diff options
| author | David Rivshin <DRivshin@allworx.com> | 2017-04-25 01:56:50 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-25 16:44:36 +0300 |
| commit | 198ab4031873b5511d6ef9b4777cabc4eebcaf18 (patch) | |
| tree | aedf7e7ceb7fcb4a4cb2f98ab776c03c9bdd06b5 | |
| parent | b77adf29b85687fd593d4dc294fb5cb946b3c0e2 (diff) | |
| download | linux-198ab4031873b5511d6ef9b4777cabc4eebcaf18.tar.xz | |
gpio: omap: return error if requested debounce time is not possible
commit 83977443938122baeed28dc9f078db3da9855f7c upstream.
omap_gpio_debounce() does not validate that the requested debounce
is within a range it can handle. Instead it lets the register value
wrap silently, and always returns success.
This can lead to all sorts of unexpected behavior, such as gpio_keys
asking for a too-long debounce, but getting a very short debounce in
practice.
Fix this by returning -EINVAL if the requested value does not fit into
the register field. If there is no debounce clock available at all,
return -ENOTSUPP.
Fixes: e85ec6c3047b ("gpio: omap: fix omap2_set_gpio_debounce")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpio/gpio-omap.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c index b98ede78c9d8..6f9c9ac6ee70 100644 --- a/drivers/gpio/gpio-omap.c +++ b/drivers/gpio/gpio-omap.c @@ -208,9 +208,11 @@ static inline void omap_gpio_dbck_disable(struct gpio_bank *bank) * OMAP's debounce time is in 31us steps * <debounce time> = (GPIO_DEBOUNCINGTIME[7:0].DEBOUNCETIME + 1) x 31 * so we need to convert and round up to the closest unit. + * + * Return: 0 on success, negative error otherwise. */ -static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, - unsigned debounce) +static int omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, + unsigned debounce) { void __iomem *reg; u32 val; @@ -218,11 +220,12 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, bool enable = !!debounce; if (!bank->dbck_flag) - return; + return -ENOTSUPP; if (enable) { debounce = DIV_ROUND_UP(debounce, 31) - 1; - debounce &= OMAP4_GPIO_DEBOUNCINGTIME_MASK; + if ((debounce & OMAP4_GPIO_DEBOUNCINGTIME_MASK) != debounce) + return -EINVAL; } l = BIT(offset); @@ -255,6 +258,8 @@ static void omap2_set_gpio_debounce(struct gpio_bank *bank, unsigned offset, bank->context.debounce = debounce; bank->context.debounce_en = val; } + + return 0; } /** @@ -964,14 +969,20 @@ static int omap_gpio_debounce(struct gpio_chip *chip, unsigned offset, { struct gpio_bank *bank; unsigned long flags; + int ret; bank = gpiochip_get_data(chip); raw_spin_lock_irqsave(&bank->lock, flags); - omap2_set_gpio_debounce(bank, offset, debounce); + ret = omap2_set_gpio_debounce(bank, offset, debounce); raw_spin_unlock_irqrestore(&bank->lock, flags); - return 0; + if (ret) + dev_info(chip->parent, + "Could not set line %u debounce to %u microseconds (%d)", + offset, debounce, ret); + + return ret; } static void omap_gpio_set(struct gpio_chip *chip, unsigned offset, int value) |