[PATCH v2 0/1] soc: add polarfire soc system controller

[conor.dooley at microchip.com]

From: Conor Dooley <conor.dooley at microchip.com>

Changes since v1:
- system controller is now an mfd
- parentage is now used to get the device node on the system controller
- mpfs_sys_controller_get() now updates the reference count
- "polarfire-soc" in compat string changed to "mpfs"

Depends on [0] to change the compat string in the dt-binding.

@Arnd Bergmann:
I sent the first version of this patch in November & you (along with
requesting referencing counting) wanted me to check if the driver was
bound to the specific device [1]. I have taken another look at this
driver now and I am still none the wiser as to how I should do this.

As I said in the previous thread, I checked other driver but was not
able to find any examples of of_find_device_by_node() where the binding
of the driver was checked. If you could point me towards an example
that would be great.

Thanks,
Conor.

For some extra context, the device tree entry for this driver will look
like:

syscontroller: syscontroller {
	compatible = "microchip,mpfs-sys-controller", "simple-mfd";
	mboxes = <&mbox 0>;

	hwrandom: hwrandom {
		compatible = "microchip,mpfs-rng";
	};

	sysserv: sysserv {
		compatible = "microchip,mpfs-generic-service";
	};
};

and the mpfs_sys_controller_get() function is called in, for example,
the mpfs-rng driver:

node_pointer = of_get_parent(dev->of_node);
if (!node_pointer) {
	dev_err(&pdev->dev,
		"Failed to find mpfs system controller node\n");
	return -ENODEV;
}

rng_priv->sys_controller =  mpfs_sys_controller_get(&pdev->dev, node_pointer);

[0] https://lore.kernel.org/linux-riscv/CAMuHMdWTjrAiHosU0cGyJYkK=9JzNgHb=tjHXPdYxTWmkVzeYQ@mail.gmail.com/T/
[1] https://lore.kernel.org/linux-riscv/CAK8P3a1m_LhOg5JGMqPz6sohJa2hPZ3GN-jQDPxigZ5DaqAGxQ@mail.gmail.com/

Conor Dooley (1):
  soc: add polarfire soc system controller

 drivers/soc/Kconfig                         |   1 +
 drivers/soc/Makefile                        |   1 +
 drivers/soc/microchip/Kconfig               |  10 ++
 drivers/soc/microchip/Makefile              |   1 +
 drivers/soc/microchip/mpfs-sys-controller.c | 169 ++++++++++++++++++++
 include/soc/microchip/mpfs.h                |   3 +-
 6 files changed, 184 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/microchip/Kconfig
 create mode 100644 drivers/soc/microchip/Makefile
 create mode 100644 drivers/soc/microchip/mpfs-sys-controller.c

-- 
2.33.1