On 16/07/2025 15:47, Michael Walle wrote: > The J722S won't let you set the clock frequency if there is no device > using it. Thus, the assigned-clocks property won't work per se. > > As a workaround, set the clock again during the probing of the driver. > > Signed-off-by: Michael Walle <[email protected]> > --- > drivers/gpu/drm/imagination/pvr_device.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/imagination/pvr_device.c > b/drivers/gpu/drm/imagination/pvr_device.c > index 8b9ba4983c4c..e7a7cc1bdf93 100644 > --- a/drivers/gpu/drm/imagination/pvr_device.c > +++ b/drivers/gpu/drm/imagination/pvr_device.c > @@ -16,6 +16,7 @@ > > #include <linux/bitfield.h> > #include <linux/clk.h> > +#include <linux/clk/clk-conf.h> > #include <linux/compiler_attributes.h> > #include <linux/compiler_types.h> > #include <linux/dma-mapping.h> > @@ -641,6 +642,14 @@ pvr_device_init(struct pvr_device *pvr_dev) > if (err) > return err; > > + /* Set any 'assigned-clocks' properties again. This is a workaround for > + * the clock handling on k3 platforms. There, one cannot set the clock > + * frequency until there is at least one (enabled) user if it. > + */ > + err = of_clk_set_defaults(drm_dev->dev->of_node, true); > + if (err) > + return err;
+Cc Abel, Bjorn, Konrad, Stephan G. and Stephen B., Interesting stuff. This touches a bit similar problems we have (and had) for Qualcomm Display PHYs, where assigned-clock-parents were called too early - before the block (PHY) is being enabled. The workaround we implemented so far was - last patch hook in: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=80dd5911cbfdc2f6ae904341d41a7a8bd8cc546c I know Stephan G. is working on something better, so probably he will Cc you once this is ready. Best regards, Krzysztof
