| From 5776ac2eb33164c77cdb4d2b48feee15616eaba3 Mon Sep 17 00:00:00 2001 |
| From: Jason Chen <jason.chen@linaro.org> |
| Date: Mon, 19 Dec 2011 11:23:28 +0800 |
| Subject: ARM:imx:fix pwm period value |
| |
| From: Jason Chen <jason.chen@linaro.org> |
| |
| 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> |
| |
| --- |
| arch/arm/plat-mxc/pwm.c | 9 +++++++++ |
| 1 file changed, 9 insertions(+) |
| |
| --- 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, i |
| 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); |
| |
