iio: adc: at91: signedness bug in at91_adc_get_trigger_value_by_name()

commit 4f3bcd878f1d3c730fe00f619b7260c6125d49eb upstream.

at91_adc_get_trigger_value_by_name() was returning -ENOMEM truncated to
a positive u8 and that doesn't work.  I've changed it to int and
refactored it to preserve the error code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index e5b88d5d3b59425cf07e79ba20937322fa8c50fc..14fdaf0f9d23c6efc88e4fb6d0e387717aa2e92f 100644 (file)
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -161,12 +161,11 @@ static int at91_adc_channel_init(struct iio_dev *idev)
        return idev->num_channels;
 }
 
-static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
+static int at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
                                             struct at91_adc_trigger *triggers,
                                             const char *trigger_name)
 {
        struct at91_adc_state *st = iio_priv(idev);
-       u8 value = 0;
        int i;
 
        for (i = 0; i < st->trigger_number; i++) {
@@ -179,15 +178,16 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
                        return -ENOMEM;
 
                if (strcmp(trigger_name, name) == 0) {
-                       value = triggers[i].value;
                        kfree(name);
-                       break;
+                       if (triggers[i].value == 0)
+                               return -EINVAL;
+                       return triggers[i].value;
                }
 
                kfree(name);
        }
 
-       return value;
+       return -EINVAL;
 }
 
 static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
@@ -197,14 +197,14 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
        struct iio_buffer *buffer = idev->buffer;
        struct at91_adc_reg_desc *reg = st->registers;
        u32 status = at91_adc_readl(st, reg->trigger_register);
-       u8 value;
+       int value;
        u8 bit;
 
        value = at91_adc_get_trigger_value_by_name(idev,
                                                   st->trigger_list,
                                                   idev->trig->name);
-       if (value == 0)
-               return -EINVAL;
+       if (value < 0)
+               return value;
 
        if (state) {
                st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);