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From: Andreas Dannenberg <dannenberg@ti.com>
To: Sebastian Reichel <sre@kernel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Laurentiu Palcu <laurentiu.palcu@intel.com>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Ramakrishna Pallala <ramakrishna.pallala@intel.com>,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	Andreas Dannenberg <dannenberg@ti.com>
Subject: [PATCH v3 05/10] power: bq24257: Add SW-based approach for Power Good determination
Date: Fri, 11 Sep 2015 15:26:37 -0500	[thread overview]
Message-ID: <1442003202-1430-6-git-send-email-dannenberg@ti.com> (raw)
In-Reply-To: <1442003202-1430-1-git-send-email-dannenberg@ti.com>

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>
---
 drivers/power/bq24257_charger.c | 49 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 6 deletions(-)

diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c
index 55e4ee4..d7488cf 100644
--- a/drivers/power/bq24257_charger.c
+++ b/drivers/power/bq24257_charger.c
@@ -103,6 +103,7 @@ struct bq24257_device {
 	struct mutex lock; /* protect state data */
 
 	bool in_ilimit_autoset_disable;
+	bool pg_gpio_disable;
 };
 
 static bool bq24257_is_volatile_reg(struct device *dev, unsigned int reg)
@@ -356,7 +357,26 @@ 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_gpio_disable)
+		/*
+		 * 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;
+		}
+	else
+		state->power_good = !gpiod_get_value_cansleep(bq->pg);
 
 	return 0;
 }
@@ -676,7 +696,7 @@ static int 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");
+		dev_info(bq->dev, "could not probe PG pin\n");
 		return PTR_ERR(bq->pg);
 	}
 
@@ -810,10 +830,27 @@ 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 we
+	 * explicitly disable this feature for this device and instead use
+	 * a SW-based approach to determine the PG state.
+	 */
+	if (bq->chip == BQ24250)
+		bq->pg_gpio_disable = true;
+
+	/*
+	 * For devices that do have a dedicated PG pin go ahead and probe it,
+	 * using the SW-based approach as a fall back solution. Note that the
+	 * use of the dedicated pin is preferred.
+	 */
+	if (!bq->pg_gpio_disable) {
+		ret = bq24257_pg_gpio_probe(bq);
+		if (ret < 0) {
+			dev_info(bq->dev,
+				 "using SW-based power-good detection\n");
+			bq->pg_gpio_disable = true;
+		}
+	}
 
 	/* reset all registers to defaults */
 	ret = bq24257_field_write(bq, F_RESET, 1);
-- 
1.9.1


  parent reply	other threads:[~2015-09-11 20:26 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-11 20:26 [PATCH v3 00/10] power: bq24257: Add support for bq24250/bq24251 Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 01/10] dt: power: bq24257-charger: Cover additional devices Andreas Dannenberg
2015-09-14  6:11   ` Krzysztof Kozlowski
2015-09-14 13:54     ` Andreas Dannenberg
2015-09-15  7:56       ` Krzysztof Kozlowski
2015-09-15  9:05         ` Laurentiu Palcu
2015-09-15 12:51           ` Krzysztof Kozlowski
2015-09-15 13:57           ` Andreas Dannenberg
     [not found] ` <1442003202-1430-1-git-send-email-dannenberg-l0cyMroinI0@public.gmane.org>
2015-09-11 20:26   ` [PATCH v3 02/10] power: bq24257: Add basic support for bq24250/bq24251 Andreas Dannenberg
2015-09-11 20:26   ` [PATCH v3 06/10] power: bq24257: Add over voltage protection setting support Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 03/10] power: bq24257: Add bit definition for temp sense enable Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 04/10] power: bq24257: Allow manual setting of input current limit Andreas Dannenberg
2015-09-11 20:26 ` Andreas Dannenberg [this message]
2015-09-11 20:26 ` [PATCH v3 07/10] power: bq24257: Add input DPM voltage threshold setting support Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 08/10] power: bq24257: Allow input current limit sysfs access Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 09/10] power: bq24257: Add various device-specific sysfs properties Andreas Dannenberg
2015-09-11 20:26 ` [PATCH v3 10/10] power: bq24257: Add platform data based initialization Andreas Dannenberg

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