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From: Luca Ceresoli <luca.ceresoli@bootlin.com>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>, Marek Vasut <marex@denx.de>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	patchwork-lst@pengutronix.de, kernel@pengutronix.de
Subject: Re: [PATCH 4/4] arm64: dts: imx8mp-evk: enable HDMI
Date: Thu, 2 Mar 2023 16:35:25 +0100	[thread overview]
Message-ID: <20230302163525.007503e4@booty> (raw)
In-Reply-To: <20220826192932.3217260-4-l.stach@pengutronix.de>

Hello Lucas,

On Fri, 26 Aug 2022 21:29:32 +0200
Lucas Stach <l.stach@pengutronix.de> wrote:

> Enable the DT nodes for HDMI TX and PHY and add the pinctrl for the few
> involved pins that are configurable.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

I'm joining late to this party... Is this the latest version of this
series? I haven't found any more recent, but if it is not the case
would you point me to the most recent one please?

> +	pinctrl_hdmi: hdmigrp {
> +		fsl,pins = <
> +			MX8MP_IOMUXC_HDMI_DDC_SCL__HDMIMIX_HDMI_SCL	0x1c3
> +			MX8MP_IOMUXC_HDMI_DDC_SDA__HDMIMIX_HDMI_SDA	0x1c3

Is the low nibble (0x3) right?BIT(0) is reserved according too the
reference manual.

Also, all the non-reserved bits in that nibble are bits 1 and 2, which
set the drive strength. For an I2C line it seems that the minimum drive
strength (0x0) should be enough for an I2C line: with any drive
strength setting the supported frequency is >= 65 MHz.

> +			MX8MP_IOMUXC_HDMI_HPD__HDMIMIX_HDMI_HPD		0x19
> +			MX8MP_IOMUXC_HDMI_CEC__HDMIMIX_HDMI_CEC		0x19

Here as well, bits 0 and 3 are reserved.

Best regards,
Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
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WARNING: multiple messages have this Message-ID (diff)
From: Luca Ceresoli <luca.ceresoli@bootlin.com>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>, Marek Vasut <marex@denx.de>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	patchwork-lst@pengutronix.de, kernel@pengutronix.de
Subject: Re: [PATCH 4/4] arm64: dts: imx8mp-evk: enable HDMI
Date: Thu, 2 Mar 2023 16:35:25 +0100	[thread overview]
Message-ID: <20230302163525.007503e4@booty> (raw)
In-Reply-To: <20220826192932.3217260-4-l.stach@pengutronix.de>

Hello Lucas,

On Fri, 26 Aug 2022 21:29:32 +0200
Lucas Stach <l.stach@pengutronix.de> wrote:

> Enable the DT nodes for HDMI TX and PHY and add the pinctrl for the few
> involved pins that are configurable.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

I'm joining late to this party... Is this the latest version of this
series? I haven't found any more recent, but if it is not the case
would you point me to the most recent one please?

> +	pinctrl_hdmi: hdmigrp {
> +		fsl,pins = <
> +			MX8MP_IOMUXC_HDMI_DDC_SCL__HDMIMIX_HDMI_SCL	0x1c3
> +			MX8MP_IOMUXC_HDMI_DDC_SDA__HDMIMIX_HDMI_SDA	0x1c3

Is the low nibble (0x3) right?BIT(0) is reserved according too the
reference manual.

Also, all the non-reserved bits in that nibble are bits 1 and 2, which
set the drive strength. For an I2C line it seems that the minimum drive
strength (0x0) should be enough for an I2C line: with any drive
strength setting the supported frequency is >= 65 MHz.

> +			MX8MP_IOMUXC_HDMI_HPD__HDMIMIX_HDMI_HPD		0x19
> +			MX8MP_IOMUXC_HDMI_CEC__HDMIMIX_HDMI_CEC		0x19

Here as well, bits 0 and 3 are reserved.

Best regards,
Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

  reply	other threads:[~2023-03-02 15:36 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-26 19:29 [PATCH 1/4] arm64: dts: imx8mp: add HDMI power-domains Lucas Stach
2022-08-26 19:29 ` Lucas Stach
2022-08-26 19:29 ` [PATCH 2/4] arm64: dts: imx8mp: add HDMI irqsteer Lucas Stach
2022-08-26 19:29   ` Lucas Stach
2022-08-26 19:29 ` [PATCH 3/4] arm64: dts: imx8mp: add HDMI display pipeline Lucas Stach
2022-08-26 19:29   ` Lucas Stach
2022-08-29  6:37   ` Alexander Stein
2022-08-29  6:37     ` Alexander Stein
2022-09-05  2:04   ` Shawn Guo
2022-09-05  2:04     ` Shawn Guo
2023-03-03 17:26   ` Luca Ceresoli
2023-03-03 17:26     ` Luca Ceresoli
2022-08-26 19:29 ` [PATCH 4/4] arm64: dts: imx8mp-evk: enable HDMI Lucas Stach
2022-08-26 19:29   ` Lucas Stach
2023-03-02 15:35   ` Luca Ceresoli [this message]
2023-03-02 15:35     ` Luca Ceresoli
2023-05-25 10:26     ` Luca Ceresoli
2023-05-25 10:26       ` Luca Ceresoli
2024-06-08 15:06       ` Laurent Pinchart
2024-06-08 15:06         ` Laurent Pinchart
2024-06-10  8:31         ` Luca Ceresoli
2024-06-10  8:31           ` Luca Ceresoli
2024-06-12 10:25           ` Luca Ceresoli
2024-06-12 21:15             ` Laurent Pinchart

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