[Letux-kernel] Status 5.0-rc2 on Pyra

Tony Lindgren tony at atomide.com
Mon Jan 21 22:27:43 CET 2019


* Andreas Kemnade <andreas at kemnade.info> [190121 21:24]:
> On Fri, 18 Jan 2019 12:01:43 -0800
> Tony Lindgren <tony at atomide.com> wrote:
> 
> > * Tony Lindgren <tony at atomide.com> [190117 14:28]:
> > > * H. Nikolaus Schaller <hns at goldelico.com> [190117 11:07]:  
> > > > This seems to break dmtimer/pwm mode for timer9 which
> > > > we use for driving display backlight while timer8
> > > > for keyboard backlight still works.  
> > > 
> > > Oops sorry about that.
> > >   
> > > > Is there an upcoming patch not yet merged in 5.0-rc2 or
> > > > what makes the difference in 5.0 between timer8 and timer9?  
> > > 
> > > I need to look. Sounds like there might be some optional clock
> > > missing in the dts. I'll take a look.
> > >   
> > > > PS: the symptom is that we don't even see a /sys/class/backlight
> > > > node for the display backlight [2].  
> > 
> > Adding Tero and linux-omap to Cc.
> > 
> > Nikolaus, care to try the below patch with also timer9 configured
> > in your board specific dts file depending what the timer source
> > clock should be:
> > 
> > &timer9 {
> > 	assigned-clocks = <&l4_per_clkctrl OMAP5_TIMER9_CLKCTRL 24>;
> > 	assigned-clock-parents = <&sys_clkin>;
> > };
> > 
> 
> diff --git a/arch/arm/boot/dts/pyra-display.dtsi b/arch/arm/boot/dts/pyra-display.dtsi
> index b219b2961020..9fc793785b89 100644
> --- a/arch/arm/boot/dts/pyra-display.dtsi
> +++ b/arch/arm/boot/dts/pyra-display.dtsi
> @@ -249,6 +249,11 @@
>  /* set to e.g. 8300 if display uses a TPS6116x instead of TPS61040 (which is limited to 500 Hz PWM) */
>  #define BACKLIGHT_FREQ_HZ      83
>  
> +&timer9 {
> +       assigned-clocks = <&l4per_clkctrl OMAP5_TIMER9_CLKCTRL 24>;
> +       assigned-clock-parents = <&sys_clkin>;
> +};
> +
>  / {
>         backlight: backlight {
>                 compatible = "pwm-backlight";
> 
> together with the patch sheds light literally on this issue.

OK good to hear.

> > If that works you might as well configure it for timer8 too
> > for future :)
> > 
> > Earlier we had TIMER9_CLKCTRL bit 0 have TIMER9_CLKCTRL bit 24
> > as it's parent. But I think we actually have bit 0 as the module
> > clock and bit 24 as the timer functional clock. So bit 24 is not
> > a parent of bit 0.
> > 
> > Tero can you check the above assumption?
> > 
> > If that's not the case then we need more patching..
> > 
> > Regards,
> > 
> > Tony
> > 
> > 8< ----------------
> > diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
> > --- a/drivers/clocksource/timer-ti-dm.c
> > +++ b/drivers/clocksource/timer-ti-dm.c
> > @@ -154,6 +154,10 @@ static int omap_dm_timer_of_set_source(struct omap_dm_timer *timer)
> >  	if (IS_ERR(parent))
> >  		return -ENODEV;
> >  
> > +	/* Bail out if both clocks point to fck */
> > +	if (clk_is_match(parent, timer->fclk))
> > +		return 0;
> > +
> >  	ret = clk_set_parent(timer->fclk, parent);
> >  	if (ret < 0)
> >  		pr_err("%s: failed to set parent\n", __func__);
> > 
> Regards,
> Andreas
> PS nit: why we have l4_per_clkctrl on omap4 and l4per_clkctrl on omap5?

No idea.. Is that maybe to follow the TRM naming?

Regards,

Tony



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