gpio: cs5535-gpio: fix input direction

commit a8a5164c297c16c2f4be776714ca47dba252cc3d upstream.

The cs5535-gpio driver's get() function was returning the output value.
This means that the GPIO pins would never work as an input, even if
configured as an input.

The driver should return the READ_BACK value, which is the sensed line
value.  To make that work when the direction is 'output', INPUT_ENABLE
needs to be set.

In addition, the driver was not disabling OUTPUT_ENABLE when the direction
is set to 'input'.  That would cause the GPIO to continue to drive the pin
if the direction was ever set to output.

This issue was noticed when attempting to use the gpiolib driver to read
an external input.  I had previously been using the char/cs5535-gpio
driver.

Signed-off-by: Ben Gardner <gardner.ben@gmail.com>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c
index 0fdbe94f24a3a0f320266d6505a3062e1aa5f6cd..0c3c498f2260632124ecac5ffcc2f5f81773e0d2 100644 (file)
--- a/drivers/gpio/cs5535-gpio.c
+++ b/drivers/gpio/cs5535-gpio.c
@@ -154,7 +154,7 @@ static int chip_gpio_request(struct gpio_chip *c, unsigned offset)
 
 static int chip_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
-       return cs5535_gpio_isset(offset, GPIO_OUTPUT_VAL);
+       return cs5535_gpio_isset(offset, GPIO_READ_BACK);
 }
 
 static void chip_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
@@ -172,6 +172,7 @@ static int chip_direction_input(struct gpio_chip *c, unsigned offset)
 
        spin_lock_irqsave(&chip->lock, flags);
        __cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
+       __cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_ENABLE);
        spin_unlock_irqrestore(&chip->lock, flags);
 
        return 0;
@@ -184,6 +185,7 @@ static int chip_direction_output(struct gpio_chip *c, unsigned offset, int val)
 
        spin_lock_irqsave(&chip->lock, flags);
 
+       __cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
        __cs5535_gpio_set(chip, offset, GPIO_OUTPUT_ENABLE);
        if (val)
                __cs5535_gpio_set(chip, offset, GPIO_OUTPUT_VAL);