refactor(allwinner): h616: prepare for more than one PMIC model

Most devices based on Allwinner SoCs come with a certain fixed
combination of Power Management ICs (PMICs) and SoC, for instance the
A64 with the AXP803, or the H6 with the AXP805. This allowed us to
include the respective PMIC support code into each build target at build
time.

Similarly on H616 devices we initially saw only the AXP305, but for a
while now the simpler (and cheaper) AXP313a is a popular companion to
the H616 on many new boards. On at least one new device the AXP717 is
used as well.
With some rudimentary AXP version check in place we at least detected
the case of an unsupported SoC, but threw an error message, and lost
support for powering off the device.

Refactor the existing PMIC code to be able to support more than one
PMIC model, detected at runtime. For this we use a variable for the RSB
runtime address instead of hardcoding the address used on the AXP305,
and read the hardware bus address from the devicetree.
Also we look up the used PMIC in the devicetree, and set the PMIC model
accordingly. To be on the safe side, we also confirm the real PMIC used
by checking its version register and comparing that with the expected
value. Finally the register offset and value to power off the PMIC is
moved direclty into the platform code, as those values differ between
the different PMICs.

This is just refactoring and better error report, we still only support
the AXP305 on RSB at the moment.

Change-Id: I00b26ce4d30bb570ee1cd4979d0cdc9d6c020729
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

plat/allwinner/sun50i_h616/platform.mk

@@ -18,5 +18,6 @@ ifeq (${SUNXI_PSCI_USE_SCPI}, 1)
     $(error "H616 does not support SCPI PSCI ops")
 endif
 
-BL31_SOURCES		+=	drivers/allwinner/axp/axp805.c		\
+BL31_SOURCES		+=	common/fdt_wrappers.c			\
+				drivers/allwinner/axp/axp805.c		\
 				drivers/allwinner/sunxi_rsb.c		\

plat/allwinner/sun50i_h616/sunxi_power.c

@@ -10,97 +10,161 @@
 
 #include <arch_helpers.h>
 #include <common/debug.h>
+#include <common/fdt_wrappers.h>
 #include <drivers/allwinner/axp.h>
 #include <drivers/allwinner/sunxi_rsb.h>
 #include <lib/mmio.h>
+#include <libfdt.h>
 
 #include <sunxi_cpucfg.h>
 #include <sunxi_def.h>
 #include <sunxi_mmap.h>
 #include <sunxi_private.h>
 
-#define AXP305_I2C_ADDR	0x36
-#define AXP305_HW_ADDR	0x745
-#define AXP305_RT_ADDR	0x3a
+static uint16_t pmic_bus_addr;
+static uint8_t rsb_rt_addr;
 
 static enum pmic_type {
 	UNKNOWN,
 	AXP305,
 } pmic;
 
-int axp_read(uint8_t reg)
+static uint8_t get_rsb_rt_address(uint16_t hw_addr)
 {
-	return rsb_read(AXP305_RT_ADDR, reg);
-}
-
-int axp_write(uint8_t reg, uint8_t val)
-{
-	return rsb_write(AXP305_RT_ADDR, reg, val);
-}
-
-static int rsb_init(void)
-{
-	int ret;
-
-	ret = rsb_init_controller();
-	if (ret)
-		return ret;
-
-	/* Switch to the recommended 3 MHz bus clock. */
-	ret = rsb_set_bus_speed(SUNXI_OSC24M_CLK_IN_HZ, 3000000);
-	if (ret)
-		return ret;
-
-	/* Initiate an I2C transaction to switch the PMIC to RSB mode. */
-	ret = rsb_set_device_mode(AXP20X_MODE_RSB << 16 | AXP20X_MODE_REG << 8);
-	if (ret)
-		return ret;
-
-	/* Associate the 8-bit runtime address with the 12-bit bus address. */
-	ret = rsb_assign_runtime_address(AXP305_HW_ADDR, AXP305_RT_ADDR);
-	if (ret)
-		return ret;
-
-	return axp_check_id();
-}
-
-int sunxi_pmic_setup(uint16_t socid, const void *fdt)
-{
-	int ret;
-
-	INFO("PMIC: Probing AXP305 on RSB\n");
-
-	ret = sunxi_init_platform_r_twi(socid, true);
-	if (ret) {
-		INFO("Could not init platform bus: %d\n", ret);
-		return ret;
+	switch (hw_addr) {
+	case 0x745: return 0x3a;
 	}
 
