[RESEND PATCH V5 03/12] drm/exynos: dp: modify driver to support drm_panel

[Thierry Reding]

On Fri, Jul 18, 2014 at 02:13:49AM +0530, Ajay Kumar wrote:
> Add drm_panel controls to support powerup/down of the
> eDP panel, if one is present at the sink side.
> 
> Signed-off-by: Ajay Kumar <ajaykumar.rs at samsung.com>
> ---
>  .../devicetree/bindings/video/exynos_dp.txt        |    2 +
>  drivers/gpu/drm/exynos/Kconfig                     |    1 +
>  drivers/gpu/drm/exynos/exynos_dp_core.c            |   45 ++++++++++++++++----
>  drivers/gpu/drm/exynos/exynos_dp_core.h            |    2 +
>  4 files changed, 41 insertions(+), 9 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/video/exynos_dp.txt b/Documentation/devicetree/bindings/video/exynos_dp.txt
> index 53dbccf..c029a09 100644
> --- a/Documentation/devicetree/bindings/video/exynos_dp.txt
> +++ b/Documentation/devicetree/bindings/video/exynos_dp.txt
> @@ -51,6 +51,8 @@ Required properties for dp-controller:
>  			LANE_COUNT1 = 1, LANE_COUNT2 = 2, LANE_COUNT4 = 4
>  	- display-timings: timings for the connected panel as described by
>  		Documentation/devicetree/bindings/video/display-timing.txt
> +	-edp-panel:
> +		phandle for the edp/lvds drm_panel node.

There's really no need for the edp- prefix here. Also please don't use
drm_panel in the binding description since it makes no sense outside of
DRM (and bindings need to be OS agnostic).

Also: "eDP" and "LVDS"

> diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/drm/exynos/exynos_dp_core.c
> index a94b114..b3d0d9b 100644
> --- a/drivers/gpu/drm/exynos/exynos_dp_core.c
> +++ b/drivers/gpu/drm/exynos/exynos_dp_core.c
> @@ -28,6 +28,7 @@
>  #include <drm/drmP.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_crtc_helper.h>
> +#include <drm/drm_panel.h>
>  #include <drm/bridge/ptn3460.h>
>  
>  #include "exynos_drm_drv.h"
> @@ -1029,6 +1030,9 @@ static int exynos_dp_create_connector(struct exynos_drm_display *display,
>  	drm_connector_register(connector);
>  	drm_mode_connector_attach_encoder(connector, encoder);
>  
> +	if (dp->edp_panel)
> +		drm_panel_attach(dp->edp_panel, &dp->connector);

This function can fail, so you really need to do some error-checking
here.

> @@ -1063,11 +1067,13 @@ static void exynos_dp_poweron(struct exynos_dp_device *dp)
>  	if (dp->dpms_mode == DRM_MODE_DPMS_ON)
>  		return;
>  
> +	drm_panel_prepare(dp->edp_panel);
>  	clk_prepare_enable(dp->clock);
>  	exynos_dp_phy_init(dp);
>  	exynos_dp_init_dp(dp);
>  	enable_irq(dp->irq);
>  	exynos_dp_setup(dp);
> +	drm_panel_enable(dp->edp_panel);

These two as well. clk_prepare_enable() can also fail by the way.

exynos_dp_init_dp() can also fail theoretically (it returns int) but
never returns anything other than 0, so it could just as well return
void.

> @@ -1075,10 +1081,12 @@ static void exynos_dp_poweroff(struct exynos_dp_device *dp)
>  	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
>  		return;
>  
> +	drm_panel_disable(dp->edp_panel);
>  	disable_irq(dp->irq);
>  	flush_work(&dp->hotplug_work);
>  	exynos_dp_phy_exit(dp);
>  	clk_disable_unprepare(dp->clock);
> +	drm_panel_unprepare(dp->edp_panel);
>  }

And these two also.

>  static void exynos_dp_dpms(struct exynos_drm_display *display, int mode)
> @@ -1209,8 +1217,17 @@ err:
>  static int exynos_dp_dt_parse_panel(struct exynos_dp_device *dp)
>  {
>  	int ret;
> +	struct device_node *videomode_parent;
> +
> +	/* Receive video timing info from panel node
> +	 * if there is a panel node
> +	 */
> +	if (dp->panel_node)
> +		videomode_parent = dp->panel_node;
> +	else
> +		videomode_parent = dp->dev->of_node;
>  
> -	ret = of_get_videomode(dp->dev->of_node, &dp->panel.vm,
> +	ret = of_get_videomode(videomode_parent, &dp->panel.vm,

You shouldn't be grabbing the video timings from some random node like
this. Instead you should use the DRM panel's .get_modes() function to
query the supported modes. The panel may not (in fact, should not, at
least under most circumstances) define video timings in the device tree.

> @@ -1341,6 +1353,21 @@ static int exynos_dp_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	dp = devm_kzalloc(&pdev->dev, sizeof(struct exynos_dp_device),
> +				GFP_KERNEL);
> +	if (!dp)
> +		return -ENOMEM;
> +
> +	dp->panel_node = of_parse_phandle(dev->of_node, "edp-panel", 0);

There should be no need to store the struct device_node * obtained here
in the context like this.

> +	if (dp->panel_node) {
> +		dp->edp_panel = of_drm_find_panel(dp->panel_node);
> +		of_node_put(dp->panel_node);

Especially since after this that pointer may become invalid.

Thierry
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