From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB51118A6B2 for ; Thu, 19 Dec 2024 17:44:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734630248; cv=none; b=kZrXg1Qy4bN6H6gmx+m1HcbLd1D8+2kK94OjigvsL9omrcN/Hw++RGKvd8Ahg6AP7gAgzm/AhsSuqdGY0ACi5R8yJ67xzCyBs2SaREGhfOHkWvQ1Ma8NhFzMbjukq1OzeFc7IFP07oWRjy5FvN6/jNE7lhTZ+ocF3imDLY3onV0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734630248; c=relaxed/simple; bh=ywFGdUPE/ErvhDSzL79KtYLPtpmEObcvfdwacxeHUa0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tmiauipXGLmTnRugYaWIJcQ8J9OtZQOQFGcuG9nQCNO4nLNUI08107W2cpWbhy/ln9Lfjzrr0sQFPi9hkywSGofoa1+a+X7ErICKSen2DKPCSvvBEWZlBKiT8NCd1Tmr3HFRGUOO/585Aa7lUp8t2F3klmEIDtejQ+13XHj2+v8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1tOKZ3-0001dj-JS; Thu, 19 Dec 2024 18:43:57 +0100 Message-ID: Date: Thu, 19 Dec 2024 18:43:56 +0100 Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 03/10] arm64: dts: imx8mp-skov: use I2C5 for DDC To: Frank Li Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Oleksij Rempel , devicetree@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20241219-skov-dt-updates-v1-0-38bf80dc22df@pengutronix.de> <20241219-skov-dt-updates-v1-3-38bf80dc22df@pengutronix.de> Content-Language: en-US From: Ahmad Fatoum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2a0a:edc0:0:900:1d::77 X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: imx@lists.linux.dev Hello Frank, On 19.12.24 18:34, Frank Li wrote: > On Thu, Dec 19, 2024 at 08:25:27AM +0100, Ahmad Fatoum wrote: >> The HDMI DDC pads can be muxed either to an i.MX I2C controller or >> to a limited I2C controller within the Designware HDMI bridge. >> >> So far we muxed the pads to the HDMI bridge, but the i.MX I2C controller >> is the better choice: > > Switch to the i.MX I2C controller because > >> >> - We use DDC/CI commands for display brightness configuration, but the >> Linux driver refuses[1] transfers to/from address 0x37, because the >> controller doesn't support multi-byte requests. > > Designware HDMI Limited I2C controller doesn't support multi-byte > requests and display brightness configuration by DDC/CI command need it. > >> >> - The driver doesn't support I2C bus recovery, but we need that, >> because some HDMI panels used with the board can be flaky. > > Designware HDMI Limited I2C controller doesn't support I2C bus > recovery. > >> >> As the i.MX I2C controller doesn't have either of these limitations, >> let's make use of it instead. > > Reduntant. can be removed. Sorry, I am very much open to review feedback, but I fail to see how your subjective take improves things. Thanks, Ahmad > > Frank >> >> [1]: https://lore.kernel.org/all/20190722181945.244395-1-mka@chromium.org/ >> >> Signed-off-by: Ahmad Fatoum >> --- >> .../boot/dts/freescale/imx8mp-skov-revb-hdmi.dts | 26 ++++++++++++++++++++-- >> 1 file changed, 24 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts b/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts >> index c1ca69da3cb8..206116be8166 100644 >> --- a/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts >> +++ b/arch/arm64/boot/dts/freescale/imx8mp-skov-revb-hdmi.dts >> @@ -9,12 +9,34 @@ / { >> compatible = "skov,imx8mp-skov-revb-hdmi", "fsl,imx8mp"; >> }; >> >> +&i2c5 { >> + pinctrl-names = "default", "gpio"; >> + pinctrl-0 = <&pinctrl_i2c5>; >> + pinctrl-1 = <&pinctrl_i2c5_gpio>; >> + scl-gpios = <&gpio3 26 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; >> + sda-gpios = <&gpio3 27 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; >> + clock-frequency = <100000>; >> + status = "okay"; >> +}; >> + >> &iomuxc { >> pinctrl_hdmi: hdmigrp { >> fsl,pins = < >> - MX8MP_IOMUXC_HDMI_DDC_SCL__HDMIMIX_HDMI_SCL 0x1c3 >> - MX8MP_IOMUXC_HDMI_DDC_SDA__HDMIMIX_HDMI_SDA 0x1c3 >> MX8MP_IOMUXC_HDMI_HPD__HDMIMIX_HDMI_HPD 0x19 >> >; >> }; >> + >> + pinctrl_i2c5: i2c5grp { >> + fsl,pins = < >> + MX8MP_IOMUXC_HDMI_DDC_SCL__I2C5_SCL 0x400001c2 >> + MX8MP_IOMUXC_HDMI_DDC_SDA__I2C5_SDA 0x400001c2 >> + >; >> + }; >> + >> + pinctrl_i2c5_gpio: i2c5gpiogrp { >> + fsl,pins = < >> + MX8MP_IOMUXC_HDMI_DDC_SCL__GPIO3_IO26 0x400001c2 >> + MX8MP_IOMUXC_HDMI_DDC_SDA__GPIO3_IO27 0x400001c2 >> + >; >> + }; >> }; >> >> -- >> 2.39.5 >> > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |