Re: [PATCH V7 RESEND 4/7] spi: spi-geni-qcom: Add interconnect support

[Doug Anderson <dianders@xxxxxxxxxxxx>]

Hi,

On Mon, Jun 8, 2020 at 10:57 PM Akash Asthana <akashast@xxxxxxxxxxxxxx> wrote:
>
> Get the interconnect paths for SPI based Serial Engine device
> and vote according to the current bus speed of the driver.
>
> Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
> Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> ---
> Changes in V2:
>  - As per Bjorn's comment, removed se == NULL check from geni_spi_icc_get
>  - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure
>  - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting
>    path handle
>  - As per Matthias comment, added error handling for icc_set_bw call
>
> Changes in V3:
>  - As per Matthias's comment, use helper ICC function from geni-se driver.
>
> Changes in V4:
>  - Move peak_bw guess as twice of avg_bw if nothing mentioned explicitly
>    to ICC core.
>
> Changes in V5:
>  - Use icc_enable/disable in power on/off call.
>  - Save some non-zero avg/peak value to ICC core by calling geni_icc_set_bw
>    from probe so that when resume/icc_enable is called NOC are running at
>    some non-zero value. No need to call icc_disable after BW vote because
>    device will resume and suspend before probe return and will leave ICC in
>    disabled state.
>
> Changes in V6:
>  - No change
>
> Changes in V7:
>  - As per Matthias's comment removed usage of peak_bw variable because we don't
>    have explicit peak requirement, we were voting peak = avg and this can be
>    tracked using single variable for avg bw.
>
>  drivers/spi/spi-geni-qcom.c | 29 ++++++++++++++++++++++++++++-
>  1 file changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index c397242..2ace5c5 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -234,6 +234,12 @@ static int setup_fifo_params(struct spi_device *spi_slv,
>                 return ret;
>         }
>
> +       /* Set BW quota for CPU as driver supports FIFO mode only. */
> +       se->icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(mas->cur_speed_hz);
> +       ret = geni_icc_set_bw(se);
> +       if (ret)
> +               return ret;
> +

I haven't done a deep review of your patch, but a quick drive-by
review since I happened to notice it while looking at this driver.
You should probably also update the other path that's adjusting the
"mas->cur_speed_hz" variable.  Specifically see setup_fifo_xfer().

For bonus points, you could even unify the two paths.  Perhaps you
could pick <https://crrev.com/c/2259624> and include it in your series
(remove the WIP if you do).


-Doug