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authorAndreas Dannenberg <dannenberg@ti.com>2015-09-28 17:33:56 -0500
committerSebastian Reichel <sre@kernel.org>2015-09-29 16:53:37 +0200
commit7c071a0a08f6c6327b86df918d2dda728355d457 (patch)
tree47a597aa6e441df1a5249afed0712141171cdcf9 /drivers/power
parenteb9fbcc6693ad73745198bbfc7c2b0e881580f59 (diff)
downloadlinux-7c071a0a08f6c6327b86df918d2dda728355d457.tar.bz2
power: bq24257: Add SW-based approach for Power Good determination
A software-based approach for determining the charger's input voltage "Power Good" state is introduced for devices like the bq24250 which don't have a dedicated hardware pin for that purpose. This SW-based approach is also used for other devices (with dedicated PG pin) as a fall back solution if that pin is not configured to be used through "pg-gpios". Signed-off-by: Andreas Dannenberg <dannenberg@ti.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/bq24257_charger.c56
1 files changed, 45 insertions, 11 deletions
diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c
index 7bbff806624f..15e0e9395371 100644
--- a/drivers/power/bq24257_charger.c
+++ b/drivers/power/bq24257_charger.c
@@ -359,7 +359,26 @@ static int bq24257_get_chip_state(struct bq24257_device *bq,
state->fault = ret;
- state->power_good = !gpiod_get_value_cansleep(bq->pg);
+ if (bq->pg)
+ state->power_good = !gpiod_get_value_cansleep(bq->pg);
+ else
+ /*
+ * If we have a chip without a dedicated power-good GPIO or
+ * some other explicit bit that would provide this information
+ * assume the power is good if there is no supply related
+ * fault - and not good otherwise. There is a possibility for
+ * other errors to mask that power in fact is not good but this
+ * is probably the best we can do here.
+ */
+ switch (state->fault) {
+ case FAULT_INPUT_OVP:
+ case FAULT_INPUT_UVLO:
+ case FAULT_INPUT_LDO_LOW:
+ state->power_good = false;
+ break;
+ default:
+ state->power_good = true;
+ }
return 0;
}
@@ -651,15 +670,21 @@ static int bq24257_power_supply_init(struct bq24257_device *bq)
return PTR_ERR_OR_ZERO(bq->charger);
}
-static int bq24257_pg_gpio_probe(struct bq24257_device *bq)
+static void bq24257_pg_gpio_probe(struct bq24257_device *bq)
{
- bq->pg = devm_gpiod_get_index(bq->dev, BQ24257_PG_GPIO, 0, GPIOD_IN);
- if (IS_ERR(bq->pg)) {
- dev_err(bq->dev, "could not probe PG pin\n");
- return PTR_ERR(bq->pg);
+ bq->pg = devm_gpiod_get_optional(bq->dev, BQ24257_PG_GPIO, GPIOD_IN);
+
+ if (PTR_ERR(bq->pg) == -EPROBE_DEFER) {
+ dev_info(bq->dev, "probe retry requested for PG pin\n");
+ return;
+ } else if (IS_ERR(bq->pg)) {
+ dev_err(bq->dev, "error probing PG pin\n");
+ bq->pg = NULL;
+ return;
}
- return 0;
+ if (bq->pg)
+ dev_dbg(bq->dev, "probed PG pin = %d\n", desc_to_gpio(bq->pg));
}
static int bq24257_fw_probe(struct bq24257_device *bq)
@@ -789,10 +814,19 @@ static int bq24257_probe(struct i2c_client *client,
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)
- return ret;
+ /*
+ * The BQ24250 doesn't have a dedicated Power Good (PG) pin so let's
+ * not probe for it and instead use a SW-based approach to determine
+ * the PG state. We also use a SW-based approach for all other devices
+ * if the PG pin is either not defined or can't be probed.
+ */
+ if (bq->chip != BQ24250)
+ bq24257_pg_gpio_probe(bq);
+
+ if (PTR_ERR(bq->pg) == -EPROBE_DEFER)
+ return PTR_ERR(bq->pg);
+ else if (!bq->pg)
+ dev_info(bq->dev, "using SW-based power-good detection\n");
/* reset all registers to defaults */
ret = bq24257_field_write(bq, F_RESET, 1);