diff options
| author | Alexandru M Stan | 2015-06-09 13:04:48 +0200 |
|---|---|---|
| committer | Lee Jones | 2015-06-15 13:18:24 +0100 |
| commit | f44c21ff6d2dc76957ddbf26fdf442ee5a9cf3c0 (patch) | |
| tree | 3fe15679d281affe3e6cc656934d48d307c2985a /Documentation | |
| parent | 57b33ff077beebb68481a2b6b8e5fe58ca998169 (diff) | |
mfd: cros_ec: spi: Add a DT property to delay asserting the CS
Some ECs need a little time for waking up before they can accept
SPI data at a high speed. Add a "google,cros-ec-spi-pre-delay"
property to the DT binding to configure this.
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 beginning of a transaction.
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/mfd/cros-ec.txt | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mfd/cros-ec.txt b/Documentation/devicetree/bindings/mfd/cros-ec.txt index 8009c3d87f33..1777916e9e28 100644 --- a/Documentation/devicetree/bindings/mfd/cros-ec.txt +++ b/Documentation/devicetree/bindings/mfd/cros-ec.txt @@ -18,6 +18,10 @@ Required properties (SPI): - reg: SPI chip select Optional properties (SPI): +- google,cros-ec-spi-pre-delay: Some implementations of the EC need a little + time to wake up from sleep before they can receive SPI transfers at a high + clock rate. This property specifies the delay, in usecs, between the + assertion of the CS to the start of the first clock pulse. - 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 |