power: pm8921-charger: Do not reset USB input current limit
When booting without a battery there is a possiblity of browning
out a device if the input current limit of USB is reset during
the device probe.
Fix this by removing the corresponding code and let the USB OTG
driver reset the current limit when initalizing. Also add a check
for the vbus_draw API to reject any settings from the OTG driver
when there is no battery present and no other available power
source but VBUS.
Change-Id: I3f275f69ce8dfe14c35562cb75e1043ac769ce07
Signed-off-by: David Keitel <dkeitel@codeaurora.org>
diff --git a/drivers/power/pm8921-charger.c b/drivers/power/pm8921-charger.c
index e7797b1..b1a16bb 100644
--- a/drivers/power/pm8921-charger.c
+++ b/drivers/power/pm8921-charger.c
@@ -1555,6 +1555,26 @@
pr_debug("Enter charge=%d\n", mA);
+ if (!the_chip) {
+ pr_err("chip not yet initalized\n");
+ return;
+ }
+
+ /*
+ * Reject VBUS requests if USB connection is the only available
+ * power source. This makes sure that if booting without
+ * battery the iusb_max value is not decreased avoiding potential
+ * brown_outs.
+ *
+ * This would also apply when the battery has been
+ * removed from the running system.
+ */
+ if (!get_prop_batt_present(the_chip)
+ && !is_dc_chg_plugged_in(the_chip)) {
+ pr_err("rejected: no other power source connected\n");
+ return;
+ }
+
if (usb_max_current && mA > usb_max_current) {
pr_warn("restricting usb current to %d instead of %d\n",
usb_max_current, mA);
@@ -3363,13 +3383,6 @@
return rc;
}
- /* init with the lowest USB current */
- rc = pm_chg_iusbmax_set(chip, 0);
- if (rc) {
- pr_err("Failed to set usb max to %d rc=%d\n", 0, rc);
- return rc;
- }
-
if (chip->safety_time != 0) {
rc = pm_chg_tchg_max_set(chip, chip->safety_time);
if (rc) {