firmware: exynos-acpm: introduce devm_acpm_get_by_node()

To allow ACPM clients to simply be children of the ACPM node in DT,
they need to be able to get the ACPM handle based on that ACPM node
directly.

Add an API to allow them to do so, devm_acpm_get_by_node().

At the same time, the previous approach of acquiring the ACPM handle
via a DT phandle is now obsolete and we can remove
devm_acpm_get_by_phandle(), which was there to facilitate that. There
are no existing or anticipated upcoming users of that API, because all
clients should be children of the ACPM node going forward.

Note that no DTs have been merged that use the old approach, so doing
this API change in this driver now will not affect any existing DTs or
client drivers.

Signed-off-by: André Draszik <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

drivers/firmware/samsung/exynos-acpm.c

···
  *
  * Return: pointer to handle on success, ERR_PTR(-errno) otherwise.
  */
-static const struct acpm_handle *acpm_get_by_phandle(struct device *dev,
-						     const char *property)
+static const struct acpm_handle *acpm_get_by_node(struct device *dev,
+						  struct device_node *acpm_np)
 {
 	struct platform_device *pdev;
-	struct device_node *acpm_np;
 	struct device_link *link;
 	struct acpm_info *acpm;
 
-	acpm_np = of_parse_phandle(dev->of_node, property, 0);
-	if (!acpm_np)
-		return ERR_PTR(-ENODEV);
-
 	pdev = of_find_device_by_node(acpm_np);
-	of_node_put(acpm_np);
 	if (!pdev)
 		return ERR_PTR(-EPROBE_DEFER);
 
···
 }
 
 /**
- * devm_acpm_get_by_phandle() - managed get handle using phandle.
- * @dev:        device pointer requesting ACPM handle.
- * @property:   property name containing phandle on ACPM node.
+ * devm_acpm_get_by_node() - managed get handle using node pointer.
+ * @dev: device pointer requesting ACPM handle.
+ * @np:  ACPM device tree node.
  *
  * Return: pointer to handle on success, ERR_PTR(-errno) otherwise.
  */
-const struct acpm_handle *devm_acpm_get_by_phandle(struct device *dev,
-						   const char *property)
+const struct acpm_handle *devm_acpm_get_by_node(struct device *dev,
+						struct device_node *np)
 {
 	const struct acpm_handle **ptr, *handle;
 
···
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	handle = acpm_get_by_phandle(dev, property);
+	handle = acpm_get_by_node(dev, np);
 	if (!IS_ERR(handle)) {
 		*ptr = handle;
 		devres_add(dev, ptr);
···
 
 	return handle;
 }
+EXPORT_SYMBOL_GPL(devm_acpm_get_by_node);
 
 static const struct acpm_match_data acpm_gs101 = {
 	.initdata_base = ACPM_GS101_INITDATA_BASE,

include/linux/firmware/samsung/exynos-acpm-protocol.h

···
 #include <linux/types.h>
 
 struct acpm_handle;
+struct device_node;
 
 struct acpm_pmic_ops {
 	int (*read_reg)(const struct acpm_handle *handle,
···
 
 struct device;
 
-const struct acpm_handle *devm_acpm_get_by_phandle(struct device *dev,
-						   const char *property);
+const struct acpm_handle *devm_acpm_get_by_node(struct device *dev,
+						struct device_node *np);
+
 #endif /* __EXYNOS_ACPM_PROTOCOL_H */