Re: [PATCH v5 2/3] media: imx: add a driver for i.MX8MQ mipi csi rx phy and controller

Hi Martin,

On Wed, Jul 14, 2021 at 08:41:58AM +0200, Martin Kepplinger wrote:

Am Dienstag, dem 13.07.2021 um 00:52 +0300 schrieb Laurent Pinchart:

quoted

Hi Martin,

Thank you for the patch.

thank you for reviewing!

quoted

On Fri, Jun 18, 2021 at 11:57:52AM +0200, Martin Kepplinger wrote:

quoted

Add a driver to support the i.MX8MQ MIPI CSI receiver. The hardware
side
is based on
 
https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/imx8/mxc-mipi-csi2_yav.c?h=imx_5.4.70_2.3.0

It's built as part of VIDEO_IMX7_CSI because that's documented to
support
i.MX8M platforms. This driver adds i.MX8MQ support where currently
only the
i.MX8MM platform has been supported.

Overall this is really nice work. I have quite a few review comments,
but hopefully nothing that should be difficult to handle.

I think so too but right now I have one question:

quoted

quoted

Signed-off-by: Martin Kepplinger <redacted>
---
 drivers/staging/media/imx/Makefile           |   1 +
 drivers/staging/media/imx/imx8mq-mipi-csi2.c | 963 +++++++++++++++++++
 2 files changed, 964 insertions(+)
 create mode 100644 drivers/staging/media/imx/imx8mq-mipi-csi2.c

[snip]

quoted

quoted

+static int imx8mq_mipi_csi_pm_suspend(struct device *dev, bool runtime)
+{
+       struct v4l2_subdev *sd = dev_get_drvdata(dev);
+       struct csi_state *state = mipi_sd_to_csi2_state(sd);
+       int ret = 0;
+
+       mutex_lock(&state->lock);
+
+       if (state->state & ST_POWERED) {
+               imx8mq_mipi_csi_stop_stream(state);
+               imx8mq_mipi_csi_clk_disable(state);
+               state->state &= ~ST_POWERED;
+               if (!runtime)
+                       state->state |= ST_SUSPENDED;
+       }
+
+       mutex_unlock(&state->lock);
+
+       ret = icc_set_bw(state->icc_path, 0, 0);
+       if (ret)
+               dev_err(dev, "icc_set_bw failed with %d\n", ret);
+
+       return ret ? -EAGAIN : 0;
+}
+
+static int imx8mq_mipi_csi_pm_resume(struct device *dev, bool runtime)
+{
+       struct v4l2_subdev *sd = dev_get_drvdata(dev);
+       struct csi_state *state = mipi_sd_to_csi2_state(sd);
+       int ret = 0;
+
+       ret = icc_set_bw(state->icc_path, 0, state->icc_path_bw);
+       if (ret) {
+               dev_err(dev, "icc_set_bw failed with %d\n", ret);
+               return ret;
+       }
+
+       mutex_lock(&state->lock);
+
+       if (!runtime && !(state->state & ST_SUSPENDED))
+               goto unlock;
+
+       if (!(state->state & ST_POWERED)) {
+               state->state |= ST_POWERED;
+               ret = imx8mq_mipi_csi_clk_enable(state);

Enabling the clocks in the PM resume handler is correct, but they should
also be disabled in the PM suspend handler.

imx8mq_mipi_csi_clk_disable() is called in suspend(). I don't know what
you mean here.

I wonder what I was thinking... You can ignore this comment.

However, imx8mq_mipi_csi_clk_disable() is also called in the error path
of the probe function and in the remove function. I don't think this is
right.

-- 
Regards,

Laurent Pinchart

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