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From: Lucas Stach <l.stach@pengutronix.de>
To: Ulf Hansson <ulf.hansson@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Haibo Chen <haibo.chen@nxp.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	NXP Linux Team <linux-imx@nxp.com>,
	kernel@pengutronix.de, linux-mmc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/3] dt-bindings: mmc: add no-mmc-hs400 flag
Date: Mon, 10 May 2021 21:03:58 +0200	[thread overview]
Message-ID: <20210510190400.105162-1-l.stach@pengutronix.de> (raw)

From: Lucas Stach <dev@lynxeye.de>

HS400 requires a data strobe line in addition to the usual MMC signal
lines. If a board design neglects to wire up this signal, HS400 mode is
not available, even if both the controller and the eMMC are claiming to
support this mode. Add a DT flag to allow boards to disable the HS400
support in this case.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/mmc/mmc-controller.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
index e141330c1114..ac80d09df3a9 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
+++ b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
@@ -220,6 +220,11 @@ properties:
     description:
       eMMC HS400 enhanced strobe mode is supported
 
+  no-mmc-hs400:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      All eMMC HS400 modes are not supported.
+
   dsr:
     description:
       Value the card Driver Stage Register (DSR) should be programmed
-- 
2.31.1


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             reply	other threads:[~2021-05-10 19:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 19:03 Lucas Stach [this message]
2021-05-10 19:03 ` [PATCH v2 2/3] mmc: sdhci-esdhc-imx: advertise HS400 mode through MMC caps Lucas Stach
2021-05-11  3:00   ` Bough Chen
2021-05-11  8:18     ` Lucas Stach
2021-05-11 12:40       ` Adrian Hunter
2021-05-12  2:23         ` Bough Chen
2021-05-24 14:10   ` Ulf Hansson
2021-05-10 19:04 ` [PATCH v2 3/3] mmc: core: add support for disabling HS400 mode via DT Lucas Stach
2021-05-11 11:14   ` Ulf Hansson
2021-05-11 11:54     ` Lucas Stach
2021-05-11 12:19       ` Ulf Hansson
2021-05-24 14:10   ` Ulf Hansson
2021-05-24 14:10 ` [PATCH v2 1/3] dt-bindings: mmc: add no-mmc-hs400 flag Ulf Hansson

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