Merge tag 'gpio-remove-gpiochip_is_requested-for-v6.8-rc1' into gpio/for-next

gpio: remove gpiochip_is_requested()

- provide a safer alternative to gpiochip_is_requested()
- convert all existing users
- remove gpiochip_is_requested()

4 files changed, 43 insertions, 25 deletions

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 27cc4da53565..6c5ee81d71b3 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -5,6 +5,7 @@
  * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
  */
 
+#include <linux/cleanup.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -255,7 +256,6 @@ static void stmpe_dbg_show_one(struct seq_file *s,
 {
 	struct stmpe_gpio *stmpe_gpio = gpiochip_get_data(gc);
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
-	const char *label = gpiochip_is_requested(gc, offset);
 	bool val = !!stmpe_gpio_get(gc, offset);
 	u8 bank = offset / 8;
 	u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB + bank];
@@ -263,6 +263,10 @@ static void stmpe_dbg_show_one(struct seq_file *s,
 	int ret;
 	u8 dir;
 
+	char *label __free(kfree) = gpiochip_dup_line_label(gc, offset);
+	if (IS_ERR(label))
+		return;
+
 	ret = stmpe_reg_read(stmpe, dir_reg);
 	if (ret < 0)
 		return;
diff --git a/drivers/gpio/gpio-wm831x.c b/drivers/gpio/gpio-wm831x.c
index 7eaf8a28638c..f7d5120ff8f1 100644
--- a/drivers/gpio/gpio-wm831x.c
+++ b/drivers/gpio/gpio-wm831x.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/cleanup.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -160,18 +161,21 @@ static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	for (i = 0; i < chip->ngpio; i++) {
 		int gpio = i + chip->base;
 		int reg;
-		const char *label, *pull, *powerdomain;
+		const char *pull, *powerdomain;
 
 		/* We report the GPIO even if it's not requested since
 		 * we're also reporting things like alternate
 		 * functions which apply even when the GPIO is not in
 		 * use as a GPIO.
 		 */
-		label = gpiochip_is_requested(chip, i);
-		if (!label)
-			label = "Unrequested";
+		char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
+		if (IS_ERR(label)) {
+			dev_err(wm831x->dev, "Failed to duplicate label\n");
+			continue;
+		}
 
-		seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
+		seq_printf(s, " gpio-%-3d (%-20.20s) ",
+			   gpio, label ?: "Unrequested");
 
 		reg = wm831x_reg_read(wm831x, WM831X_GPIO1_CONTROL + i);
 		if (reg < 0) {
diff --git a/drivers/gpio/gpio-wm8994.c b/drivers/gpio/gpio-wm8994.c
index f4a474cef32d..bf05c9b5882b 100644
--- a/drivers/gpio/gpio-wm8994.c
+++ b/drivers/gpio/gpio-wm8994.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/cleanup.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -193,18 +194,20 @@ static void wm8994_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	for (i = 0; i < chip->ngpio; i++) {
 		int gpio = i + chip->base;
 		int reg;
-		const char *label;
 
 		/* We report the GPIO even if it's not requested since
 		 * we're also reporting things like alternate
 		 * functions which apply even when the GPIO is not in
 		 * use as a GPIO.
 		 */
-		label = gpiochip_is_requested(chip, i);
-		if (!label)
-			label = "Unrequested";
+		char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
+		if (IS_ERR(label)) {
+			dev_err(wm8994->dev, "Failed to duplicate label\n");
+			continue;
+		}
 
-		seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
+		seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio,
+			   label ?: "Unrequested");
 
 		reg = wm8994_reg_read(wm8994, WM8994_GPIO_1 + i);
 		if (reg < 0) {
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a5faaea6915d..4e190be75dc2 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1085,7 +1085,7 @@ void gpiochip_remove(struct gpio_chip *gc)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 	for (i = 0; i < gdev->ngpio; i++) {
-		if (gpiochip_is_requested(gc, i))
+		if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags))
 			break;
 	}
 	spin_unlock_irqrestore(&gpio_lock, flags);
@@ -2374,31 +2374,38 @@ void gpiod_free(struct gpio_desc *desc)
 }
 
 /**
- * gpiochip_is_requested - return string iff signal was requested
- * @gc: controller managing the signal
- * @offset: of signal within controller's 0..(ngpio - 1) range
+ * gpiochip_dup_line_label - Get a copy of the consumer label.
+ * @gc: GPIO chip controlling this line.
+ * @offset: Hardware offset of the line.
  *
- * Returns NULL if the GPIO is not currently requested, else a string.
- * The string returned is the label passed to gpio_request(); if none has been
- * passed it is a meaningless, non-NULL constant.
+ * Returns:
+ * Pointer to a copy of the consumer label if the line is requested or NULL
+ * if it's not. If a valid pointer was returned, it must be freed using
+ * kfree(). In case of a memory allocation error, the function returns %ENOMEM.
  *
- * This function is for use by GPIO controller drivers.  The label can
- * help with diagnostics, and knowing that the signal is used as a GPIO
- * can help avoid accidentally multiplexing it to another controller.
+ * Must not be called from atomic context.
  */
-const char *gpiochip_is_requested(struct gpio_chip *gc, unsigned int offset)
+char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_desc *desc;
+	char *label;
 
 	desc = gpiochip_get_desc(gc, offset);
 	if (IS_ERR(desc))
 		return NULL;
 
-	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
+	guard(spinlock_irqsave)(&gpio_lock);
+
+	if (!test_bit(FLAG_REQUESTED, &desc->flags))
 		return NULL;
-	return desc->label;
+
+	label = kstrdup(desc->label, GFP_KERNEL);
+	if (!label)
+		return ERR_PTR(-ENOMEM);
+
+	return label;
 }
-EXPORT_SYMBOL_GPL(gpiochip_is_requested);
+EXPORT_SYMBOL_GPL(gpiochip_dup_line_label);
 
 /**
  * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor