pwm: lpss: Remove suspend/resume handlers

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

drivers/pwm/pwm-lpss-platform.c

@@ -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[] = {

drivers/pwm/pwm-lpss.c

@@ -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");

drivers/pwm/pwm-lpss.h

@@ -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 */