netdev - [PATCH 5/5] nvmem: core: add cell name based matching of DT cell nodes

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Message-Id: <20211223110755.22722-6-zajec5@gmail.com>
Date:   Thu, 23 Dec 2021 12:07:55 +0100
From:   Rafał Miłecki <zajec5@...il.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: [PATCH 5/5] nvmem: core: add cell name based matching of DT cell nodes

From: Rafał Miłecki <rafal@...ecki.pl>

When adding NVMEM cells defined by driver it's important to match them
with DT nodes that specify matching names. That way other bindings &
drivers can reference such "dynamic" NVMEM cells.

Signed-off-by: Rafał Miłecki <rafal@...ecki.pl>
---
 drivers/nvmem/core.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 45c39ac401bd..5fe92751645a 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -499,6 +499,33 @@ static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 	return 0;
 }
 
+/**
+ * nvmem_find_cell_of_node() - Find DT node matching nvmem cell
+ *
+ * @nvmem: nvmem device to add cells to.
+ * @name: nvmem cell name
+ *
+ * Runtime created nvmem cells (those not coming from DT) may still need to be
+ * referenced in DT. This function allows finding DT node referencing nvmem cell
+ * by its name. Such a DT node can be used by nvmem consumers.
+ *
+ * Return: NULL or pointer to DT node
+ */
+static struct device_node *nvmem_find_cell_of_node(struct nvmem_device *nvmem,
+						   const char *name)
+{
+	struct device_node *child;
+	const char *label;
+
+	for_each_child_of_node(nvmem->dev.of_node, child) {
+		if (!of_property_read_string(child, "label", &label) &&
+		    !strcmp(label, name))
+			return child;
+	}
+
+	return NULL;
+}
+
 /**
  * nvmem_add_cells() - Add cell information to an nvmem device
  *
@@ -532,6 +559,8 @@ static int nvmem_add_cells(struct nvmem_device *nvmem,
 			goto err;
 		}
 
+		cells[i]->np = nvmem_find_cell_of_node(nvmem, cells[i]->name);
+
 		nvmem_cell_entry_add(cells[i]);
 	}
 
-- 
2.31.1