-	ret = rsb_init();
-	if (ret) {
-		INFO("Could not init RSB: %d\n", ret);
-		return ret;
-	}
-
-	pmic = AXP305;
-	axp_setup_regulators(fdt);
-
-	/* Switch the PMIC back to I2C mode. */
-	ret = axp_write(AXP20X_MODE_REG, AXP20X_MODE_I2C);
-	if (ret)
-		return ret;
-
 	return 0;
 }
 
+int axp_read(uint8_t reg)
+{
+	return rsb_read(rsb_rt_addr, reg);
+}
+
+int axp_write(uint8_t reg, uint8_t val)
+{
+	return rsb_write(rsb_rt_addr, reg, val);
+}
+
+static int rsb_init(int rsb_hw_addr)
+{
+	int ret;
+
+	ret = rsb_init_controller();
+	if (ret) {
+		return ret;
+	}
+
+	/* Switch to the recommended 3 MHz bus clock. */
+	ret = rsb_set_bus_speed(SUNXI_OSC24M_CLK_IN_HZ, 3000000);
+	if (ret) {
+		return ret;
+	}
+
+	/* Initiate an I2C transaction to switch the PMIC to RSB mode. */
+	ret = rsb_set_device_mode(AXP20X_MODE_RSB << 16 | AXP20X_MODE_REG << 8);
+	if (ret) {
+		return ret;
+	}
+
+	/* Associate the 8-bit runtime address with the 12-bit bus address. */
+	ret = rsb_assign_runtime_address(rsb_hw_addr, rsb_rt_addr);
+	if (ret) {
+		return ret;
+	}
+
+	return 0;
+}
+
+static int pmic_bus_init(uint16_t socid, uint16_t rsb_hw_addr)
+{
+	int ret;
+
+	ret = sunxi_init_platform_r_twi(socid, true);
+	if (ret) {
+		INFO("Could not init platform bus: %d\n", ret);
+		pmic = UNKNOWN;
+		return ret;
+	}
+
+	ret = rsb_init(rsb_hw_addr);
+	if (ret) {
+		pmic = UNKNOWN;
+		return ret;
+	}
+
+	return 0;
+}
+
+int sunxi_pmic_setup(uint16_t socid, const void *fdt)
+{
+	int node, ret;
+	uint32_t reg;
+
+	node = fdt_node_offset_by_compatible(fdt, 0, "x-powers,axp806");
+	if (node >= 0) {
+		pmic = AXP305;
+	}
+
+	if (pmic == UNKNOWN) {
+		INFO("PMIC: No known PMIC in DT, skipping setup.\n");
+		return -ENODEV;
+	}
+
+	if (fdt_read_uint32(fdt, node, "reg", &reg)) {
+		ERROR("PMIC: PMIC DT node does not contain reg property.\n");
+		return -EINVAL;
+	}
+
+	pmic_bus_addr = reg;
+	rsb_rt_addr = get_rsb_rt_address(pmic_bus_addr);
+	if (rsb_rt_addr == 0) {
+		ERROR("PMIC: no mapping for RSB address 0x%x\n", reg);
+		return -EINVAL;
+	}
+
+	INFO("Probing for PMIC on RSB:\n");
+
+	ret = pmic_bus_init(socid, pmic_bus_addr);
+	if (ret) {
+		return ret;
+	}
+
+	ret = axp_read(0x03);
+	switch (ret & 0xcf) {
+	case 0x40:				/* AXP305 */
+		if (pmic == AXP305) {
+			INFO("PMIC: found AXP305, setting up regulators\n");
+			axp_setup_regulators(fdt);
+		} else {
+			pmic = UNKNOWN;
+		}
+		break;
+	}
+
+	/* Switch the PMIC back to I2C mode. */
+	return rsb_write(rsb_rt_addr, AXP20X_MODE_REG, AXP20X_MODE_I2C);
+}
+
 void sunxi_power_down(void)
 {
+	int ret;
+
+	if (pmic == UNKNOWN) {
+		return;
+	}
+
+	/* Re-initialise after rich OS might have used it. */
+	ret = pmic_bus_init(SUNXI_SOC_H616, pmic_bus_addr);
+	if (ret) {
+		return;
+	}
+
 	switch (pmic) {
 	case AXP305:
-		/* Re-initialise after rich OS might have used it. */
-		sunxi_init_platform_r_twi(SUNXI_SOC_H616, true);
-		rsb_init();
-		axp_power_off();
+		axp_setbits(0x32, BIT(7));
 		break;
 	default:
 		break;