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pwm: lpss: Remove suspend/resume handlers

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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
This commit is contained in:
Hans de Goede 2020-09-03 13:23:27 +02:00
parent d6d54bacb1
commit 547d9e9261
3 changed files with 0 additions and 28 deletions
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1
drivers/pwm/pwm-lpss-platform.c
View File

@ -89,7 +89,6 @@ static int pwm_lpss_prepare(struct device *dev)
static const struct dev_pm_ops pwm_lpss_platform_pm_ops = {
.prepare = pwm_lpss_prepare,
SET_SYSTEM_SLEEP_PM_OPS(pwm_lpss_suspend, pwm_lpss_resume)
};
static const struct acpi_device_id pwm_lpss_acpi_match[] = {

24
drivers/pwm/pwm-lpss.c
View File

@ -260,30 +260,6 @@ int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
}
EXPORT_SYMBOL_GPL(pwm_lpss_remove);
int pwm_lpss_suspend(struct device *dev)
{
struct pwm_lpss_chip *lpwm = dev_get_drvdata(dev);
int i;
for (i = 0; i < lpwm->info->npwm; i++)
lpwm->saved_ctrl[i] = readl(lpwm->regs + i * PWM_SIZE + PWM);
return 0;
}
EXPORT_SYMBOL_GPL(pwm_lpss_suspend);
int pwm_lpss_resume(struct device *dev)
{
struct pwm_lpss_chip *lpwm = dev_get_drvdata(dev);
int i;
for (i = 0; i < lpwm->info->npwm; i++)
writel(lpwm->saved_ctrl[i], lpwm->regs + i * PWM_SIZE + PWM);
return 0;
}
EXPORT_SYMBOL_GPL(pwm_lpss_resume);
MODULE_DESCRIPTION("PWM driver for Intel LPSS");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_LICENSE("GPL v2");

3
drivers/pwm/pwm-lpss.h
View File

@ -19,7 +19,6 @@ 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 {
@ -37,7 +36,5 @@ struct pwm_lpss_boardinfo {
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 */