i2c: Add a DM_I2C driver for the sun8i RSB controller

This bus controller is used to communicate with an X-Powers AXP PMIC.
Currently, various drivers access PMIC registers through a platform-
specific non-DM "pmic_bus" interface, which depends on the legacy I2C
framework. In order to convert those drivers to use DM_PMIC, this bus
needs a DM_I2C driver.

Refactor the rsb functions to take the base address as a parameter,
and implement both the existing interface (which is still needed in
SPL) and the DM_I2C interface on top of them.

The register for switching between I2C/P2WI/RSB mode is the same across
all PMIC variants, so move that to the common header.

There are only a couple of pairs of hardware/runtime addresses used
across all PMIC variants. So far the code expected only the "primary"
pair, but some PMICs like the AXP305 and AXP805 use the secondary pair,
so add support for that to the DM driver as well.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index f4a4528..10401d3 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -100,14 +100,6 @@
 	  Select this PMIC bus access helpers for Sunxi platform PRCM or other
 	  AXP family PMIC devices.
 
-config SUN8I_RSB
-	bool "Allwinner sunXi Reduced Serial Bus Driver"
-	help
-	  Say y here to enable support for Allwinner's Reduced Serial Bus
-	  (RSB) support. This controller is responsible for communicating
-	  with various RSB based devices, such as AXP223, AXP8XX PMICs,
-	  and AC100/AC200 ICs.
-
 config SUNXI_SRAM_ADDRESS
 	hex
 	default 0x10000 if MACH_SUN9I || MACH_SUN50I || MACH_SUN50I_H5
@@ -250,9 +242,10 @@
 	select ARCH_SUPPORT_PSCI
 	select DRAM_SUN8I_A23
 	select PHY_SUN4I_USB
-	select SUN8I_RSB
+	select SPL_I2C
 	select SUNXI_GEN_SUN6I
 	select SUPPORT_SPL
+	select SYS_I2C_SUN8I_RSB
 	select ARMV7_BOOT_SEC_DEFAULT if OLD_SUNXI_KERNEL_COMPAT
 	imply CONS_INDEX_5 if !DM_SERIAL
 
@@ -264,9 +257,10 @@
 	select ARCH_SUPPORT_PSCI
 	select DRAM_SUN8I_A33
 	select PHY_SUN4I_USB
-	select SUN8I_RSB
+	select SPL_I2C
 	select SUNXI_GEN_SUN6I
 	select SUPPORT_SPL
+	select SYS_I2C_SUN8I_RSB
 	select ARMV7_BOOT_SEC_DEFAULT if OLD_SUNXI_KERNEL_COMPAT
 	imply CONS_INDEX_5 if !DM_SERIAL
 
@@ -275,11 +269,12 @@
 	select CPU_V7A
 	select DRAM_SUN8I_A83T
 	select PHY_SUN4I_USB
-	select SUN8I_RSB
+	select SPL_I2C
 	select SUNXI_GEN_SUN6I
 	select MMC_SUNXI_HAS_NEW_MODE
 	select MMC_SUNXI_HAS_MODE_SWITCH
 	select SUPPORT_SPL
+	select SYS_I2C_SUN8I_RSB
 
 config MACH_SUN8I_H3
 	bool "sun8i (Allwinner H3)"
@@ -320,6 +315,7 @@
 	bool "sun9i (Allwinner A80)"
 	select CPU_V7A
 	select DRAM_SUN9I
+	select SPL_I2C
 	select SUN6I_PRCM
 	select SUNXI_GEN_SUN6I
 	select SUPPORT_SPL