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fdb1ada57c
The _CRS ACPI resources table has 2 entries for the host wakeup GPIO,
the first one being a regular GpioIo () resource while the second one
is a GpioInt () resource for the same pin.
The acpi_gpio_mapping table used by vsc-tp.c maps the first Gpio ()
resource to "wakeuphost-gpios" where as the second GpioInt () entry
is mapped to "wakeuphostint-gpios".
Using "wakeuphost" to request the GPIO as was done until now, means
that the gpiolib-acpi code does not know that the GPIO is active-low
as that info is only available in the GpioInt () entry.
Things were still working before due to the following happening:
1. Since the 2 entries point to the same pin they share a struct gpio_desc
2. The SPI core creates the SPI device vsc-tp.c binds to and calls
acpi_dev_gpio_irq_get(). This does use the second entry and sets
FLAG_ACTIVE_LOW in gpio_desc.flags .
3. vsc_tp_probe() requests the "wakeuphost" GPIO and inherits the
active-low flag set by acpi_dev_gpio_irq_get()
But there is a possible scenario where things do not work:
1. - 3. happen as above
4. After requesting the "wakeuphost" GPIO, the "resetfw" GPIO is requested
next, but its USB GPIO controller is not available yet, so this call
returns -EPROBE_DEFER.
5. The gpio_desc for "wakeuphost" is put() and during this the active-low
flag is cleared from gpio_desc.flags .
6. Later on vsc_tp_probe() requests the "wakeuphost" GPIO again, but now it
is not marked active-low.
The difference can also be seen in /sys/kernel/debug/gpio, which contains
the following line for this GPIO:
gpio-535 ( |wakeuphost ) in hi IRQ ACTIVE LOW
If the second scenario is hit the "ACTIVE LOW" at the end disappears and
things do not work.
Fix this by requesting the GPIO through the "wakeuphostint" mapping instead
which provides active-low info without relying on acpi_dev_gpio_irq_get()
pre-populating this info in the gpio_desc.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2316918
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Tested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Fixes:
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