linux-kernel - [PATCH 06/21] clocksource/drivers/timer-ti-dm: Do not update counter on updating the period

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Date:   Wed, 18 Mar 2020 18:41:16 +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 06/21] 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.

Signed-off-by: Lokesh Vutla <lokeshvutla@...com>
Tested-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Link: https://lore.kernel.org/r/20200224050753.17784-3-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 269a994d6a99..acc93600d351 100644
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -577,7 +577,6 @@ 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);
 	/* Save the context */
 	timer->context.tclr = l;
 	timer->context.tldr = load;
-- 
2.17.1