Messages in this thread | | | Subject | Re: [PATCH] pinctrl: nsp-gpio: fix type of iterator | From | Ray Jui <> | Date | Wed, 23 Dec 2015 14:35:57 -0800 |
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+ Reddy
On 12/23/2015 2:37 AM, Andrzej Hajda wrote: > Iterator i declared as unsigned is always non-negative so the > loop will never end. > > The problem has been detected using proposed semantic patch > scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1]. > > [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576 > > Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> > --- > drivers/pinctrl/bcm/pinctrl-nsp-gpio.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c b/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > index 34648f6..ad5b04c 100644 > --- a/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > +++ b/drivers/pinctrl/bcm/pinctrl-nsp-gpio.c > @@ -439,7 +439,8 @@ static int nsp_gpio_set_strength(struct nsp_gpio *chip, unsigned gpio, > static int nsp_gpio_get_strength(struct nsp_gpio *chip, unsigned gpio, > u16 *strength) > { > - unsigned int i, offset, shift; > + unsigned int offset, shift; > + int i; > u32 val; > unsigned long flags; > >
The fix is a valid fix. And at the same time it exposes other potential issues in the driver. I just found the loop used in _set_strength and _get_strength is inconsistent:
In _set_strength:
427 for (i = GPIO_DRV_STRENGTH_BITS; i > 0; i--) {
For i to start at GPIO_DRV_STRENGTH_BITS, it seems to be wrong.
428 val = readl(chip->io_ctrl + offset); 429 val &= ~BIT(shift); 430 val |= ((strength >> (i-1)) & 0x1) << shift; 431 writel(val, chip->io_ctrl + offset); 432 offset += 4; 433 }
In _get_strength:
451 for (i = (GPIO_DRV_STRENGTH_BITS - 1); i >= 0; i--) { 452 val = readl(chip->io_ctrl + offset) & BIT(shift); 453 val >>= shift; 454 *strength += (val << i); 455 offset += 4; 456 }
Reddy, could you please review and comment?
Thanks,
Ray
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