[PATCH] POWER: jz4740-battery: Protect against concurrent battery readings

From: Lars-Peter Clausen
Date: Thu Nov 11 2010 - 13:01:31 EST


We can not handle more then one ADC request at a time to the battery. The patch
adds a mutex around the ADC read code to ensure this.

Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---
drivers/power/jz4740-battery.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
---
This patch should also go into the 2.6.36.x stable tree

diff --git a/drivers/power/jz4740-battery.c b/drivers/power/jz4740-battery.c
index a8108a7..2bbe04a 100644
--- a/drivers/power/jz4740-battery.c
+++ b/drivers/power/jz4740-battery.c
@@ -47,6 +47,8 @@ struct jz_battery {

struct power_supply battery;
struct delayed_work work;
+
+ struct mutex lock;
};

static inline struct jz_battery *psy_to_jz_battery(struct power_supply *psy)
@@ -68,6 +70,8 @@ static long jz_battery_read_voltage(struct jz_battery *battery)
unsigned long val;
long voltage;

+ mutex_lock(&battery->lock);
+
INIT_COMPLETION(battery->read_completion);

enable_irq(battery->irq);
@@ -91,6 +95,8 @@ static long jz_battery_read_voltage(struct jz_battery *battery)
battery->cell->disable(battery->pdev);
disable_irq(battery->irq);

+ mutex_unlock(&battery->lock);
+
return voltage;
}

@@ -291,6 +297,7 @@ static int __devinit jz_battery_probe(struct platform_device *pdev)
jz_battery->pdev = pdev;

init_completion(&jz_battery->read_completion);
+ mutex_init(&jz_battery->lock);

INIT_DELAYED_WORK(&jz_battery->work, jz_battery_work);

--
1.5.6.5

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