Re: [PATCH 1/3] spi: spi-geni-qcom: Avoid clock setting if not needed

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On 7/2/2020 6:15 AM, Douglas Anderson wrote:
Every SPI transfer could have a different clock rate.  The
spi-geni-qcom controller code to deal with this was never very well
optimized and has always had a lot of code plus some calls into the
clk framework which, at the very least, would grab a mutex.  However,
until recently, the overhead wasn't _too_ much.  That changed with
commit 0e3b8a81f5df ("spi: spi-geni-qcom: Add interconnect support")
we're now calling geni_icc_set_bw(), which leads to a bunch of math
plus:
   geni_icc_set_bw()
     icc_set_bw()
       apply_constraints()
         qcom_icc_set()
           qcom_icc_bcm_voter_commit()
             rpmh_invalidate()
             rpmh_write_batch()
...and those rpmh commands can be a bit beefy if you call them too
often.

Reviewed-by: Akash Asthana<akashast@xxxxxxxxxxxxxx>

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The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project




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