lkml.org 
[lkml]   [2012]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[41/75] ARM:imx:fix pwm period value
    3.1-stable 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
    @@ -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);




    \
     
     \ /
      Last update: 2012-01-03 23:55    [W:0.030 / U:0.452 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site