[PATCH 1/2] usb: ljca: Order ACPI hardware IDs alphabetically

[PATCH 1/2] usb: ljca: Order ACPI hardware IDs alphabetically

[Sakari Ailus]

The driver has three lists of ACPI hardware IDs, for GPIO, I²C and SPI.
Order them alphabetically.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/usb/misc/usb-ljca.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
index c562630d862c..cf01cc727685 100644
--- a/drivers/usb/misc/usb-ljca.c
+++ b/drivers/usb/misc/usb-ljca.c
@@ -165,26 +165,26 @@ struct ljca_match_ids_walk_data {
 };
 
 static const struct acpi_device_id ljca_gpio_hids[] = {
+	{ "INTC100B" },
 	{ "INTC1074" },
 	{ "INTC1096" },
-	{ "INTC100B" },
-	{ "INTC10D1" },
 	{ "INTC10B5" },
+	{ "INTC10D1" },
 	{},
 };
 
 static const struct acpi_device_id ljca_i2c_hids[] = {
+	{ "INTC100C" },
 	{ "INTC1075" },
 	{ "INTC1097" },
-	{ "INTC100C" },
 	{ "INTC10D2" },
 	{},
 };
 
 static const struct acpi_device_id ljca_spi_hids[] = {
+	{ "INTC100D" },
 	{ "INTC1091" },
 	{ "INTC1098" },
-	{ "INTC100D" },
 	{ "INTC10D3" },
 	{},
 };
-- 
2.47.3

[PATCH 2/2] usb: ljca: Improve ACPI hardware ID documentation

[Sakari Ailus]

Document the differences between the LJCA client device ACPI hardware IDs,
including the USBIO IDs used for LJCA devices.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/usb/misc/usb-ljca.c | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
index cf01cc727685..ebc18fae76e8 100644
--- a/drivers/usb/misc/usb-ljca.c
+++ b/drivers/usb/misc/usb-ljca.c
@@ -164,28 +164,39 @@ struct ljca_match_ids_walk_data {
 	struct acpi_device *adev;
 };
 
+/*
+ * ACPI hardware IDs for LJCA client devices.
+ *
+ * [1] Some BIOS implementations use these IDs for denoting LJCA client devices
+ *     even though the IDs have been allocated for USBIO. This isn't a problem
+ *     as the usb-ljca driver is probed based on the USB device's vendor and
+ *     product IDs and its client drivers are probed based on auxiliary device
+ *     names, not these ACPI _HIDs. List of such systems:
+ *
+ *     Dell Precision 5490
+ */
 static const struct acpi_device_id ljca_gpio_hids[] = {
-	{ "INTC100B" },
-	{ "INTC1074" },
-	{ "INTC1096" },
-	{ "INTC10B5" },
-	{ "INTC10D1" },
+	{ "INTC100B" }, /* RPL LJCA GPIO */
+	{ "INTC1074" }, /* CVF LJCA GPIO */
+	{ "INTC1096" }, /* ADL LJCA GPIO */
+	{ "INTC10B5" }, /* LNL LJCA GPIO */
+	{ "INTC10D1" }, /* MTL (CVF VSC) USBIO GPIO [1] */
 	{},
 };
 
 static const struct acpi_device_id ljca_i2c_hids[] = {
-	{ "INTC100C" },
-	{ "INTC1075" },
-	{ "INTC1097" },
-	{ "INTC10D2" },
+	{ "INTC100C" }, /* RPL LJCA I2C */
+	{ "INTC1075" }, /* CVF LJCA I2C */
+	{ "INTC1097" }, /* ADL LJCA I2C */
+	{ "INTC10D2" }, /* MTL (CVF VSC) USBIO I2C [1] */
 	{},
 };
 
 static const struct acpi_device_id ljca_spi_hids[] = {
-	{ "INTC100D" },
-	{ "INTC1091" },
-	{ "INTC1098" },
-	{ "INTC10D3" },
+	{ "INTC100D" }, /* RPL LJCA SPI */
+	{ "INTC1091" }, /* TGL/ADL LJCA SPI */
+	{ "INTC1098" }, /* ADL LJCA SPI */
+	{ "INTC10D3" }, /* MTL (CVF VSC) USBIO SPI [1] */
 	{},
 };
 
-- 
2.47.3

Re: [PATCH 1/2] usb: ljca: Order ACPI hardware IDs alphabetically

[Hans de Goede]

Hi,

On 10-Oct-25 7:56 AM, Sakari Ailus wrote:
> The driver has three lists of ACPI hardware IDs, for GPIO, I²C and SPI.
> Order them alphabetically.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@kernel.org>

Note 1 remark to maybe be addressed in a separate patch
below.



> ---
>  drivers/usb/misc/usb-ljca.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
> index c562630d862c..cf01cc727685 100644
> --- a/drivers/usb/misc/usb-ljca.c
> +++ b/drivers/usb/misc/usb-ljca.c
> @@ -165,26 +165,26 @@ struct ljca_match_ids_walk_data {
>  };
>  
>  static const struct acpi_device_id ljca_gpio_hids[] = {
> +	{ "INTC100B" },
>  	{ "INTC1074" },
>  	{ "INTC1096" },
> -	{ "INTC100B" },
> -	{ "INTC10D1" },
>  	{ "INTC10B5" },

This "INTC10B5" looks weird here, I don't think this actually
is in use. As can be seen by the matching "INTC10B6" HID
missing from ljca_i2c_hids[]. if we really needed "INTC10B5"
then I would expect "INTC10B6" to also be in the i2c list.

