Add lock protection from race conditions in the 104-quad-8 counter
driver for filter clock prescaler related changes. There is no IRQ
handling so used spin_lock calls for protection.
Fixes: 9b74dddf79be ("counter: 104-quad-8: Support Filter Clock Prescaler")
Signed-off-by: Syed Nayyar Waris <syednwaris@xxxxxxxxx>
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
Changes in v4:
- Shift review-comments section so that it is not in commit message.
drivers/counter/104-quad-8.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 9dab190..58615e4 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -1230,6 +1230,8 @@ static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
if (ret)
return ret;
+ spin_lock(&priv->lock);
+
priv->fck_prescaler[channel_id] = prescaler;
/* Reset Byte Pointer */
@@ -1240,6 +1242,8 @@ static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
base_offset + 1);
+ spin_unlock(&priv->lock);
+
return len;
}
--
2.7.4
