From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120103223034.139196922@clark.kroah.org> Date: Tue, 03 Jan 2012 14:29:51 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jason Chen , Sascha Hauer Subject: [33/67] ARM:imx:fix pwm period value In-Reply-To: <20120103223043.GA26738@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Chen 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 Signed-off-by: Sascha Hauer Signed-off-by: Greg Kroah-Hartman --- 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);