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nvmem: core: Add nvmem_cell_read_u32 

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>
hifive-unleashed-5.1
Leonard Crestez 2017-07-26 11:34:46 +02:00 committed by Greg Kroah-Hartman
parent 5f214ccdd1
commit d026d70a2e
2 changed files with 44 additions and 0 deletions
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37
drivers/nvmem/core.c
View File

@ -1110,6 +1110,43 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
}
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
*

7
include/linux/nvmem-consumer.h
View File

@ -35,6 +35,7 @@ void nvmem_cell_put(struct nvmem_cell *cell);
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);
@ -85,6 +86,12 @@ static inline int nvmem_cell_write(struct nvmem_cell *cell,
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)
{