linux/drivers/pwm/pwm-lpss.h
Hans de Goede 6a425ecd19 pwm: lpss: Check PWM powerstate after resume on Cherry Trail devices
The _PS0 method for the integrated graphics on some Cherry Trail devices
(observed on a HP Pavilion X2 10-p0XX) turns on the PWM chip (puts it in
D0), causing an inconsistency between the state the pm-core thinks it is
in (left runtime suspended as it was before the suspend/resume) and the
state it actually is in.

Interestingly enough this is done on a device where the pwm controller is
not used for the backlight at all, since it uses an eDP panel. On devices
where the PWM is used this is not a problem since we will resume it
ourselves anyways.

This inconsistency causes us to never suspend the pwm controller again,
which causes the device to not be able to reach S0ix states when suspended.

This commit adds a resume-complete handler, which when we think the device
is still run-time suspended checks the actual power-state and if necessary
updates the rpm-core's internal state.

This fixes the Pavilion X2 10-p0XX not reaching S0ix states when suspended.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-10-12 12:31:58 +02:00

44 lines
1.1 KiB
C

/*
* Intel Low Power Subsystem PWM controller driver
*
* Copyright (C) 2014, Intel Corporation
*
* Derived from the original pwm-lpss.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#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;
u32 saved_ctrl[MAX_PWMS];
};
struct pwm_lpss_boardinfo {
unsigned long clk_rate;
unsigned int npwm;
unsigned long base_unit_bits;
bool bypass;
/* Some devices have AML code messing with the state underneath us */
bool check_power_on_resume;
};
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);
int pwm_lpss_suspend(struct device *dev);
int pwm_lpss_resume(struct device *dev);
#endif /* __PWM_LPSS_H */