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FAILED: patch "[PATCH] gpio: mvebu: fix pwm .get_state period calculation" failed to apply to 4.19-stable tree

PATCH [email protected] 1 participant 1 message Jan 25, 2021

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The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e73b0101ae5124bf7cd3fb5d250302ad2f16a416 Mon Sep 17 00:00:00 2001
From: Baruch Siach <[email protected]>
Date: Sun, 17 Jan 2021 15:17:02 +0200
Subject: [PATCH] gpio: mvebu: fix pwm .get_state period calculation
MIME-Version: 1.0
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The period is the sum of on and off values. That is, calculate period as

($on + $off) / clkrate

instead of

$off / clkrate - $on / clkrate

that makes no sense.

Reported-by Russell King <[email protected]>
Reviewed-by Uwe Kleine-König <[email protected]>
Fixes 757642f9a584e ("gpio: mvebu: Add limited PWM support")
Signed-off-by Baruch Siach <[email protected]>
Signed-off-by Bartosz Golaszewski <[email protected]>
drivers/gpio/gpio-mvebu.c +8 -11
index 672681a976f5..a912a8fed197 100644
@@ -676,20 +676,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
 	else
 		state->duty_cycle = 1;
 
+	val = (unsigned long long) u; /* on duration */
 	regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
-	val = (unsigned long long) u * NSEC_PER_SEC;
+	val += (unsigned long long) u; /* period = on + off duration */
+	val *= NSEC_PER_SEC;
 	do_div(val, mvpwm->clk_rate);
-	if (val < state->duty_cycle) {
+	if (val > UINT_MAX)
+		state->period = UINT_MAX;
+	else if (val)
+		state->period = val;
+	else
 		state->period = 1;
-	} else {
-		val -= state->duty_cycle;
-		if (val > UINT_MAX)
-			state->period = UINT_MAX;
-		else if (val)
-			state->period = val;
-		else
-			state->period = 1;
-	}
 
 	regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
 	if (u)