[PATCH 0/2] spi: amlogic: meson-spicc: Use pinctrl to drive CLK line when idle
Neil Armstrong
neil.armstrong at linaro.org
Tue Sep 27 01:30:06 PDT 2022
Hi Amjad,
On 09/08/2022 19:20, Amjad Ouled-Ameur wrote:
> Between SPI transactions, all SPI pins are in HiZ state. When using the SS
> signal from the SPICC controller it's not an issue because when the
> transaction resumes all pins come back to the right state at the same time
> as SS.
>
> The problem is when we use CS as a GPIO. In fact, between the GPIO CS
> state change and SPI pins state change from idle, you can have a missing or
> spurious clock transition.
>
> Set a bias on the clock depending on the clock polarity requested before CS
> goes active, by passing a special "idle-low" and "idle-high" pinctrl state
> and setting the right state at a start of a message.
>
> Amjad Ouled-Ameur (2):
> spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI
> signal states
> spi: meson-spicc: Use pinctrl to drive CLK line when idle
>
> .../bindings/spi/amlogic,meson-gx-spicc.yaml | 15 +++++++
> arch/arm64/boot/dts/amlogic/meson-gxl.dtsi | 14 +++++++
> drivers/spi/spi-meson-spicc.c | 39 ++++++++++++++++++-
> 3 files changed, 67 insertions(+), 1 deletion(-)
>
Will you send a v2 with comments adresses ?
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