH v3] HID: i2c-hid: Refactor _DSM helper and add i2c-hid-acpi-prp0001 driver

[Hans de Goede <hansg@kernel.org>]

Hi,

On 6-Jun-26 6:06 PM, 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@Red54.com>

Thank you for the new version.

> ---
> 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().
> 
>  drivers/hid/i2c-hid/Kconfig                | 18 ++++
>  drivers/hid/i2c-hid/Makefile               |  1 +
>  drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c | 98 ++++++++++++++++++++++
>  drivers/hid/i2c-hid/i2c-hid-acpi.c         | 52 ++++--------
>  drivers/hid/i2c-hid/i2c-hid-acpi.h         | 32 +++++++
>  5 files changed, 163 insertions(+), 38 deletions(-)
>  create mode 100644 drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c
>  create mode 100644 drivers/hid/i2c-hid/i2c-hid-acpi.h
> 
> diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
> index e8d51f410cc1..7db8b2abff78 100644
> --- 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.
> +
>  config I2C_HID_OF
>  	tristate "HID over I2C transport layer Open Firmware driver"
>  	# No "depends on OF" because this can also be used for manually
> diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile
> index 55bd5e0f35af..da420c1a8ec6 100644
> --- a/drivers/hid/i2c-hid/Makefile
> +++ b/drivers/hid/i2c-hid/Makefile
> @@ -9,6 +9,7 @@ i2c-hid-objs					=  i2c-hid-core.o
>  i2c-hid-$(CONFIG_DMI)				+= i2c-hid-dmi-quirks.o
>  
>  obj-$(CONFIG_I2C_HID_ACPI)			+= i2c-hid-acpi.o
> +obj-$(CONFIG_I2C_HID_ACPI_PRP0001)		+= i2c-hid-acpi-prp0001.o
>  obj-$(CONFIG_I2C_HID_OF)			+= i2c-hid-of.o
>  obj-$(CONFIG_I2C_HID_OF_ELAN)			+= i2c-hid-of-elan.o
>  obj-$(CONFIG_I2C_HID_OF_GOODIX)			+= i2c-hid-of-goodix.o
> diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c b/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c
> new file mode 100644
> index 000000000000..b54370a938ab
> --- /dev/null
> +++ b/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * HID over I2C driver for PRP0001 devices missing hid-descr-addr
> + *
> + * Some devices, for example the Lenovo KaiTian N60d and Inspur CP300L3, use
> + * _HID "PRP0001" with _DSD compatible "hid-over-i2c" but lack "hid-descr-addr"
> + * from the _DSD. The HID descriptor address is provided only through an ACPI
> + * _DSM. The TPD0 node in the DSDT shows _DSM Function 1 returning 0x20.
> + *
> + * Copyright (C) 2026 谢致邦 (XIE Zhibang) <Yeking@Red54.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +
> +#include "i2c-hid.h"
> +#include "i2c-hid-acpi.h"
> +
> +static int i2c_hid_acpi_prp0001_power_up(struct i2chid_ops *ops)
> +{
> +	/* give the device time to power up */
> +	msleep(250);
> +	return 0;
> +}
> +
> +static struct i2chid_ops i2c_hid_acpi_prp0001_ops = {
> +	.power_up = i2c_hid_acpi_prp0001_power_up,
> +	/*
> +	 * No .restore_sequence needed: the _DSM on these devices returns a
> +	 * constant (0x20) with no side effects, unlike some PNP0C50 _DSM
> +	 * implementations that switch the hardware between PS/2 and I2C modes.
> +	 */
> +};
> +
> +static int i2c_hid_acpi_prp0001_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct acpi_device *adev;
> +	u16 hid_descriptor_address;
> +	int ret;
> +
> +	/* If hid-descr-addr is present, let i2c-hid-of handle it */
> +	if (device_property_present(dev, "hid-descr-addr"))
> +		return -ENODEV;
> +
> +	adev = ACPI_COMPANION(dev);
> +	if (!adev)
> +		return -ENODEV;
> +
> +	ret = i2c_hid_acpi_get_descriptor(adev);
> +	if (ret < 0)
> +		return ret;
> +	dev_warn(dev,
> +		 "hid-descr-addr device property NOT found, using ACPI _DSM fallback. Contact vendor for firmware update!\n");
> +	hid_descriptor_address = ret;
> +
> +	/*
> +	 * No acpi_device_fix_up_power() needed: TPD0 has no _PS0, _PS3, _PSC
> +	 * or _PRx methods and follows I2C bus power.
> +	 */
> +	return i2c_hid_core_probe(client, &i2c_hid_acpi_prp0001_ops,
> +				  hid_descriptor_address, 0);
> +}
> +
> +static const struct of_device_id i2c_hid_acpi_prp0001_of_match[] = {
> +	{ .compatible = "hid-over-i2c" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, i2c_hid_acpi_prp0001_of_match);
> +
> +static const struct i2c_device_id i2c_hid_acpi_prp0001_id[] = {
> +	{ .name = "hid-over-i2c" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, i2c_hid_acpi_prp0001_id);
> +
> +static struct i2c_driver i2c_hid_acpi_prp0001_driver = {
> +	.driver = {
> +		.name	= "i2c_hid_acpi_prp0001",
> +		.pm	= &i2c_hid_core_pm,
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> +		.of_match_table = of_match_ptr(i2c_hid_acpi_prp0001_of_match),
> +	},
> +
> +	.probe		= i2c_hid_acpi_prp0001_probe,
> +	.remove		= i2c_hid_core_remove,
> +	.shutdown	= i2c_hid_core_shutdown,
> +	.id_table	= i2c_hid_acpi_prp0001_id,
> +};
> +
> +module_i2c_driver(i2c_hid_acpi_prp0001_driver);
> +
> +MODULE_DESCRIPTION("HID over I2C driver for PRP0001 devices missing hid-descr-addr");
> +MODULE_AUTHOR("谢致邦 (XIE Zhibang) <Yeking@Red54.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi.c b/drivers/hid/i2c-hid/i2c-hid-acpi.c
> index abd700a101f4..13f977d6aab6 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-acpi.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-acpi.c
> @@ -25,9 +25,9 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/pm.h>
> -#include <linux/uuid.h>
>  
>  #include "i2c-hid.h"
> +#include "i2c-hid-acpi.h"
>  
>  struct i2c_hid_acpi {
>  	struct i2chid_ops ops;
> @@ -48,39 +48,11 @@ static const struct acpi_device_id i2c_hid_acpi_blacklist[] = {
>  	{ }
>  };
>  
> -/* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
> -static guid_t i2c_hid_guid =
> -	GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
> -		  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
> -
> -static int i2c_hid_acpi_get_descriptor(struct i2c_hid_acpi *ihid_acpi)
> -{
> -	struct acpi_device *adev = ihid_acpi->adev;
> -	acpi_handle handle = acpi_device_handle(adev);
> -	union acpi_object *obj;
> -	u16 hid_descriptor_address;
> -
> -	if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
> -		return -ENODEV;
> -
> -	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid, 1, 1, NULL,
> -				      ACPI_TYPE_INTEGER);
> -	if (!obj) {
> -		acpi_handle_err(handle, "Error _DSM call to get HID descriptor address failed\n");
> -		return -ENODEV;
> -	}
> -
> -	hid_descriptor_address = obj->integer.value;
> -	ACPI_FREE(obj);
> -
> -	return hid_descriptor_address;
> -}
> -

