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path: root/drivers/pwm/pwm-bcm2835.c
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* pwm: bcm2835: Improve precision of PWMSean Young2019-06-261-3/+5
| | | | | | | | | | | | | | | If sending IR with carrier of 455kHz using the pwm-ir-tx driver, the carrier ends up being 476kHz. The clock is set to bcm2835-pwm with a rate of 10MHz. A carrier of 455kHz has a period of 2198ns, but the arithmetic truncates this to 2100ns rather than 2200ns. So, use DIV_ROUND_CLOSEST() to reduce rounding errors, and we have a much more accurate carrier of 454.5kHz. Reported-by: Andreas Christ <andreas@christ-faesch.ch> Signed-off-by: Sean Young <sean@mess.org> Acked-by: Stefan Wahren <wahrenst@gmx.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: bcm2835: Switch to SPDX identifierStefan Wahren2018-12-241-4/+1Star
| | | | | | | | | | Adopt the SPDX license identifier headers to ease license compliance management. Cc: Bart Tanghe <bart.tanghe@thomasmore.be> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: bcm2835: Support for polarity setting via DTStefan Wahren2017-08-211-0/+2
| | | | | | | | | This adds support for the third (optional) pwm cell to specify the polarity, which is needed by display backlights for example. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: bcm2835: Fix email address specificationStefan Wahren2015-12-161-1/+1
| | | | | | Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: bcm2835: Prevent division by zeroStefan Wahren2015-12-161-1/+9
| | | | | | | | | It's possible that the PWM clock becomes an orphan. So better check the result of clk_get_rate() in order to prevent a division by zero. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: bcm2835: Calculate scaler in ->config()Stefan Wahren2015-12-161-5/+3Star
| | | | | | | | | | | Currently pwm-bcm2835 assumes a fixed clock rate and stores the resulting scaler in the driver structure. But with the upcoming PWM clock support for clk-bcm2835 the rate could change, so calculate the scaler in the ->config() callback. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Add BCM2835 PWM driverBart Tanghe2014-11-171-0/+205
Add PWM driver for Broadcom BCM2835 processor (Raspberry Pi) Signed-off-by: Bart Tanghe <bart.tanghe@thomasmore.be> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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