From: Dmitry Osipenko <digetx@gmail.com>
To: Sowjanya Komatineni <skomatineni@nvidia.com>,
thierry.reding@gmail.com, jonathanh@nvidia.com,
frankc@nvidia.com, hverkuil@xs4all.nl, sakari.ailus@iki.fi,
robh+dt@kernel.org, helen.koike@collabora.com
Cc: sboyd@kernel.org, gregkh@linuxfoundation.org,
linux-media@vger.kernel.org, devicetree@vger.kernel.org,
linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v6 09/10] media: tegra-video: Add CSI MIPI pads calibration
Date: Fri, 31 Jul 2020 23:42:29 +0300 [thread overview]
Message-ID: <7d904a86-3189-7ef8-a7b9-1a84564f9278@gmail.com> (raw)
In-Reply-To: <ace047fe-8a1a-666a-b91b-9d63b1d68567@nvidia.com>
31.07.2020 19:29, Sowjanya Komatineni пишет:
>
> On 7/31/20 9:14 AM, Dmitry Osipenko wrote:
>> 31.07.2020 18:46, Sowjanya Komatineni пишет:
>>> On 7/31/20 4:39 AM, Dmitry Osipenko wrote:
>>>> 31.07.2020 12:02, Sowjanya Komatineni пишет:
>>>> ...
>>>>> @@ -249,13 +249,47 @@ static int tegra_csi_enable_stream(struct
>>>>> v4l2_subdev *subdev)
>>>>> return ret;
>>>>> }
>>>>> + if (csi_chan->mipi) {
>>>>> + ret = tegra_mipi_enable(csi_chan->mipi);
>>>>> + if (ret < 0) {
>>>>> + dev_err(csi->dev,
>>>>> + "failed to enable MIPI pads: %d\n", ret);
>>>>> + goto rpm_put;
>>>>> + }
>>>>> +
>>>>> + /*
>>>>> + * CSI MIPI pads PULLUP, PULLDN and TERM impedances need to
>>>>> + * be calibrated after power on.
>>>>> + * So, trigger the calibration start here and results will
>>>>> + * be latched and applied to the pads when link is in LP11
>>>>> + * state during start of sensor streaming.
>>>>> + */
>>>>> + ret = tegra_mipi_start_calibration(csi_chan->mipi);
>>>>> + if (ret < 0) {
>>>>> + dev_err(csi->dev,
>>>>> + "failed to start MIPI calibration: %d\n", ret);
>>>>> + goto disable_mipi;
>>>>> + }
>>>> What would happen if CSI stream is enabled and then immediately
>>>> disabled
>>>> without enabling camera sensor?
>>> Nothing will happen as during stream enable csi receiver is kept ready.
>>>
>>> But actual capture will not happen during that point.
>> Could you please show how the full call chain looks like? It's not clear
>> to me what keeps CSI stream "ready".
>
> VI is the main video input (video device) and on streaming it starts
> stream of CSI subdev prior to stream of Sensor.
>
> HW path, sensor stream (CSI TX) -> CSI stream (RX)
>
> During CSI stream on, CSI PHY receiver is enabled to start receiving the
> data but internally capture assembled to active state will happen only
> when Tegra VI single shot is issues where VI thru pixel parser gets
> captures data into the memory
Alright, I see now.
Will be great if you could change this hunk:
{
ret = v4l2_subdev_call(src_subdev, video, s_stream, true);
if (ret < 0 && ret != -ENOIOCTLCMD) {
tegra_mipi_cancel_calibration(csi_chan->mipi);
v4l2_subdev_call(csi_subdev, video, s_stream, false);
return ret;
}
}
to look like this:
{
err = v4l2_subdev_call(src_subdev, video, s_stream, true);
if (err < 0 && err != -ENOIOCTLCMD)
goto err_disable_csi_stream;
...
return 0;
err_disable_csi_stream:
tegra_mipi_cancel_calibration(csi_chan->mipi);
v4l2_subdev_call(csi_subdev, video, s_stream, false);
return err;
}
It should make code a bit easier to read and follow.
Otherwise this patch looks good to me, thanks.
next prev parent reply other threads:[~2020-07-31 20:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 9:02 [RFC PATCH v6 00/10] Support for Tegra video capture from external sensor Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 01/10] media: tegra-video: Fix channel format alignment Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 02/10] media: tegra-video: Enable TPG based on kernel config Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 03/10] media: tegra-video: Update format lookup to offset based Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 04/10] dt-bindings: tegra: Update VI and CSI bindings with port info Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 05/10] media: tegra-video: Separate CSI stream enable and disable implementations Sowjanya Komatineni
2020-07-31 12:06 ` Dmitry Osipenko
2020-07-31 9:02 ` [RFC PATCH v6 06/10] media: tegra-video: Add support for external sensor capture Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 07/10] media: tegra-video: Add support for selection ioctl ops Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till calibration is done Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 09/10] media: tegra-video: Add CSI MIPI pads calibration Sowjanya Komatineni
2020-07-31 11:39 ` Dmitry Osipenko
2020-07-31 15:46 ` Sowjanya Komatineni
2020-07-31 16:14 ` Dmitry Osipenko
2020-07-31 16:29 ` Sowjanya Komatineni
2020-07-31 20:42 ` Dmitry Osipenko [this message]
2020-07-31 21:03 ` Sowjanya Komatineni
2020-07-31 9:02 ` [RFC PATCH v6 10/10] media: tegra-video: Compute settle times based on the clock rate Sowjanya Komatineni
2020-07-31 13:40 ` [RFC PATCH v6 00/10] Support for Tegra video capture from external sensor Wolfram Sang
2020-07-31 15:49 ` Sowjanya Komatineni
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