From: Greg KH <gregkh@suse.de>
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 <jason.chen@linaro.org>,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: [5/7] ARM:imx:fix pwm period value
Date: Tue, 03 Jan 2012 14:01:35 -0800 [thread overview]
Message-ID: <20120103220242.485129929@clark.kroah.org> (raw)
In-Reply-To: <20120103220302.GA28338@kroah.com>
2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
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
@@ -76,6 +76,15 @@ 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);
next prev parent reply other threads:[~2012-01-03 22:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-03 22:03 [0/7] 2.6.32.53-longterm review Greg KH
2012-01-03 22:01 ` [1/7] cfq-iosched: fix cfq_cic_link() race confition Greg KH
2012-01-03 22:01 ` [2/7] SCSI: mpt2sas: _scsih_smart_predicted_fault uses GFP_KERNEL in interrupt context Greg KH
2012-01-03 22:01 ` [3/7] MXC PWM: should active during DOZE/WAIT/DBG mode Greg KH
2012-01-03 22:01 ` [4/7] vfs: __read_cache_page should use gfp argument rather than GFP_KERNEL Greg KH
2012-01-03 22:01 ` Greg KH [this message]
2012-01-03 22:01 ` [6/7] ARM: 7220/1: mmc: mmci: Fixup error handling for dma Greg KH
2012-01-03 22:01 ` [7/7] watchdog: hpwdt: Changes to handle NX secure bit in 32bit path Greg KH
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