Re: [PATCH v5 4/4] platform/x86: Add ACPI i2c-multi-instantiate pseudo driver

From: Wolfram Sang
Date: Thu Aug 09 2018 - 05:59:36 EST


On Thu, Aug 09, 2018 at 11:15:58AM +0200, Hans de Goede wrote:
> On systems with ACPI instantiated i2c-clients, normally there is 1 fw_node
> per i2c-device and that fw-node contains 1 I2cSerialBus resource for that 1
> i2c-device.
>
> But in some rare cases the manufacturer has decided to describe multiple
> i2c-devices in a single ACPI fwnode with multiple I2cSerialBus resources.
>
> An earlier attempt to fix this in the i2c-core resulted in a lot of extra
> code to support this corner-case.
>
> This commit introduces a new i2c-multi-instantiate driver which fixes this
> in a different way. This new driver can be built as a module which will
> only loaded on affected systems.
>
> This driver will instantiate a new i2c-client per I2cSerialBus resource,
> using the driver_data from the acpi_device_id it is binding to to tell it
> which chip-type (and optional irq-resource) to use when instantiating.
>
> Note this driver depends on a platform device being instantiated for the
> ACPI fwnode, see the i2c_multi_instantiate_ids list of ACPI device-ids in
> drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>

From my I2C PoV:

Acked-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>

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