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Message-ID: <7f565036-df78-a4e7-db5e-259115daaf79@collabora.com>
Date:   Mon, 27 Jun 2022 14:55:29 +0200
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Subject: Re: [PATCH] drm/bridge: add it6505 driver read config from dt
 property
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To:     allen <allen.chen@ite.com.tw>
Cc:     Pin-yen Lin <treapking@google.com>,
        Jau-Chih Tseng <Jau-Chih.Tseng@ite.com.tw>,
        Hermes Wu <Hermes.Wu@ite.com.tw>,
        Kenneth Hung <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>
References: <20220623093154.52701-1-allen.chen@ite.com.tw>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20220623093154.52701-1-allen.chen@ite.com.tw>
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Precedence: bulk

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