x1000: Correctly limit USB charging current

The way this was done before was wrong - limiting the charge
current is not enough since the device will draw additional
power to run. Use the AXP192's vbus current limit control to
stay compliant with the USB specification.

Change-Id: I91b84e3480a432e49bec53cf2a17e4e3444404a4

firmware/target/mips/ingenic_x1000/erosqnative/power-erosqnative.c

@@ -62,7 +62,8 @@ void power_init(void)
     /* FIXME: Copy paste from M3K. Probably not necessary */
     axp_modify(AXP_REG_DCDCMODE, 0, 0xc0);
 
-    /* Power on required supplies */
+    /* Power on required supplies
+     * TODO: This should be checked, though likely all but EXTEN are needed */
     axp_set_enabled_supplies(
         (1 << AXP_SUPPLY_EXTEN) |
         (1 << AXP_SUPPLY_DCDC1) |
@@ -81,6 +82,10 @@ void power_init(void)
         (1 << AXP_ADC_INTERNAL_TEMP) |
         (1 << AXP_ADC_APS_VOLTAGE));
 
+    /* Configure USB charging */
+    axp_set_vhold_level(4400);
+    usb_charging_maxcurrent_change(100);
+
     /* Delay to give power outputs time to stabilize.
      * With the power thread delay, this can apparently go as low as 50,
      * Keeping a higher value here just to ensure the bootloader works
@@ -91,7 +96,22 @@ void power_init(void)
 #ifdef HAVE_USB_CHARGING_ENABLE
 void usb_charging_maxcurrent_change(int maxcurrent)
 {
-    axp_set_charge_current(maxcurrent);
+    int vbus_limit;
+    int charge_current;
+
+    /* Note that the charge current setting is a maximum: it will be
+     * reduced dynamically by the AXP192 so the combined load is less
+     * than the set VBUS current limit. */
+    if(maxcurrent <= 100) {
+        vbus_limit = AXP_VBUS_LIMIT_100mA;
+        charge_current = 550;
+    } else {
+        vbus_limit = AXP_VBUS_LIMIT_500mA;
+        charge_current = 550;
+    }
+
+    axp_set_vbus_limit(vbus_limit);
+    axp_set_charge_current(charge_current);
 }
 #endif
 

firmware/target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c

@@ -78,6 +78,10 @@ void power_init(void)
         (1 << AXP_ADC_INTERNAL_TEMP) |
         (1 << AXP_ADC_APS_VOLTAGE));
 
+    /* Configure USB charging */
+    axp_set_vhold_level(4400);
+    usb_charging_maxcurrent_change(100);
+
     /* Short delay to give power outputs time to stabilize */
     mdelay(200);
 }
@@ -85,7 +89,22 @@ void power_init(void)
 #ifdef HAVE_USB_CHARGING_ENABLE
 void usb_charging_maxcurrent_change(int maxcurrent)
 {
-    axp_set_charge_current(maxcurrent);
+    int vbus_limit;
+    int charge_current;
+
+    /* Note that the charge current setting is a maximum: it will be
+     * reduced dynamically by the AXP192 so the combined load is less
+     * than the set VBUS current limit. */
+    if(maxcurrent <= 100) {
+        vbus_limit = AXP_VBUS_LIMIT_100mA;
+        charge_current = 550;
+    } else {
+        vbus_limit = AXP_VBUS_LIMIT_500mA;
+        charge_current = 550;
+    }
+
+    axp_set_vbus_limit(vbus_limit);
+    axp_set_charge_current(charge_current);
 }
 #endif
 

firmware/target/mips/ingenic_x1000/shanlingq1/power-shanlingq1.c

@@ -86,7 +86,7 @@ void power_init(void)
         (1 << AXP_SUPPLY_DCDC2) | /* LCD (1.2 V) */
         (1 << AXP_SUPPLY_DCDC3) | /* CPU (1.8 V) */
         (1 << AXP_SUPPLY_LDO2) |  /* Touchscreen (3.3 V) */
-        (1 << AXP_SUPPLY_LDO3));  /* not sure (2.5 V) */
+        (1 << AXP_SUPPLY_LDO3));  /* USB analog (2.5 V) */
 
     /* Enable required ADCs */
     axp_set_enabled_adcs(
@@ -98,6 +98,10 @@ void power_init(void)
         (1 << AXP_ADC_INTERNAL_TEMP) |
         (1 << AXP_ADC_APS_VOLTAGE));
 
+    /* Configure USB charging */
+    axp_set_vhold_level(4400);
+    usb_charging_maxcurrent_change(100);
+
     /* Delay to give power output time to stabilize */
     mdelay(20);
 }
@@ -105,7 +109,22 @@ void power_init(void)
 #ifdef HAVE_USB_CHARGING_ENABLE
 void usb_charging_maxcurrent_change(int maxcurrent)
 {
-    axp_set_charge_current(maxcurrent);
+    int vbus_limit;
+    int charge_current;
+
+    /* Note that the charge current setting is a maximum: it will be
+     * reduced dynamically by the AXP192 so the combined load is less
+     * than the set VBUS current limit. */
+    if(maxcurrent <= 100) {
+        vbus_limit = AXP_VBUS_LIMIT_100mA;
+        charge_current = 550;
+    } else {
+        vbus_limit = AXP_VBUS_LIMIT_500mA;
+        charge_current = 550;
+    }
+
+    axp_set_vbus_limit(vbus_limit);
+    axp_set_charge_current(charge_current);
 }
 #endif