Re: [PATCH 05/14] media: sun6i-csi: Only configure the interface data width for parallel

Maxime Ripard
2020-10-27T18:31:16Z

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On Tue, Oct 27, 2020 at 10:31:19AM +0100, Paul Kocialkowski wrote:
> Hi,
>
> On Mon 26 Oct 20, 17:00, Maxime Ripard wrote:
> > On Fri, Oct 23, 2020 at 07:45:37PM +0200, Paul Kocialkowski wrote:
> > > Bits related to the interface data width do not have any effect when
> > > the CSI controller is taking input from the MIPI CSI-2 controller.
> >
> > I guess it would be clearer to mention that the data width is only
> > applicable for parallel here.
>
> Understood, will change the wording in the next version.
>
> > > In prevision of adding support for this case, set these bits
> > > conditionally so there is no ambiguity.
> > >
> > > Co-developed-by: Kévin L'hôpital <kevin.lhopital@bootlin.com>
> > > Signed-off-by: Kévin L'hôpital <kevin.lhopital@bootlin.com>
> > > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > > ---
> > > .../platform/sunxi/sun6i-csi/sun6i_csi.c | 42 +++++++++++--------
> > > 1 file changed, 25 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > > index 5d2389a5cd17..a876a05ea3c7 100644
> > > --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > > +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > > @@ -378,8 +378,13 @@ static void sun6i_csi_setup_bus(struct sun6i_csi_dev *sdev)
> > > unsigned char bus_width;
> > > u32 flags;
> > > u32 cfg;
> > > + bool input_parallel = false;
> > > bool input_interlaced = false;
> > >
> > > + if (endpoint->bus_type == V4L2_MBUS_PARALLEL ||
> > > + endpoint->bus_type == V4L2_MBUS_BT656)
> > > + input_parallel = true;
> > > +
> > > if (csi->config.field == V4L2_FIELD_INTERLACED
> > > || csi->config.field == V4L2_FIELD_INTERLACED_TB
> > > || csi->config.field == V4L2_FIELD_INTERLACED_BT)
> > > @@ -395,6 +400,26 @@ static void sun6i_csi_setup_bus(struct sun6i_csi_dev *sdev)
> > > CSI_IF_CFG_HREF_POL_MASK | CSI_IF_CFG_FIELD_MASK |
> > > CSI_IF_CFG_SRC_TYPE_MASK);
> > >
> > > + if (input_parallel) {
> > > + switch (bus_width) {
> > > + case 8:
> > > + cfg |= CSI_IF_CFG_IF_DATA_WIDTH_8BIT;
> > > + break;
> > > + case 10:
> > > + cfg |= CSI_IF_CFG_IF_DATA_WIDTH_10BIT;
> > > + break;
> > > + case 12:
> > > + cfg |= CSI_IF_CFG_IF_DATA_WIDTH_12BIT;
> > > + break;
> > > + case 16: /* No need to configure DATA_WIDTH for 16bit */
> > > + break;
> > > + default:
> > > + dev_warn(sdev->dev, "Unsupported bus width: %u\n",
> > > + bus_width);
> > > + break;
> > > + }
> > > + }
> > > +
> > > if (input_interlaced)
> > > cfg |= CSI_IF_CFG_SRC_TYPE_INTERLACED;
> > > else
> > > @@ -440,23 +465,6 @@ static void sun6i_csi_setup_bus(struct sun6i_csi_dev *sdev)
> > > break;
> > > }
> > >
> > > - switch (bus_width) {
> > > - case 8:
> > > - cfg |= CSI_IF_CFG_IF_DATA_WIDTH_8BIT;
> > > - break;
> > > - case 10:
> > > - cfg |= CSI_IF_CFG_IF_DATA_WIDTH_10BIT;
> > > - break;
> > > - case 12:
> > > - cfg |= CSI_IF_CFG_IF_DATA_WIDTH_12BIT;
> > > - break;
> > > - case 16: /* No need to configure DATA_WIDTH for 16bit */
> > > - break;
> > > - default:
> > > - dev_warn(sdev->dev, "Unsupported bus width: %u\n", bus_width);
> > > - break;
> > > - }
> > > -
> >
> > Is there any reason to move it around?
>
> The main reason is cosmetics: input_parallel is introduced to match the already
> existing input_interlaced variable, so it made sense to me to have both of these
> conditionals one after the other instead of spreading them randomly.
>
> I can mention this in the commit log if you prefer.

Yeah, that would great

Maxime

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