Re: [PATCH] drm/arcpgu: Get rid of "encoder-slave" property

[Liviu Dudau <Liviu.Dudau@arm.com>]

On Fri, Mar 03, 2017 at 06:19:24PM +0300, Alexey Brodkin wrote:
> We used to use "encoder-slave" property in PGU's
> Device Tree node to refer to the encoder, but since there's
> a way to find it with some code smarts we get rid of
> obviously extra complication in PGU node.
> 
> Again inspired by ARM's HDLCD code.

Again, Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com>  :)

> 
> Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
> Cc: Liviu Dudau <Liviu.Dudau@arm.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Rob Herring <robh+dt@kernel.org>
> ---
>  arch/arc/boot/dts/axs10x_mb.dtsi |  1 -
>  drivers/gpu/drm/arc/arcpgu_drv.c | 23 +++++++++++++++++------
>  2 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arc/boot/dts/axs10x_mb.dtsi b/arch/arc/boot/dts/axs10x_mb.dtsi
> index 41cfb29b62c1..2fe030186b9d 100644
> --- a/arch/arc/boot/dts/axs10x_mb.dtsi
> +++ b/arch/arc/boot/dts/axs10x_mb.dtsi
> @@ -287,7 +287,6 @@
>  		pgu@17000 {
>  			compatible = "snps,arcpgu";
>  			reg = <0x17000 0x400>;
> -			encoder-slave = <&adv7511>;
>  			clocks = <&pguclk>;
>  			clock-names = "pxlclk";
>  			memory-region = <&frame_buffer>;
> diff --git a/drivers/gpu/drm/arc/arcpgu_drv.c b/drivers/gpu/drm/arc/arcpgu_drv.c
> index 5c82f52fba80..b1b2286bda95 100644
> --- a/drivers/gpu/drm/arc/arcpgu_drv.c
> +++ b/drivers/gpu/drm/arc/arcpgu_drv.c
> @@ -19,6 +19,7 @@
>  #include <drm/drm_fb_cma_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_atomic_helper.h>
> +#include <linux/of_graph.h>
>  #include <linux/of_reserved_mem.h>
>  
>  #include "arcpgu.h"
> @@ -83,7 +84,7 @@ static int arcpgu_load(struct drm_device *drm)
>  {
>  	struct platform_device *pdev = to_platform_device(drm->dev);
>  	struct arcpgu_drm_private *arcpgu;
> -	struct device_node *encoder_node;
> +	struct device_node *encoder, *port;
>  	struct resource *res;
>  	int ret;
>  
> @@ -118,14 +119,24 @@ static int arcpgu_load(struct drm_device *drm)
>  	if (arc_pgu_setup_crtc(drm) < 0)
>  		return -ENODEV;
>  
> -	/* find the encoder node and initialize it */
> -	encoder_node = of_parse_phandle(drm->dev->of_node, "encoder-slave", 0);
> -	if (encoder_node) {
> -		ret = arcpgu_drm_hdmi_init(drm, encoder_node);
> -		of_node_put(encoder_node);
> +	/* There is only one output port inside each device, find it */
> +	port = of_graph_get_next_endpoint(pdev->dev.of_node, NULL);
> +
> +	if (port) {
> +		if (of_device_is_available(port))
> +			encoder = of_graph_get_remote_port_parent(port);
> +		of_node_put(port);
> +	}

You must've been looking at some old version. Current version in -next uses
of_graph_get_remote_node() to replace all those lines you have added (see Rob
Herring's series to introduce of_graph_get_remote_node() function)

Best regards,
Liviu


> +
> +	if (encoder && of_device_is_available(encoder)) {
> +		dev_info(drm->dev, "Found encoder node %s, proceeding with it\n",
> +			 encoder->name);
> +		ret = arcpgu_drm_hdmi_init(drm, encoder);
> +		of_node_put(encoder);
>  		if (ret < 0)
>  			return ret;
>  	} else {
> +		dev_info(drm->dev, "No encoder node, assume simulation\n");
>  		ret = arcpgu_drm_sim_init(drm, NULL);
>  		if (ret < 0)
>  			return ret;
> -- 
> 2.7.4
> 

-- 
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