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authorJason Chen <jason.chen@linaro.org>2011-12-19 11:23:28 +0800
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-06 15:38:02 -0800
commit82cfa7a65105edd27c5a91a793093209c412ba9a (patch)
treee5c6fe965585a48058a2999efae98cb766e1e948
parentf1ab682d4e723d87408f384e79496ba61c1686c1 (diff)
ARM:imx:fix pwm period value
commit 5776ac2eb33164c77cdb4d2b48feee15616eaba3 upstream. According to imx pwm RM, the real period value should be PERIOD value in PWMPR plus 2. PWMO (Hz) = PCLK(Hz) / (period +2) Signed-off-by: Jason Chen <jason.chen@linaro.org> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/arm/plat-mxc/pwm.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c
index 99d060cd362..16404864fde 100644
--- a/arch/arm/plat-mxc/pwm.c
+++ b/arch/arm/plat-mxc/pwm.c
@@ -76,6 +76,15 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
do_div(c, period_ns);
duty_cycles = c;
+ /*
+ * according to imx pwm RM, the real period value should be
+ * PERIOD value in PWMPR plus 2.
+ */
+ if (period_cycles > 2)
+ period_cycles -= 2;
+ else
+ period_cycles = 0;
+
writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
writel(period_cycles, pwm->mmio_base + MX3_PWMPR);