gpio: define gpio_is_valid()

Introduce a gpio_is_valid() predicate; use it in gpiolib. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de> [ use inline function; follow the gpio_* naming convention; work without gpiolib; all programming interfaces need docs ] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

gpio: define gpio_is_valid()
Introduce a gpio_is_valid() predicate; use it in gpiolib. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de> [ use inline function; follow the gpio_* naming convention; work without gpiolib; all programming interfaces need docs ] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Guennadi Liakhovetski · Linus Torvalds
1 parent d72cbed0c4
Showing 3 changed files with 29 additions and 7 deletions Side-by-side Diff
Documentation/gpio.txt
drivers/gpio/gpiolib.c
include/asm-generic/gpio.h
@@ -107,6 +107,16 @@
 The numbers need not be contiguous; either of those platforms could also
 use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders.
  
+If you want to initialize a structure with an invalid GPIO number, use
+some negative number (perhaps "-EINVAL"); that will never be valid.  To
+test if a number could reference a GPIO, you may use this predicate:
+
+	int gpio_is_valid(int number);
+
+A number that's not valid will be rejected by calls which may request
+or free GPIOs (see below).  Other numbers may also be rejected; for
+example, a number might be valid but unused on a given board.
+
 Whether a platform supports multiple GPIO controllers is currently a
 platform-specific implementation issue.
  
@@ -99,7 +99,7 @@
 	 * dynamic allocation.  We don't currently support that.
 	 */
  
-	if (chip->base < 0 || (chip->base  + chip->ngpio) >= ARCH_NR_GPIOS) {
+	if (chip->base < 0 || !gpio_is_valid(chip->base  + chip->ngpio)) {
 		status = -EINVAL;
 		goto fail;
 	}
@@ -174,7 +174,7 @@
  
 	spin_lock_irqsave(&gpio_lock, flags);
  
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto done;
 	desc = &gpio_desc[gpio];
 	if (desc->chip == NULL)
@@ -209,7 +209,7 @@
 	unsigned long		flags;
 	struct gpio_desc	*desc;
  
-	if (gpio >= ARCH_NR_GPIOS) {
+	if (!gpio_is_valid(gpio)) {
 		WARN_ON(extra_checks);
 		return;
 	}
@@ -245,7 +245,7 @@
 {
 	unsigned gpio = chip->base + offset;
  
-	if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip)
+	if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
 		return NULL;
 	if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
 		return NULL;
@@ -276,7 +276,7 @@
  
 	spin_lock_irqsave(&gpio_lock, flags);
  
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->get || !chip->direction_input)
@@ -314,7 +314,7 @@
  
 	spin_lock_irqsave(&gpio_lock, flags);
  
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->direction_output)
@@ -531,7 +531,7 @@
  
 	/* REVISIT this isn't locked against gpio_chip removal ... */
  
-	for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
+	for (gpio = 0; gpio_is_valid(gpio); gpio++) {
 		if (chip == gpio_desc[gpio].chip)
 			continue;
 		chip = gpio_desc[gpio].chip;
@@ -16,6 +16,12 @@
 #define ARCH_NR_GPIOS		256
 #endif
  
+static inline int gpio_is_valid(int number)
+{
+	/* only some non-negative numbers are valid */
+	return ((unsigned)number) < ARCH_NR_GPIOS;
+}
+
 struct seq_file;
 struct module;
  
@@ -98,6 +104,12 @@
  
  
 #else
+
+static inline int gpio_is_valid(int number)
+{
+	/* only non-negative numbers are valid */
+	return number >= 0;
+}
  
