From: Michael Walle <michael@walle.cc>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Heiko Thiery <heiko.thiery@gmail.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Fabio Estevam <festevam@gmail.com>,
Shengjiu Wang <shengjiu.wang@nxp.com>,
Joakim Zhang <qiangqing.zhang@nxp.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [PATCH v2] arm64: dts: imx8mq-kontron-pitx-imx8m: remove vqmmc-supply node
Date: Tue, 14 Sep 2021 10:32:26 +0200 [thread overview]
Message-ID: <79fb60ea9a002ea553a92ea08b28b866@walle.cc> (raw)
In-Reply-To: <449f718706fd5af03190bdda986de37aa8fa14e3.camel@pengutronix.de>
Hi Lucas,
Am 2021-09-14 10:20, schrieb Lucas Stach:
> Am Dienstag, dem 14.09.2021 um 09:26 +0200 schrieb Heiko Thiery:
>> The sw4 output (V_1V8_S0 voltage) from the PMIC is the main supply for
>> the 1V8 power domain. It is not only used as supply for the eMMC.
>> So this voltage can not be changed and is not allowed to switched off.
>> Therefore we do not want to provide this regulator to the SDHC driver
>> to
>> control this voltage.
>>
> This specific requirement should not be solved by removing the
> regulator connection from the SDHCI node, but instead by constraining
> the regulator voltage range to a fixed 3.3V and marking the regulator
> as always-on to reflect the hardware requirements in the DT.
>
> Also if your eMMC vqmmc is a fixed 3.3V, I don't think you need the
> faster pinctrl states, as you can't use the faster pin states anyways,
> as they require a 1.8V signaling voltage.
Are you speaking of the 1.8V signalling modes? As far as I know the
IMX SDHC controller will switch the voltage by its own function pin.
That is, its not a GPIO.
-michael
next prev parent reply other threads:[~2021-09-14 8:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 7:26 [PATCH v2] arm64: dts: imx8mq-kontron-pitx-imx8m: remove vqmmc-supply node Heiko Thiery
2021-09-14 8:20 ` Lucas Stach
2021-09-14 8:32 ` Michael Walle [this message]
2021-09-14 8:52 ` Lucas Stach
2021-09-14 9:12 ` Michael Walle
2021-09-14 9:37 ` Heiko Thiery
2023-12-12 13:41 ` Uwe Kleine-König
[not found] ` <CAEyMn7Y_ZsGQjKJtFn6zuqzRzUzf_ueSi7JWhjOX0zeDsBzM8w@mail.gmail.com>
2023-12-12 15:58 ` Uwe Kleine-König
2021-09-14 9:39 ` Michael Walle
2021-09-14 12:34 ` Lucas Stach
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