Commit 7c071a0a authored by Andreas Dannenberg's avatar Andreas Dannenberg Committed by Sebastian Reichel
Browse files

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: default avatarAndreas Dannenberg <dannenberg@ti.com>
Reviewed-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
parent eb9fbcc6

drivers/power/bq24257_charger.c

+45 −11
Original line number Diff line number Diff line
@@ -359,7 +359,26 @@ static int bq24257_get_chip_state(struct bq24257_device *bq, 


	state->fault = ret;



	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);

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