From: Leonard Crestez <leonard.crestez@nxp.com>
Date: Wed, 26 Jul 2017 11:34:46 +0200
Subject: nvmem: core: Add nvmem_cell_read_u32
Patch-mainline: v4.14-rc1
Git-commit: d026d70a2e9460dc701d20b48672b80a2656006d
References: FATE#323952, FATE#322506

This function does a quick and easy read of an u32 value without any
kind of resource management code on the consumer side.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/nvmem/core.c           |   37 +++++++++++++++++++++++++++++++++++++
 include/linux/nvmem-consumer.h |    7 +++++++
 2 files changed, 44 insertions(+)

--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1104,6 +1104,43 @@ int nvmem_cell_write(struct nvmem_cell *
 EXPORT_SYMBOL_GPL(nvmem_cell_write);
 
 /**
+ * nvmem_cell_read_u32() - Read a cell value as an u32
+ *
+ * @dev: Device that requests the nvmem cell.
+ * @cell_id: Name of nvmem cell to read.
+ * @val: pointer to output value.
+ *
+ * Return: 0 on success or negative errno.
+ */
+int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
+{
+	struct nvmem_cell *cell;
+	void *buf;
+	size_t len;
+
+	cell = nvmem_cell_get(dev, cell_id);
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	buf = nvmem_cell_read(cell, &len);
+	if (IS_ERR(buf)) {
+		nvmem_cell_put(cell);
+		return PTR_ERR(buf);
+	}
+	if (len != sizeof(*val)) {
+		kfree(buf);
+		nvmem_cell_put(cell);
+		return -EINVAL;
+	}
+	memcpy(val, buf, sizeof(*val));
+
+	kfree(buf);
+	nvmem_cell_put(cell);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
+
+/**
  * nvmem_device_cell_read() - Read a given nvmem device and cell
  *
  * @nvmem: nvmem device to read from.
--- a/include/linux/nvmem-consumer.h
+++ b/include/linux/nvmem-consumer.h
@@ -35,6 +35,7 @@ void nvmem_cell_put(struct nvmem_cell *c
 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell);
 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len);
 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len);
+int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val);
 
 /* direct nvmem device read/write interface */
 struct nvmem_device *nvmem_device_get(struct device *dev, const char *name);
@@ -84,6 +85,12 @@ static inline int nvmem_cell_write(struc
 {
 	return -ENOSYS;
 }
+
+static inline int nvmem_cell_read_u32(struct device *dev,
+				      const char *cell_id, u32 *val)
+{
+	return -ENOSYS;
+}
 
 static inline struct nvmem_device *nvmem_device_get(struct device *dev,
 						    const char *name)