From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Dannenberg Subject: [PATCH v3 05/10] power: bq24257: Add SW-based approach for Power Good determination Date: Fri, 11 Sep 2015 15:26:37 -0500 Message-ID: <1442003202-1430-6-git-send-email-dannenberg@ti.com> References: <1442003202-1430-1-git-send-email-dannenberg@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1442003202-1430-1-git-send-email-dannenberg@ti.com> Sender: linux-pm-owner@vger.kernel.org To: Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse , Laurentiu Palcu , Krzysztof Kozlowski Cc: Ramakrishna Pallala , linux-pm@vger.kernel.org, devicetree@vger.kernel.org, Andreas Dannenberg List-Id: devicetree@vger.kernel.org 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 --- 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