From e3aa45f2f88b6779ab798c63a4deb7ddff949ac7 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 9 Nov 2020 11:57:26 +0100 Subject: pwm: lpss: Set DPM_FLAG_SMART_SUSPEND on Cherry Trail devices As the comment above the code setting the DPM_FLAG_NO_DIRECT_COMPLETE flag explains: /* * 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 */ The pm-core must not skip resume to avoid the GFX0._PS0 AML code messing with the PWM controller behind our back. But leaving the controller runtime-suspended (skipping runtime-resume + normal-suspend) during suspend is fine. Set the DPM_FLAG_SMART_SUSPEND flag to allow this. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding --- drivers/pwm/pwm-lpss-platform.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/pwm/pwm-lpss-platform.c b/drivers/pwm/pwm-lpss-platform.c index ac33861edb48..986786be1e49 100644 --- a/drivers/pwm/pwm-lpss-platform.c +++ b/drivers/pwm/pwm-lpss-platform.c @@ -69,9 +69,13 @@ static int pwm_lpss_probe_platform(struct platform_device *pdev) * 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 + * + * Leaving the controller runtime-suspended (skipping runtime-resume + + * normal-suspend) during suspend is fine. */ if (info->other_devices_aml_touches_pwm_regs) - dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE); + dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE| + DPM_FLAG_SMART_SUSPEND); pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); -- cgit 1.4.1