[PATCH] ARM:imx:fix pwm period value
From: Jason Chen <hidden>
Date: 2011-12-19 03:23:28
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
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 <redacted> --- 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 6b78490..0b112d2 100644
--- a/arch/arm/plat-mxc/pwm.c
+++ b/arch/arm/plat-mxc/pwm.c@@ -78,6 +78,15 @@ 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);
--
1.7.4.1