From 5776ac2eb33164c77cdb4d2b48feee15616eaba3 Mon Sep 17 00:00:00 2001 From: Jason Chen Date: Mon, 19 Dec 2011 11:23:28 +0800 Subject: [PATCH] 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 Signed-off-by: Sascha Hauer Cc: stable@kernel.org --- arch/arm/plat-mxc/pwm.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c index 845de59f07ed..e032717f7d02 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); -- 2.34.1