On Fri, Nov 18, 2022 at 09:38:52AM +0000, Jon Hunter wrote: > > On 17/11/2022 10:04, Akhil R wrote: > > Set ACPI node as the primary fwnode of I2C adapter to allow > > enumeration of child devices from the ACPI table > > > > Signed-off-by: Zubair Waheed <zwaheed@xxxxxxxxxx> > > Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx> > > --- > > drivers/i2c/busses/i2c-tegra.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > > index 954022c04cc4..69c9ae161bbe 100644 > > --- a/drivers/i2c/busses/i2c-tegra.c > > +++ b/drivers/i2c/busses/i2c-tegra.c > > @@ -1826,6 +1826,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) > > i2c_dev->adapter.class = I2C_CLASS_DEPRECATED; > > i2c_dev->adapter.algo = &tegra_i2c_algo; > > i2c_dev->adapter.nr = pdev->id; > > + ACPI_COMPANION_SET(&i2c_dev->adapter.dev, ACPI_COMPANION(&pdev->dev)); > > if (i2c_dev->hw->supports_bus_clear) > > i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info; > > > Do we always want to set as the primary fwnode even when booting with > device-tree? I some other drivers do, but I also see some others ... > > if (has_acpi_companion(dev)) > ACPI_COMPANION_SET(&i2c_dev->adapter.dev, > ACPI_COMPANION(&pdev->dev)); > > It would be nice to know why it is OK to always do this even for device-tree > because it is not clear to me. ACPI_COMPANION() returns NULL if there is no ACPI companion, which will cause ACPI_COMPANION_SET() to set the primary fwnode to NULL. If I read the code for set_primary_fwnode() correctly, that's essentially a no-op for DT devices. I guess that the extra check might save a few cycles by not having to run through all the various conditionals, but it seems a rather minor saving. Either way is fine with me, though. Thierry
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