[PATCH 3/5] power_supply: max14577: Properly handle error conditions

From: Krzysztof Kozlowski
Date: Tue Feb 24 2015 - 04:59:43 EST

Re-work and fix handling of errors when retrieving power supply
properties:

1. Return errno values directly from get_property() instead of
storing 'unknown' as intval for given property.

2. Handle regmap_read() errors and return errno code. Previously the
regmap_read() return code was ignored so an uninitialized value from
the stack could be used for calculating the property.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
---
drivers/power/max14577_charger.c | 109 ++++++++++++++++++++++++++-------------
1 file changed, 73 insertions(+), 36 deletions(-)

diff --git a/drivers/power/max14577_charger.c b/drivers/power/max14577_charger.c
index c72238aa011b..4736dc478578 100644
--- a/drivers/power/max14577_charger.c
+++ b/drivers/power/max14577_charger.c
@@ -54,10 +54,10 @@ static enum max14577_muic_charger_type maxim_get_charger_type(
}
}

-static int max14577_get_charger_state(struct max14577_charger *chg)
+static int max14577_get_charger_state(struct max14577_charger *chg, int *val)
{
struct regmap *rmap = chg->max14577->regmap;
- int state = POWER_SUPPLY_STATUS_DISCHARGING;
+ int ret;
u8 reg_data;

/*
@@ -71,22 +71,32 @@ static int max14577_get_charger_state(struct max14577_charger *chg)
* - handle properly dead-battery charging (respect timer)
* - handle timers (fast-charge and prequal) /MBCCHGERR/
*/
- max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
- if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0)
- goto state_set;
+ ret = max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
+ if (ret < 0)
+ goto out;
+
+ if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0) {
+ *val = POWER_SUPPLY_STATUS_DISCHARGING;
+ goto out;
+ }
+
+ ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
+ if (ret < 0)
+ goto out;

- max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
if (reg_data & STATUS3_CGMBC_MASK) {
/* Charger or USB-cable is connected */
if (reg_data & STATUS3_EOC_MASK)
- state = POWER_SUPPLY_STATUS_FULL;
+ *val = POWER_SUPPLY_STATUS_FULL;
else
- state = POWER_SUPPLY_STATUS_CHARGING;
- goto state_set;
+ *val = POWER_SUPPLY_STATUS_CHARGING;
+ goto out;
}

-state_set:
- return state;
+ *val = POWER_SUPPLY_STATUS_DISCHARGING;
+
+out:
+ return ret;
}

/*
@@ -94,8 +104,10 @@ state_set:
* - POWER_SUPPLY_CHARGE_TYPE_NONE
* - POWER_SUPPLY_CHARGE_TYPE_FAST
*/
-static int max14577_get_charge_type(struct max14577_charger *chg)
+static int max14577_get_charge_type(struct max14577_charger *chg, int *val)
{
+ int ret, charging;
+
/*
* TODO: CHARGE_TYPE_TRICKLE (VCHGR_RC or EOC)?
* As spec says:
@@ -104,18 +116,29 @@ static int max14577_get_charge_type(struct max14577_charger *chg)
* top-off timer starts. The device continues to trickle
* charge the battery until the top-off timer runs out."
*/
- if (max14577_get_charger_state(chg) == POWER_SUPPLY_STATUS_CHARGING)
- return POWER_SUPPLY_CHARGE_TYPE_FAST;
- return POWER_SUPPLY_CHARGE_TYPE_NONE;
+ ret = max14577_get_charger_state(chg, &charging);
+ if (ret < 0)
+ return ret;
+
+ if (charging == POWER_SUPPLY_STATUS_CHARGING)
+ *val = POWER_SUPPLY_CHARGE_TYPE_FAST;
+ else
+ *val = POWER_SUPPLY_CHARGE_TYPE_NONE;
+
+ return 0;
}

-static int max14577_get_online(struct max14577_charger *chg)
+static int max14577_get_online(struct max14577_charger *chg, int *val)
{
struct regmap *rmap = chg->max14577->regmap;
u8 reg_data;
+ int ret;
enum max14577_muic_charger_type chg_type;

- max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
+ ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
+ if (ret < 0)
+ return ret;
+
reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data);
switch (chg_type) {
@@ -125,14 +148,17 @@ static int max14577_get_online(struct max14577_charger *chg)
case MAX14577_CHARGER_TYPE_SPECIAL_1A:
case MAX14577_CHARGER_TYPE_DEAD_BATTERY:
case MAX77836_CHARGER_TYPE_SPECIAL_BIAS:
- return 1;
+ *val = 1;
+ break;
case MAX14577_CHARGER_TYPE_NONE:
case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT:
case MAX14577_CHARGER_TYPE_RESERVED:
case MAX77836_CHARGER_TYPE_RESERVED:
default:
- return 0;
+ *val = 0;
}
+
+ return 0;
}

/*
@@ -141,29 +167,38 @@ static int max14577_get_online(struct max14577_charger *chg)
* - POWER_SUPPLY_HEALTH_OVERVOLTAGE
* - POWER_SUPPLY_HEALTH_GOOD
*/
-static int max14577_get_battery_health(struct max14577_charger *chg)
+static int max14577_get_battery_health(struct max14577_charger *chg, int *val)
{
struct regmap *rmap = chg->max14577->regmap;
- int state = POWER_SUPPLY_HEALTH_GOOD;
+ int ret;
u8 reg_data;
enum max14577_muic_charger_type chg_type;

- max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
+ ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
+ if (ret < 0)
+ goto out;
+
reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data);
if (chg_type == MAX14577_CHARGER_TYPE_DEAD_BATTERY) {
- state = POWER_SUPPLY_HEALTH_DEAD;
- goto state_set;
+ *val = POWER_SUPPLY_HEALTH_DEAD;
+ goto out;
}

- max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
+ ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
+ if (ret < 0)
+ goto out;
+
if (reg_data & STATUS3_OVP_MASK) {
- state = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
- goto state_set;
+ *val = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+ goto out;
}

-state_set:
- return state;
+ /* Not dead, not overvoltage */
+ *val = POWER_SUPPLY_HEALTH_GOOD;
+
+out:
+ return ret;
}

/*
@@ -171,9 +206,11 @@ state_set:
* The max14577 chip doesn't report any status of battery presence.
* Lets assume that it will always be used with some battery.
*/
-static int max14577_get_present(struct max14577_charger *chg)
+static int max14577_get_present(struct max14577_charger *chg, int *val)
{
- return 1;
+ *val = 1;
+
+ return 0;
}

static int max14577_set_fast_charge_timer(struct max14577_charger *chg,
@@ -391,19 +428,19 @@ static int max14577_charger_get_property(struct power_supply *psy,

switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
- val->intval = max14577_get_charger_state(chg);
+ ret = max14577_get_charger_state(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_CHARGE_TYPE:
- val->intval = max14577_get_charge_type(chg);
+ ret = max14577_get_charge_type(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_HEALTH:
- val->intval = max14577_get_battery_health(chg);
+ ret = max14577_get_battery_health(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_PRESENT:
- val->intval = max14577_get_present(chg);
+ ret = max14577_get_present(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_ONLINE:
- val->intval = max14577_get_online(chg);
+ ret = max14577_get_online(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_MODEL_NAME:
BUILD_BUG_ON(ARRAY_SIZE(model_names) != MAXIM_DEVICE_TYPE_NUM);
--
1.9.1

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