From 0cfbfde65aec4cd9ae4e7971f8a3e42c69e8e24f Mon Sep 17 00:00:00 2001 From: Andreas Dannenberg Date: Mon, 28 Sep 2015 17:33:59 -0500 Subject: [PATCH] power: bq24257: Allow input current limit sysfs access This patch allows reading and writing of the input current limit through the power supply's input_current_limit sysfs property. This allows userspace to see what charger was detected (if the D+/D- USB signal- based charger type detection is enabled) and to re-configure the maximum current drawn from the external supply at runtime based on system-level knowledge or user input. Note that upon charger disconnection and re-connection the limit configured through firmware becomes active again (or the D+/D- USB signal-based charger detection will be run again). Signed-off-by: Andreas Dannenberg Reviewed-by: Krzysztof Kozlowski Signed-off-by: Sebastian Reichel --- drivers/power/bq24257_charger.c | 85 ++++++++++++++++++++++++++++++--- 1 file changed, 79 insertions(+), 6 deletions(-) diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c index ebb22f3be487..db719bf96452 100644 --- a/drivers/power/bq24257_charger.c +++ b/drivers/power/bq24257_charger.c @@ -267,6 +267,47 @@ enum bq24257_fault { FAULT_INPUT_LDO_LOW, }; +static int bq24257_get_input_current_limit(struct bq24257_device *bq, + union power_supply_propval *val) +{ + int ret; + + ret = bq24257_field_read(bq, F_IILIMIT); + if (ret < 0) + return ret; + + /* + * The "External ILIM" and "Production & Test" modes are not exposed + * through this driver and not being covered by the lookup table. + * Should such a mode have become active let's return an error rather + * than exceeding the bounds of the lookup table and returning + * garbage. + */ + if (ret >= BQ24257_IILIMIT_MAP_SIZE) + return -ENODATA; + + val->intval = bq24257_iilimit_map[ret]; + + return 0; +} + +static int bq24257_set_input_current_limit(struct bq24257_device *bq, + const union power_supply_propval *val) +{ + /* + * Address the case where the user manually sets an input current limit + * while the charger auto-detection mechanism is is active. In this + * case we want to abort and go straight to the user-specified value. + */ + if (bq->iilimit_autoset_enable) + cancel_delayed_work_sync(&bq->iilimit_setup_work); + + return bq24257_field_write(bq, F_IILIMIT, + bq24257_find_idx(val->intval, + bq24257_iilimit_map, + BQ24257_IILIMIT_MAP_SIZE)); +} + static int bq24257_power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val) @@ -351,6 +392,9 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, val->intval = bq24257_iterm_map[bq->init_data.iterm]; break; + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + return bq24257_get_input_current_limit(bq, val); + default: return -EINVAL; } @@ -358,6 +402,31 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, return 0; } +static int bq24257_power_supply_set_property(struct power_supply *psy, + enum power_supply_property prop, + const union power_supply_propval *val) +{ + struct bq24257_device *bq = power_supply_get_drvdata(psy); + + switch (prop) { + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + return bq24257_set_input_current_limit(bq, val); + default: + return -EINVAL; + } +} + +static int bq24257_power_supply_property_is_writeable(struct power_supply *psy, + enum power_supply_property psp) +{ + switch (psp) { + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + return true; + default: + return false; + } +} + static int bq24257_get_chip_state(struct bq24257_device *bq, struct bq24257_state *state) { @@ -559,13 +628,14 @@ static void bq24257_handle_state_change(struct bq24257_device *bq, ret = bq24257_field_write(bq, F_DPDM_EN, 1); if (ret < 0) goto error; - - /* reset input current limit */ - ret = bq24257_field_write(bq, F_IILIMIT, - bq->init_data.iilimit); - if (ret < 0) - goto error; } + /* + * When power is removed always return to the default input + * current limit as configured during probe. + */ + ret = bq24257_field_write(bq, F_IILIMIT, bq->init_data.iilimit); + if (ret < 0) + goto error; } else if (!old_state.power_good) { dev_dbg(bq->dev, "Power inserted\n"); @@ -682,6 +752,7 @@ static enum power_supply_property bq24257_power_supply_props[] = { POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE, POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX, POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT, + POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, }; static char *bq24257_charger_supplied_to[] = { @@ -694,6 +765,8 @@ static const struct power_supply_desc bq24257_power_supply_desc = { .properties = bq24257_power_supply_props, .num_properties = ARRAY_SIZE(bq24257_power_supply_props), .get_property = bq24257_power_supply_get_property, + .set_property = bq24257_power_supply_set_property, + .property_is_writeable = bq24257_power_supply_property_is_writeable, }; static ssize_t bq24257_show_ovp_voltage(struct device *dev,