This commit extends the use of the existing mutex to pave the way for using direct device access inside sysfs getter/setter routines in a way that the access during interrupts and timer routines does not interfere with device access by the CPU or between multiple cores.
This also addresses a potential race condition that could be caused by bq24257_irq_handler_thread() and bq24257_iilimit_autoset() accessing the device simultaneously. Signed-off-by: Andreas Dannenberg <[email protected]> --- drivers/power/bq24257_charger.c | 60 ++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 25 deletions(-) diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c index 2271a88..ad3fd2d 100644 --- a/drivers/power/bq24257_charger.c +++ b/drivers/power/bq24257_charger.c @@ -99,7 +99,7 @@ struct bq24257_device { struct bq24257_init_data init_data; struct bq24257_state state; - struct mutex lock; /* protect state data */ + struct mutex lock; /* protect device access and state data */ bool in_ilimit_autoset_disable; bool pg_gpio_disable; @@ -268,10 +268,10 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, { struct bq24257_device *bq = power_supply_get_drvdata(psy); struct bq24257_state state; + int ret = 0; mutex_lock(&bq->lock); state = bq->state; - mutex_unlock(&bq->lock); switch (psp) { case POWER_SUPPLY_PROP_STATUS: @@ -351,10 +351,12 @@ static int bq24257_power_supply_get_property(struct power_supply *psy, break; default: - return -EINVAL; + ret = -EINVAL; } - return 0; + mutex_unlock(&bq->lock); + + return ret; } static int bq24257_get_chip_state(struct bq24257_device *bq, @@ -401,15 +403,9 @@ static int bq24257_get_chip_state(struct bq24257_device *bq, static bool bq24257_state_changed(struct bq24257_device *bq, struct bq24257_state *new_state) { - int ret; - - mutex_lock(&bq->lock); - ret = (bq->state.status != new_state->status || - bq->state.fault != new_state->fault || - bq->state.power_good != new_state->power_good); - mutex_unlock(&bq->lock); - - return ret; + return bq->state.status != new_state->status || + bq->state.fault != new_state->fault || + bq->state.power_good != new_state->power_good; } enum bq24257_loop_status { @@ -532,7 +528,9 @@ static void bq24257_iilimit_setup_work(struct work_struct *work) struct bq24257_device *bq = container_of(work, struct bq24257_device, iilimit_setup_work.work); + mutex_lock(&bq->lock); bq24257_iilimit_autoset(bq); + mutex_unlock(&bq->lock); } static void bq24257_handle_state_change(struct bq24257_device *bq, @@ -543,9 +541,7 @@ static void bq24257_handle_state_change(struct bq24257_device *bq, bool reset_iilimit = false; bool config_iilimit = false; - mutex_lock(&bq->lock); old_state = bq->state; - mutex_unlock(&bq->lock); /* * Handle BQ2425x state changes observing whether the D+/D- based input @@ -600,25 +596,30 @@ static irqreturn_t bq24257_irq_handler_thread(int irq, void *private) struct bq24257_device *bq = private; struct bq24257_state state; + mutex_lock(&bq->lock); + ret = bq24257_get_chip_state(bq, &state); if (ret < 0) - return IRQ_HANDLED; + goto out; if (!bq24257_state_changed(bq, &state)) - return IRQ_HANDLED; + goto out; dev_dbg(bq->dev, "irq(state changed): status/fault/pg = %d/%d/%d\n", state.status, state.fault, state.power_good); bq24257_handle_state_change(bq, &state); - - mutex_lock(&bq->lock); bq->state = state; + mutex_unlock(&bq->lock); power_supply_changed(bq->charger); return IRQ_HANDLED; + +out: + mutex_unlock(&bq->lock); + return IRQ_HANDLED; } static int bq24257_hw_init(struct bq24257_device *bq) @@ -658,9 +659,7 @@ static int bq24257_hw_init(struct bq24257_device *bq) if (ret < 0) return ret; - mutex_lock(&bq->lock); bq->state = state; - mutex_unlock(&bq->lock); if (bq->in_ilimit_autoset_disable) { dev_dbg(bq->dev, "manually setting iilimit = %d\n", @@ -1002,11 +1001,15 @@ static int bq24257_suspend(struct device *dev) if (!bq->in_ilimit_autoset_disable) cancel_delayed_work_sync(&bq->iilimit_setup_work); + mutex_lock(&bq->lock); + /* reset all registers to default (and activate standalone mode) */ ret = bq24257_field_write(bq, F_RESET, 1); if (ret < 0) dev_err(bq->dev, "Cannot reset chip to standalone mode.\n"); + mutex_unlock(&bq->lock); + return ret; } @@ -1015,24 +1018,31 @@ static int bq24257_resume(struct device *dev) int ret; struct bq24257_device *bq = dev_get_drvdata(dev); + mutex_lock(&bq->lock); + ret = regcache_drop_region(bq->rmap, BQ24257_REG_1, BQ24257_REG_7); if (ret < 0) - return ret; + goto err; ret = bq24257_field_write(bq, F_RESET, 0); if (ret < 0) - return ret; + goto err; ret = bq24257_hw_init(bq); if (ret < 0) { dev_err(bq->dev, "Cannot init chip after resume.\n"); - return ret; + goto err; } + mutex_unlock(&bq->lock); + /* signal userspace, maybe state changed while suspended */ power_supply_changed(bq->charger); - return 0; + +err: + mutex_unlock(&bq->lock); + return ret; } #endif -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
