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Commit ca26475b authored by Robert Jarzmik's avatar Robert Jarzmik
Browse files

ARM: pxa: fix GPIO double shifts 



The commit 9bf448c6 ("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: 9bf448c6 ("ARM: pxa: use generic gpio operation instead of
gpio register")
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: default avatarRobert Jarzmik <robert.jarzmik@free.fr>
parent cd0f319b

arch/arm/mach-pxa/corgi_pm.c

+4 −9
Original line number Diff line number Diff line
@@ -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)

arch/arm/mach-pxa/sharpsl_pm.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

arch/arm/mach-pxa/sharpsl_pm.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/arm/mach-pxa/spitz_pm.c

+3 −6
Original line number Diff line number Diff line
@@ -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)