Regards,

Hans




> +	{ "INTC10D1" },
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_i2c_hids[] = {
> +	{ "INTC100C" },
>  	{ "INTC1075" },
>  	{ "INTC1097" },
> -	{ "INTC100C" },
>  	{ "INTC10D2" },
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_spi_hids[] = {
> +	{ "INTC100D" },
>  	{ "INTC1091" },
>  	{ "INTC1098" },
> -	{ "INTC100D" },
>  	{ "INTC10D3" },
>  	{},
>  };

Re: [PATCH 2/2] usb: ljca: Improve ACPI hardware ID documentation

[Hans de Goede]

Hi,

On 10-Oct-25 7:56 AM, Sakari Ailus wrote:
> Document the differences between the LJCA client device ACPI hardware IDs,
> including the USBIO IDs used for LJCA devices.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@kernel.org>

Regards,

Hans



> ---
>  drivers/usb/misc/usb-ljca.c | 37 ++++++++++++++++++++++++-------------
>  1 file changed, 24 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
> index cf01cc727685..ebc18fae76e8 100644
> --- a/drivers/usb/misc/usb-ljca.c
> +++ b/drivers/usb/misc/usb-ljca.c
> @@ -164,28 +164,39 @@ struct ljca_match_ids_walk_data {
>  	struct acpi_device *adev;
>  };
>  
> +/*
> + * ACPI hardware IDs for LJCA client devices.
> + *
> + * [1] Some BIOS implementations use these IDs for denoting LJCA client devices
> + *     even though the IDs have been allocated for USBIO. This isn't a problem
> + *     as the usb-ljca driver is probed based on the USB device's vendor and
> + *     product IDs and its client drivers are probed based on auxiliary device
> + *     names, not these ACPI _HIDs. List of such systems:
> + *
> + *     Dell Precision 5490
> + */
>  static const struct acpi_device_id ljca_gpio_hids[] = {
> -	{ "INTC100B" },
> -	{ "INTC1074" },
> -	{ "INTC1096" },
> -	{ "INTC10B5" },
> -	{ "INTC10D1" },
> +	{ "INTC100B" }, /* RPL LJCA GPIO */
> +	{ "INTC1074" }, /* CVF LJCA GPIO */
> +	{ "INTC1096" }, /* ADL LJCA GPIO */
> +	{ "INTC10B5" }, /* LNL LJCA GPIO */
> +	{ "INTC10D1" }, /* MTL (CVF VSC) USBIO GPIO [1] */
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_i2c_hids[] = {
> -	{ "INTC100C" },
> -	{ "INTC1075" },
> -	{ "INTC1097" },
> -	{ "INTC10D2" },
> +	{ "INTC100C" }, /* RPL LJCA I2C */
> +	{ "INTC1075" }, /* CVF LJCA I2C */
> +	{ "INTC1097" }, /* ADL LJCA I2C */
> +	{ "INTC10D2" }, /* MTL (CVF VSC) USBIO I2C [1] */
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_spi_hids[] = {
> -	{ "INTC100D" },
> -	{ "INTC1091" },
> -	{ "INTC1098" },
> -	{ "INTC10D3" },
> +	{ "INTC100D" }, /* RPL LJCA SPI */
> +	{ "INTC1091" }, /* TGL/ADL LJCA SPI */
> +	{ "INTC1098" }, /* ADL LJCA SPI */
> +	{ "INTC10D3" }, /* MTL (CVF VSC) USBIO SPI [1] */
>  	{},
>  };
>  

Re: [PATCH 1/2] usb: ljca: Order ACPI hardware IDs alphabetically

[Alan Stern]

On Fri, Oct 10, 2025 at 08:56:24AM +0300, Sakari Ailus wrote:
> The driver has three lists of ACPI hardware IDs, for GPIO, I²C and SPI.
> Order them alphabetically.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/usb/misc/usb-ljca.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
> index c562630d862c..cf01cc727685 100644
> --- a/drivers/usb/misc/usb-ljca.c
> +++ b/drivers/usb/misc/usb-ljca.c
> @@ -165,26 +165,26 @@ struct ljca_match_ids_walk_data {
>  };
>  
>  static const struct acpi_device_id ljca_gpio_hids[] = {
> +	{ "INTC100B" },
>  	{ "INTC1074" },
>  	{ "INTC1096" },
> -	{ "INTC100B" },
> -	{ "INTC10D1" },
>  	{ "INTC10B5" },
> +	{ "INTC10D1" },
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_i2c_hids[] = {
> +	{ "INTC100C" },
>  	{ "INTC1075" },
>  	{ "INTC1097" },
> -	{ "INTC100C" },
>  	{ "INTC10D2" },
>  	{},
>  };
>  
>  static const struct acpi_device_id ljca_spi_hids[] = {
> +	{ "INTC100D" },
>  	{ "INTC1091" },
>  	{ "INTC1098" },
> -	{ "INTC100D" },
>  	{ "INTC10D3" },
>  	{},
>  };

In the absence of any comments saying that the entries should be kept in 
alphabetical order, people will just add new entries to the end of each 
list.  They won't remain in alphabetical order very long.

(Even with comments about the ordering requirement, people will submit 
patches with entries in the wrong positions.  But at least then you can 
tell them to go back, read the comments, and resubmit their patches with 
the proper ordering.)

Just a quick observation from personal experience...

Alan Stern

Re: [PATCH 1/2] usb: ljca: Order ACPI hardware IDs alphabetically

[Greg Kroah-Hartman]

On Fri, Oct 10, 2025 at 08:56:24AM +0300, Sakari Ailus wrote:
> The driver has three lists of ACPI hardware IDs, for GPIO, I²C and SPI.
> Order them alphabetically.

In the future, please say _why_ you need to do such a thing.  The code
will work either way, and as Alan said, this will get out-of-order over
time :(

thanks,

greg k-h