clk: mmp: pxa1908: Instantiate power driver through auxiliary bus

The power domain driver shares the APMU clock controller's registers.
Instantiate the power domain driver through the APMU clock driver using
the auxiliary bus.

Also create a separate Kconfig entry for the PXA1908 clock driver to
allow (de)selecting the driver at will and selecting
CONFIG_AUXILIARY_BUS.

Signed-off-by: Duje Mihanović <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

MAINTAINERS

···
 M:	Duje Mihanović <[e-mail]>
 L:	[e-mail] (moderated for non-subscribers)
 S:	Maintained
+F:	Documentation/devicetree/bindings/clock/marvell,pxa1908.yaml
 F:	arch/arm64/boot/dts/marvell/mmp/
+F:	drivers/clk/mmp/Kconfig
 F:	drivers/clk/mmp/clk-pxa1908*.c
 F:	include/dt-bindings/clock/marvell,pxa1908.h
 

drivers/clk/Kconfig

···
 source "drivers/clk/ingenic/Kconfig"
 source "drivers/clk/keystone/Kconfig"
 source "drivers/clk/mediatek/Kconfig"
+source "drivers/clk/mmp/Kconfig"
 source "drivers/clk/meson/Kconfig"
 source "drivers/clk/mstar/Kconfig"
 source "drivers/clk/microchip/Kconfig"

drivers/clk/mmp/Kconfig

···
+# SPDX-License-Identifier: GPL-2.0-only
+
+config COMMON_CLK_PXA1908
+	bool "Clock driver for Marvell PXA1908"
+	depends on ARCH_MMP || COMPILE_TEST
+	depends on OF
+	default y if ARCH_MMP && ARM64
+	select AUXILIARY_BUS
+	help
+	  This driver supports the Marvell PXA1908 SoC clocks.

drivers/clk/mmp/Makefile

···
 obj-$(CONFIG_COMMON_CLK_MMP2) += clk-of-mmp2.o clk-pll.o pwr-island.o
 obj-$(CONFIG_COMMON_CLK_MMP2_AUDIO) += clk-audio.o
 
-obj-$(CONFIG_ARCH_MMP) += clk-of-pxa1928.o clk-pxa1908-apbc.o clk-pxa1908-apbcp.o clk-pxa1908-apmu.o clk-pxa1908-mpmu.o
+obj-$(CONFIG_COMMON_CLK_PXA1908) += clk-pxa1908-apbc.o clk-pxa1908-apbcp.o \
+	clk-pxa1908-mpmu.o clk-pxa1908-apmu.o
+
+obj-$(CONFIG_ARCH_MMP) += clk-of-pxa1928.o

drivers/clk/mmp/clk-pxa1908-apmu.c

···
 // SPDX-License-Identifier: GPL-2.0-only
+#include <linux/auxiliary_bus.h>
 #include <linux/clk-provider.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
···
 static int pxa1908_apmu_probe(struct platform_device *pdev)
 {
 	struct pxa1908_clk_unit *pxa_unit;
+	struct auxiliary_device *adev;
 
 	pxa_unit = devm_kzalloc(&pdev->dev, sizeof(*pxa_unit), GFP_KERNEL);
 	if (!pxa_unit)
···
 	pxa_unit->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pxa_unit->base))
 		return PTR_ERR(pxa_unit->base);
+
+	adev = devm_auxiliary_device_create(&pdev->dev, "power", NULL);
+	if (IS_ERR(adev))
+		return dev_err_probe(&pdev->dev, PTR_ERR(adev),
+				     "Failed to register power controller\n");
 
 	mmp_clk_init(pdev->dev.of_node, &pxa_unit->unit, APMU_NR_CLKS);