gpio: Prevent an integer overflow in the pca953x driver
Interrupts were missed if an 8-bit integer overflow occurred. This was
observed when bank0,pin7 and bank1,pin7 changed simultaniously.
As the 8-bit totals were only checked against zero, replace them with
booleans. Name the booleans so that their purpose is clear.
Signed-off-by: Joshua Scott <joshua.scott@alliedtelesis.co.nz>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index eed4203..d233eb3 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -443,12 +443,13 @@
.irq_set_type = pca953x_irq_set_type,
};
-static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending)
+static bool pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending)
{
u8 cur_stat[MAX_BANK];
u8 old_stat[MAX_BANK];
- u8 pendings = 0;
- u8 trigger[MAX_BANK], triggers = 0;
+ bool pending_seen = false;
+ bool trigger_seen = false;
+ u8 trigger[MAX_BANK];
int ret, i, offset = 0;
switch (chip->chip_type) {
@@ -461,7 +462,7 @@
}
ret = pca953x_read_regs(chip, offset, cur_stat);
if (ret)
- return 0;
+ return false;
/* Remove output pins from the equation */
for (i = 0; i < NBANK(chip); i++)
@@ -471,11 +472,12 @@
for (i = 0; i < NBANK(chip); i++) {
trigger[i] = (cur_stat[i] ^ old_stat[i]) & chip->irq_mask[i];
- triggers += trigger[i];
+ if (trigger[i])
+ trigger_seen = true;
}
- if (!triggers)
- return 0;
+ if (!trigger_seen)
+ return false;
memcpy(chip->irq_stat, cur_stat, NBANK(chip));
@@ -483,10 +485,11 @@
pending[i] = (old_stat[i] & chip->irq_trig_fall[i]) |
(cur_stat[i] & chip->irq_trig_raise[i]);
pending[i] &= trigger[i];
- pendings += pending[i];
+ if (pending[i])
+ pending_seen = true;
}
- return pendings;
+ return pending_seen;
}
static irqreturn_t pca953x_irq_handler(int irq, void *devid)