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path: root/drivers/pwm/pwm-atmel.c
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2014-09-25pwm: atmel: Fix calculation of prescale valueNikolaus Voss1-13/+11
The prescale value used for calculating the period was incremented afterwards, thus the resulting prescale value is by one too high. This resulted in a PWM frequency only half as high as requested. This patch moves the 64 bit division out of the prescale loop to correct the above issue and make the calculation more efficient. Signed-off-by: Nikolaus Voss <n.voss@weinmann-emt.de> Tested-by: Bo Shen <voice.shen@atmel.com> Acked-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-21pwm: atmel: set pwm_chip can_sleep flagAlexandre Belloni1-0/+1
atmel_pwm_config() calls clk_get_rate() which might sleep, so we need to set pwm_chip can_sleep flag. 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>
2014-03-18pwm: atmel: correct CDTY calculationAlexandre Belloni1-1/+1
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>
2014-03-18pwm: atmel: Fix polarity handlingAlexandre Belloni1-1/+6
When atmel_pwm_config() calculates and then sets the prescaler, it is overwriting the channel's CMR register so we are losing the CPOL configuration. As atmel_pwm_config() is always called before enabling a channel, inverting the polarity doesn't work. Fix that by reading CMR first and only overwriting the prescaler bits. 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>
2013-12-20pwm: atmel-pwm: Do not unprepare clock after successful registrationBo Shen1-0/+2
When the PWM controller is registered successfully, the clock can not unprepare, so fix it. Signed-off-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-12-17pwm: atmel-pwm: Add Atmel PWM controller driverBo Shen1-0/+393
Add a PWM framework driver for the PWM controller found on Atmel SoCs. Signed-off-by: Bo Shen <voice.shen@atmel.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> [thierry.reding: coding style and other minor cleanups] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>