Hi Ezequiel,
On Mon, Jan 18, 2021 at 05:21:12PM -0300, Ezequiel Garcia wrote:
> On Mon, 2021-01-18 at 18:36 +0200, Sakari Ailus wrote:
> > Hi Ezequiel,
> >
> > Thanks for the patch.
> >
> > On Tue, Jan 12, 2021 at 04:49:14PM -0300, Ezequiel Garcia wrote:
> > > The pxa-camera capture driver currently registers a v4l2-clk
> > > clock, named "mclk", to represent the mt9m111 sensor clock.
> > >
> > > Register a proper fixed-rate clock using the generic clock framework,
> > > which will allow to remove the v4l2-clk clock in the pxa-camera
> > > driver in a follow-up commit.
> >
> > Where is the clock generated?
> >
> > If it's the same device, shouldn't it be registered in the pxa_camera
> > driver?
> >
>
> Apparently, as Petr explained, the PXA camera controller
> can provide a clock.
>
> However, it seems to me this is not necesarily the only
> way to provide a clock to a sensor, is it?
It isn't. But that's what the clock framework is for.
>
> Moreover, doing the proper clock conversion in the PXA driver
> doesn't seem trivial and I don't have hardware to test it.
I guess it's possible to do that later, too. The platform appears to rely
still on platform data, too.
This set is still a major improvement, to get rid of v4l2-clk.
>
> I'd rather keep things simple, and just register a fixed-rate
> clock at mach-pxa level, which will be removed anyway
> once these non-DT platforms are finally converted to DT
> or dropped.
>
> This way is at least a tiny bit less ugly than the current
> dummy v4l2-clk.
>
> Thanks,
> Ezequiel
>
> > >
> > > Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> > > Acked-by: Arnd Bergmann <arnd@xxxxxxxx> (for arch/arm/mach-*/)
> > > ---
> > > Quoting Arnd:
> > > """
> > > If there are no objections to the change itself, please take it through
> > > the v4l2 git tree.
> > > """
> > >
> > > arch/arm/mach-pxa/devices.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > >
> > > diff --git a/arch/arm/mach-pxa/devices.c b/arch/arm/mach-pxa/devices.c
> > > index 524d6093e0c7..09b8495f3fd9 100644
> > > --- a/arch/arm/mach-pxa/devices.c
> > > +++ b/arch/arm/mach-pxa/devices.c
> > > @@ -4,6 +4,7 @@
> > > #include <linux/init.h>
> > > #include <linux/platform_device.h>
> > > #include <linux/clkdev.h>
> > > +#include <linux/clk-provider.h>
> > > #include <linux/dma-mapping.h>
> > > #include <linux/dmaengine.h>
> > > #include <linux/spi/pxa2xx_spi.h>
> > > @@ -634,6 +635,13 @@ static struct platform_device pxa27x_device_camera = {
> > >
> > > void __init pxa_set_camera_info(struct pxacamera_platform_data *info)
> > > {
> > > + struct clk *mclk;
> > > +
> > > + /* Register a fixed-rate clock for camera sensors. */
> > > + mclk = clk_register_fixed_rate(NULL, "pxa_camera_clk", NULL, 0,
> > > + info->mclk_10khz * 10000);
> > > + if (!IS_ERR(mclk))
> > > + clkdev_create(mclk, "mclk", NULL);
> > > pxa_register_device(&pxa27x_device_camera, info);
> > > }
> > >
> >
>
>
--
Sakari Ailus
