[PATCH 10/10] power: supply: bq25890: Add new linux,iinlim-percentage property

Hans de Goede
2022-11-27T18:03:57Z

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>
---
drivers/power/supply/bq25890_charger.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c
index b0d07ff24ace..2bd7721b969f 100644
--- 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);
@@ -1390,6 +1403,11 @@ 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);

+ /* Optional, left at 100% if property is not present */
+ bq->iinlim_percentage = 100;
+ device_property_read_u32(bq->dev, "linux,iinlim-percentage",
+ &bq->iinlim_percentage);
+
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");
--
2.38.1