Re: [PATCH] clocksource/drivers/timer-ti-dm: Register clocksource/event only for am654

[Andreas Kemnade <andreas@kemnade.info>]

On Fri, 28 Aug 2026 20:47:45 +0200
"Markus Schneider-Pargmann (TI)" <msp@baylibre.com> wrote:

> Registering clocksource/clockevent for the older platforms breaks
> booting them. The older platforms have their own implementation in early
> boot that is used to register clocksource/clockevent in
> timer-ti-dm-systimer.c.
> 
> With am654, the timer is much more complex with more dependencies so
> doing this in early boot with the other driver is very difficult and
> gets ugly. Instead it is implemented in the platform driver for am654.
> However the old platforms may not register clocksource/clockevent in
> this driver as that would break the boot.
> 
> Add a system_timer_capable flag that is only set for am654-timer that
> gates the clocksource/clockevent registration.
> 
> Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
> Closes: https://lore.kernel.org/r/2013A99A-0502-4128-ACFA-B04886224393@goldelico.com
> Fixes: b8eeeca55456 ("clocksource/drivers/timer-ti-dm: Add clocksource support")
> Signed-off-by: Markus Schneider-Pargmann (TI) <msp@baylibre.com>

Tested-by: Andreas Kemnade <andreas@kemnade.info> # OMAP3 GTA04
> ---
>  drivers/clocksource/timer-ti-dm.c          | 4 +++-
>  include/linux/platform_data/dmtimer-omap.h | 2 ++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
> index 6787acac9a43..ae8777d03215 100644
> --- a/drivers/clocksource/timer-ti-dm.c
> +++ b/drivers/clocksource/timer-ti-dm.c
> @@ -1475,7 +1475,8 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
>  
>  	timer->pdev = pdev;
>  
> -	if (timer->capability & OMAP_TIMER_ALWON && !IS_ERR_OR_NULL(timer->fclk)) {
> +	if (pdata->system_timer_capable &&
> +	    timer->capability & OMAP_TIMER_ALWON && !IS_ERR_OR_NULL(timer->fclk)) {
>  		if (!omap_dm_timer_sched_clock_counter) {
>  			ret = omap_dm_timer_setup_clocksource(timer);
>  			if (ret)
> @@ -1585,6 +1586,7 @@ static const struct dmtimer_platform_data omap3plus_pdata = {
>  
>  static const struct dmtimer_platform_data am6_pdata = {
>  	.timer_ops = &dmtimer_ops,
> +	.system_timer_capable = true,
>  };
>  
>  static const struct of_device_id omap_timer_match[] = {
> diff --git a/include/linux/platform_data/dmtimer-omap.h b/include/linux/platform_data/dmtimer-omap.h
> index 726d89143842..b78ee4676b98 100644
> --- a/include/linux/platform_data/dmtimer-omap.h
> +++ b/include/linux/platform_data/dmtimer-omap.h
> @@ -57,6 +57,8 @@ struct dmtimer_platform_data {
>  	u32 timer_errata;
>  	int (*get_context_loss_count)(struct device *);
>  	const struct omap_dm_timer_ops *timer_ops;
> +	/* always-on timers can be used for clocksource/clockevent */
> +	bool system_timer_capable;
>  };
>  
>  #endif /* __PLATFORM_DATA_DMTIMER_OMAP_H__ */
> 
> ---
> base-commit: e30626823a406725ce29bc75cb8ec467d3e1e326
> change-id: 20260828-v7-3-next-topic-ti-timer-dm-clocksource-omap-fix-418786f115bc
> 
> Best regards,
> --  
> Markus Schneider-Pargmann (TI) <msp@baylibre.com>
> 
>