linux-kernel - [PATCH 16/21] clocksource/drivers/timer-ti-dm: Do not update counter on updating the period

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Date:   Wed, 18 Mar 2020 18:41:26 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     tglx@...utronix.de
Cc:     linux-kernel@...r.kernel.org, Lokesh Vutla <lokeshvutla@...com>,
        Tony Lindgren <tony@...mide.com>
Subject: [PATCH 16/21] clocksource/drivers/timer-ti-dm: Do not update counter on updating the period

From: Lokesh Vutla <lokeshvutla@...com>

Write to trigger register(OMAP_TIMER_TRIGGER_REG) will load the value
in Load register(OMAP_TIMER_LOAD_REG) into Counter register
(OMAP_TIMER_COUNTER_REG).

omap_dm_timer_set_load() writes into trigger register every time load
register is updated. When timer is configured in pwm mode, this causes
disruption in current pwm cycle, which is not expected especially when
pwm is used as PPS signal for synchronized PTP clocks. So do not write
into trigger register on updating the period.

Tested-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@...com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Link: https://lore.kernel.org/r/20200305082715.15861-5-lokeshvutla@ti.com
---
 drivers/clocksource/timer-ti-dm.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
index 1d1bea79cbf1..b565b8456e5c 100644
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -579,7 +579,6 @@ static int omap_dm_timer_set_load(struct omap_dm_timer *timer, int autoreload,
 	omap_dm_timer_write_reg(timer, OMAP_TIMER_CTRL_REG, l);
 	omap_dm_timer_write_reg(timer, OMAP_TIMER_LOAD_REG, load);
 
-	omap_dm_timer_write_reg(timer, OMAP_TIMER_TRIGGER_REG, 0);
 	omap_dm_timer_disable(timer);
 	return 0;
 }
-- 
2.17.1