[patch 062/123] gpio: cs5535-gpio: fix input direction
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From: Greg KH on 12 Mar 2010 20:30 2.6.33-stable review patch. If anyone has any objections, please let me know. ----------------- From: Ben Gardner <gardner.ben(a)gmail.com> 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(a)gmail.com> Acked-by: Andres Salomon <dilinger(a)collabora.co.uk> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: David Brownell <dbrownell(a)users.sourceforge.net> Cc: Mark Brown <broonie(a)opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de> --- drivers/gpio/cs5535-gpio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/gpio/cs5535-gpio.c +++ b/drivers/gpio/cs5535-gpio.c @@ -154,7 +154,7 @@ static int chip_gpio_request(struct gpio 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 g 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 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |