Re: [PATCH 03/10] media: ar0521: Set maximum resolution to 2592x1944

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, Oct 06, 2022 at 03:57:16PM +0100, Dave Stevenson wrote:
> Hi Jacopo
> 
> On Wed, 5 Oct 2022 at 20:06, Jacopo Mondi <jacopo@jmondi.org> wrote:
> >
> > Change the largest visibile resolution to 2592x1944, which corresponds
> > to the active pixel array area size. Take into account the horizontal
> > and vertical limits when programming the visible sizes to skip
> > dummy/inactive pixels.
> >
> > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> > ---
> >  drivers/media/i2c/ar0521.c | 23 +++++++++++++++++------
> >  1 file changed, 17 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
> > index 581f5e42994d..2b19ba898ce8 100644
> > --- a/drivers/media/i2c/ar0521.c
> > +++ b/drivers/media/i2c/ar0521.c
> > @@ -28,10 +28,17 @@
> >  #define AR0521_PIXEL_CLOCK_MIN  (168 * 1000 * 1000)
> >  #define AR0521_PIXEL_CLOCK_MAX  (414 * 1000 * 1000)
> >
> > +#define AR0521_NATIVE_WIDTH            2604u
> > +#define AR0521_NATIVE_HEIGHT           1964u
> > +#define AR0521_MIN_X_ADDR_START                4u
> > +#define AR0521_MIN_Y_ADDR_START                4u
> > +#define AR0521_MAX_X_ADDR_END          2603u
> > +#define AR0521_MAX_Y_ADDR_END          1963u
> 
> The register list I have (downloaded from OnSemi today) states that
> y_addr_max is 0x07a3, or 1955, readable from register 0x1186.

And it also states, in the documentation of y_addr_start, that legal
values are [0, 2463]. Who do we trust ? :-) [0, 2463] sounds like a copy
& paste mistake to me. Another data point is from the developer guide,
which states on the first page that the maximum values for x_addr_start
and y_addr_start are 2603 and 1963 respectively. 2603 matches the
documentation of x_addr_max.

It would be useful to dump the limits registers (0x1000 - 0x1300).

> Otherwise this looks reasonable.
> 
> > +
> >  #define AR0521_WIDTH_MIN              8u
> > -#define AR0521_WIDTH_MAX           2608u
> > +#define AR0521_WIDTH_MAX           2592u
> >  #define AR0521_HEIGHT_MIN             8u
> > -#define AR0521_HEIGHT_MAX          1958u
> > +#define AR0521_HEIGHT_MAX          1944u
> >
> >  #define AR0521_WIDTH_BLANKING_MIN     572u
> >  #define AR0521_HEIGHT_BLANKING_MIN     38u /* must be even */
> > @@ -208,13 +215,17 @@ static int ar0521_read_reg(struct ar0521_dev *sensor, u16 reg, u16 *val)
> >
> >  static int ar0521_set_geometry(struct ar0521_dev *sensor)
> >  {
> > +       /* Center the image in the visible ouput window. */
> > +       u16 x = clamp((AR0521_WIDTH_MAX - sensor->fmt.width) / 2,
> > +                      AR0521_MIN_X_ADDR_START, AR0521_MAX_X_ADDR_END);
> > +       u16 y = clamp(((AR0521_HEIGHT_MAX - sensor->fmt.height) / 2) & ~1,
> > +                      AR0521_MIN_Y_ADDR_START, AR0521_MAX_Y_ADDR_END);
> > +
> >         /* All dimensions are unsigned 12-bit integers */
> > -       u16 x = (AR0521_WIDTH_MAX - sensor->fmt.width) / 2;
> > -       u16 y = ((AR0521_HEIGHT_MAX - sensor->fmt.height) / 2) & ~1;
> >         __be16 regs[] = {
> >                 be(AR0521_REG_FRAME_LENGTH_LINES),
> > -               be(sensor->total_height),
> > -               be(sensor->total_width),
> > +               be(sensor->fmt.height + sensor->ctrls.vblank->val),
> > +               be(sensor->fmt.width + sensor->ctrls.hblank->val),
> >                 be(x),
> >                 be(y),
> >                 be(x + sensor->fmt.width - 1),

-- 
Regards,

Laurent Pinchart