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path: root/drivers/pwm/pwm-omap-dmtimer.c
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2016-05-17pwm: Use pwm_get/set_xxx() helpers where appropriateBoris Brezillon1-1/+1
Use pwm_get/set_xxx() helpers instead of directly accessing the pwm->xxx field. Doing that will ease adaptation of the PWM framework to support atomic update. Signed-off-by: Boris Brezillon <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
2016-03-23pwm: omap-dmtimer: Add debug message for effective period and duty cycleDavid Rivshin1-1/+8
After going through the math and constraints checking to compute load and match values, it is helpful to know what the resultant period and duty cycle are. Signed-off-by: David Rivshin <[email protected]> Acked-by: Neil Armstrong <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
2016-03-23pwm: omap-dmtimer: Round load and match values rather than truncateDavid Rivshin1-5/+1
When converting period and duty_cycle from nanoseconds to fclk cycles, the error introduced by the integer division can be appreciable, especially in the case of slow fclk or short period. Use DIV_ROUND_CLOSEST_ULL() so that the error is kept to +/- 0.5 clock cycles. Fixes: 6604c6556db9 ("pwm: Add PWM driver for OMAP using dual-mode timers") Signed-off-by: David Rivshin <[email protected]> Acked-by: Neil Armstrong <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
2016-03-23pwm: omap-dmtimer: Add sanity checking for load and match valuesDavid Rivshin1-4/+30
Add sanity checking to ensure that we do not program load or match values that are out of range if a user requests period or duty_cycle values which are not achievable. The match value cannot be less than the load value (but can be equal), and neither can be 0xffffffff. This means that there must be at least one fclk cycle between load and match, and another between match and overflow. Fixes: 6604c6556db9 ("pwm: Add PWM driver for OMAP using dual-mode timers") Signed-off-by: David Rivshin <[email protected]> Acked-by: Neil Armstrong <[email protected]> [[email protected]: minor coding style cleanups] Signed-off-by: Thierry Reding <[email protected]>
2016-03-23pwm: omap-dmtimer: Fix inaccurate period and duty cycle calculationsDavid Rivshin1-7/+20
Fix the calculation of load_value and match_value. Currently they are slightly too low, which produces a noticeably wrong PWM rate with sufficiently short periods (i.e. when 1/period approaches clk_rate/2). Example: clk_rate=32768Hz, period=122070ns, duty_cycle=61035ns (8192Hz/50% PWM) Correct values: load = 0xfffffffc, match = 0xfffffffd Current values: load = 0xfffffffa, match = 0xfffffffc effective PWM: period=183105ns, duty_cycle=91553ns (5461Hz/50% PWM) Fixes: 6604c6556db9 ("pwm: Add PWM driver for OMAP using dual-mode timers") Signed-off-by: David Rivshin <[email protected]> Acked-by: Neil Armstrong <[email protected]> Tested-by: Adam Ford <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
2016-01-04pwm: omap-dmtimer: Potential NULL dereference on errorDan Carpenter1-1/+1
"omap" is NULL so we can't dereference it. Signed-off-by: Dan Carpenter <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
2015-12-16pwm: Add PWM driver for OMAP using dual-mode timersNeil Armstrong1-0/+327
Adds support for using a OMAP dual-mode timer with PWM capability as a Linux PWM device. The driver controls the timer by using the dmtimer API. Add a platform_data structure for each pwm-omap-dmtimer nodes containing the dmtimers functions in order to get driver not rely on platform specific functions. Cc: Grant Erickson <[email protected]> Cc: NeilBrown <[email protected]> Cc: Joachim Eastwood <[email protected]> Suggested-by: Tony Lindgren <[email protected]> Signed-off-by: Neil Armstrong <[email protected]> Acked-by: Tony Lindgren <[email protected]> [[email protected]: coding style bikeshed, fix timer leak] Signed-off-by: Thierry Reding <[email protected]>
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