Merge tag 'gpio-remove-gpiochip_is_requested-for-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into devel

gpio: remove gpiochip_is_requested()

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

Author: linusw

drivers/gpio/gpio-stmpe.c

@@ -5,6 +5,7 @@
  * Author: Rabin Vincent <[email protected]> for ST-Ericsson
  */
 
+#include <linux/cleanup.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -255,14 +256,17 @@ 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];
 	u8 mask = BIT(offset % 8);
 	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;

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) {

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) {

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

drivers/pinctrl/intel/pinctrl-baytrail.c

@@ -9,6 +9,7 @@
 #include <linux/acpi.h>
 #include <linux/array_size.h>
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/gpio/driver.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
@@ -1173,7 +1174,6 @@ static void byt_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 		const char *pull_str = NULL;
 		const char *pull = NULL;
 		unsigned long flags;
-		const char *label;
 		unsigned int pin;
 
 		pin = vg->soc->pins[i].number;
@@ -1200,9 +1200,10 @@ static void byt_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 			seq_printf(s, "Pin %i: can't retrieve community\n", pin);
 			continue;
 		}
-		label = gpiochip_is_requested(chip, i);
-		if (!label)
-			label = "Unrequested";
+
+		char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
+		if (IS_ERR(label))
+			continue;
 
 		switch (conf0 & BYT_PULL_ASSIGN_MASK) {
 		case BYT_PULL_ASSIGN_UP:
@@ -1231,7 +1232,7 @@ static void byt_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 		seq_printf(s,
 			   " gpio-%-3d (%-20.20s) %s %s %s pad-%-3d offset:0x%03x mux:%d %s%s%s",
 			   pin,
-			   label,
+			   label ?: "Unrequested",
 			   val & BYT_INPUT_EN ? "  " : "in",
 			   val & BYT_OUTPUT_EN ? "   " : "out",
 			   str_hi_lo(val & BYT_LEVEL),

drivers/pinctrl/nomadik/pinctrl-abx500.c

@@ -6,7 +6,9 @@
  *
  * Driver allows to use AxB5xx unused pins to be used as GPIO
  */
+
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/gpio/driver.h>
 #include <linux/init.h>
@@ -453,12 +455,11 @@ static void abx500_gpio_dbg_show_one(struct seq_file *s,
 				     unsigned offset, unsigned gpio)
 {
 	struct abx500_pinctrl *pct = pinctrl_dev_get_drvdata(pctldev);
-	const char *label = gpiochip_is_requested(chip, offset - 1);
 	u8 gpio_offset = offset - 1;
 	int mode = -1;
 	bool is_out;
 	bool pd;
-	int ret;
+	int ret = -ENOMEM;
 
 	const char *modes[] = {
 		[ABX500_DEFAULT]	= "default",
@@ -474,6 +475,10 @@ static void abx500_gpio_dbg_show_one(struct seq_file *s,
 		[ABX500_GPIO_PULL_UP]		= "pull up",
 	};
 
+	char *label __free(kfree) = gpiochip_dup_line_label(chip, offset - 1);
+	if (IS_ERR(label))
+		goto out;
+
 	ret = abx500_gpio_get_bit(chip, AB8500_GPIO_DIR1_REG,
 			gpio_offset, &is_out);
 	if (ret < 0)

drivers/pinctrl/nomadik/pinctrl-nomadik.c

@@ -8,6 +8,7 @@
  * Copyright (C) 2011-2013 Linus Walleij <[email protected]>
  */
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -917,7 +918,6 @@ static void nmk_gpio_dbg_show_one(struct seq_file *s,
 	struct pinctrl_dev *pctldev, struct gpio_chip *chip,
 	unsigned offset, unsigned gpio)
 {
-	const char *label = gpiochip_is_requested(chip, offset);
 	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
 	int mode;
 	bool is_out;
@@ -934,6 +934,10 @@ static void nmk_gpio_dbg_show_one(struct seq_file *s,
 		[NMK_GPIO_ALT_C+4]	= "altC4",
 	};
 
+	char *label = gpiochip_dup_line_label(chip, offset);
+	if (IS_ERR(label))
+		return;
+
 	clk_enable(nmk_chip->clk);
 	is_out = !!(readl(nmk_chip->addr + NMK_GPIO_DIR) & BIT(offset));
 	pull = !(readl(nmk_chip->addr + NMK_GPIO_PDIS) & BIT(offset));

drivers/pinctrl/sunplus/sppctl.c

@@ -4,6 +4,7 @@
  * Copyright (C) Sunplus Tech / Tibbo Tech.
  */
 
+#include <linux/cleanup.h>
 #include <linux/bitfield.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -500,16 +501,15 @@ static int sppctl_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 
 static void sppctl_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 {
-	const char *label;
 	int i;
 
 	for (i = 0; i < chip->ngpio; i++) {
-		label = gpiochip_is_requested(chip, i);
-		if (!label)
-			label = "";
+		char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
+		if (IS_ERR(label))
+			continue;
 
 		seq_printf(s, " gpio-%03d (%-16.16s | %-16.16s)", i + chip->base,
-			   chip->names[i], label);
+			   chip->names[i], label ?: "");
 		seq_printf(s, " %c", sppctl_gpio_get_direction(chip, i) ? 'I' : 'O');
 		seq_printf(s, ":%d", sppctl_gpio_get(chip, i));
 		seq_printf(s, " %s", sppctl_first_get(chip, i) ? "gpi" : "mux");

include/linux/gpio/driver.h

@@ -531,19 +531,40 @@ struct gpio_chip {
 #endif /* CONFIG_OF_GPIO */
 };
 
-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 _gpiochip_for_each_data {
+	const char **label;
+	unsigned int *i;
+};
+
+DEFINE_CLASS(_gpiochip_for_each_data,
+	     struct _gpiochip_for_each_data,
+	     if (*_T.label) kfree(*_T.label),
+	     ({
+		struct _gpiochip_for_each_data _data = { label, i };
+		*_data.i = 0;
+		_data;
+	     }),
+	     const char **label, int *i)
 
 /**
  * for_each_requested_gpio_in_range - iterates over requested GPIOs in a given range
- * @chip:	the chip to query
- * @i:		loop variable
- * @base:	first GPIO in the range
- * @size:	amount of GPIOs to check starting from @base
- * @label:	label of current GPIO
+ * @_chip:	the chip to query
+ * @_i:		loop variable
+ * @_base:	first GPIO in the range
+ * @_size:	amount of GPIOs to check starting from @base
+ * @_label:	label of current GPIO
  */
-#define for_each_requested_gpio_in_range(chip, i, base, size, label)			\
-	for (i = 0; i < size; i++)							\
-		if ((label = gpiochip_is_requested(chip, base + i)) == NULL) {} else
+#define for_each_requested_gpio_in_range(_chip, _i, _base, _size, _label)		\
+	for (CLASS(_gpiochip_for_each_data, _data)(&_label, &_i);			\
+	     *_data.i < _size;								\
+	     (*_data.i)++, kfree(*(_data.label)), *_data.label = NULL)			\
+		if ((*_data.label =							\
+			gpiochip_dup_line_label(_chip, _base + *_data.i)) == NULL) {}	\
+		else if (IS_ERR(*_data.label)) {}					\
+		else
 
 /* Iterates over all requested GPIO of the given @chip */
 #define for_each_requested_gpio(chip, i, label)						\