From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Dannenberg Subject: [PATCH v6 07/14] power: bq24257: Add SW-based approach for Power Good determination Date: Thu, 24 Sep 2015 22:26:51 -0500 Message-ID: <1443151618-29742-8-git-send-email-dannenberg@ti.com> References: <1443151618-29742-1-git-send-email-dannenberg@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1443151618-29742-1-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, linux-api@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, 39 insertions(+), 10 deletions(-) diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c index 6daaac2..9d2b412 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; } @@ -649,15 +668,18 @@ static int bq24257_power_supply_init(struct bq24257_device *bq) return 0; } -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); + bq->pg = devm_gpiod_get_optional(bq->dev, BQ24257_PG_GPIO, GPIOD_IN); + if (IS_ERR(bq->pg)) { - dev_err(bq->dev, "could not probe PG pin\n"); - return PTR_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", desc_to_gpio(bq->pg)); } static int bq24257_fw_probe(struct bq24257_device *bq) @@ -787,10 +809,17 @@ 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 (!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); -- 1.9.1