[PATCH v5 04/10] regulator: Do pure DT regulator lookup in of_regulator_bulk_get_all()

[Chen-Yu Tsai <wenst@chromium.org>]

The to-be-introduced I2C component prober needs to enable regulator
supplies (and toggle GPIO pins) for the various components it intends
to probe. To support this, a new "pure DT lookup" method for getting
regulator supplies is needed, since the device normally requesting
the supply won't get created until after the component is probed to
be available.

Convert the existing of_regulator_bulk_get_all() for this purpose.
This function has no in-tree users, as the original patch [1] that
used it was never landed. This patch changes the function ABI, but
it is straightforward to convert users.

The underlying code that supports the existing regulator_get*()
functions has been reworked in previous patches to support this
specific case. An internal OF-specific version of regulator_get(),
of_regulator_get_optional(), is added for this.

[1] https://lore.kernel.org/all/20231220203537.83479-2-jernej.skrabec@gmail.com/

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v4:
- Was "regulator: Add regulator_of_get_optional() for pure DT" in v4
- Restore platform-agnostic regulator consumer code to original state
- Move OF-specific regulator code to of_regulator.c (separate patch)
- Split _regulator_get() into three parts for reuse (separate patch)
- Add OF-specific _of_regulator_get() function
- Rename regulator_of_get_optional() to of_regulator_get_optional() for
  consistency
- Make of_regulator_get_optional() static, as it is only used internally
- Convert of_regulator_bulk_get_all()
Changes since v3:
- New patch
---
 drivers/regulator/core.c         |  2 +-
 drivers/regulator/internal.h     |  2 ++
 drivers/regulator/of_regulator.c | 54 +++++++++++++++++++++++++++-----
 3 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 4d1c640cc030..d70302e30731 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1950,7 +1950,7 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 
 	/* first do a dt based lookup */
 	if (dev && dev->of_node) {
-		r = of_regulator_dev_lookup(dev, supply);
+		r = of_regulator_dev_lookup(dev, dev->of_node, supply);
 		if (!IS_ERR(r))
 			return r;
 		if (PTR_ERR(r) == -EPROBE_DEFER)
diff --git a/drivers/regulator/internal.h b/drivers/regulator/internal.h
index 3718459fb0c5..44680ce3587b 100644
--- a/drivers/regulator/internal.h
+++ b/drivers/regulator/internal.h
@@ -67,6 +67,7 @@ static inline struct regulator_dev *dev_to_rdev(struct device *dev)
 
 #ifdef CONFIG_OF
 struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+					      struct device_node *np,
 					      const char *supply);
 struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
 			         const struct regulator_desc *desc,
@@ -82,6 +83,7 @@ bool of_check_coupling_data(struct regulator_dev *rdev);
 
 #else
 static inline struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+							    struct device_node *np,
 							    const char *supply)
 {
 	return -ENODEV;
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index d924f5c1de59..67a5882a917e 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -587,22 +587,24 @@ static struct device_node *of_get_child_regulator(struct device_node *parent,
 
 /**
  * of_get_regulator - get a regulator device node based on supply name
- * @dev: Device pointer for the consumer (of regulator) device
+ * @dev: Device pointer for dev_printk messages
+ * @node: Device node pointer for supply property lookup
  * @supply: regulator supply name
  *
  * Extract the regulator device node corresponding to the supply name.
  * returns the device node corresponding to the regulator if found, else
  * returns NULL.
  */
-static struct device_node *of_get_regulator(struct device *dev, const char *supply)
+static struct device_node *of_get_regulator(struct device *dev, struct device_node *node,
+					    const char *supply)
 {
 	struct device_node *regnode = NULL;
 	char prop_name[64]; /* 64 is max size of property name */
 
-	dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);
+	dev_dbg(dev, "Looking up %s-supply from device node %pOF\n", supply, node);
 
 	snprintf(prop_name, 64, "%s-supply", supply);
-	regnode = of_parse_phandle(dev->of_node, prop_name, 0);
+	regnode = of_parse_phandle(node, prop_name, 0);
 
 	if (!regnode) {
 		regnode = of_get_child_regulator(dev->of_node, prop_name);
@@ -626,7 +628,8 @@ static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
 }
 
 /** of_regulator_dev_lookup - lookup a regulator device with device tree only
- * @dev: Device pointer for regulator supply lookup.
+ * @dev: Device pointer for dev_printk messages.
+ * @node: Device node pointer for regulator supply lookup.
  * @supply: Supply name or regulator ID.
  *
  * If successful, returns a struct regulator_dev that corresponds to the name
@@ -636,13 +639,13 @@ static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
  * -ENODEV if lookup fails permanently, -EPROBE_DEFER if lookup could succeed
  * in the future.
  */
-struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+struct regulator_dev *of_regulator_dev_lookup(struct device *dev, struct device_node *np,
 					      const char *supply)
 {
 	struct regulator_dev *r;
 	struct device_node *node;
 
-	node = of_get_regulator(dev, supply);
+	node = of_get_regulator(dev, np, supply);
 	if (node) {
 		r = of_find_regulator_by_node(node);
 		of_node_put(node);
@@ -659,6 +662,41 @@ struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
+static struct regulator *_of_regulator_get(struct device *dev, struct device_node *node,
+					   const char *id, enum regulator_get_type get_type)
+{
+	struct regulator_dev *r;
+	int ret;
+
+	ret = _regulator_get_common_check(dev, id, get_type);
+	if (ret)
+		return ERR_PTR(ret);
+
+	r = of_regulator_dev_lookup(dev, node, id);
+	return _regulator_get_common(r, dev, id, get_type);
+}
+
+/**
+ * of_regulator_get_optional - get optional regulator via device tree lookup
+ * @dev: device used for dev_printk messages
+ * @node: device node for regulator "consumer"
+ * @id: Supply name
+ *
+ * Returns a struct regulator corresponding to the regulator producer,
+ * or IS_ERR() condition containing errno.
+ *
+ * This is intended for use by consumers that want to get a regulator
+ * supply directly from a device node, and can and want to deal with
+ * absence of such supplies. This will _not_ consider supply aliases.
+ * See regulator_dev_lookup().
+ */
+static struct regulator *of_regulator_get_optional(struct device *dev,
+						   struct device_node *node,
+						   const char *id)
+{
+	return _of_regulator_get(NULL, node, id, OPTIONAL_GET);
+}
+
 /*
  * Returns number of regulators coupled with rdev.
  */
@@ -875,7 +913,7 @@ int of_regulator_bulk_get_all(struct device *dev, struct device_node *np,
 		} else {
 			memcpy(name, prop->name, i);
 			name[i] = '\0';
-			tmp = regulator_get(dev, name);
+			tmp = of_regulator_get_optional(dev, np, name);
 			if (IS_ERR(tmp)) {
 				ret = PTR_ERR(tmp);
 				goto error;
-- 
2.46.0.184.g6999bdac58-goog