A new optional device property called "ti,current-limit" is introduced
to allow disabling the D+/D- USB signal-based charger type auto-
detection algorithm used to set the input current limit and instead to
use a fixed input current limit.

Signed-off-by: Andreas Dannenberg <dannenb...@ti.com>
---
 drivers/power/bq24257_charger.c | 100 +++++++++++++++++++++++++++++++---------
 1 file changed, 79 insertions(+), 21 deletions(-)

diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c
index 670ca57..d83898f 100644
--- a/drivers/power/bq24257_charger.c
+++ b/drivers/power/bq24257_charger.c
@@ -74,6 +74,7 @@ struct bq24257_init_data {
        u8 ichg;        /* charge current      */
        u8 vbat;        /* regulation voltage  */
        u8 iterm;       /* termination current */
+       u8 in_ilimit;   /* input current limit */
 };
 
 struct bq24257_state {
@@ -100,6 +101,8 @@ struct bq24257_device {
        struct bq24257_state state;
 
        struct mutex lock; /* protect state data */
+
+       bool in_ilimit_autoset_disable;
 };
 
 static bool bq24257_is_volatile_reg(struct device *dev, unsigned int reg)
@@ -188,6 +191,12 @@ static const u32 bq24257_iterm_map[] = {
 
 #define BQ24257_ITERM_MAP_SIZE         ARRAY_SIZE(bq24257_iterm_map)
 
+static const u32 bq24257_iilimit_map[] = {
+       100000, 150000, 500000, 900000, 1500000, 2000000
+};
+
+#define BQ24257_IILIMIT_MAP_SIZE       ARRAY_SIZE(bq24257_iilimit_map)
+
 static int bq24257_field_read(struct bq24257_device *bq,
                              enum bq24257_fields field_id)
 {
@@ -479,24 +488,35 @@ static void bq24257_handle_state_change(struct 
bq24257_device *bq,
        old_state = bq->state;
        mutex_unlock(&bq->lock);
 
-       if (!new_state->power_good) {                        /* power removed */
-               cancel_delayed_work_sync(&bq->iilimit_setup_work);
-
-               /* activate D+/D- port detection algorithm */
-               ret = bq24257_field_write(bq, F_DPDM_EN, 1);
-               if (ret < 0)
-                       goto error;
+       /*
+        * Handle BQ2425x state changes observing whether the D+/D- based input
+        * current limit autoset functionality is enabled.
+        */
+       if (!new_state->power_good) {
+               dev_dbg(bq->dev, "Power removed\n");
+               if (!bq->in_ilimit_autoset_disable) {
+                       cancel_delayed_work_sync(&bq->iilimit_setup_work);
 
-               reset_iilimit = true;
-       } else if (!old_state.power_good) {                 /* power inserted */
-               config_iilimit = true;
-       } else if (new_state->fault == FAULT_NO_BAT) {     /* battery removed */
-               cancel_delayed_work_sync(&bq->iilimit_setup_work);
+                       /* activate D+/D- port detection algorithm */
+                       ret = bq24257_field_write(bq, F_DPDM_EN, 1);
+                       if (ret < 0)
+                               goto error;
 
-               reset_iilimit = true;
-       } else if (old_state.fault == FAULT_NO_BAT) {    /* battery connected */
-               config_iilimit = true;
-       } else if (new_state->fault == FAULT_TIMER) { /* safety timer expired */
+                       reset_iilimit = true;
+               }
+       } else if (!old_state.power_good) {
+               dev_dbg(bq->dev, "Power inserted\n");
+               config_iilimit = !bq->in_ilimit_autoset_disable;
+       } else if (new_state->fault == FAULT_NO_BAT) {
+               dev_warn(bq->dev, "Battery removed\n");
+               if (!bq->in_ilimit_autoset_disable) {
+                       cancel_delayed_work_sync(&bq->iilimit_setup_work);
+                       reset_iilimit = true;
+               }
+       } else if (old_state.fault == FAULT_NO_BAT) {
+               dev_warn(bq->dev, "Battery connected\n");
+               config_iilimit = !bq->in_ilimit_autoset_disable;
+       } else if (new_state->fault == FAULT_TIMER) {
                dev_err(bq->dev, "Safety timer expired! Battery dead?\n");
        }
 
