Re: [PATCH v4 02/11] i2c: acpi: Use acpi_dev_ready_for_enumeration() helper

[Rafael J. Wysocki]

On Mon, Oct 25, 2021 at 11:42 AM Hans de Goede <hdegoede@xxxxxxxxxx> 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.
>
> Acked-by: Wolfram Sang <wsa@xxxxxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

> ---
>  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 546cc935e035..71eee5bc17ab 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;
>
> --
> 2.31.1
>