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From: Yann Gautier <yann.gautier@foss.st.com>
To: Marek Vasut <marex@denx.de>, Ulf Hansson <ulf.hansson@linaro.org>,
	Russell King <linux@armlinux.org.uk>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Vladimir Zapolskiy <vz@mleia.com>,
	<u.kleine-koenig@pengutronix.de>,
	Christophe Kerello <christophe.kerello@foss.st.com>,
	Ludovic Barre <ludovic.barre@foss.st.com>,
	<linux-mmc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] mmc: mmci: add hs200 support for stm32 sdmmc
Date: Thu, 16 Dec 2021 10:44:09 +0100	[thread overview]
Message-ID: <b7ef5887-ce9e-9ba1-5819-765e68104cc5@foss.st.com> (raw)
In-Reply-To: <c4528bc5-a826-a4ed-c4d6-e0ab84651ea2@denx.de>

On 12/16/21 10:14 AM, Marek Vasut wrote:
> On 12/15/21 15:17, Yann Gautier wrote:
>> Use feedback clock for HS200 mode, as for SDR104.
>> The HS200 mode can be enabled through DT by using mmc-hs200-1_8v.
>> It is possible to use it on STM32MP13, but not STM32MP15 platforms.
> 
> HS200 is possible even on the MP15, it just doesn't yield any 
> (performance) benefits due to the slower bus clock (125 MHz or so?), so 
> it isn't worth enabling it on MP15. It is nice to see MP13 can do better.

Hi Marek,

There is a limitation on MP15, please see errata sheet [1], chapter 2.3.19.
HS200 (and SDR104) shouldn't be enabled on MP15.

Best regards,
Yann

[1] https://www.st.com/resource/en/errata_sheet/dm00516256.pdf

  reply	other threads:[~2021-12-16  9:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-15 14:17 [PATCH 0/4] mmc: mmci: updates for STM32MP13 Yann Gautier
2021-12-15 14:17 ` [PATCH 1/4] mmc: mmci: Add support for sdmmc variant revision v2.2 Yann Gautier
2021-12-15 14:17 ` [PATCH 2/4] mmc: mmci: increase stm32 sdmmcv2 clock max freq Yann Gautier
2021-12-15 14:17 ` [PATCH 3/4] mmc: mmci: stm32: clear DLYB_CR after sending tuning command Yann Gautier
2021-12-16  9:13   ` Marek Vasut
2021-12-16  9:48     ` Yann Gautier
2021-12-21 13:02       ` Ulf Hansson
2021-12-15 14:17 ` [PATCH 4/4] mmc: mmci: add hs200 support for stm32 sdmmc Yann Gautier
2021-12-16  9:14   ` Marek Vasut
2021-12-16  9:44     ` Yann Gautier [this message]
2021-12-16 10:15       ` Marek Vasut
2021-12-16  3:23 ` [PATCH 0/4] mmc: mmci: updates for STM32MP13 Linus Walleij
2021-12-21 13:02 ` Ulf Hansson

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