From: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
Some faulty i2c slave devices might hold the sda/scl line and cause the
i2c bus driver to wait indefinitely in the busbusy loop. Add a timeout
to the loop so the bus master can recover without locking up everything.
Signed-off-by: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
Signed-off-by: Mike Frysinger <vapier@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-bfin-twi.c | 14 ++++++++++++--
1 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index 64d4b64..f2628a7 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -288,6 +288,8 @@ static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id)
return IRQ_HANDLED;
}
+#define BFIN_TWI_BUSY_TIMEOUT 1000
+
/*
* One i2c master transfer
*/
@@ -297,12 +299,16 @@ static int bfin_twi_do_master_xfer(struct i2c_adapter *adap,
struct bfin_twi_iface *iface = adap->algo_data;
struct i2c_msg *pmsg;
int rc = 0;
+ unsigned int busy_timeout = BFIN_TWI_BUSY_TIMEOUT;
if (!(read_CONTROL(iface) & TWI_ENA))
return -ENXIO;
- while (read_MASTER_STAT(iface) & BUSBUSY)
+ while (read_MASTER_STAT(iface) & BUSBUSY) {
+ if (--busy_timeout == 0)
+ return -EBUSY;
yield();
+ }
iface->pmsg = msgs;
iface->msg_num = num;
@@ -397,12 +403,16 @@ int bfin_twi_do_smbus_xfer(struct i2c_adapter *adap, u16 addr,
{
struct bfin_twi_iface *iface = adap->algo_data;
int rc = 0;
+ unsigned int busy_timeout = BFIN_TWI_BUSY_TIMEOUT;
if (!(read_CONTROL(iface) & TWI_ENA))
return -ENXIO;
- while (read_MASTER_STAT(iface) & BUSBUSY)
+ while (read_MASTER_STAT(iface) & BUSBUSY) {
+ if (--busy_timeout == 0)
+ return -EBUSY;
yield();
+ }
iface->writeNum = 0;
iface->readNum = 0;
--
1.7.5.rc3
--
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