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>
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index f24008b..1d00f56 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1335,6 +1335,43 @@
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.
diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h
index 312bfa5..8f8be5b 100644
--- a/include/linux/nvmem-consumer.h
+++ b/include/linux/nvmem-consumer.h
@@ -61,6 +61,7 @@
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_u16(struct device *dev, const char *cell_id, u16 *val);
int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val);
/* direct nvmem device read/write interface */
@@ -122,6 +123,12 @@
return -EOPNOTSUPP;
}
+static inline int nvmem_cell_read_u16(struct device *dev,
+ const char *cell_id, u16 *val)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int nvmem_cell_read_u32(struct device *dev,
const char *cell_id, u32 *val)
{
