diff options
| author | Rhyland Klein | 2013-12-09 12:36:09 +0100 |
|---|---|---|
| committer | Lee Jones | 2014-01-21 08:28:06 +0000 |
| commit | 01e73c89cf03c020e586dc9e30d52a6e098853f6 (patch) | |
| tree | daef78c50110f4fed3218742bf8c6560e3645639 /Documentation | |
| parent | daf93d2287ff8eb4a2f28224275fb02d623df2ab (diff) | |
mfd: cros ec: spi: Add delay for raising CS
The EC has specific timing it requires. Add support for an optional delay
after raising CS to fix timing issues. This is configurable based on
a DT property "google,cros-ec-spi-msg-delay".
If this property isn't set, then no delay will be added. However, if set
it will cause a delay equal to the value passed to it to be inserted at
the end of a transaction.
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/mfd/cros-ec.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mfd/cros-ec.txt b/Documentation/devicetree/bindings/mfd/cros-ec.txt index 5f229c5f6da9..8009c3d87f33 100644 --- a/Documentation/devicetree/bindings/mfd/cros-ec.txt +++ b/Documentation/devicetree/bindings/mfd/cros-ec.txt @@ -17,6 +17,15 @@ Required properties (SPI): - compatible: "google,cros-ec-spi" - reg: SPI chip select +Optional properties (SPI): +- google,cros-ec-spi-msg-delay: Some implementations of the EC require some + additional processing time in order to accept new transactions. If the delay + between transactions is not long enough the EC may not be able to respond + properly to subsequent transactions and cause them to hang. This property + specifies the delay, in usecs, introduced between transactions to account + for the time required by the EC to get back into a state in which new data + can be accepted. + Required properties (LPC): - compatible: "google,cros-ec-lpc" - reg: List of (IO address, size) pairs defining the interface uses |