The spmi-dev-container binding is intended for SPMI
configurations that have multiple device nodes associated with
only one spmi_device. By default, if this flag is not specified,
each device node will create a new spmi_device.
Sometimes having multiple spmi_devices for SPMI device nodes is
superfluous. One example of this is gpios. In some architectures,
a single gpio is treated as a unique device. But from a gpio_chip
perspective, the chip is comprised of many gpios. Beyond wasting
memory allocating a unique spmi_device per gpio, the implication
of not coalescing spmi_devices is that the clients probe() routine
would be called N number of times. But this sort of behavior makes
it difficult to realize when a gpio_chip starts and stops. If we
assume that one gpio_chip represents one call to probe(), then
this problem is solved, since all gpios in that chip will be
passed as resources.
In order to support multiple device nodes per spmi_device, we
also need to extend the data structures for spmi_resources.
This change also makes an effort to cleanup some of the error
handling for illegal combinations of device bindings, as well as
adding some additional documentation.
Change-Id: If3ce2aaaa07bdf79e0d9fdedf16419e74a00fbec
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
This change adds SPMI Device Tree parsing. The
of_spmi_register_devices() API should be called from the probe()
routine of each SPMI controller to parse the subtree and add the
respective SPMI devices.
The SPMI subtree is nested up to two levels deep. The first level
is the most basic and treats the address as the SPMI slave ID.
This should be used for simple devices that has no notion of
segmented SPMI address spaces.
An optional second level specifies the address as an offset
within the outer layer's slave ID. This is used to specify
multiple devices on the same slave ID that have different address
ranges. In fact, it's reasonable to specify any number of address
ranges at this level.
Devices can also specify any number of interrupts that's decoding
is done by an external interrupt device.
Sections of this code were taken from drivers/of/platform.c.
Change-Id: Ib9f06764a9bd85e3b2aab43b72aa7132885aa044
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
