sunxi: Add axp152 pmic support

Add support for the x-powers axp152 pmic which is found on most A10s boards
and enable it for the r7-tv-dongle board.

Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/drivers/power/axp152.c b/drivers/power/axp152.c
new file mode 100644
index 0000000..fa4ea05
--- /dev/null
+++ b/drivers/power/axp152.c
@@ -0,0 +1,97 @@
+/*
+ * (C) Copyright 2012
+ * Henrik Nordstrom <henrik@henriknordstrom.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#include <common.h>
+#include <i2c.h>
+#include <axp152.h>
+
+enum axp152_reg {
+	AXP152_CHIP_VERSION = 0x3,
+	AXP152_DCDC2_VOLTAGE = 0x23,
+	AXP152_DCDC3_VOLTAGE = 0x27,
+	AXP152_DCDC4_VOLTAGE = 0x2B,
+	AXP152_LDO2_VOLTAGE = 0x2A,
+	AXP152_SHUTDOWN = 0x32,
+};
+
+#define AXP152_POWEROFF			(1 << 7)
+
+static int axp152_write(enum axp152_reg reg, u8 val)
+{
+	return i2c_write(0x30, reg, 1, &val, 1);
+}
+
+static int axp152_read(enum axp152_reg reg, u8 *val)
+{
+	return i2c_read(0x30, reg, 1, val, 1);
+}
+
+static u8 axp152_mvolt_to_target(int mvolt, int min, int max, int div)
+{
+	if (mvolt < min)
+		mvolt = min;
+	else if (mvolt > max)
+		mvolt = max;
+
+	return (mvolt - min) / div;
+}
+
+int axp152_set_dcdc2(int mvolt)
+{
+	int rc;
+	u8 current, target;
+
+	target = axp152_mvolt_to_target(mvolt, 700, 2275, 25);
+
+	/* Do we really need to be this gentle? It has built-in voltage slope */
+	while ((rc = axp152_read(AXP152_DCDC2_VOLTAGE, &current)) == 0 &&
+	       current != target) {
+		if (current < target)
+			current++;
+		else
+			current--;
+		rc = axp152_write(AXP152_DCDC2_VOLTAGE, current);
+		if (rc)
+			break;
+	}
+	return rc;
+}
+
+int axp152_set_dcdc3(int mvolt)
+{
+	u8 target = axp152_mvolt_to_target(mvolt, 700, 3500, 25);
+
+	return axp152_write(AXP152_DCDC3_VOLTAGE, target);
+}
+
+int axp152_set_dcdc4(int mvolt)
+{
+	u8 target = axp152_mvolt_to_target(mvolt, 700, 3500, 25);
+
+	return axp152_write(AXP152_DCDC4_VOLTAGE, target);
+}
+
+int axp152_set_ldo2(int mvolt)
+{
+	u8 target = axp152_mvolt_to_target(mvolt, 700, 3500, 100);
+
+	return axp152_write(AXP152_LDO2_VOLTAGE, target);
+}
+
+int axp152_init(void)
+{
+	u8 ver;
+	int rc;
+
+	rc = axp152_read(AXP152_CHIP_VERSION, &ver);
+	if (rc)
+		return rc;
+
+	if (ver != 0x05)
+		return -1;
+
+	return 0;
+}