Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1503352

[RFC 1/2] mmc: sdhci: dt: Add device tree property sdhci-cap-speed-modes-broken

From Zach Brown <zach.brown@ni.com>
Newsgroups linux.kernel
Subject [RFC 1/2] mmc: sdhci: dt: Add device tree property sdhci-cap-speed-modes-broken
Date 2016-10-18 23:10 +0200
Message-ID <stJO2-7sS-23@gated-at.bofh.it> (permalink)
References <stJO2-7sS-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On some systems the sdhci capabilty registers are incorrect for one
reason or another.

The sdhci-cap-speed-modes-broken property will let the driver know that
the sdhci capability registers should not be relied on for speed modes.
Instead the driver should check the mmc generic DT bindings.

Signed-off-by: Zach Brown <zach.brown@ni.com>
---
 Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index 8a37782..671d6c0 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -52,6 +52,9 @@ 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
+- sdhci-cap-speed-modes-broken: One or more of the bits in the sdhci
+  capabilities registers representing speed modes are incorrect. All the bits
+  representing speed modes should be ignored.
 
 *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

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[RFC 0/2] Ignore capability registers when it comes to speeds and use DT binding instead. Zach Brown <zach.brown@ni.com> - 2016-10-18 23:10 +0200
  [RFC 1/2] mmc: sdhci: dt: Add device tree property sdhci-cap-speed-modes-broken Zach Brown <zach.brown@ni.com> - 2016-10-18 23:10 +0200
    Re: [RFC 1/2] mmc: sdhci: dt: Add device tree property  sdhci-cap-speed-modes-broken Rob Herring <robh@kernel.org> - 2016-10-26 23:10 +0200
  [RFC 2/2] mmc: sdhci: Ignore capability register when it comes to speeds and use DT binding instead when sdhci-cap-speed-modes-broken is set. Zach Brown <zach.brown@ni.com> - 2016-10-18 23:10 +0200
    Re: [RFC 2/2] mmc: sdhci: Ignore capability register when it comes to  speeds and use DT binding instead when sdhci-cap-speed-modes-broken is set. Ulf Hansson <ulf.hansson@linaro.org> - 2016-10-19 16:40 +0200

csiph-web