sun6i: axp221: Add axp221_get_sid function

For sun6i the SID is stored in the pmic, rather then in the SoC itself,
add a function to retreive the sid.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

drivers/power/axp221.c

@@ -184,3 +184,30 @@ int axp221_init(void)
 
 	return 0;
 }
+
+int axp221_get_sid(unsigned int *sid)
+{
+	u8 *dest = (u8 *)sid;
+	int i, ret;
+
+	ret = axp221_init();
+	if (ret)
+		return ret;
+
+	ret = p2wi_write(AXP221_PAGE, 1);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < 16; i++) {
+		ret = p2wi_read(AXP221_SID + i, &dest[i]);
+		if (ret)
+			return ret;
+	}
+
+	p2wi_write(AXP221_PAGE, 0);
+
+	for (i = 0; i < 4; i++)
+		sid[i] = be32_to_cpu(sid[i]);
+
+	return 0;
+}

include/axp221.h

@@ -10,6 +10,7 @@
 #define AXP221_CTRL_ADDR 0x3e
 #define AXP221_INIT_DATA 0x3e
 
+/* Page 0 addresses */
 #define AXP221_CHIP_ID		0x03
 #define AXP221_OUTPUT_CTRL1	0x10
 #define AXP221_OUTPUT_CTRL1_ALDO1_EN	(1 << 6)
@@ -34,6 +35,10 @@
 #define AXP221_ALDO1_CTRL	0x28
 #define AXP221_ALDO2_CTRL	0x29
 #define AXP221_ALDO3_CTRL	0x2a
+#define AXP221_PAGE		0xff
+
+/* Page 1 addresses */
+#define AXP221_SID		0x20
 
 int axp221_set_dcdc1(unsigned int mvolt);
 int axp221_set_dcdc2(unsigned int mvolt);
@@ -48,3 +53,4 @@ int axp221_set_aldo1(unsigned int mvolt);
 int axp221_set_aldo2(unsigned int mvolt);
 int axp221_set_aldo3(unsigned int mvolt);
 int axp221_init(void);
+int axp221_get_sid(unsigned int *sid);