FAILED: patch "[PATCH] pwm: jz4740: Enhance precision in calculation of duty cycle" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-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 9017dc4fbd59c09463019ce494cfe36d654495a8 Mon Sep 17 00:00:00 2001
From: Paul Cercueil <[email protected]>
Date: Wed, 27 May 2020 13:52:23 +0200
Subject: [PATCH] pwm: jz4740: Enhance precision in calculation of duty cycle
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Calculating the hardware value for the duty from the hardware value of the period resulted in a precision loss versus calculating it from the clock rate directly.

(Also remove a cast that doesn't really need to be here)

index 3cd5c054ad9a..4fe9d99ac9a9 100644
@@ -158,11 +158,11 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	/* Calculate period value */
 	tmp = (unsigned long long)rate * state->period;
 	do_div(tmp, NSEC_PER_SEC);
-	period = (unsigned long)tmp;
+	period = tmp;
 
 	/* Calculate duty value */
-	tmp = (unsigned long long)period * state->duty_cycle;
-	do_div(tmp, state->period);
+	tmp = (unsigned long long)rate * state->duty_cycle;
+	do_div(tmp, NSEC_PER_SEC);
 	duty = period - tmp;
 
 	if (duty >= period)