diff options
| author | Jason Chen <jason.chen@linaro.org> | 2011-12-19 11:23:28 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-06 14:13:56 -0800 |
| commit | 8048ac75378918eab0f68ba175915e72ef73e0da (patch) | |
| tree | 6aeb17f8c843fe352836db6f1512058e28764ef5 /arch/arm/plat-mxc/pwm.c | |
| parent | f3545737cf06d342d34483b7a8421d0bb90b9c1b (diff) | |
| download | kernel_samsung_smdk4412-8048ac75378918eab0f68ba175915e72ef73e0da.zip kernel_samsung_smdk4412-8048ac75378918eab0f68ba175915e72ef73e0da.tar.gz kernel_samsung_smdk4412-8048ac75378918eab0f68ba175915e72ef73e0da.tar.bz2 | |
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>
Diffstat (limited to 'arch/arm/plat-mxc/pwm.c')
| -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 7bf2a00..f4b68be 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); |