linux-kernel - [PATCH 3/4] pwm: omap-dmtimer: Do not disable pwm before changing period/duty

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Message-ID: <20200224052135.17278-4-lokeshvutla@ti.com>
Date:   Mon, 24 Feb 2020 10:51:34 +0530
From:   Lokesh Vutla <lokeshvutla@...com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
CC:     Tony Lindgren <tony@...mide.com>,
        Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-pwm@...r.kernel.org>,
        Sekhar Nori <nsekhar@...com>, Lokesh Vutla <lokeshvutla@...com>
Subject: [PATCH 3/4] pwm: omap-dmtimer: Do not disable pwm before changing period/duty_cycle

Only the Timer control register(TCLR) can be updated only when the timer
is stopped. Registers like Counter register(TCRR), loader register(TLDR),
match register(TMAR) can be updated when the counter is running. Since
TCLR is not updated in pwm_omap_dmtimer_config(), do not stop the
timer for period/duty_cycle update.

Signed-off-by: Lokesh Vutla <lokeshvutla@...com>
---
 drivers/pwm/pwm-omap-dmtimer.c | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index f13be7216847..58c61559e72f 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -102,7 +102,6 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 	u32 load_value, match_value;
 	struct clk *fclk;
 	unsigned long clk_rate;
-	bool timer_active;
 
 	dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",
 		duty_ns, period_ns);
@@ -178,25 +177,12 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 	load_value = (DM_TIMER_MAX - period_cycles) + 1;
 	match_value = load_value + duty_cycles - 1;
 
-	/*
-	 * We MUST stop the associated dual-mode timer before attempting to
-	 * write its registers, but calls to omap_dm_timer_start/stop must
-	 * be balanced so check if timer is active before calling timer_stop.
-	 */
-	timer_active = pm_runtime_active(&omap->dm_timer_pdev->dev);
-	if (timer_active)
-		omap->pdata->stop(omap->dm_timer);
-
 	omap->pdata->set_load(omap->dm_timer, true, load_value);
 	omap->pdata->set_match(omap->dm_timer, true, match_value);
 
 	dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n",
 		load_value, load_value,	match_value, match_value);
 
-	/* If config was called while timer was running it must be reenabled. */
-	if (timer_active)
-		pwm_omap_dmtimer_start(omap);
-
 	mutex_unlock(&omap->mutex);
 
 	return 0;
-- 
2.23.0