gpiolib: let gpio_chip reference its descriptors

Add a pointer to the gpio_chip structure that references the array of GPIO descriptors belonging to the chip, and update gpiolib code to use this pointer instead of the global gpio_desc[] array. This is another step towards the removal of the gpio_desc[] global array. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.orh> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

gpiolib: let gpio_chip reference its descriptors
Add a pointer to the gpio_chip structure that references the array of GPIO descriptors belonging to the chip, and update gpiolib code to use this pointer instead of the global gpio_desc[] array. This is another step towards the removal of the gpio_desc[] global array. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.orh> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Alexandre Courbot · Grant Likely
1 parent 372e722ea4
Showing 2 changed files with 26 additions and 16 deletions Side-by-side Diff
drivers/gpio/gpiolib.c
include/asm-generic/gpio.h
@@ -72,6 +72,8 @@
 };
 static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
  
+#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
+
 static LIST_HEAD(gpio_chips);
  
 #ifdef CONFIG_GPIO_SYSFS
@@ -112,7 +114,7 @@
  */
 static int gpio_chip_hwgpio(const struct gpio_desc *desc)
 {
-	return (desc - &gpio_desc[0]) - desc->chip->base;
+	return desc - &desc->chip->desc[0];
 }
  
 /**
@@ -133,7 +135,7 @@
  */
 static int desc_to_gpio(const struct gpio_desc *desc)
 {
-	return desc - &gpio_desc[0];
+	return desc->chip->base + gpio_chip_hwgpio(desc);
 }
  
  
@@ -1007,9 +1009,9 @@
 		unsigned	gpio;
  
 		spin_lock_irqsave(&gpio_lock, flags);
-		gpio = chip->base;
-		while (gpio_desc[gpio].chip == chip)
-			gpio_desc[gpio++].chip = NULL;
+		gpio = 0;
+		while (gpio < chip->ngpio)
+			chip->desc[gpio++].chip = NULL;
 		spin_unlock_irqrestore(&gpio_lock, flags);
  
 		pr_debug("%s: chip %s status %d\n", __func__,
  
@@ -1186,9 +1188,12 @@
 	status = gpiochip_add_to_list(chip);
  
 	if (status == 0) {
-		for (id = base; id < base + chip->ngpio; id++) {
-			gpio_desc[id].chip = chip;
+		chip->desc = &gpio_desc[chip->base];
  
+		for (id = 0; id < chip->ngpio; id++) {
+			struct gpio_desc *desc = &chip->desc[id];
+			desc->chip = chip;
+
 			/* REVISIT:  most hardware initializes GPIOs as
 			 * inputs (often with pullups enabled) so power
 			 * usage is minimized.  Linux code should set the
@@ -1196,7 +1201,7 @@
 			 * and in case chip->get_direction is not set,
 			 * we may expose the wrong direction in sysfs.
 			 */
-			gpio_desc[id].flags = !chip->direction_input
+			desc->flags = !chip->direction_input
 				? (1 << FLAG_IS_OUT)
 				: 0;
 		}
  
@@ -1249,15 +1254,15 @@
 	gpiochip_remove_pin_ranges(chip);
 	of_gpiochip_remove(chip);
  
-	for (id = chip->base; id < chip->base + chip->ngpio; id++) {
-		if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
+	for (id = 0; id < chip->ngpio; id++) {
+		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
 			status = -EBUSY;
 			break;
 		}
 	}
 	if (status == 0) {
-		for (id = chip->base; id < chip->base + chip->ngpio; id++)
-			gpio_desc[id].chip = NULL;
+		for (id = 0; id < chip->ngpio; id++)
+			chip->desc[id].chip = NULL;
  
 		list_del(&chip->list);
 	}
  
  
@@ -1582,11 +1587,13 @@
  */
 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
 {
-	unsigned gpio = chip->base + offset;
-	struct gpio_desc *desc = &gpio_desc[gpio];
+	struct gpio_desc *desc;
  
-	if (!gpio_is_valid(gpio) || desc->chip != chip)
+	if (!GPIO_OFFSET_VALID(chip, offset))
 		return NULL;
+
+	desc = &chip->desc[offset];
+
 	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
 		return NULL;
 #ifdef CONFIG_DEBUG_FS
@@ -2025,7 +2032,7 @@
 {
 	unsigned		i;
 	unsigned		gpio = chip->base;
-	struct gpio_desc	*gdesc = &gpio_desc[gpio];
+	struct gpio_desc	*gdesc = &chip->desc[0];
 	int			is_out;
  
 	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
@@ -47,6 +47,7 @@
 struct seq_file;
 struct module;
 struct device_node;
+struct gpio_desc;
  
