From: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
To: heiko@sntech.de, linux-rockchip@lists.infradead.org,
Andy Yan <andyshrk@163.com>
Cc: simic@manjaro.org, krzk+dt@kernel.org, robh@kernel.org,
devicetree@vger.kernel.org, conor+dt@kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
algea.cao@rock-chips.com, Andy Yan <andy.yan@rock-chips.com>
Subject: Re: [PATCH v2] arm64: dts: rockchip: Adjust the HDMI DDC IO driver strength for rk3588
Date: Tue, 27 May 2025 13:53:56 +0200 [thread overview]
Message-ID: <3704844.aeNJFYEL58@workhorse> (raw)
In-Reply-To: <20250522020537.1884771-1-andyshrk@163.com>
On Thursday, 22 May 2025 04:05:24 Central European Summer Time Andy Yan wrote:
> From: Andy Yan <andy.yan@rock-chips.com>
>
> For the RK3588 HDMI controller, the falling edge of DDC SDA and SCL
> almost coincide and cannot be adjusted by HDMI registrer, resulting
> in poor compatibility of DDC communication.
>
> An improvement of the compatibility of DDC can be done by increasing
> the driver strength of SCL and decreasing the driver strength of SDA
> to increase the slope of the falling edge.
>
> It should be noted that the maximum driving strength of hdmim0_tx1_scl
> is only 3, which is different from that of the other IOs.
>
> Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
>
> ---
>
> Changes in v2:
> - Correct the max drive level of hdmim0_tx1_scl.
>
> .../dts/rockchip/rk3588-base-pinctrl.dtsi | 20 +++++------
> .../dts/rockchip/rk3588-extra-pinctrl.dtsi | 5 +--
> .../boot/dts/rockchip/rockchip-pinconf.dtsi | 35 +++++++++++++++++++
> 3 files changed, 48 insertions(+), 12 deletions(-)
>
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Quickly tested this on both HDMI ports of a ROCK 5T with an HDMI capture
card on the other end. While I didn't originally have any issues to begin
with, this patch does not introduce any new ones, so seems good to me.
WARNING: multiple messages have this Message-ID (diff)
From: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
To: heiko@sntech.de, linux-rockchip@lists.infradead.org,
Andy Yan <andyshrk@163.com>
Cc: simic@manjaro.org, krzk+dt@kernel.org, robh@kernel.org,
devicetree@vger.kernel.org, conor+dt@kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
algea.cao@rock-chips.com, Andy Yan <andy.yan@rock-chips.com>
Subject: Re: [PATCH v2] arm64: dts: rockchip: Adjust the HDMI DDC IO driver strength for rk3588
Date: Tue, 27 May 2025 13:53:56 +0200 [thread overview]
Message-ID: <3704844.aeNJFYEL58@workhorse> (raw)
In-Reply-To: <20250522020537.1884771-1-andyshrk@163.com>
On Thursday, 22 May 2025 04:05:24 Central European Summer Time Andy Yan wrote:
> From: Andy Yan <andy.yan@rock-chips.com>
>
> For the RK3588 HDMI controller, the falling edge of DDC SDA and SCL
> almost coincide and cannot be adjusted by HDMI registrer, resulting
> in poor compatibility of DDC communication.
>
> An improvement of the compatibility of DDC can be done by increasing
> the driver strength of SCL and decreasing the driver strength of SDA
> to increase the slope of the falling edge.
>
> It should be noted that the maximum driving strength of hdmim0_tx1_scl
> is only 3, which is different from that of the other IOs.
>
> Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
>
> ---
>
> Changes in v2:
> - Correct the max drive level of hdmim0_tx1_scl.
>
> .../dts/rockchip/rk3588-base-pinctrl.dtsi | 20 +++++------
> .../dts/rockchip/rk3588-extra-pinctrl.dtsi | 5 +--
> .../boot/dts/rockchip/rockchip-pinconf.dtsi | 35 +++++++++++++++++++
> 3 files changed, 48 insertions(+), 12 deletions(-)
>
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Quickly tested this on both HDMI ports of a ROCK 5T with an HDMI capture
card on the other end. While I didn't originally have any issues to begin
with, this patch does not introduce any new ones, so seems good to me.
_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip
next prev parent reply other threads:[~2025-05-27 11:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-22 2:05 [PATCH v2] arm64: dts: rockchip: Adjust the HDMI DDC IO driver strength for rk3588 Andy Yan
2025-05-22 2:05 ` Andy Yan
2025-05-27 11:53 ` Nicolas Frattaroli [this message]
2025-05-27 11:53 ` Nicolas Frattaroli
2025-05-28 8:49 ` Andy Yan
2025-05-28 8:49 ` Andy Yan
2025-06-09 10:22 ` Heiko Stuebner
2025-06-09 10:22 ` Heiko Stuebner
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