gpiolib: improve coding style for local variables

[mirror_ubuntu-jammy-kernel.git] / drivers / gpio / gpiolib.c

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index d1b9b721218f2c5e9362024445008e2f29f13609..a87c4cd94f7aca14c559db74067c421d890e8411 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -594,11 +594,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
                               struct lock_class_key *request_key)
 {
        struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL;
-       unsigned long   flags;
-       int             ret = 0;
-       unsigned        i;
-       int             base = gc->base;
        struct gpio_device *gdev;
+       unsigned long flags;
+       int base = gc->base;
+       unsigned int i;
+       int ret = 0;
 
        /*
         * First: allocate and populate the internal stat container, and
@@ -1368,6 +1368,16 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
        struct irq_domain *domain = gc->irq.domain;
 
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+       /*
+        * Avoid race condition with other code, which tries to lookup
+        * an IRQ before the irqchip has been properly registered,
+        * i.e. while gpiochip is still being brought up.
+        */
+       if (!gc->irq.initialized)
+               return -EPROBE_DEFER;
+#endif
+
        if (!gpiochip_irqchip_irq_valid(gc, offset))
                return -ENXIO;
 
@@ -1550,6 +1560,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
 
        gpiochip_set_irq_hooks(gc);
 
+       /*
+        * Using barrier() here to prevent compiler from reordering
+        * gc->irq.initialized before initialization of above
+        * GPIO chip irq members.
+        */
+       barrier();
+
+       gc->irq.initialized = true;
+
        acpi_gpiochip_request_interrupts(gc);
 
        return 0;
@@ -2186,6 +2205,16 @@ static int gpio_set_bias(struct gpio_desc *desc)
        return gpio_set_config_with_argument_optional(desc, bias, arg);
 }
 
+/**
+ * gpio_set_debounce_timeout() - Set debounce timeout
+ * @desc:      GPIO descriptor to set the debounce timeout
+ * @debounce:  Debounce timeout in microseconds
+ *
+ * The function calls the certain GPIO driver to set debounce timeout
+ * in the hardware.
+ *
+ * Returns 0 on success, or negative error code otherwise.
+ */
 int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce)
 {
        return gpio_set_config_with_argument_optional(desc,
@@ -3106,6 +3135,16 @@ int gpiod_to_irq(const struct gpio_desc *desc)
 
                return retirq;
        }
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+       if (gc->irq.chip) {
+               /*
+                * Avoid race condition with other code, which tries to lookup
+                * an IRQ before the irqchip has been properly registered,
+                * i.e. while gpiochip is still being brought up.
+                */
+               return -EPROBE_DEFER;
+       }
+#endif
        return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(gpiod_to_irq);