pwm: omap-dmtimer: Round load and match values rather than truncate
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>
diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index 54641e45..e0679eb 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -49,11 +49,7 @@
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)