Commit b9b469ed authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Ben Hutchings

staging: iio: ad5933: avoid uninitialized variable in error case

commit 34eee70a upstream.

The ad5933_i2c_read function returns an error code to indicate
whether it could read data or not. However ad5933_work() ignores
this return code and just accesses the data unconditionally,
which gets detected by gcc as a possible bug:

drivers/staging/iio/impedance-analyzer/ad5933.c: In function 'ad5933_work':
drivers/staging/iio/impedance-analyzer/ad5933.c:649:16: warning: 'status' may be used uninitialized in this function [-Wmaybe-uninitialized]

This adds minimal error handling so we only evaluate the
data if it was correctly read.

Link: https://patchwork.kernel.org/patch/8110281/Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent a0228da0
...@@ -626,6 +626,7 @@ static void ad5933_work(struct work_struct *work) ...@@ -626,6 +626,7 @@ static void ad5933_work(struct work_struct *work)
struct iio_buffer *ring = indio_dev->buffer; struct iio_buffer *ring = indio_dev->buffer;
signed short buf[2]; signed short buf[2];
unsigned char status; unsigned char status;
int ret;
mutex_lock(&indio_dev->mlock); mutex_lock(&indio_dev->mlock);
if (st->state == AD5933_CTRL_INIT_START_FREQ) { if (st->state == AD5933_CTRL_INIT_START_FREQ) {
...@@ -633,17 +634,20 @@ static void ad5933_work(struct work_struct *work) ...@@ -633,17 +634,20 @@ static void ad5933_work(struct work_struct *work)
ad5933_cmd(st, AD5933_CTRL_START_SWEEP); ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
st->state = AD5933_CTRL_START_SWEEP; st->state = AD5933_CTRL_START_SWEEP;
schedule_delayed_work(&st->work, st->poll_time_jiffies); schedule_delayed_work(&st->work, st->poll_time_jiffies);
mutex_unlock(&indio_dev->mlock); goto out;
return;
} }
ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status); ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
if (ret)
goto out;
if (status & AD5933_STAT_DATA_VALID) { if (status & AD5933_STAT_DATA_VALID) {
ad5933_i2c_read(st->client, ret = ad5933_i2c_read(st->client,
test_bit(1, ring->scan_mask) ? test_bit(1, ring->scan_mask) ?
AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA, AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
ring->scan_count * 2, (u8 *)buf); ring->scan_count * 2, (u8 *)buf);
if (ret)
goto out;
if (ring->scan_count == 2) { if (ring->scan_count == 2) {
buf[0] = be16_to_cpu(buf[0]); buf[0] = be16_to_cpu(buf[0]);
...@@ -656,8 +660,7 @@ static void ad5933_work(struct work_struct *work) ...@@ -656,8 +660,7 @@ static void ad5933_work(struct work_struct *work)
} else { } else {
/* no data available - try again later */ /* no data available - try again later */
schedule_delayed_work(&st->work, st->poll_time_jiffies); schedule_delayed_work(&st->work, st->poll_time_jiffies);
mutex_unlock(&indio_dev->mlock); goto out;
return;
} }
if (status & AD5933_STAT_SWEEP_DONE) { if (status & AD5933_STAT_SWEEP_DONE) {
...@@ -669,7 +672,7 @@ static void ad5933_work(struct work_struct *work) ...@@ -669,7 +672,7 @@ static void ad5933_work(struct work_struct *work)
ad5933_cmd(st, AD5933_CTRL_INC_FREQ); ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
schedule_delayed_work(&st->work, st->poll_time_jiffies); schedule_delayed_work(&st->work, st->poll_time_jiffies);
} }
out:
mutex_unlock(&indio_dev->mlock); mutex_unlock(&indio_dev->mlock);
} }
......
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