Instead of moving this to i2c-hid-acpi.h, please make it non static an
export it using EXPORT_SYMBOL_GPL() and only put a prototype in i2c-hid-acpi.h .

The change to make it take an acpi_device pointer instead of i2c_hid_acpi *ihid_acpi
should be kept, but without moving the function to the .h file.

Regards,

Hans



>  static void i2c_hid_acpi_restore_sequence(struct i2chid_ops *ops)
>  {
>  	struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);
>  
> -	i2c_hid_acpi_get_descriptor(ihid_acpi);
> +	i2c_hid_acpi_get_descriptor(ihid_acpi->adev);
>  }
>  
>  static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
> @@ -93,24 +65,28 @@ static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
>  static int i2c_hid_acpi_probe(struct i2c_client *client)
>  {
>  	struct device *dev = &client->dev;
> +	struct acpi_device *adev = ACPI_COMPANION(dev);
>  	struct i2c_hid_acpi *ihid_acpi;
>  	u16 hid_descriptor_address;
>  	int ret;
>  
> -	ihid_acpi = devm_kzalloc(&client->dev, sizeof(*ihid_acpi), GFP_KERNEL);
> +	if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
> +		return -ENODEV;
> +
> +	ret = i2c_hid_acpi_get_descriptor(adev);
> +	if (ret < 0)
> +		return ret;
> +	hid_descriptor_address = ret;
> +
> +	ihid_acpi = devm_kzalloc(dev, sizeof(*ihid_acpi), GFP_KERNEL);
>  	if (!ihid_acpi)
>  		return -ENOMEM;
>  
> -	ihid_acpi->adev = ACPI_COMPANION(dev);
> +	ihid_acpi->adev = adev;
>  	ihid_acpi->ops.shutdown_tail = i2c_hid_acpi_shutdown_tail;
>  	ihid_acpi->ops.restore_sequence = i2c_hid_acpi_restore_sequence;
>  
> -	ret = i2c_hid_acpi_get_descriptor(ihid_acpi);
> -	if (ret < 0)
> -		return ret;
> -	hid_descriptor_address = ret;
> -
> -	acpi_device_fix_up_power(ihid_acpi->adev);
> +	acpi_device_fix_up_power(adev);
>  
>  	return i2c_hid_core_probe(client, &ihid_acpi->ops,
>  				  hid_descriptor_address, 0);
> diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi.h b/drivers/hid/i2c-hid/i2c-hid-acpi.h
> new file mode 100644
> index 000000000000..8cebbeebcc23
> --- /dev/null
> +++ b/drivers/hid/i2c-hid/i2c-hid-acpi.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef _I2C_HID_ACPI_H
> +#define _I2C_HID_ACPI_H
> +
> +#include <linux/acpi.h>
> +#include <linux/uuid.h>
> +
> +static inline int i2c_hid_acpi_get_descriptor(struct acpi_device *adev)
> +{
> +	/* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
> +	static const guid_t i2c_hid_guid =
> +		GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
> +			  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
> +
> +	acpi_handle handle = acpi_device_handle(adev);
> +	union acpi_object *obj;
> +	u16 addr;
> +
> +	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid,
> +				      1, 1, NULL, ACPI_TYPE_INTEGER);
> +	if (!obj) {
> +		acpi_handle_err(handle, "Error _DSM call to get HID descriptor address failed\n");
> +		return -ENODEV;
> +	}
> +
> +	addr = obj->integer.value;
> +	ACPI_FREE(obj);
> +	return addr;
> +}
> +
> +#endif