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: [RFC 1/2] sdhci: Add device tree property sd-broken-highspeed
Date: Fri, 23 Sep 2016 15:01:08 -0500 [thread overview]
Message-ID: <1474660869-15532-2-git-send-email-zach.brown@ni.com> (raw)
In-Reply-To: <1474660869-15532-1-git-send-email-zach.brown@ni.com>
Certain board configurations can make highspeed malfunction 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 sd-broken-highspeed property will let the sdhci driver know that
highspeed will not work.
Signed-off-by: Zach Brown <zach.brown@ni.com>
---
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..59332ea 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
+- sd-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:[~2016-09-23 20:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-23 20:01 [RFC 0/2] Add device tree property and quirk for supporting sdhci Zach Brown
2016-09-23 20:01 ` Zach Brown [this message]
[not found] ` <1474660869-15532-2-git-send-email-zach.brown-acOepvfBmUk@public.gmane.org>
2016-10-03 17:37 ` [RFC 1/2] sdhci: Add device tree property sd-broken-highspeed Rob Herring
2016-10-05 18:33 ` Ulf Hansson
2016-10-05 20:03 ` Rob Herring
[not found] ` <CAL_JsqLjtn2-FaO_h9JWOsZqttQ35yV6KOnQz2Z-cMr=0GHJCg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-10-05 21:22 ` Julia Cartwright
2016-10-06 1:34 ` Shawn Lin
[not found] ` <5972c8f4-23b5-7dbb-b87c-7be7ec5b1a17-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2016-10-06 6:13 ` Adrian Hunter
2016-10-07 18:56 ` Zach Brown
2016-10-06 8:03 ` Ulf Hansson
2016-10-17 21:49 ` Zach Brown
2016-09-23 20:01 ` [RFC 2/2] sdhci: Prevent SD from doing highspeed timing when sd-broken-highspeed property is set Zach Brown
[not found] ` <1474660869-15532-3-git-send-email-zach.brown-acOepvfBmUk@public.gmane.org>
2016-10-06 6:39 ` Adrian Hunter
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