Re: [PATCH 2/2] spi: cadence: Configure SPI clock in the prepare_message() callback

[Harini Katakam <harinikatakamlinux@xxxxxxxxx>]

Hi,

On Thu, Jul 10, 2014 at 2:56 PM, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote:
> Currently the cadence SPI driver does the SPI clock configuration (setup CPOL
> and CPHA) in the prepare_transfer_hardware() callback. The
> prepare_transfer_hardware() callback is only called though when the controller
> transitions from a idle state to a non-idle state. Such a transitions happens
> when the message queue goes from empty to non-empty. If multiple messages from
> different SPI slaves with different clock settings are in the message queue the
> clock settings will not be properly updated when switching from one slave device
> to another. Instead do the updating of the clock configuration in the
> prepare_message() callback which will be called for each individual message.
>

Yes, the requirement from the controller is that CPOL/CPHA setting changes
will not take effect when SPI is enabled. CPOL/CPHA setting is done in
prepare_hardware
before SPI is enabled. So this works.
According to your patches I understand that you might change CPOL/CPHA for
each message. Is this possible? Is this a requirement?

Regards,
Harini
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