 /* platforms that don't directly support access to GPIOs through I2C, SPI,
  * or other blocking infrastructure can use these wrappers.
...	...	@@ -107,6 +107,16 @@
107	107	The numbers need not be contiguous; either of those platforms could also
108	108	use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders.
109	109
	110	+If you want to initialize a structure with an invalid GPIO number, use
	111	+some negative number (perhaps "-EINVAL"); that will never be valid. To
	112	+test if a number could reference a GPIO, you may use this predicate:
	113	+
	114	+ int gpio_is_valid(int number);
	115	+
	116	+A number that's not valid will be rejected by calls which may request
	117	+or free GPIOs (see below). Other numbers may also be rejected; for
	118	+example, a number might be valid but unused on a given board.
	119	+
110	120	Whether a platform supports multiple GPIO controllers is currently a
111	121	platform-specific implementation issue.
112	122
...	...	@@ -99,7 +99,7 @@
99	99	* dynamic allocation. We don't currently support that.
100	100	*/
101	101
102		- if (chip->base < 0 \|\| (chip->base + chip->ngpio) >= ARCH_NR_GPIOS) {
	102	+ if (chip->base < 0 \|\| !gpio_is_valid(chip->base + chip->ngpio)) {
103	103	status = -EINVAL;
104	104	goto fail;
105	105	}
...	...	@@ -174,7 +174,7 @@
174	174
175	175	spin_lock_irqsave(&gpio_lock, flags);
176	176
177		- if (gpio >= ARCH_NR_GPIOS)
	177	+ if (!gpio_is_valid(gpio))
178	178	goto done;
179	179	desc = &gpio_desc[gpio];
180	180	if (desc->chip == NULL)
...	...	@@ -209,7 +209,7 @@
209	209	unsigned long flags;
210	210	struct gpio_desc *desc;
211	211
212		- if (gpio >= ARCH_NR_GPIOS) {
	212	+ if (!gpio_is_valid(gpio)) {
213	213	WARN_ON(extra_checks);
214	214	return;
215	215	}
...	...	@@ -245,7 +245,7 @@
245	245	{
246	246	unsigned gpio = chip->base + offset;
247	247
248		- if (gpio >= ARCH_NR_GPIOS \|\| gpio_desc[gpio].chip != chip)
	248	+ if (!gpio_is_valid(gpio) \|\| gpio_desc[gpio].chip != chip)
249	249	return NULL;
250	250	if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
251	251	return NULL;
...	...	@@ -276,7 +276,7 @@
276	276
277	277	spin_lock_irqsave(&gpio_lock, flags);
278	278
279		- if (gpio >= ARCH_NR_GPIOS)
	279	+ if (!gpio_is_valid(gpio))
280	280	goto fail;
281	281	chip = desc->chip;
282	282	if (!chip \|\| !chip->get \|\| !chip->direction_input)
...	...	@@ -314,7 +314,7 @@
314	314
315	315	spin_lock_irqsave(&gpio_lock, flags);
316	316
317		- if (gpio >= ARCH_NR_GPIOS)
	317	+ if (!gpio_is_valid(gpio))
318	318	goto fail;
319	319	chip = desc->chip;
320	320	if (!chip \|\| !chip->set \|\| !chip->direction_output)
...	...	@@ -531,7 +531,7 @@
531	531
532	532	/* REVISIT this isn't locked against gpio_chip removal ... */
533	533
534		- for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
	534	+ for (gpio = 0; gpio_is_valid(gpio); gpio++) {
535	535	if (chip == gpio_desc[gpio].chip)
536	536	continue;
537	537	chip = gpio_desc[gpio].chip;
...	...	@@ -16,6 +16,12 @@
16	16	#define ARCH_NR_GPIOS 256
17	17	#endif
18	18
	19	+static inline int gpio_is_valid(int number)
	20	+{
	21	+ /* only some non-negative numbers are valid */
	22	+ return ((unsigned)number) < ARCH_NR_GPIOS;
	23	+}
	24	+
19	25	struct seq_file;
20	26	struct module;
21	27
...	...	@@ -98,6 +104,12 @@
98	104
99	105
100	106	#else
	107	+
	108	+static inline int gpio_is_valid(int number)
	109	+{
	110	+ /* only non-negative numbers are valid */
	111	+ return number >= 0;
	112	+}
101	113
102	114	/* platforms that don't directly support access to GPIOs through I2C, SPI,
103	115	* or other blocking infrastructure can use these wrappers.