 /**
  * struct gpio_chip - abstract a GPIO controller
@@ -76,6 +77,7 @@
  *	negative during registration, requests dynamic ID allocation.
  * @ngpio: the number of GPIOs handled by this controller; the last GPIO
  *	handled is (base + ngpio - 1).
+ * @desc: array of ngpio descriptors. Private.
  * @can_sleep: flag must be set iff get()/set() methods sleep, as they
  *	must while accessing GPIO expander chips over I2C or SPI
  * @names: if set, must be an array of strings to use as alternative
@@ -126,6 +128,7 @@
 						struct gpio_chip *chip);
 	int			base;
 	u16			ngpio;
+	struct gpio_desc	*desc;
 	const char		*const *names;
 	unsigned		can_sleep:1;
 	unsigned		exported:1;
...	...	@@ -72,6 +72,8 @@
72	72	};
73	73	static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
74	74
	75	+#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
	76	+
75	77	static LIST_HEAD(gpio_chips);
76	78
77	79	#ifdef CONFIG_GPIO_SYSFS
...	...	@@ -112,7 +114,7 @@
112	114	*/
113	115	static int gpio_chip_hwgpio(const struct gpio_desc *desc)
114	116	{
115		- return (desc - &gpio_desc[0]) - desc->chip->base;
	117	+ return desc - &desc->chip->desc[0];
116	118	}
117	119
118	120	/**
...	...	@@ -133,7 +135,7 @@
133	135	*/
134	136	static int desc_to_gpio(const struct gpio_desc *desc)
135	137	{
136		- return desc - &gpio_desc[0];
	138	+ return desc->chip->base + gpio_chip_hwgpio(desc);
137	139	}
138	140
139	141
...	...	@@ -1007,9 +1009,9 @@
1007	1009	unsigned gpio;
1008	1010
1009	1011	spin_lock_irqsave(&gpio_lock, flags);
1010		- gpio = chip->base;
1011		- while (gpio_desc[gpio].chip == chip)
1012		- gpio_desc[gpio++].chip = NULL;
	1012	+ gpio = 0;
	1013	+ while (gpio < chip->ngpio)
	1014	+ chip->desc[gpio++].chip = NULL;
1013	1015	spin_unlock_irqrestore(&gpio_lock, flags);
1014	1016
1015	1017	pr_debug("%s: chip %s status %d\n", __func__,
1016	1018
...	...	@@ -1186,9 +1188,12 @@
1186	1188	status = gpiochip_add_to_list(chip);
1187	1189
1188	1190	if (status == 0) {
1189		- for (id = base; id < base + chip->ngpio; id++) {
1190		- gpio_desc[id].chip = chip;
	1191	+ chip->desc = &gpio_desc[chip->base];
1191	1192
	1193	+ for (id = 0; id < chip->ngpio; id++) {
	1194	+ struct gpio_desc *desc = &chip->desc[id];
	1195	+ desc->chip = chip;
	1196	+
1192	1197	/* REVISIT: most hardware initializes GPIOs as
1193	1198	* inputs (often with pullups enabled) so power
1194	1199	* usage is minimized. Linux code should set the
...	...	@@ -1196,7 +1201,7 @@
1196	1201	* and in case chip->get_direction is not set,
1197	1202	* we may expose the wrong direction in sysfs.
1198	1203	*/
1199		- gpio_desc[id].flags = !chip->direction_input
	1204	+ desc->flags = !chip->direction_input
1200	1205	? (1 << FLAG_IS_OUT)
1201	1206	: 0;
1202	1207	}
1203	1208
...	...	@@ -1249,15 +1254,15 @@
1249	1254	gpiochip_remove_pin_ranges(chip);
1250	1255	of_gpiochip_remove(chip);
1251	1256
1252		- for (id = chip->base; id < chip->base + chip->ngpio; id++) {
1253		- if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
	1257	+ for (id = 0; id < chip->ngpio; id++) {
	1258	+ if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
1254	1259	status = -EBUSY;
1255	1260	break;
1256	1261	}
1257	1262	}
1258	1263	if (status == 0) {
1259		- for (id = chip->base; id < chip->base + chip->ngpio; id++)
1260		- gpio_desc[id].chip = NULL;
	1264	+ for (id = 0; id < chip->ngpio; id++)
	1265	+ chip->desc[id].chip = NULL;
1261	1266
1262	1267	list_del(&chip->list);
1263	1268	}
1264	1269
1265	1270
...	...	@@ -1582,11 +1587,13 @@
1582	1587	*/
1583	1588	const char gpiochip_is_requested(struct gpio_chip chip, unsigned offset)
1584	1589	{
1585		- unsigned gpio = chip->base + offset;
1586		- struct gpio_desc *desc = &gpio_desc[gpio];
	1590	+ struct gpio_desc *desc;
1587	1591
1588		- if (!gpio_is_valid(gpio) \|\| desc->chip != chip)
	1592	+ if (!GPIO_OFFSET_VALID(chip, offset))
1589	1593	return NULL;
	1594	+
	1595	+ desc = &chip->desc[offset];
	1596	+
1590	1597	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1591	1598	return NULL;
1592	1599	#ifdef CONFIG_DEBUG_FS
...	...	@@ -2025,7 +2032,7 @@
2025	2032	{
2026	2033	unsigned i;
2027	2034	unsigned gpio = chip->base;
2028		- struct gpio_desc *gdesc = &gpio_desc[gpio];
	2035	+ struct gpio_desc *gdesc = &chip->desc[0];
2029	2036	int is_out;
2030	2037
2031	2038	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
...	...	@@ -47,6 +47,7 @@
47	47	struct seq_file;
48	48	struct module;
49	49	struct device_node;
	50	+struct gpio_desc;
50	51
51	52	/**
52	53	* struct gpio_chip - abstract a GPIO controller
...	...	@@ -76,6 +77,7 @@
76	77	* negative during registration, requests dynamic ID allocation.
77	78	* @ngpio: the number of GPIOs handled by this controller; the last GPIO
78	79	* handled is (base + ngpio - 1).
	80	+ * @desc: array of ngpio descriptors. Private.
79	81	* @can_sleep: flag must be set iff get()/set() methods sleep, as they
80	82	* must while accessing GPIO expander chips over I2C or SPI
81	83	* @names: if set, must be an array of strings to use as alternative
...	...	@@ -126,6 +128,7 @@
126	128	struct gpio_chip *chip);
127	129	int base;
128	130	u16 ngpio;
	131	+ struct gpio_desc *desc;
129	132	const char const names;
130	133	unsigned can_sleep:1;
131	134	unsigned exported:1;