2 files changed, 76 insertions, 27 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index aa6a11b..8fbc67a 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1458,26 +1458,14 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
  * on each other, and help provide better diagnostics in debugfs.
  * They're called even less than the "set direction" calls.
  */
-static int gpiod_request(struct gpio_desc *desc, const char *label)
+static int __gpiod_request(struct gpio_desc *desc, const char *label)
 {
-	struct gpio_chip	*chip;
-	int			status = -EPROBE_DEFER;
+	struct gpio_chip	*chip = desc->chip;
+	int			status;
 	unsigned long		flags;
 
-	if (!desc) {
-		pr_warn("%s: invalid GPIO\n", __func__);
-		return -EINVAL;
-	}
-
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	chip = desc->chip;
-	if (chip == NULL)
-		goto done;
-
-	if (!try_module_get(chip->owner))
-		goto done;
-
 	/* NOTE:  gpio_request() can be called in early boot,
 	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
 	 */
@@ -1487,7 +1475,6 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 		status = 0;
 	} else {
 		status = -EBUSY;
-		module_put(chip->owner);
 		goto done;
 	}
 
@@ -1499,7 +1486,6 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 
 		if (status < 0) {
 			desc_set_label(desc, NULL);
-			module_put(chip->owner);
 			clear_bit(FLAG_REQUESTED, &desc->flags);
 			goto done;
 		}
@@ -1511,9 +1497,34 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 		spin_lock_irqsave(&gpio_lock, flags);
 	}
 done:
+	spin_unlock_irqrestore(&gpio_lock, flags);
+	return status;
+}
+
+static int gpiod_request(struct gpio_desc *desc, const char *label)
+{
+	int status = -EPROBE_DEFER;
+	struct gpio_chip *chip;
+
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
+	chip = desc->chip;
+	if (!chip)
+		goto done;
+
+	if (try_module_get(chip->owner)) {
+		status = __gpiod_request(desc, label);
+		if (status < 0)
+			module_put(chip->owner);
+	}
+
+done:
 	if (status)
 		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
-	spin_unlock_irqrestore(&gpio_lock, flags);
+
 	return status;
 }
 
@@ -1523,18 +1534,14 @@ int gpio_request(unsigned gpio, const char *label)
 }
 EXPORT_SYMBOL_GPL(gpio_request);
 
-static void gpiod_free(struct gpio_desc *desc)
+static bool __gpiod_free(struct gpio_desc *desc)
 {
+	bool			ret = false;
 	unsigned long		flags;
 	struct gpio_chip	*chip;
 
 	might_sleep();
 
-	if (!desc) {
-		WARN_ON(extra_checks);
-		return;
-	}
-
 	gpiod_unexport(desc);
 
 	spin_lock_irqsave(&gpio_lock, flags);
@@ -1548,15 +1555,23 @@ static void gpiod_free(struct gpio_desc *desc)
 			spin_lock_irqsave(&gpio_lock, flags);
 		}
 		desc_set_label(desc, NULL);
-		module_put(desc->chip->owner);
 		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
 		clear_bit(FLAG_REQUESTED, &desc->flags);
 		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
 		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
-	} else
-		WARN_ON(extra_checks);
+		ret = true;
+	}
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
+	return ret;
+}
+
+static void gpiod_free(struct gpio_desc *desc)
+{
+	if (desc && __gpiod_free(desc))
+		module_put(desc->chip->owner);
+	else
+		WARN_ON(extra_checks);
 }
 
 void gpio_free(unsigned gpio)
@@ -1678,6 +1693,37 @@ const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
 }
 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
 
+/**
+ * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
+ * @desc: GPIO descriptor to request
+ * @label: label for the GPIO
+ *
+ * Function allows GPIO chip drivers to request and use their own GPIO
+ * descriptors via gpiolib API. Difference to gpiod_request() is that this
+ * function will not increase reference count of the GPIO chip module. This
+ * allows the GPIO chip module to be unloaded as needed (we assume that the
+ * GPIO chip driver handles freeing the GPIOs it has requested).
+ */
+int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label)
+{
+	if (!desc || !desc->chip)
+		return -EINVAL;
+
+	return __gpiod_request(desc, label);
+}
+
+/**
+ * gpiochip_free_own_desc - Free GPIO requested by the chip driver
+ * @desc: GPIO descriptor to free
+ *
+ * Function frees the given GPIO requested previously with
+ * gpiochip_request_own_desc().
+ */
+void gpiochip_free_own_desc(struct gpio_desc *desc)
+{
+	if (desc)
+		__gpiod_free(desc);
+}
 
 /* Drivers MUST set GPIO direction before making get/set calls.  In
  * some cases this is done in early boot, before IRQs are enabled.
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 82be586..cf09294 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -43,4 +43,7 @@ acpi_get_gpiod_by_index(struct device *dev, int index,
 }
 #endif
 
+int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label);
+void gpiochip_free_own_desc(struct gpio_desc *desc);
+
 #endif /* GPIOLIB_H */