ab8500-bm: Add usb power path support

AB8540 supports power path function in USB charging mode for fast
power up with dead and weak battery, and it could extend
the battery age.

When USB charging starts, if the Vbattrue is below than SW cut off
voltage, power path and pre-charge should be enabled. If Vbattrue
is higher than SW cut off voltage, power path and pre-charge should
be disabled. This is to make sure full current to battery charge.
At the end of charge, power path should be enable again to reduce
charging the battery again.

Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/power/ab8500_charger.c b/drivers/power/ab8500_charger.c
index 6fea4fdf8701..f249a65b02e1 100644
--- a/drivers/power/ab8500_charger.c
+++ b/drivers/power/ab8500_charger.c
@@ -1925,6 +1925,67 @@ static int ab8500_charger_update_charger_current(struct ux500_charger *charger,
         return ret;
 }
 
+/**
+ * ab8540_charger_power_path_enable() - enable usb power path mode
+ * @charger:    pointer to the ux500_charger structure
+ * @enable:     enable/disable flag
+ *
+ * Enable or disable the power path for usb mode
+ * Returns error code in case of failure else 0(on success)
+ */
+static int ab8540_charger_power_path_enable(struct ux500_charger *charger,
+                bool enable)
+{
+        int ret;
+        struct ab8500_charger *di;
+
+        if (charger->psy.type == POWER_SUPPLY_TYPE_USB)
+                di = to_ab8500_charger_usb_device_info(charger);
+        else
+                return -ENXIO;
+
+        ret = abx500_mask_and_set_register_interruptible(di->dev,
+                                AB8500_CHARGER, AB8540_USB_PP_MODE_REG,
+                                BUS_POWER_PATH_MODE_ENA, enable);
+        if (ret) {
+                dev_err(di->dev, "%s write failed\n", __func__);
+                return ret;
+        }
+
+        return ret;
+}
+
+
+/**
+ * ab8540_charger_usb_pre_chg_enable() - enable usb pre change
+ * @charger:    pointer to the ux500_charger structure
+ * @enable:     enable/disable flag
+ *
+ * Enable or disable the pre-chage for usb mode
+ * Returns error code in case of failure else 0(on success)
+ */
+static int ab8540_charger_usb_pre_chg_enable(struct ux500_charger *charger,
+                bool enable)
+{
+        int ret;
+        struct ab8500_charger *di;
+
+        if (charger->psy.type == POWER_SUPPLY_TYPE_USB)
+                di = to_ab8500_charger_usb_device_info(charger);
+        else
+                return -ENXIO;
+
+        ret = abx500_mask_and_set_register_interruptible(di->dev,
+                                AB8500_CHARGER, AB8540_USB_PP_CHR_REG,
+                                BUS_POWER_PATH_PRECHG_ENA, enable);
+        if (ret) {
+                dev_err(di->dev, "%s write failed\n", __func__);
+                return ret;
+        }
+
+        return ret;
+}
+
 static int ab8500_charger_get_ext_psy_data(struct device *dev, void *data)
 {
         struct power_supply *psy;
@@ -3201,6 +3262,23 @@ static int ab8500_charger_init_hw_registers(struct ab8500_charger *di)
         if (ret < 0)
                 dev_err(di->dev, "%s mask and set failed\n", __func__);
 
+        if (is_ab8540(di->parent)) {
+                ret = abx500_mask_and_set_register_interruptible(di->dev,
+                        AB8500_CHARGER, AB8540_USB_PP_MODE_REG,
+                        BUS_VSYS_VOL_SELECT_MASK, BUS_VSYS_VOL_SELECT_3P6V);
+                if (ret) {
+                        dev_err(di->dev, "failed to setup usb power path vsys voltage\n");
+                        goto out;
+                }
+                ret = abx500_mask_and_set_register_interruptible(di->dev,
+                        AB8500_CHARGER, AB8540_USB_PP_CHR_REG,
+                        BUS_PP_PRECHG_CURRENT_MASK, 0);
+                if (ret) {
+                        dev_err(di->dev, "failed to setup usb power path prechage current\n");
+                        goto out;
+                }
+        }
+
 out:
         return ret;
 }
@@ -3484,6 +3562,8 @@ static int ab8500_charger_probe(struct platform_device *pdev)
         di->usb_chg.ops.check_enable = &ab8500_charger_usb_check_enable;
         di->usb_chg.ops.kick_wd = &ab8500_charger_watchdog_kick;
         di->usb_chg.ops.update_curr = &ab8500_charger_update_charger_current;
+        di->usb_chg.ops.pp_enable = &ab8540_charger_power_path_enable;
+        di->usb_chg.ops.pre_chg_enable = &ab8540_charger_usb_pre_chg_enable;
         di->usb_chg.max_out_volt = ab8500_charger_voltage_map[
                 ARRAY_SIZE(ab8500_charger_voltage_map) - 1];
         di->usb_chg.max_out_curr = ab8500_charger_current_map[
@@ -3491,6 +3571,7 @@ static int ab8500_charger_probe(struct platform_device *pdev)
         di->usb_chg.wdt_refresh = CHG_WD_INTERVAL;
         di->usb_chg.enabled = di->bm->usb_enabled;
         di->usb_chg.external = false;
+        di->usb_chg.power_path = di->bm->usb_power_path;
         di->usb_state.usb_current = -1;
 
         /* Create a work queue for the charger */