dm: gpio: Add dm_gpio_lookup_name() to look up a GPIO name

Provide a driver-model function to look up a GPIO name. Make the standard
function use it.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/gpio/gpio-uclass.c

@@ -48,8 +48,7 @@ static int gpio_to_device(unsigned int gpio, struct gpio_desc *desc)
 	return ret ? ret : -ENOENT;
 }
 
-int gpio_lookup_name(const char *name, struct udevice **devp,
-		     unsigned int *offsetp, unsigned int *gpiop)
+int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc)
 {
 	struct gpio_dev_priv *uc_priv = NULL;
 	struct udevice *dev;
@@ -57,8 +56,6 @@ int gpio_lookup_name(const char *name, struct udevice **devp,
 	int numeric;
 	int ret;
 
-	if (devp)
-		*devp = NULL;
 	numeric = isdigit(*name) ? simple_strtoul(name, NULL, 10) : -1;
 	for (ret = uclass_first_device(UCLASS_GPIO, &dev);
 	     dev;
@@ -84,12 +81,33 @@ int gpio_lookup_name(const char *name, struct udevice **devp,
 	if (!dev)
 		return ret ? ret : -EINVAL;
 
+	desc->dev = dev;
+	desc->offset = offset;
+
+	return 0;
+}
+
+int gpio_lookup_name(const char *name, struct udevice **devp,
+		     unsigned int *offsetp, unsigned int *gpiop)
+{
+	struct gpio_desc desc;
+	int ret;
+
+	if (devp)
+		*devp = NULL;
+	ret = dm_gpio_lookup_name(name, &desc);
+	if (ret)
+		return ret;
+
 	if (devp)
-		*devp = dev;
+		*devp = desc.dev;
 	if (offsetp)
-		*offsetp = offset;
-	if (gpiop)
-		*gpiop = uc_priv->gpio_base + offset;
+		*offsetp = desc.offset;
+	if (gpiop) {
+		struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(desc.dev);
+
+		*gpiop = uc_priv->gpio_base + desc.offset;
+	}
 
 	return 0;
 }

include/asm-generic/gpio.h

@@ -322,6 +322,19 @@ struct gpio_dev_priv {
 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
 
 /**
+ * dm_gpio_lookup_name() - Look up a named GPIO and return its description
+ *
+ * The name of a GPIO is typically its bank name followed by a number from 0.
+ * For example A0 is the first GPIO in bank A. Each bank is a separate driver
+ * model device.
+ *
+ * @name:	Name to look up
+ * @desc:	Returns description, on success
+ * @return 0 if OK, -ve on error
+ */
+int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
+
+/**
  * gpio_lookup_name - Look up a GPIO name and return its details
  *
  * This is used to convert a named GPIO into a device, offset and GPIO