Re: [PATCH 2/2] spi/rockchip: Add device tree property to configure Rx Sample Delay

From: Doug Anderson
Date: Thu Mar 26 2015 - 20:29:32 EST


Julius,

On Thu, Mar 26, 2015 at 4:30 PM, Julius Werner <jwerner@xxxxxxxxxxxx> wrote:
> We have found that we can sometimes see read failures on boards with
> high-capacitance SPI lines. It seems that the controller samples the Rx
> data line too early, and its register interface has an "Rx Sample Delay"
> setting to fine-tune against this issue.
>
> This patch adds a new optional device tree entry that can configure this
> delay in terms of nanoseconds. The kernel will calculate the
> best-fitting amount of parent clock ticks to program the controller with
> based on that.
>
> Signed-off-by: Julius Werner <jwerner@xxxxxxxxxxxx>
> ---
> .../devicetree/bindings/spi/spi-rockchip.txt | 4 ++++
> drivers/spi/spi-rockchip.c | 21 +++++++++++++++++++++
> 2 files changed, 25 insertions(+)

Reviewed-by: Doug Anderson <dianders@xxxxxxxxxxxx>
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