nvmem: core: add nvmem_cell_read_u16

Add nvmem_cell_read_u16() helper to ease read of an u16 value on consumer
side. This is inspired by nvmem_cell_read_u32() function.
This helper is useful on stm32 that has 16 bits data cells stored in non
volatile memory.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index f24008b66826..1d00f5671368 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1335,6 +1335,43 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
 EXPORT_SYMBOL_GPL(nvmem_cell_write);
 
 /**
+ * nvmem_cell_read_u16() - Read a cell value as an u16
+ *
+ * @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_u16(struct device *dev, const char *cell_id, u16 *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_u16);
+
+/**
  * nvmem_cell_read_u32() - Read a cell value as an u32
  *
  * @dev: Device that requests the nvmem cell.