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gpio: 104-dio-48e: Fix control port offset computation off-by-one error

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There are only two control ports, each controlling three distinct I/O
ports. To compute the control port address offset for a respective I/O
port, the I/O port address offset should be divided by 3; dividing by 2
may result in not only the wrong address offset but possibly also an
out-of-bounds array memory access for a non-existent third control port.

Fixes: 1b06d64f73 ("gpio: Add GPIO support for the ACCES 104-DIO-48E")
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
William Breathitt Gray 2016-06-02 16:00:09 -04:00 committed by Linus Walleij
parent af8c34ce6a
commit d15d6cf916
1 changed files with 2 additions and 2 deletions
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4
drivers/gpio/gpio-104-dio-48e.c
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@ -75,7 +75,7 @@ static int dio48e_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned io_port = offset / 8;
const unsigned control_port = io_port / 2;
const unsigned int control_port = io_port / 3;
const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
unsigned long flags;
unsigned control;
@ -115,7 +115,7 @@ static int dio48e_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned io_port = offset / 8;
const unsigned control_port = io_port / 2;
const unsigned int control_port = io_port / 3;
const unsigned mask = BIT(offset % 8);
const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
const unsigned out_port = (io_port > 2) ? io_port + 1 : io_port;