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

From: Akash Asthana <akashast@codeaurora.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Wolfram Sang <wsa@the-dreams.de>, Mark Brown <broonie@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	linux-i2c@vger.kernel.org, linux-spi <linux-spi@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>, Stephen Boyd <swboyd@chromium.org>,
	Manu Gautam <mgautam@codeaurora.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	linux-serial@vger.kernel.org,
	Matthias Kaehlcke <mka@chromium.org>,
	Evan Green <evgreen@chromium.org>,
	msavaliy@codeaurora.org, Rajendra Nayak <rnayak@codeaurora.org>
Subject: Re: [PATCH V7 RESEND 4/7] spi: spi-geni-qcom: Add interconnect support
Date: Tue, 23 Jun 2020 16:03:05 +0530	[thread overview]
Message-ID: <4160ce9e-ee40-703c-1f13-c20ab90e0a96@codeaurora.org> (raw)
In-Reply-To: <CAD=FV=XwV-8J9-j1j2gwQ08oF8izDv=hB9vj_SogbagOBQfN6Q@mail.gmail.com>

Hi Doug,

On 6/23/2020 10:36 AM, Doug Anderson wrote:
> Hi,
>
> On Mon, Jun 8, 2020 at 10:57 PM Akash Asthana <akashast@codeaurora.org> 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@codeaurora.org>
>> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
>> ---
>> 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).

Yeah, we can adjust ICC vote per transfer like we are doing for clock.

I will include your patch to v8 series.

Thanks for review.

regards,

Akash

>
> -Doug

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