lkml.org 
[lkml]   [2014]   [Feb]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] gpio: clamp returned values to the boolean range
Date
Nothing prevents GPIO drivers from returning values outside the
boolean range, and as it turns out a few drivers are actually doing so.
These values were passed as-is to unsuspecting consumers and created
confusion.

This patch makes the internal _gpiod_get_raw_value() function return a
bool, effectively clamping the GPIO value to the boolean range no
matter what the driver does.

While we are at it, we also change the value parameter of
_gpiod_set_raw_value() to bool type before drivers start doing funny
things with non-boolean values.

Another way to fix this would be to change the prototypes of the driver
interface to use bool directly, but this would require a huge
cross-systems patch so this simpler solution is preferred.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
This issue was discussed some time ago already
(https://www.mail-archive.com/linux-gpio@vger.kernel.org/msg02019.html),
here is finally the fix for it. Not exactly what we planned but who would
take a hundreds-lines change when a two-liner does the same?

drivers/gpio/gpiolib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 50c4922fe53a..45cefccbf4bf 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1928,7 +1928,7 @@ EXPORT_SYMBOL_GPL(gpiod_is_active_low);
* that the GPIO was actually requested.
*/

-static int _gpiod_get_raw_value(const struct gpio_desc *desc)
+static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
{
struct gpio_chip *chip;
int value;
@@ -2041,7 +2041,7 @@ static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
__func__, err);
}

-static void _gpiod_set_raw_value(struct gpio_desc *desc, int value)
+static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
{
struct gpio_chip *chip;

--
1.9.0


\
 
 \ /
  Last update: 2014-02-26 03:21    [W:0.070 / U:1.680 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site