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| author | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2014-03-14 15:19:09 +0100 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2014-03-18 20:47:48 +0100 |
| commit | 916030db4399f9237beef480fee6b11dd83cacd5 (patch) | |
| tree | f290ef1a4c72a5d6d0c0aea11b43062ddf80cfaf /drivers/pwm | |
| parent | 8db9e29fe540c9640ea60f37ecf99d3a73bd12c5 (diff) | |
| download | blackbird-op-linux-916030db4399f9237beef480fee6b11dd83cacd5.tar.gz blackbird-op-linux-916030db4399f9237beef480fee6b11dd83cacd5.zip | |
pwm: atmel: correct CDTY calculation
From the datasheet, the actual duty cycle is:
(period - (1 / clk) * CDTY) / period
This actually correct the polarity of the PWM and solves the issue that
pwm-leds exhibits: when setting a duty cycle of 0 and then disabling a
channel, the level was wrong (1 when the polarity was normal and 0 when
the polarity was inversed).
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-atmel.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c index 2d69e9c431dd..0adc952cc4ef 100644 --- a/drivers/pwm/pwm-atmel.c +++ b/drivers/pwm/pwm-atmel.c @@ -133,7 +133,7 @@ static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, prd = div; div *= duty_ns; do_div(div, period_ns); - dty = div; + dty = prd - div; ret = clk_enable(atmel_pwm->clk); if (ret) { |
