allwinner: sun50i_h6: add initial AXP805 PMIC code

The OTT reference design of Allwinner H6 SoC uses an X-Powers AXP805
PMIC.

Add initial code for it.

Currently it's only detected.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

plat/allwinner/sun50i_h6/platform.mk

@@ -7,6 +7,7 @@
 include lib/xlat_tables_v2/xlat_tables.mk
 
 AW_PLAT			:=	plat/allwinner
+AW_DRIVERS		:=	drivers/allwinner
 
 PLAT_INCLUDES		:=	-Iinclude/plat/arm/common		\
 				-Iinclude/plat/arm/common/aarch64	\
@@ -15,6 +16,7 @@ PLAT_INCLUDES		:=	-Iinclude/plat/arm/common		\
 
 PLAT_BL_COMMON_SOURCES	:=	drivers/console/${ARCH}/console.S	\
 				drivers/ti/uart/${ARCH}/16550_console.S	\
+				${AW_DRIVERS}/sunxi_i2c.c		\
 				${XLAT_TABLES_LIB_SRCS}			\
 				${AW_PLAT}/common/plat_helpers.S	\
 				${AW_PLAT}/common/sunxi_common.c

plat/allwinner/sun50i_h6/sunxi_power.c

@@ -6,11 +6,116 @@
  */
 
 #include <debug.h>
+#include <delay_timer.h>
+#include <errno.h>
+#include <mmio.h>
+#include <mentor/mi2cv.h>
+#include <string.h>
+#include <sunxi_mmap.h>
+
+#define AXP805_ADDR	0x36
+#define AXP805_ID	0x03
+
+enum pmic_type {
+	NO_PMIC,
+	AXP805,
+};
+
+enum pmic_type pmic;
+
+static int sunxi_init_r_i2c(void)
+{
+	uint32_t reg;
+
+	/* get currently configured function for pins PL0 and PL1 */
+	reg = mmio_read_32(SUNXI_R_PIO_BASE + 0x00);
+	if ((reg & 0xff) == 0x33) {
+		NOTICE("PMIC: already configured for TWI\n");
+	}
+
+	/* switch pins PL0 and PL1 to I2C */
+	mmio_write_32(SUNXI_R_PIO_BASE + 0x00, (reg & ~0xff) | 0x33);
+
+	/* level 2 drive strength */
+	reg = mmio_read_32(SUNXI_R_PIO_BASE + 0x14);
+	mmio_write_32(SUNXI_R_PIO_BASE + 0x14, (reg & ~0x0f) | 0xa);
+
+	/* set both ports to pull-up */
+	reg = mmio_read_32(SUNXI_R_PIO_BASE + 0x1c);
+	mmio_write_32(SUNXI_R_PIO_BASE + 0x1c, (reg & ~0x0f) | 0x5);
+
+	/* assert & de-assert reset of R_I2C */
+	reg = mmio_read_32(SUNXI_R_PRCM_BASE + 0x19c);
+	mmio_write_32(SUNXI_R_PRCM_BASE + 0x19c, 0);
+	reg = mmio_read_32(SUNXI_R_PRCM_BASE + 0x19c);
+	mmio_write_32(SUNXI_R_PRCM_BASE + 0x19c, reg | 0x00010000);
+
+	/* un-gate R_I2C clock */
+	reg = mmio_read_32(SUNXI_R_PRCM_BASE + 0x19c);
+	mmio_write_32(SUNXI_R_PRCM_BASE + 0x19c, reg | 0x00000001);
+
+	/* call mi2cv driver */
+	i2c_init((void *)SUNXI_R_I2C_BASE);
+
+	return 0;
+}
+
+int axp_i2c_read(uint8_t chip, uint8_t reg, uint8_t *val)
+{
+	int ret;
+
+	ret = i2c_write(chip, 0, 0, &reg, 1);
+	if (ret)
+		return ret;
+
+	return i2c_read(chip, 0, 0, val, 1);
+}
+
+int axp_i2c_write(uint8_t chip, uint8_t reg, uint8_t val)
+{
+	return i2c_write(chip, reg, 1, &val, 1);
+}
+
+static int axp805_probe(void)
+{
+	int ret;
+	uint8_t val;
+
+	ret = axp_i2c_write(AXP805_ADDR, 0xff, 0x0);
+	if (ret) {
+		ERROR("PMIC: Cannot put AXP805 to master mode.\n");
+		return -EPERM;
+	}
+
+	ret = axp_i2c_read(AXP805_ADDR, AXP805_ID, &val);
+
+	if (!ret && ((val & 0xcf) == 0x40))
+		NOTICE("PMIC: AXP805 detected\n");
+	else if (ret) {
+		ERROR("PMIC: Cannot communicate with AXP805.\n");
+		return -EPERM;
+	} else {
+		ERROR("PMIC: Non-AXP805 chip attached at AXP805's address.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
 
 int sunxi_pmic_setup(void)
 {
-	/* STUB */
-	NOTICE("BL31: STUB PMIC setup code called\n");
+	int ret;
+
+	sunxi_init_r_i2c();
+
+	NOTICE("PMIC: Probing AXP805\n");
+	pmic = AXP805;
+
+	ret = axp805_probe();
+	if (ret)
+		pmic = NO_PMIC;
+	else
+		pmic = AXP805;
 
 	return 0;
 }