RE: [PATCH] drm/bridge: add it6505 driver read config from dt property

[<allen.chen@ite.com.tw>]

Hi AngeloGioacchino

According to video-interfaces.yaml, property data-lanes should in the endpoint. It6505 has dpi input and no data-lanes parameters. It6505 has dp output and has data-lanes parameters. We want to use data-lanes in the output, but output point use extcon instead of endpoint. Do not have output endpoint.
Which line in dts should data-lanes be in?
Below is it6505 dts 

Thanks for your suggestion!

dp-bridge@5c {
            compatible = "ite,it6505";
            interrupts = <152 IRQ_TYPE_EDGE_FALLING 152 0>;
            reg = <0x5c>;
            pinctrl-names = "default";
            pinctrl-0 = <&it6505_pins>;
            ovdd-supply = <&mt6358_vsim1_reg>;
            pwr18-supply = <&it6505_pp18_reg>;
            reset-gpios = <&pio 179 1>;
            extcon = <&usbc_extcon>;

            port {
                it6505_in: endpoint {
                    remote-endpoint = <&dpi_out>;
                };
            };
        };


-----Original Message-----
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> 
Sent: Monday, June 27, 2022 8:55 PM
To: Allen Chen (陳柏宇) <allen.chen@ite.com.tw>
Cc: Pin-yen Lin <treapking@google.com>; Jau-Chih Tseng (曾昭智) <Jau-Chih.Tseng@ite.com.tw>; Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>; Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; Allen-kh Cheng <allen-kh.cheng@mediatek.corp-partner.google.com>; Pin-yen Lin <treapking@chromium.org>; Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong <narmstrong@baylibre.com>; Robert Foss <robert.foss@linaro.org>; Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>; David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Matthias Brugger <matthias.bgg@gmail.com>; open list:DRM DRIVERS <dri-devel@lists.freedesktop.org>; open list <linux-kernel@vger.kernel.org>; moderated list:ARM/Mediatek SoC support <linux-arm-kernel@lists.infradead.org>; moderated list:ARM/Mediatek SoC support <linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH] drm/bridge: add it6505 driver read config from dt property

Il 23/06/22 11:31, allen ha scritto:
> From: allen chen <allen.chen@ite.com.tw>
> 
> add read max-lane and max-pixel-clock from dt property
> 
> Signed-off-by: Allen-kh Cheng 
> <allen-kh.cheng@mediatek.corp-partner.google.com>
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>

Hello Allen,

as Sam also pointed out, please fix your S-o-b email: it has to match with the author one.

Anyway, you're adding devicetree properties, so this implies that you should also change the dt-bindings documentation for this driver... and also, I have some more comments, check below:

> ---
>   drivers/gpu/drm/bridge/ite-it6505.c | 35 ++++++++++++++++++++++++++---
>   1 file changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c 
> b/drivers/gpu/drm/bridge/ite-it6505.c
> index 4b673c4792d77..c9121d4635a52 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -436,6 +436,8 @@ struct it6505 {
>   	bool powered;
>   	bool hpd_state;
>   	u32 afe_setting;
> +	u32 max_dpi_pixel_clock;
> +	u32 max_lane_count;
>   	enum hdcp_state hdcp_status;
>   	struct delayed_work hdcp_work;
>   	struct work_struct hdcp_wait_ksv_list; @@ -1466,7 +1468,8 @@ static 
> void it6505_parse_link_capabilities(struct it6505 *it6505)
>   	it6505->lane_count = link->num_lanes;
>   	DRM_DEV_DEBUG_DRIVER(dev, "Sink support %d lanes training",
>   			     it6505->lane_count);
> -	it6505->lane_count = min_t(int, it6505->lane_count, MAX_LANE_COUNT);
> +	it6505->lane_count = min_t(int, it6505->lane_count,
> +				   it6505->max_lane_count);
>   
>   	it6505->branch_device = drm_dp_is_branch(it6505->dpcd);
>   	DRM_DEV_DEBUG_DRIVER(dev, "Sink %sbranch device", @@ -2895,7 
> +2898,7 @@ it6505_bridge_mode_valid(struct drm_bridge *bridge,
>   	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
>   		return MODE_NO_INTERLACE;
>   
> -	if (mode->clock > DPI_PIXEL_CLK_MAX)
> +	if (mode->clock > it6505->max_dpi_pixel_clock)
>   		return MODE_CLOCK_HIGH;
>   
>   	it6505->video_info.clock = mode->clock; @@ -3057,6 +3060,8 @@ 
> static void it6505_parse_dt(struct it6505 *it6505)
>   {
>   	struct device *dev = &it6505->client->dev;
>   	u32 *afe_setting = &it6505->afe_setting;
> +	u32 *max_lane_count = &it6505->max_lane_count;
> +	u32 *max_dpi_pixel_clock = &it6505->max_dpi_pixel_clock;
>   
>   	it6505->lane_swap_disabled =
>   		device_property_read_bool(dev, "no-laneswap"); @@ -3072,7 +3077,31 
> @@ static void it6505_parse_dt(struct it6505 *it6505)
>   	} else {
>   		*afe_setting = 0;
>   	}
> -	DRM_DEV_DEBUG_DRIVER(dev, "using afe_setting: %d", *afe_setting);
> +
> +	if (device_property_read_u32(dev, "max-lane-count",

Please use the standard property "data-lanes" from video-interfaces.yaml.

> +				     max_lane_count) == 0) {
> +		if (*max_lane_count > 4 || *max_lane_count == 3) {
> +			dev_err(dev, "max lane count error, use default");
> +			*max_lane_count = MAX_LANE_COUNT;
> +		}
> +	} else {
> +		*max_lane_count = MAX_LANE_COUNT;
> +	}
> +
> +	if (device_property_read_u32(dev, "max-dpi-pixel-clock",
> +				     max_dpi_pixel_clock) == 0) {

What about "max-pixel-clock-khz" or "max-pixel-clock-hz"?


Regards,
Angelo