ACPI LPSS devices use direct-complete style suspend/resume handling by
default. We set the DPM_FLAG_SMART_PREPARE and define a prepare handler
to disable this on Cherry Trail devices.
Clean this up a bit by setting the DPM_FLAG_NO_DIRECT_COMPLETE flag for
Cherry Trail devices, instead of defining a prepare handler.
While at it also improve the comment explaining why this is necessary.
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/pwm/pwm-lpss-platform.c | 35 ++++++++++++++-------------------
1 file changed, 15 insertions(+), 20 deletions(-)
diff --git a/drivers/pwm/pwm-lpss-platform.c b/drivers/pwm/pwm-lpss-platform.c
index c6502cf7a7af..ac33861edb48 100644
--- a/drivers/pwm/pwm-lpss-platform.c
+++ b/drivers/pwm/pwm-lpss-platform.c
@@ -58,7 +58,21 @@ static int pwm_lpss_probe_platform(struct platform_device *pdev)
platform_set_drvdata(pdev, lpwm);
- dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_SMART_PREPARE);
+ /*
+ * On Cherry Trail devices the GFX0._PS0 AML checks if the controller
+ * is on and if it is not on it turns it on and restores what it
+ * believes is the correct state to the PWM controller.
+ * Because of this we must disallow direct-complete, which keeps the
+ * controller (runtime)suspended on resume, to avoid 2 issues:
+ * 1. The controller getting turned on without the linux-pm code
+ * knowing about this. On devices where the controller is unused
+ * this causes it to stay on during the next suspend causing high
+ * battery drain (because S0i3 is not reached)
+ * 2. The state restoring code unexpectedly messing with the controller
+ */
+ if (info->other_devices_aml_touches_pwm_regs)
+ dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE);
+
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
@@ -73,24 +87,6 @@ static int pwm_lpss_remove_platform(struct platform_device *pdev)
return pwm_lpss_remove(lpwm);
}
-static int pwm_lpss_prepare(struct device *dev)
-{
- struct pwm_lpss_chip *lpwm = dev_get_drvdata(dev);
-
- /*
- * If other device's AML code touches the PWM regs on suspend/resume
- * force runtime-resume the PWM controller to allow this.
- */
- if (lpwm->info->other_devices_aml_touches_pwm_regs)
- return 0; /* Force runtime-resume */
-
- return 1; /* If runtime-suspended leave as is */
-}
-
-static const struct dev_pm_ops pwm_lpss_platform_pm_ops = {
- .prepare = pwm_lpss_prepare,
-};
-
static const struct acpi_device_id pwm_lpss_acpi_match[] = {
{ "80860F09", (unsigned long)&pwm_lpss_byt_info },
{ "80862288", (unsigned long)&pwm_lpss_bsw_info },
@@ -104,7 +100,6 @@ static struct platform_driver pwm_lpss_driver_platform = {
.driver = {
.name = "pwm-lpss",
.acpi_match_table = pwm_lpss_acpi_match,
- .pm = &pwm_lpss_platform_pm_ops,
},
.probe = pwm_lpss_probe_platform,
.remove = pwm_lpss_remove_platform,
--
2.28.0
