Re: [PATCH v7 7/8] mfd: cros_ec: spi: Add a DT property to delay asserting the CS

Lee Jones
2015-06-15T12:25:22Z

On Tue, 09 Jun 2015, Javier Martinez Canillas wrote:

> From: Alexandru M Stan <amstan@chromium.org>
>
> 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>

Applied, thanks.

> ---
>
> Changes since v6:
> - Add Olof Johansson Acked-by tag
>
> Changes since v5: None.
>
> Changes since v4: None.
>
> Changes since v3:
> - Split DT binding and driver change as suggested by Lee Jones.
> - Add tested-by tag from Heiko Stuebner
> - Add acked-by tag from Lee Jones.
>
> Changes since v2: None
>
> Changes since v1: None, new patch
> ---
> Documentation/devicetree/bindings/mfd/cros-ec.txt | 4 ++++
> 1 file changed, 4 insertions(+)
>
> 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

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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