4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Rivshin <drivs...@allworx.com>
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 <drivs...@allworx.com>
Acked-by: Grygorii Strashko <grygorii.stras...@ti.com>
Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/gpio/gpio-omap.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -208,9 +208,11 @@ static inline void omap_gpio_dbck_disabl
* 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(stru
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(stru
bank->context.debounce = debounce;
bank->context.debounce_en = val;
}
+
+ return 0;
}
/**
@@ -964,14 +969,20 @@ static int omap_gpio_debounce(struct gpi
{
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)
