ab8500-charger: AB workaround for invalid charger

AB8500 refuses to start charging when some types of non standard
chargers are connected. This change force the AB to start charging.

Signed-off-by: Henrik Sölver <henrik.solver@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Yvan FILLION <yvan.fillion@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Tested-by: Yvan FILLION <yvan.fillion@stericsson.com>

1 files changed, 55 insertions, 4 deletions

diff --git a/drivers/power/ab8500_charger.c b/drivers/power/ab8500_charger.c
index 43ec82ba4275..4c66172aaa64 100644
--- a/drivers/power/ab8500_charger.c
+++ b/drivers/power/ab8500_charger.c
@@ -207,6 +207,7 @@ struct ab8500_charger_usb_state {
  * @usb_device_is_unrecognised  USB device is unrecognised by the hardware
  * @autopower           Indicate if we should have automatic pwron after pwrloss
  * @autopower_cfg       platform specific power config support for "pwron after pwrloss"
+ * @invalid_charger_detect_state State when forcing AB to use invalid charger
  * @parent:             Pointer to the struct ab8500
  * @gpadc:              Pointer to the struct gpadc
  * @bm:                 Platform specific battery management information
@@ -251,6 +252,7 @@ struct ab8500_charger {
         bool usb_device_is_unrecognised;
         bool autopower;
         bool autopower_cfg;
+        int invalid_charger_detect_state;
         struct ab8500 *parent;
         struct ab8500_gpadc *gpadc;
         struct abx500_bm_data *bm;
@@ -659,7 +661,6 @@ static int ab8500_charger_max_usb_curr(struct ab8500_charger *di,
                         break;
                 }
         case USB_STAT_HM_IDGND:
-        case USB_STAT_NOT_VALID_LINK:
                 dev_err(di->dev, "USB Type - Charging not allowed\n");
                 di->max_usb_in_curr = USB_CH_IP_CUR_LVL_0P05;
                 ret = -ENXIO;
@@ -688,6 +689,9 @@ static int ab8500_charger_max_usb_curr(struct ab8500_charger *di,
                 di->max_usb_in_curr = USB_CH_IP_CUR_LVL_0P5;
                 dev_dbg(di->dev, "USB Type - 0x%02x MaxCurr: %d", link_status,
                                 di->max_usb_in_curr);
+        case USB_STAT_NOT_VALID_LINK:
+                dev_err(di->dev, "USB Type invalid - try charging anyway\n");
+                di->max_usb_in_curr = USB_CH_IP_CUR_LVL_0P5;
                 break;
 
         default:
@@ -1957,7 +1961,9 @@ static void ab8500_charger_usb_link_attach_work(struct work_struct *work)
  */
 static void ab8500_charger_usb_link_status_work(struct work_struct *work)
 {
+        int detected_chargers;
         int ret;
+        u8 val;
 
         struct ab8500_charger *di = container_of(work,
                 struct ab8500_charger, usb_link_status_work);
@@ -1967,11 +1973,55 @@ static void ab8500_charger_usb_link_status_work(struct work_struct *work)
          * synchronously, we have the check if  is
          * connected by reading the status register
          */
-        ret = ab8500_charger_detect_chargers(di);
-        if (ret < 0)
+        detected_chargers = ab8500_charger_detect_chargers(di);
+        if (detected_chargers < 0)
                 return;
 
-        if (!(ret & USB_PW_CONN)) {
+        /*
+         * Some chargers that breaks the USB spec is
+         * identified as invalid by AB8500 and it refuse
+         * to start the charging process. but by jumping
+         * thru a few hoops it can be forced to start.
+         */
+        ret = abx500_get_register_interruptible(di->dev, AB8500_USB,
+                        AB8500_USB_LINE_STAT_REG, &val);
+        if (ret >= 0)
+                dev_dbg(di->dev, "UsbLineStatus register = 0x%02x\n", val);
+        else
+                dev_dbg(di->dev, "Error reading USB link status\n");
+
+        if (detected_chargers & USB_PW_CONN) {
+                if (((val & AB8500_USB_LINK_STATUS) >> 3) == USB_STAT_NOT_VALID_LINK &&
+                                di->invalid_charger_detect_state == 0) {
+                        dev_dbg(di->dev, "Invalid charger detected, state= 0\n");
+                        /*Enable charger*/
+                        abx500_mask_and_set_register_interruptible(di->dev,
+                                        AB8500_CHARGER, AB8500_USBCH_CTRL1_REG, 0x01, 0x01);
+                        /*Enable charger detection*/
+                        abx500_mask_and_set_register_interruptible(di->dev, AB8500_USB,
+                                        AB8500_MCH_IPT_CURLVL_REG, 0x01, 0x01);
+                        di->invalid_charger_detect_state = 1;
+                        /*exit and wait for new link status interrupt.*/
+                        return;
+
+                }
+                if (di->invalid_charger_detect_state == 1) {
+                        dev_dbg(di->dev, "Invalid charger detected, state= 1\n");
+                        /*Stop charger detection*/
+                        abx500_mask_and_set_register_interruptible(di->dev, AB8500_USB,
+                                        AB8500_MCH_IPT_CURLVL_REG, 0x01, 0x00);
+                        /*Check link status*/
+                        ret = abx500_get_register_interruptible(di->dev, AB8500_USB,
+                                        AB8500_USB_LINE_STAT_REG, &val);
+                        dev_dbg(di->dev, "USB link status= 0x%02x\n",
+                                        (val & AB8500_USB_LINK_STATUS) >> 3);
+                        di->invalid_charger_detect_state = 2;
+                }
+        } else {
+                di->invalid_charger_detect_state = 0;
+        }
+
+        if (!(detected_chargers & USB_PW_CONN)) {
                 di->vbus_detected = 0;
                 ab8500_charger_set_usb_connected(di, false);
                 ab8500_power_supply_changed(di, &di->usb_chg.psy);
@@ -2884,6 +2934,7 @@ static int ab8500_charger_probe(struct platform_device *pdev)
         spin_lock_init(&di->usb_state.usb_lock);
 
         di->autopower = false;
+        di->invalid_charger_detect_state = 0;
 
         /* AC supply */
         /* power_supply base class */