Re: [PATCH 4/5] drm: convert drivers to use drm_of_find_panel_or_bridge

From: Fabio Estevam
Date: Sat Feb 04 2017 - 15:26:33 EST


Hi Rob,

On Sat, Feb 4, 2017 at 1:36 AM, Rob Herring <robh@xxxxxxxxxx> wrote:

> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_out.c b/drivers/gpu/drm/mxsfb/mxsfb_out.c
> index fa8d17399407..f7d729aa09bd 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_out.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_out.c
> @@ -19,6 +19,7 @@
> #include <drm/drm_crtc_helper.h>
> #include <drm/drm_fb_cma_helper.h>
> #include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_of.h>
> #include <drm/drm_panel.h>
> #include <drm/drm_plane_helper.h>
> #include <drm/drm_simple_kms_helper.h>
> @@ -82,20 +83,15 @@ static const struct drm_connector_funcs mxsfb_panel_connector_funcs = {
> .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> };
>
> -static int mxsfb_attach_endpoint(struct drm_device *drm,
> - const struct of_endpoint *ep)
> +int mxsfb_create_output(struct drm_device *drm)
> {
> struct mxsfb_drm_private *mxsfb = drm->dev_private;
> - struct device_node *np;
> struct drm_panel *panel;
> - int ret = -EPROBE_DEFER;
> -
> - np = of_graph_get_remote_port_parent(ep->local_node);
> - panel = of_drm_find_panel(np);
> - of_node_put(np);
> + int ret;
>
> - if (!panel)
> - return -EPROBE_DEFER;
> + ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel, NULL);
> + if (ret)
> + return ret;

I fixed some build issues of this series and I am trying to use it
with the mxsfb drm driver.

I would like to add bridge support for this driver, so that I can use
the TDA19988 HDMI bridge on a imx6sx-udoo-neo-full board.

My dts looks like this:

--- a/arch/arm/boot/dts/imx6sx-udoo-neo.dtsi
+++ b/arch/arm/boot/dts/imx6sx-udoo-neo.dtsi
@@ -185,6 +185,41 @@
};
};

+&i2c3 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_i2c3>;
+ clock-frequency = <100000>;
+ status = "okay";
+
+ hdmi-transmitter@70 {
+ compatible = "nxp,tda998x";
+ reg = <0x70>;
+ pinctrl-0 = <&pinctrl_hdmi>;
+ pinctrl-names = "default";
+ interrupt-parent = <&gpio3>;
+ interrupts = <27 IRQ_TYPE_EDGE_FALLING>;
+ clocks = <&clks IMX6SX_CLK_CKO2>;
+
+ port {
+ tda998x_input: endpoint {
+ remote-endpoint = <&lcdif1_output>;
+ };
+ };
+ };
+};
+
+&lcdif1 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_lcd>;
+ status = "okay";
+
+ port {
+ lcdif1_output: endpoint {
+ remote-endpoint = <&tda998x_input>;
+ };
+ };
+};

and I changed it to:

ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel, &bridge);

,but drm_of_find_panel_or_bridge() always returns -EPROBE_DEFER.

Shouldn't it be able to find the bridge chip in this case? Any ideas
of what it is missing?

Thanks