[RFC 3/4] platform/x86: i2c-multi-instantiate: Pass ACPI fwnode to instantiated I2C-clients

[Hans de Goede <hdegoede@redhat.com>]

The ACPI fwnode may contain additional info which is useful for the
I2C-driver. E.g. some accelerometer ACPI fwnode's contain an ACPI method
providing rotation/mount matrix info.

Pass the ACPI-fwnode to the instantiated I2C-clients by setting
i2c_board_info.fwnode, so that the I2C-drivers can access this info.

Now that we set i2c_board_info.irq to -ENOENT if there is no IRQ,
avoiding the I2C-core assigning the first IRQ described in the ACPI
resources to the client, this is safe to do.

Setting the fwnode also influences acpi_device_[uevent_]modalias and
acpi_dev_pm_attach, but these both call acpi_device_is_first_physical_node
and are a no-op if this returns false.

The first physical node for the ACPI fwnode is actually the ACPI core
instantiated platform-device to which the I2C-multi-instantiate driver
binds, so acpi_device_is_first_physical_node always returns false for
the instantiated I2C-clients and thus we can safely pass the fwnode.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/platform/x86/i2c-multi-instantiate.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/platform/x86/i2c-multi-instantiate.c b/drivers/platform/x86/i2c-multi-instantiate.c
index cb4688bdd6b6..cbccfcbed44c 100644
--- a/drivers/platform/x86/i2c-multi-instantiate.c
+++ b/drivers/platform/x86/i2c-multi-instantiate.c
@@ -93,6 +93,7 @@ static int i2c_multi_inst_probe(struct platform_device *pdev)
 		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev),
 			 inst_data[i].type, i);
 		board_info.dev_name = name;
+		board_info.fwnode = dev->fwnode;
 		switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) {
 		case IRQ_RESOURCE_GPIO:
 			ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
-- 
2.28.0