Re: [PATCH v3 02/11] i2c: acpi: Use acpi_dev_ready_for_enumeration() helper

Rafael J. Wysocki
2021-10-13T17:39:56Z

On Sun, Oct 10, 2021 at 8:57 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> The clk and regulator frameworks expect clk/regulator consumer-devices
> to have info about the consumed clks/regulators described in the device's
> fw_node.
>
> To work around cases where this info is not present in the firmware tables,
> which is often the case on x86/ACPI devices, both frameworks allow the
> provider-driver to attach info about consumers to the clks/regulators
> when registering these.
>
> This causes problems with the probe ordering wrt drivers for consumers
> of these clks/regulators. Since the lookups are only registered when the
> provider-driver binds, trying to get these clks/regulators before then
> results in a -ENOENT error for clks and a dummy regulator for regulators.
>
> To ensure the correct probe-ordering the ACPI core has code to defer the
> enumeration of consumers affected by this until the providers are ready.
>
> Call the new acpi_dev_ready_for_enumeration() helper to avoid
> enumerating / instantiating i2c-clients too early.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/i2c/i2c-core-acpi.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index aaeeacc12121..688cc71d650d 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -144,9 +144,12 @@ static int i2c_acpi_do_lookup(struct acpi_device *adev,
> struct list_head resource_list;
> int ret;
>
> - if (acpi_bus_get_status(adev) || !adev->status.present)
> + if (acpi_bus_get_status(adev))
> return -EINVAL;
>
> + if (!acpi_dev_ready_for_enumeration(adev))
> + return -ENODEV;
> +
> if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
> return -ENODEV;

I kind of prefer combining checks that cause the same error code to be
returned, but this is fine with me too.