linux-imx

ACPI / LPSS: Resume BYT/CHT I2C controllers from resume_noirq

On some Cherry Trail systems the GPU ACPI fwnode has power-resources which
point to the PMIC, which is connected over a LPSS I2C controller.

We add a device-link to make sure that the I2C controller is resumed before
the GPU is. But the pci-core changes the power-state of PCI devices from
D3 to D0 at noirq time (to restore the PCI config registers) and before
this commit we were bringing up the I2C controllers from a resume_early
handler which runs later. More specifically the pm-core will first run
all resume_noirq handlers in order and then all resume_early handlers.

So we must not only make sure that the handlers are run in the right order,
but also that the resume of the I2C controller is done at noirq time.

The behavior before this commit, resuming the I2C controller from a
resume_early handler leads to the following errors:

 i2c_designware 808622C1:06: controller timed out
 ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
 ACPI Error: Method parse/execution failed \_SB.P18W._ON, AE_ERROR
 video LNXVIDEO:00: Failed to change power state to D0

This commit changes the acpi_lpss.c code to resume the BYT/CHT I2C
controllers at resume_noirq time fixing this.

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>