power: supply: bq25890: Add new linux,iinlim-percentage property

Some devices, such as the Lenovo Yoga Tab 3 Pro (YT3-X90F) have
multiple batteries with a separate bq25890 charger for each battery.

This requires the maximum current the external power-supply can deliver
to be divided over the chargers. The Android vendor kernel shipped
on the YT3-X90F divides this current with a 40/60 percent split so that
batteries are done charging at approx. the same time if both were fully
empty at the start.

Add support for a new "linux,iinlim-percentage" percentage property which
can be set to indicate that a bq25890 charger should only use that
percentage of the external power-supply's maximum current.

So far this new property is only used on x86/ACPI (non devicetree) devs,
IOW it is not used in actual devicetree files. The devicetree-bindings
maintainers have requested properties like these to not be added to the
devicetree-bindings, so the new property is deliberately not added
to the existing devicetree-bindings.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c
index aff55bf..bfe08d7 100644 (file)
--- a/drivers/power/supply/bq25890_charger.c
+++ b/drivers/power/supply/bq25890_charger.c
@@ -126,6 +126,7 @@ struct bq25890_device {
        bool read_back_init_data;
        bool force_hiz;
        u32 pump_express_vbus_max;
+       u32 iinlim_percentage;
        enum bq25890_chip_version chip_version;
        struct bq25890_init_data init_data;
        struct bq25890_state state;
@@ -727,6 +728,18 @@ static int bq25890_power_supply_property_is_writeable(struct power_supply *psy,
        }
 }
 
+/*
+ * If there are multiple chargers the maximum current the external power-supply
+ * can deliver needs to be divided over the chargers. This is done according
+ * to the bq->iinlim_percentage setting.
+ */
+static int bq25890_charger_get_scaled_iinlim_regval(struct bq25890_device *bq,
+                                                   int iinlim_ua)
+{
+       iinlim_ua = iinlim_ua * bq->iinlim_percentage / 100;
+       return bq25890_find_idx(iinlim_ua, TBL_IINLIM);
+}
+
 /* On the BQ25892 try to get charger-type info from our supplier */
 static void bq25890_charger_external_power_changed(struct power_supply *psy)
 {
@@ -745,7 +758,7 @@ static void bq25890_charger_external_power_changed(struct power_supply *psy)
 
        switch (val.intval) {
        case POWER_SUPPLY_USB_TYPE_DCP:
-               input_current_limit = bq25890_find_idx(2000000, TBL_IINLIM);
+               input_current_limit = bq25890_charger_get_scaled_iinlim_regval(bq, 2000000);
                if (bq->pump_express_vbus_max) {
                        queue_delayed_work(system_power_efficient_wq,
                                           &bq->pump_express_work,
@@ -754,11 +767,11 @@ static void bq25890_charger_external_power_changed(struct power_supply *psy)
                break;
        case POWER_SUPPLY_USB_TYPE_CDP:
        case POWER_SUPPLY_USB_TYPE_ACA:
-               input_current_limit = bq25890_find_idx(1500000, TBL_IINLIM);
+               input_current_limit = bq25890_charger_get_scaled_iinlim_regval(bq, 1500000);
                break;
        case POWER_SUPPLY_USB_TYPE_SDP:
        default:
-               input_current_limit = bq25890_find_idx(500000, TBL_IINLIM);
+               input_current_limit = bq25890_charger_get_scaled_iinlim_regval(bq, 500000);
        }
 
        bq25890_field_write(bq, F_IINLIM, input_current_limit);
@@ -1378,6 +1391,7 @@ static int bq25890_fw_probe(struct bq25890_device *bq)
        int ret;
        struct bq25890_init_data *init = &bq->init_data;
        const char *str;
+       u32 val;
 
        ret = device_property_read_string(bq->dev, "linux,secondary-charger-name", &str);
        if (ret == 0) {
@@ -1390,6 +1404,17 @@ static int bq25890_fw_probe(struct bq25890_device *bq)
        device_property_read_u32(bq->dev, "linux,pump-express-vbus-max",
                                 &bq->pump_express_vbus_max);
 
+       ret = device_property_read_u32(bq->dev, "linux,iinlim-percentage", &val);
+       if (ret == 0) {
+               if (val > 100) {
+                       dev_err(bq->dev, "Error linux,iinlim-percentage %u > 100\n", val);
+                       return -EINVAL;
+               }
+               bq->iinlim_percentage = val;
+       } else {
+               bq->iinlim_percentage = 100;
+       }
+
        bq->skip_reset = device_property_read_bool(bq->dev, "linux,skip-reset");
        bq->read_back_init_data = device_property_read_bool(bq->dev,
                                                "linux,read-back-settings");