[PATCH 0/2] spi: amlogic: meson-spicc: Use pinctrl to drive CLK line when idle
Amjad Ouled-Ameur
aouledameur at baylibre.com
Tue Sep 27 02:36:49 PDT 2022
Hi Neil,
On 9/27/22 10:30, Neil Armstrong wrote:
> 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 ?
Planning to send it soon, thank you for the review.
Regards,
Amjad
More information about the linux-amlogic
mailing list