On 18/11/2022 14:27, Akhil R wrote:
On 18/11/2022 10:18, Thierry Reding wrote:
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.
Yes it does, but doesn't it is not clear to me if it is a good idea to
pass NULL to set_primary_fwnode(). It does seem to handle this but my
biggest gripe is the lack of explanation in the commit message why this
is OK.
I saw ACPI_COMPANION_SET() as an empty function if CONFIG_ACPI is not set.
That's not the issue. By default CONFIG_ACPI is enabled for arm64 but
for Tegra we typically boot with device-tree. So I was more concerned
about the case where ACPI_COMPANION_SET() is not an empty function.
Yes, I agree that I should have mentioned this in the commit message.
Shall I send a v2 with the details added in the commit description?
No need, especially as Thierry has already applied. I am not familiar
with this function and primary/secondary fwnodes so wanted to understand
there is no issue for device tree.
Jon
--
nvpublic
