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In most cases when a VCM is used there is a single integrated module with the sensor + VCM + lens. This means that the sensor and VCM often share regulators and possibly also something like a powerdown pin. In the ACPI tables this is modelled as a single ACPI device with multiple I2cSerialBus resources. On atomisp devices the regulators and clks are modelled as ACPI power-resources, which are controlled by the (ACPI) power state of the sensor. So the sensor must be in D0 power state for the VCM to work. To make this work add a device-link with DL_FLAG_PM_RUNTIME flag so that the sensor will automatically be runtime-resumed whenever the VCM is runtime-resumed. This requires the probing of the VCM and thus the creation of the VCM I2C-client to be delayed till after the sensor driver has bound. Move the instantiation of the VCM I2C-client to the v4l2_async_notifier bound op, so that it is done after the sensor driver has bound; and add code to add the device-link. This fixes the problem with the shared ACPI power-resources on atomisp2 and this avoids the need for VCM related workarounds on IPU3 / IPU6. E.g. until now the dw9719 driver needed to get and control a Vsio (V sensor IO) regulator since that needs to be enabled to enable I2C pass-through on the PMIC on the sensor module. So the driver was controlling this regulator even though the actual dw9719 chip has no Vsio pin / power-plane. This also removes the need for ipu_bridge_init() to return -EPROBE_DEFER since the VCM is now instantiated later. Reviewed-by: Andy Shevchenko <andy@kernel.org> Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com> Tested-by: Daniel Scally <dan.scally@ideasonboard.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.