[1/6] nvmem: core: add nvmem_dev_size() helper

From: Rafał Miłecki <rafal@milecki.pl>

This is required by layouts that need to read whole NVMEM space. It
applies to NVMEM devices without hardcoded layout (like U-Boot
environment data block).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/nvmem/core.c           | 13 +++++++++++++
 include/linux/nvmem-consumer.h |  1 +
 2 files changed, 14 insertions(+)

Hi Rafał,

I love your patch! Perhaps something to improve:

[auto build test WARNING on next-20230110]
[also build test WARNING on v6.2-rc7]
[cannot apply to robh/for-next shawnguo/for-next mtd/mtd/next mtd/mtd/fixes linus/master v6.2-rc3 v6.2-rc2 v6.2-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Rafa-Mi-ecki/nvmem-core-allow-read_post_process-callbacks-to-adjust-data-length/20230110-185915
patch link:    https://lore.kernel.org/r/20230110105425.13188-1-zajec5%40gmail.com
patch subject: [PATCH 1/6] nvmem: core: add nvmem_dev_size() helper
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230211/202302112138.XOdXy4yF-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/4d5cc61f8d02a82344468f172a852ffc56cf0d5c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Rafa-Mi-ecki/nvmem-core-allow-read_post_process-callbacks-to-adjust-data-length/20230110-185915
        git checkout 4d5cc61f8d02a82344468f172a852ffc56cf0d5c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/nvmem/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202302112138.XOdXy4yF-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/nvmem/core.c:16:
>> include/linux/nvmem-consumer.h:81:1: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
      81 | const size_t nvmem_dev_size(struct nvmem_device *nvmem);
         | ^~~~~
>> drivers/nvmem/core.c:2070:1: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
    2070 | const size_t nvmem_dev_size(struct nvmem_device *nvmem)
         | ^~~~~
--
   In file included from drivers/nvmem/brcm_nvram.c:10:
>> include/linux/nvmem-consumer.h:81:1: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
      81 | const size_t nvmem_dev_size(struct nvmem_device *nvmem);
         | ^~~~~


vim +81 include/linux/nvmem-consumer.h

    49	
    50	/* Cell based interface */
    51	struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id);
    52	struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id);
    53	void nvmem_cell_put(struct nvmem_cell *cell);
    54	void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell);
    55	void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len);
    56	int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len);
    57	int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val);
    58	int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val);
    59	int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val);
    60	int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val);
    61	int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
    62					    u32 *val);
    63	int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
    64					    u64 *val);
    65	
    66	/* direct nvmem device read/write interface */
    67	struct nvmem_device *nvmem_device_get(struct device *dev, const char *name);
    68	struct nvmem_device *devm_nvmem_device_get(struct device *dev,
    69						   const char *name);
    70	void nvmem_device_put(struct nvmem_device *nvmem);
    71	void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem);
    72	int nvmem_device_read(struct nvmem_device *nvmem, unsigned int offset,
    73			      size_t bytes, void *buf);
    74	int nvmem_device_write(struct nvmem_device *nvmem, unsigned int offset,
    75			       size_t bytes, void *buf);
    76	ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
    77				   struct nvmem_cell_info *info, void *buf);
    78	int nvmem_device_cell_write(struct nvmem_device *nvmem,
    79				    struct nvmem_cell_info *info, void *buf);
    80	
  > 81	const size_t nvmem_dev_size(struct nvmem_device *nvmem);
    82	const char *nvmem_dev_name(struct nvmem_device *nvmem);
    83