@@ -581,7 +601,16 @@ static int bq24257_hw_init(struct bq24257_device *bq)
        bq->state = state;
        mutex_unlock(&bq->lock);
 
-       if (!state.power_good)
+       if (bq->in_ilimit_autoset_disable) {
+               dev_dbg(bq->dev, "manually setting iilimit = %d\n",
+                               bq->init_data.in_ilimit);
+
+               /* program fixed input current limit */
+               ret = bq24257_field_write(bq, F_IILIMIT,
+                                         bq->init_data.in_ilimit);
+               if (ret < 0)
+                       return ret;
+       } else if (!state.power_good)
                /* activate D+/D- detection algorithm */
                ret = bq24257_field_write(bq, F_DPDM_EN, 1);
        else if (state.fault != FAULT_NO_BAT)
@@ -659,6 +688,7 @@ static int bq24257_fw_probe(struct bq24257_device *bq)
        int ret;
        u32 property;
 
+       /* Required properties */
        ret = device_property_read_u32(bq->dev, "ti,charge-current", &property);
        if (ret < 0)
                return ret;
@@ -682,6 +712,22 @@ static int bq24257_fw_probe(struct bq24257_device *bq)
        bq->init_data.iterm = bq24257_find_idx(property, bq24257_iterm_map,
                                               BQ24257_ITERM_MAP_SIZE);
 
+       /* Optional properties. If not provided use reasonable default. */
+       ret = device_property_read_u32(bq->dev, "ti,current-limit",
+                                      &property);
+       if (ret < 0)
+               /*
+                * Explicitly set a default value which will be needed for
+                * devices that don't support the automatic setting of the input
+                * current limit through the charger type detection mechanism.
+                */
+               bq->init_data.in_ilimit = IILIMIT_500;
+       else {
+               bq->in_ilimit_autoset_disable = true;
+               bq->init_data.in_ilimit = bq24257_find_idx(property,
+                               bq24257_iilimit_map, BQ24257_IILIMIT_MAP_SIZE);
+       }
+
        return 0;
 }
 
@@ -740,8 +786,6 @@ static int bq24257_probe(struct i2c_client *client,
 
        i2c_set_clientdata(client, bq);
 
-       INIT_DELAYED_WORK(&bq->iilimit_setup_work, bq24257_iilimit_setup_work);
-
        if (!dev->platform_data) {
                ret = bq24257_fw_probe(bq);
                if (ret < 0) {
@@ -752,6 +796,18 @@ static int bq24257_probe(struct i2c_client *client,
                return -ENODEV;
        }
 
+       /*
+        * The BQ24250 doesn't support the D+/D- based charger type detection
+        * used for the automatic setting of the input current limit setting so
+        * explicitly disable that feature.
+        */
+       if (bq->chip == BQ24250)
+               bq->in_ilimit_autoset_disable = true;
+
+       if (!bq->in_ilimit_autoset_disable)
+               INIT_DELAYED_WORK(&bq->iilimit_setup_work,
+                               bq24257_iilimit_setup_work);
+
        /* we can only check Power Good status by probing the PG pin */
        ret = bq24257_pg_gpio_probe(bq);
        if (ret < 0)
@@ -804,7 +860,8 @@ static int bq24257_remove(struct i2c_client *client)
 {
        struct bq24257_device *bq = i2c_get_clientdata(client);
 
-       cancel_delayed_work_sync(&bq->iilimit_setup_work);
+       if (!bq->in_ilimit_autoset_disable)
+               cancel_delayed_work_sync(&bq->iilimit_setup_work);
 
        power_supply_unregister(bq->charger);
 
@@ -819,7 +876,8 @@ static int bq24257_suspend(struct device *dev)
        struct bq24257_device *bq = dev_get_drvdata(dev);
        int ret = 0;
 
-       cancel_delayed_work_sync(&bq->iilimit_setup_work);
+       if (!bq->in_ilimit_autoset_disable)
+               cancel_delayed_work_sync(&bq->iilimit_setup_work);
 
        /* reset all registers to default (and activate standalone mode) */
        ret = bq24257_field_write(bq, F_RESET, 1);
-- 
1.9.1

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