From: Zach Brown <zach.brown@ni.com>
To: ulf.hansson@linaro.org
Cc: adrian.hunter@intel.com, robh+dt@kernel.org,
mark.rutland@arm.com, linux-mmc@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
zach.brown@ni.com
Subject: [PATCH 1/2] sdhci: Add device tree property broken-highspeed
Date: Tue, 18 Oct 2016 10:37:05 -0500 [thread overview]
Message-ID: <1476805026-677-2-git-send-email-zach.brown@ni.com> (raw)
In-Reply-To: <1476805026-677-1-git-send-email-zach.brown@ni.com>
Certain board configurations can make highspeed malfuction due to timing
issues. In these cases a way is needed to force the controller and card
into standard speed even if they otherwise appear to be capable of
highspeed.
The broken-highspeed property will let the sdhci driver know that
highspeed will not work.
Signed-off-by: Zach Brown <zach.brown@ni.com>
Acked-by: Rob Herring <robh@kernel.org>
---
Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index 8a37782..a2b298c 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -52,6 +52,8 @@ Optional properties:
- no-sdio: controller is limited to send sdio cmd during initialization
- no-sd: controller is limited to send sd cmd during initialization
- no-mmc: controller is limited to send mmc cmd during initialization
+- broken-highspeed: Highspeed is broken, even if the controller and card
+ themselves claim they support highspeed.
*NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
polarity properties, we have to fix the meaning of the "normal" and "inverted"
--
2.7.4
next prev parent reply other threads:[~2016-10-18 15:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-18 15:37 [PATCH 0/2] Add device tree property and quirk for supporting sdhci Zach Brown
2016-10-18 15:37 ` Zach Brown [this message]
[not found] ` <1476805026-677-1-git-send-email-zach.brown-acOepvfBmUk@public.gmane.org>
2016-10-18 15:37 ` [PATCH 2/2] sdhci: Prevent SD from doing high-speed timing when broken-highspeed property is set Zach Brown
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