Re: [PATCH v2 5/6] ACPI: scan: Extract MIPI DiSco for Imaging data into swnodes

Sakari Ailus
2023-10-31T14:00:24Z

Hi Rafael,

On Tue, Oct 31, 2023 at 02:46:51PM +0100, Rafael J. Wysocki wrote:
> Hi Sakari,
>
> On Tue, Oct 31, 2023 at 11:33 AM Sakari Ailus
> <sakari.ailus@linux.intel.com> wrote:
> >
> > Hi Rafael,
> >
> > On subject:
> >
> > s/DiSco/DisCo/
>
> Huh
>
> Thanks for catching this!
>
> > On Fri, Oct 20, 2023 at 04:39:27PM +0200, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > >
> > > Add information extracted from the MIPI DiSco for Imaging device
> >
> > Ditto.
> >
> > > properties to software nodes created during the CSI-2 connection graph
> > > discovery.
> > >
> > > Link: https://www.mipi.org/specifications/mipi-di
> >
> > This URL is broken. The correct URL is:
> >
> > https://www.mipi.org/specifications/mipi-disco-imaging
>
> OK
>
> > > Co-developed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > ---
> > > drivers/acpi/internal.h | 1
> > > drivers/acpi/mipi-di.c | 240 +++++++++++++++++++++++++++++++++++++++++++++++-
> >
> > How about mipi-disco.c? I wouldn't mind having mipi-disco-imaging.c either.
>
> Well, mipi-disco-imaging is a bit too long and the meaning of
> mipi-disco would not be clear IMO.
>
> What about mipi-disco-img?

Seems fine to me.

>
> [cut]
>
> > > + ret = fwnode_property_count_u8(port_fwnode, "mipi-img-lane-polarities");
> > > + if (ret > 0) {
> > > + unsigned long mask;
> > > + unsigned int i;
> > > +
> > > + /*
> > > + * Total number of lanes here is clock lane + data lanes.
> > > + * Require that number to be low enough so they all can be
> > > + * covered by the bits in one byte.
> > > + */
> > > + BUILD_BUG_ON(BITS_PER_TYPE(u8) <= ARRAY_SIZE(port->data_lanes));
> > > +
> > > + fwnode_property_read_u8_array(port_fwnode,
> > > + "mipi-img-lane-polarities",
> > > + val, 1);
> > > +
> > > + for (mask = val[0], i = 0; i < num_lanes + 1; i++)
> > > + port->lane_polarities[i] = test_bit(i, &mask);
> >
> > This works only up to seven lanes.
>
> True, but then ACPI_DEVICE_CSI2_DATA_LANES is defined as 4.

The spec has no limit and in practice 4 is relatively common while 8 exists
(but is somewhat rare). I actually think it'd be a good idea to bump this
to 8 already.

--
Regards,

Sakari Ailus