On Thu, Mar 12, 2009 at 10:25:35AM +0100, Guennadi Liakhovetski wrote:
> On Thu, 12 Mar 2009, Sascha Hauer wrote:
>
> > On Thu, Mar 12, 2009 at 09:40:46AM +0100, Guennadi Liakhovetski wrote:
> > > One more thing I noticed while looking at your patch 3/4:
> > >
> > > > +static int pcm990_camera_set_bus_param(struct device *dev,
> > > > + unsigned long flags)
> > > > +{
> > > > + if (gpio_bus_switch <= 0)
> > > > + return 0;
> > > > +
> > > > + if (flags & SOCAM_DATAWIDTH_8)
> > > > + gpio_set_value(NR_BUILTIN_GPIO + 1, 1);
> > > > + else
> > > > + gpio_set_value(NR_BUILTIN_GPIO + 1, 0);
> > >
> > > Originally the logic here was "only if flags == SOCAM_DATAWIDTH_8, switch
> > > to 8 bits, otherwise do 10 bits. I.e., if flags == SOCAM_DATAWIDTH_8 |
> > > SOCAM_DATAWIDTH_10, it would still do the default (and wider) 10 bits. Do
> > > you have any reason to change that logic?
> >
> > I was not aware that I changed any logic. I thought I would get here
> > with only one of the SOCAM_DATAWIDTH_* set. Isn't it a bug when we get
> > here with more than one width flags set?
> >
> > The mt9v022 driver has this in set_bus_param:
> >
> > >
> > > /* Only one width bit may be set */
> > > if (!is_power_of_2(width_flag))
> > > return -EINVAL;
> > >
> >
> > And I think it makes sense.
>
> Ok, then, could you, please add the same test to mt9m001? And, as I
> mentioned in a comment to 3/4, please, return an error if switching is
> requested but unsupported.
Ok, will do.
It may be that we need a different approach to the bus width setting in
the longer term. For example the mt9m001 can support any thinkable bus
width of 1 to inf. bits. This depends on the hardware designer who wired
up the connection and not the physical count of data lines the chip has.
I have no idea how to implement this though.
Sascha
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