Re: [PATCH v2 02/12] media: v4l: fwnode: Support ACPI's _PLD for v4l2_fwnode_device_parse

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Ricardo,

Thanks for the update.

On 6/5/25 20:52, Ricardo Ribalda wrote:
> Currently v4l2_fwnode_device_parse() obtains the orientation and
> rotation via fwnode properties.
> 
> Extend the function to support as well ACPI devices with _PLD info.
> 
> We give a higher priority to fwnode, because it might contain quirks
> injected via swnodes.
> 
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
>   drivers/media/v4l2-core/v4l2-fwnode.c | 85 ++++++++++++++++++++++++++++++++---
>   1 file changed, 79 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index cb153ce42c45d69600a3ec4e59a5584d7e791a2a..379290ab3cfde74c8f663d61837a9a95011b5ae0 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -15,6 +15,7 @@
>    * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
>    */
>   #include <linux/acpi.h>
> +#include <acpi/acpi_bus.h>
>   #include <linux/kernel.h>
>   #include <linux/mm.h>
>   #include <linux/module.h>
> @@ -807,16 +808,65 @@ int v4l2_fwnode_connector_add_link(struct fwnode_handle *fwnode,
>   }
>   EXPORT_SYMBOL_GPL(v4l2_fwnode_connector_add_link);
>   
> -int v4l2_fwnode_device_parse(struct device *dev,
> -			     struct v4l2_fwnode_device_properties *props)
> +static int v4l2_fwnode_device_parse_acpi(struct device *dev,
> +					 struct v4l2_fwnode_device_properties *props)
> +{
> +	struct acpi_pld_info *pld;
> +	int ret = 0;
> +
> +	if (!is_acpi_device_node(dev_fwnode(dev)))
> +		return 0;
> +
> +	if (!acpi_get_physical_device_location(ACPI_HANDLE(dev), &pld)) {
> +		dev_dbg(dev, "acpi _PLD call failed\n");

I'd do:

acpi_handle_debug(ACPI_HANDLE(dev), "cannot obtain _PLD\n");

> +		return 0;
> +	}
> +
> +	if (props->orientation != V4L2_FWNODE_PROPERTY_UNSET) {
> +		switch (pld->panel) {
> +		case ACPI_PLD_PANEL_FRONT:
> +			props->orientation = V4L2_FWNODE_ORIENTATION_FRONT;
> +			break;
> +		case ACPI_PLD_PANEL_BACK:
> +			props->orientation = V4L2_FWNODE_ORIENTATION_BACK;
> +			break;
> +		case ACPI_PLD_PANEL_TOP:
> +		case ACPI_PLD_PANEL_LEFT:
> +		case ACPI_PLD_PANEL_RIGHT:
> +		case ACPI_PLD_PANEL_UNKNOWN:
> +			props->orientation = V4L2_FWNODE_ORIENTATION_EXTERNAL;
> +			break;
> +		default:
> +			dev_dbg(dev, "Unknown _PLD panel val %d\n", pld->panel);

Similarly:

acpi_handle_debug(ACPI_HANDLE(dev), "invalid panel %u in _PLD\n",
		  pld->panel);

> +			ret = -EINVAL;

Should this be an error or should we simply ignore it here (and maybe 
use acpi_handle_warn())?

> +			goto done;
> +		}
> +	}
> +
> +	if (props->rotation != V4L2_FWNODE_PROPERTY_UNSET) {
> +		switch (pld->rotation) {
> +		case 0 ... 7:
> +			props->rotation = pld->rotation * 45;
> +			break;
> +		default:
> +			dev_dbg(dev, "Unknown _PLD rotation val %d\n", pld->panel);

acpi_handle_debug(ACPI_HANDLE(dev), "invalid rotation %u in _PLD\n",
		  pld->rotation);

> +			ret = -EINVAL;
> +			goto done;
> +		}
> +	}
> +
> +done:
> +	ACPI_FREE(pld);
> +	return ret;
> +}
> +
> +static int v4l2_fwnode_device_parse_dt(struct device *dev,

I'd call this v4l2_fwnode_device_parse_of() as we're parsing OF nodes 
and properties here.

> +				       struct v4l2_fwnode_device_properties *props)
>   {
>   	struct fwnode_handle *fwnode = dev_fwnode(dev);
>   	u32 val;
>   	int ret;
>   
> -	memset(props, 0, sizeof(*props));
> -
> -	props->orientation = V4L2_FWNODE_PROPERTY_UNSET;
>   	ret = fwnode_property_read_u32(fwnode, "orientation", &val);
>   	if (!ret) {
>   		switch (val) {
> @@ -833,7 +883,6 @@ int v4l2_fwnode_device_parse(struct device *dev,
>   		dev_dbg(dev, "device orientation: %u\n", val);
>   	}
>   
> -	props->rotation = V4L2_FWNODE_PROPERTY_UNSET;
>   	ret = fwnode_property_read_u32(fwnode, "rotation", &val);
>   	if (!ret) {
>   		if (val >= 360) {
> @@ -847,6 +896,30 @@ int v4l2_fwnode_device_parse(struct device *dev,
>   
>   	return 0;
>   }
> +
> +int v4l2_fwnode_device_parse(struct device *dev,
> +			     struct v4l2_fwnode_device_properties *props)
> +{
> +	int ret;
> +
> +	memset(props, 0, sizeof(*props));
> +
> +	props->orientation = V4L2_FWNODE_PROPERTY_UNSET;
> +	props->rotation = V4L2_FWNODE_PROPERTY_UNSET;
> +
> +	/* Start by looking into swnodes and dt. */
> +	ret =  v4l2_fwnode_device_parse_dt(dev, props);
> +	if (ret)
> +		return ret;
> +
> +	/* Orientation and rotation found!, we are ready. */
> +	if (props->orientation != V4L2_FWNODE_PROPERTY_UNSET &&
> +	    props->rotation != V4L2_FWNODE_PROPERTY_UNSET)
> +		return 0;

I think you can remove this check without affecting the functionality.

> +
> +	/* Let's check the acpi table. */
> +	return v4l2_fwnode_device_parse_acpi(dev, props);
> +}
>   EXPORT_SYMBOL_GPL(v4l2_fwnode_device_parse);
>   
>   /*
> 

-- 
Regards,

Sakari Ailus