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| author | Jason Chen <jason.chen@linaro.org> | 2011-12-19 11:23:28 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-06 15:38:02 -0800 |
| commit | 82cfa7a65105edd27c5a91a793093209c412ba9a (patch) | |
| tree | e5c6fe965585a48058a2999efae98cb766e1e948 | |
| parent | f1ab682d4e723d87408f384e79496ba61c1686c1 (diff) | |
| download | linux-stable-82cfa7a65105edd27c5a91a793093209c412ba9a.tar.gz linux-stable-82cfa7a65105edd27c5a91a793093209c412ba9a.tar.bz2 linux-stable-82cfa7a65105edd27c5a91a793093209c412ba9a.zip | |
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.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c index 99d060cd3622..16404864fdee 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); |