Patch "pwm: omap-dmtimer: Round load and match values rather than truncate" has been added to the 4.5-stable tree

Patch "pwm: omap-dmtimer: Round load and match values rather than truncate" has been added to the 4.5-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    pwm: omap-dmtimer: Round load and match values rather than truncate

to the 4.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pwm-omap-dmtimer-round-load-and-match-values-rather-than-truncate.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7b0883f33809ff0aeca9848193c31629a752bb77 Mon Sep 17 00:00:00 2001
From: David Rivshin <drivshin@allworx.com>
Date: Fri, 29 Jan 2016 23:26:53 -0500
Subject: pwm: omap-dmtimer: Round load and match values rather than truncate

From: David Rivshin <drivshin@allworx.com>

commit 7b0883f33809ff0aeca9848193c31629a752bb77 upstream.

When converting period and duty_cycle from nanoseconds to fclk cycles,
the error introduced by the integer division can be appreciable, especially
in the case of slow fclk or short period. Use DIV_ROUND_CLOSEST_ULL() so
that the error is kept to +/- 0.5 clock cycles.

Fixes: 6604c6556db9 ("pwm: Add PWM driver for OMAP using dual-mode timers")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pwm/pwm-omap-dmtimer.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -49,11 +49,7 @@ to_pwm_omap_dmtimer_chip(struct pwm_chip
 
 static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns)
 {
-	u64 c = (u64)clk_rate * ns;
-
-	do_div(c, NSEC_PER_SEC);
-
-	return c;
+	return DIV_ROUND_CLOSEST_ULL((u64)clk_rate * ns, NSEC_PER_SEC);
 }
 
 static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)


Patches currently in stable-queue which might be from drivshin@allworx.com are

queue-4.5/pwm-omap-dmtimer-fix-inaccurate-period-and-duty-cycle-calculations.patch
queue-4.5/pwm-omap-dmtimer-add-sanity-checking-for-load-and-match-values.patch
queue-4.5/pwm-omap-dmtimer-round-load-and-match-values-rather-than-truncate.patch