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	The latest kernel PWM drivers enable the polarity settings. When system run from U-Boot to kerenl, if there are differences in polarity set or duty cycle, the PMW will re-init: close -> set polarity and duty cycle -> enable the PWM. The power supply controled by pwm regulator may have voltage shaking, which lead to the system not stable. Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com> Signed-off-by: Kever Yang <kever.yang@rock-chips.com> Acked-by: Simon Glass <sjg@chromium.org>
		
			
				
	
	
		
			47 lines
		
	
	
		
			891 B
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			47 lines
		
	
	
		
			891 B
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2016 Google, Inc
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|  * Written by Simon Glass <sjg@chromium.org>
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|  *
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|  * SPDX-License-Identifier:	GPL-2.0+
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|  */
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| 
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| #include <common.h>
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| #include <dm.h>
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| #include <pwm.h>
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| 
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| int pwm_set_invert(struct udevice *dev, uint channel, bool polarity)
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| {
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| 	struct pwm_ops *ops = pwm_get_ops(dev);
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| 
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| 	if (!ops->set_invert)
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| 		return -ENOSYS;
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| 
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| 	return ops->set_invert(dev, channel, polarity);
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| }
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| 
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| int pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
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| 		   uint duty_ns)
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| {
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| 	struct pwm_ops *ops = pwm_get_ops(dev);
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| 
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| 	if (!ops->set_config)
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| 		return -ENOSYS;
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| 
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| 	return ops->set_config(dev, channel, period_ns, duty_ns);
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| }
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| 
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| int pwm_set_enable(struct udevice *dev, uint channel, bool enable)
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| {
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| 	struct pwm_ops *ops = pwm_get_ops(dev);
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| 
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| 	if (!ops->set_enable)
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| 		return -ENOSYS;
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| 
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| 	return ops->set_enable(dev, channel, enable);
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| }
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| 
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| UCLASS_DRIVER(pwm) = {
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| 	.id		= UCLASS_PWM,
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| 	.name		= "pwm",
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| };
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