mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Hans de Goede](/assets/img/avatar_default.png)
PWM controller drivers should not restore the PWM state on resume. The convention is that PWM consumers do this by calling pwm_apply_state(), so that it can be done at the exact moment when the consumer needs the state to be stored, avoiding e.g. backlight flickering. The only in kernel consumers of the pwm-lpss code, the i915 driver and the pwm-class sysfs interface code both correctly restore the state on resume, so there is no need to do this in the pwm-lpss code. More-over the removed resume handler is buggy, since it blindly restores the ctrl-register contents without setting the update bit, which is necessary to get the controller to actually use/apply the restored base-unit and on-time-div values. Acked-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-8-hdegoede@redhat.com
40 lines
903 B
C
40 lines
903 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Intel Low Power Subsystem PWM controller driver
|
|
*
|
|
* Copyright (C) 2014, Intel Corporation
|
|
*
|
|
* Derived from the original pwm-lpss.c
|
|
*/
|
|
|
|
#ifndef __PWM_LPSS_H
|
|
#define __PWM_LPSS_H
|
|
|
|
#include <linux/device.h>
|
|
#include <linux/pwm.h>
|
|
|
|
#define MAX_PWMS 4
|
|
|
|
struct pwm_lpss_chip {
|
|
struct pwm_chip chip;
|
|
void __iomem *regs;
|
|
const struct pwm_lpss_boardinfo *info;
|
|
};
|
|
|
|
struct pwm_lpss_boardinfo {
|
|
unsigned long clk_rate;
|
|
unsigned int npwm;
|
|
unsigned long base_unit_bits;
|
|
bool bypass;
|
|
/*
|
|
* On some devices the _PS0/_PS3 AML code of the GPU (GFX0) device
|
|
* messes with the PWM0 controllers state,
|
|
*/
|
|
bool other_devices_aml_touches_pwm_regs;
|
|
};
|
|
|
|
struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
|
|
const struct pwm_lpss_boardinfo *info);
|
|
int pwm_lpss_remove(struct pwm_lpss_chip *lpwm);
|
|
|
|
#endif /* __PWM_LPSS_H */
|