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authorJason Chen <jason.chen@linaro.org>2011-12-19 11:23:28 +0800
committerSascha Hauer <s.hauer@pengutronix.de>2011-12-19 12:25:35 +0100
commit5776ac2eb33164c77cdb4d2b48feee15616eaba3 (patch)
treeff2dee4d0f3aa296190dc1a7a7812587c199f14c /arch/arm
parent384703b8e6cd4c8ef08512e596024e028c91c339 (diff)
downloadop-kernel-dev-5776ac2eb33164c77cdb4d2b48feee15616eaba3.zip
op-kernel-dev-5776ac2eb33164c77cdb4d2b48feee15616eaba3.tar.gz
ARM:imx:fix pwm period value
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> Cc: stable@kernel.org
Diffstat (limited to 'arch/arm')
-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 845de59..e032717 100644
--- a/arch/arm/plat-mxc/pwm.c
+++ b/arch/arm/plat-mxc/pwm.c
@@ -77,6 +77,15 @@ 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);
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