Make the code a bit more readable.
Instead of casting an int to an unsigned then comparing to
MAX_NR_GPIOS, add a >= 0 test and let the compiler optimizer
do the conversion to unsigned.
The generated code should be the same.
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
This came up because of a new pinmux subsystem that used
a style copied from gpio and a request from Linus Walleij.
On Wed, 2011-05-11 at 00:52 +0200, Linus Walleij wrote:
> 2011/5/11 Joe Perches <joe@xxxxxxxxxxx>:
> > On Wed, 2011-05-11 at 00:18 +0200, Linus Walleij wrote:
> >> 2011/5/2 Joe Perches <joe@xxxxxxxxxxx>:
> >> > On Mon, 2011-05-02 at 21:16 +0200, Linus Walleij wrote:
> >> >> From: Linus Walleij <linus.walleij@xxxxxxxxxx>
> >> >> diff --git a/drivers/pinmux/core.c b/drivers/pinmux/core.c
> >> > Trivial comments follow
> >> >> +static inline int pin_is_valid(int pin)
> >> >> +{
> >> >> + return ((unsigned)pin) < MACH_NR_PINS;
> >> >> +}
> >> > Couldn't pin just be declared unsigned or maybe u32?
> >> No, because like in the GPIO subsystem you *may* want to send in invalid
> >> pins, and those are identified by negative numbers.
> > Then I think this is clearer and the compiler
> > should produce the same code.
> > static inline bool pin_is_valid(int pin)
> > {
> > return pin >= 0 && pin < MACH_NR_PINS;
> > }
> Yes indeed, I'll fix. Can you propose a patch to the same pattern
> found in include/asm-generic/gpio.h? It would bring equal
> clarity there I believe.
include/asm-generic/gpio.h | 6 +++---
include/linux/gpio.h | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index ce16e70..315ecb7 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -35,9 +35,9 @@
* platform data and other tables.
*/
-static inline int gpio_is_valid(int number)
+static inline bool gpio_is_valid(int number)
{
- return ((unsigned)number) < ARCH_NR_GPIOS;
+ return number >= 0 && number < ARCH_NR_GPIOS;
}
struct device;
@@ -216,7 +216,7 @@ extern void gpio_unexport(unsigned gpio);
#else /* !CONFIG_GPIOLIB */
-static inline int gpio_is_valid(int number)
+static inline bool gpio_is_valid(int number)
{
/* only non-negative numbers are valid */
return number >= 0;
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index fa92e50..0af3bca 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -79,9 +79,9 @@ struct gpio_chip;
* warning when something is wrongly called.
*/
-static inline int gpio_is_valid(int number)
+static inline bool gpio_is_valid(int number)
{
- return 0;
+ return false;
}
static inline int gpio_request(unsigned gpio, const char *label)
--
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