From: Jernej Skrabec <jernej.skrabec@gmail.com>
To: mripard@kernel.org, wens@csie.org
Cc: robh+dt@kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
Jernej Skrabec <jernej.skrabec@gmail.com>
Subject: [PATCH 0/2] dts: Add CEC clock to DW HDMI
Date: Sat, 20 Nov 2021 08:34:46 +0100 [thread overview]
Message-ID: <20211120073448.32480-1-jernej.skrabec@gmail.com> (raw)
Experimentation proved that CEC controller in H3-like DW-HDMI core
depends on 32 kHz clock output from RTC. If board has external 32768 Hz
crystal, HDMI CEC always work. However, if external crystal is missing
and 32 kHz clock is generated by internal oscillator, CEC communication
may or may not work, depending on accuracy. Changing internal oscillator
prescaler can make CEC work.
This was totally missed when implementing HDMI support, because user
manual has no CEC information besides the fact that it exists.
Please take a look.
Best regards,
Jernej
Jernej Skrabec (2):
arm64: dts: allwinner: a64: Add CEC clock to HDMI
ARM: dts: sunxi: Add CEC clock to DW-HDMI
arch/arm/boot/dts/sun8i-r40.dtsi | 4 ++--
arch/arm/boot/dts/sunxi-h3-h5.dtsi | 4 ++--
arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 4 ++--
3 files changed, 6 insertions(+), 6 deletions(-)
--
2.34.0
next reply other threads:[~2021-11-20 7:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 7:34 Jernej Skrabec [this message]
2021-11-20 7:34 ` [PATCH 1/2] arm64: dts: allwinner: a64: Add CEC clock to HDMI Jernej Skrabec
2021-11-20 7:34 ` [PATCH 2/2] ARM: dts: sunxi: Add CEC clock to DW-HDMI Jernej Skrabec
2021-11-22 9:07 ` [PATCH 0/2] dts: Add CEC clock to DW HDMI Maxime Ripard
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