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ARM: pxa: fix GPIO double shifts

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The commit 9bf448c66d ("ARM: pxa: use generic gpio operation instead of
gpio register") from Oct 17, 2011, leads to the following static checker
warning:
  arch/arm/mach-pxa/spitz_pm.c:172 spitz_charger_wakeup()
  warn: double left shift '!gpio_get_value(SPITZ_GPIO_KEY_INT)
        << (1 << ((SPITZ_GPIO_KEY_INT) & 31))'

As Dan reported, the value is shifted three times :
 - once by gpio_get_value(), which returns either 0 or BIT(gpio)
 - once by the shift operation '<<'
 - a last time by GPIO_bit(gpio) which is BIT(gpio)

Therefore the calculation lead to a chained or operator of :
 - (1 << gpio) << (1 << gpio) = (2^gpio)^gpio = 2 ^ (gpio * gpio)

It is be sheer luck the former statement works, only because each gpio
used is strictly smaller than 6, and therefore 2^(gpio^2) never
overflows a 32 bits value, and because it is used as a boolean value to
check a gpio activation.

As the xxx_charger_wakeup() functions are used as a true/false detection
mechanism, take that opportunity to change their prototypes from integer
return value to boolean one.

Fixes: 9bf448c66d ("ARM: pxa: use generic gpio operation instead of
gpio register")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
This commit is contained in:
Robert Jarzmik 2016-08-02 00:01:32 +02:00
parent cd0f319bfb
commit ca26475bf0
4 changed files with 9 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
arch/arm/mach-pxa/corgi_pm.c
View file

@ -131,16 +131,11 @@ static int corgi_should_wakeup(unsigned int resume_on_alarm)
return is_resume;
}
static unsigned long corgi_charger_wakeup(void)
static bool corgi_charger_wakeup(void)
{
unsigned long ret;
ret = (!gpio_get_value(CORGI_GPIO_AC_IN) << GPIO_bit(CORGI_GPIO_AC_IN))
| (!gpio_get_value(CORGI_GPIO_KEY_INT)
<< GPIO_bit(CORGI_GPIO_KEY_INT))
| (!gpio_get_value(CORGI_GPIO_WAKEUP)
<< GPIO_bit(CORGI_GPIO_WAKEUP));
return ret;
return !gpio_get_value(CORGI_GPIO_AC_IN) ||
!gpio_get_value(CORGI_GPIO_KEY_INT) ||
!gpio_get_value(CORGI_GPIO_WAKEUP);
}
unsigned long corgipm_read_devdata(int type)

2
arch/arm/mach-pxa/sharpsl_pm.c
View file

@ -744,7 +744,7 @@ static int sharpsl_off_charge_battery(void)
time = RCNR;
while (1) {
/* Check if any wakeup event had occurred */
if (sharpsl_pm.machinfo->charger_wakeup() != 0)
if (sharpsl_pm.machinfo->charger_wakeup())
return 0;
/* Check for timeout */
if ((RCNR - time) > SHARPSL_WAIT_CO_TIME)

2
arch/arm/mach-pxa/sharpsl_pm.h
View file

@ -34,7 +34,7 @@ struct sharpsl_charger_machinfo {
#define SHARPSL_STATUS_LOCK 5
#define SHARPSL_STATUS_CHRGFULL 6
#define SHARPSL_STATUS_FATAL 7
unsigned long (*charger_wakeup)(void);
bool (*charger_wakeup)(void);
int (*should_wakeup)(unsigned int resume_on_alarm);
void (*backlight_limit)(int);
int (*backlight_get_status) (void);

9
arch/arm/mach-pxa/spitz_pm.c
View file

@ -165,13 +165,10 @@ static int spitz_should_wakeup(unsigned int resume_on_alarm)
return is_resume;
}
static unsigned long spitz_charger_wakeup(void)
static bool spitz_charger_wakeup(void)
{
unsigned long ret;
ret = ((!gpio_get_value(SPITZ_GPIO_KEY_INT)
<< GPIO_bit(SPITZ_GPIO_KEY_INT))
| gpio_get_value(SPITZ_GPIO_SYNC));
return ret;
return !gpio_get_value(SPITZ_GPIO_KEY_INT) ||
gpio_get_value(SPITZ_GPIO_SYNC);
}
unsigned long spitzpm_read_devdata(int type)