diff options
| author | Joshua Scott <joshua.scott@alliedtelesis.co.nz> | 2015-05-22 00:35:12 (GMT) |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2015-06-01 14:53:55 (GMT) |
| commit | b6ac1280b6969607c5a01e316cc4ab693490c333 (patch) | |
| tree | 08f9f9f49b0014d3942d9cf34b5280aff50239ef /drivers/gpio/gpio-pca953x.c | |
| parent | 121dcb760426ca67ee90a8b2db6a75eee010f8e3 (diff) | |
| download | linux-b6ac1280b6969607c5a01e316cc4ab693490c333.tar.xz | |
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>
Diffstat (limited to 'drivers/gpio/gpio-pca953x.c')
| -rw-r--r-- | drivers/gpio/gpio-pca953x.c | 21 |
1 files changed, 12 insertions, 9 deletions
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 @@ static struct irq_chip pca953x_irq_chip = { .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 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) } 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 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) 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 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) 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) |