Messages in this thread | | | Subject | Re: [RFC PATCH v3 16/18] gpu: host1x: mipi: Split tegra_mipi_calibrate and tegra_mipi_wait | From | Sowjanya Komatineni <> | Date | Thu, 16 Jul 2020 15:49:35 -0700 |
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On 7/16/20 2:18 PM, Dmitry Osipenko wrote: > 17.07.2020 00:09, Sowjanya Komatineni пишет: >> On 7/16/20 1:38 PM, Dmitry Osipenko wrote: >>> 15.07.2020 07:20, Sowjanya Komatineni пишет: >>>> SW can trigger MIPI pads calibration any time after power on >>>> but calibration results will be latched and applied to the pads >>>> by MIPI CAL unit only when the link is in LP-11 state and then >>>> status register will be updated. >>>> >>>> For CSI, trigger of pads calibration happen during CSI stream >>>> enable where CSI receiver is kept ready prior to sensor or CSI >>>> transmitter stream start. >>>> >>>> So, pads may not be in LP-11 at this time and waiting for the >>>> calibration to be done immediate after calibration start will >>>> result in timeout. >>>> >>>> This patch splits tegra_mipi_calibrate() and tegra_mipi_wait() >>>> so triggering for calibration and waiting for it to complete can >>>> happen at different stages. >>>> >>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com> >>>> --- >>> ... >>>> int tegra_mipi_calibrate(struct tegra_mipi_device *device) >>>> { >>>> @@ -370,12 +381,10 @@ int tegra_mipi_calibrate(struct >>>> tegra_mipi_device *device) >>>> value |= MIPI_CAL_CTRL_START; >>>> tegra_mipi_writel(device->mipi, value, MIPI_CAL_CTRL); >>>> - err = tegra_mipi_wait(device->mipi); >>> Doesn't MIPI clock need to be enabled during of the calibration process? >> MIPI clock is already enabled in tegra_mipi_calibrate >>>> mutex_unlock(&device->mipi->lock); >>>> clk_disable(device->mipi->clk); > What keeps MIPI clock enabled after completion of the > tegra_mipi_calibrate() invocation?
MIPI clock is disabled at end of tegra_mipi_calibrate and is re-enabled during tegra_mipi_wait.
I think I should fix this to keep the clock enabled till calibration results are latched.
All consumers of tegra_mipi_calibrate() will call tegra_mipi_wait().
So will remove clk_disable mipi clk at end of tegra_mipi_calibrate() and clk_enable mipi_clk at beginning of tegra_mipi_wait()
> >>>> - return err; >>>> + return 0; >>>> } >>>> EXPORT_SYMBOL(tegra_mipi_calibrate);
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