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| author | Roel Kluin <roel.kluin@gmail.com> | 2009-03-28 21:34:42 +0100 |
|---|---|---|
| committer | Jean Delvare <khali@linux-fr.org> | 2009-03-28 21:34:42 +0100 |
| commit | 94d78e180c0323422854bc1718e657ac2d0cac1b (patch) | |
| tree | 7db1c35614e593f80ee17c10915dda76d2ee2836 /drivers/i2c | |
| parent | 0c168ceb9e1898a7f2895e80ce9915835b083bd3 (diff) | |
| download | lwn-94d78e180c0323422854bc1718e657ac2d0cac1b.tar.gz lwn-94d78e180c0323422854bc1718e657ac2d0cac1b.zip | |
i2c-algo-pcf: Handle timeout correctly
With a postfix decrement these timeouts reach -1 rather than 0, but after the
loop it is tested whether they have become 0.
As pointed out by Jean Delvare, the msg_num should be tested before the timeout.
With the current order, you could exit with a timeout error while all the
messages were successfully transferred.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Eric Brower <ebrower@gmail.com>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/algos/i2c-algo-pcf.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c index 5906986d013b..65a769f3ae79 100644 --- a/drivers/i2c/algos/i2c-algo-pcf.c +++ b/drivers/i2c/algos/i2c-algo-pcf.c @@ -115,15 +115,17 @@ static int wait_for_bb(struct i2c_algo_pcf_data *adap) status = get_pcf(adap, 1); - while (timeout-- && !(status & I2C_PCF_BB)) { + while (!(status & I2C_PCF_BB) && --timeout) { udelay(100); /* wait for 100 us */ status = get_pcf(adap, 1); } - if (timeout <= 0) + if (timeout == 0) { printk(KERN_ERR "Timeout waiting for Bus Busy\n"); + return -ETIMEDOUT; + } - return timeout <= 0; + return 0; } static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) @@ -133,7 +135,7 @@ static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) *status = get_pcf(adap, 1); - while (timeout-- && (*status & I2C_PCF_PIN)) { + while ((*status & I2C_PCF_PIN) && --timeout) { adap->waitforpin(adap->data); *status = get_pcf(adap, 1); } @@ -142,10 +144,10 @@ static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) return -EINTR; } - if (timeout <= 0) - return -1; - else - return 0; + if (timeout == 0) + return -ETIMEDOUT; + + return 0; } /* |