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Diffstat (limited to 'Documentation/driver-api/nvmem.rst')
| -rw-r--r-- | Documentation/driver-api/nvmem.rst | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/Documentation/driver-api/nvmem.rst b/Documentation/driver-api/nvmem.rst index e3366322d46c..790e2dc652c0 100644 --- a/Documentation/driver-api/nvmem.rst +++ b/Documentation/driver-api/nvmem.rst @@ -41,7 +41,7 @@ A NVMEM provider can register with NVMEM core by supplying relevant nvmem configuration to nvmem_register(), on success core would return a valid nvmem_device pointer. -nvmem_unregister(nvmem) is used to unregister a previously registered provider. +nvmem_unregister() is used to unregister a previously registered provider. For example, a simple nvram case:: @@ -59,10 +59,10 @@ For example, a simple nvram case:: devm_nvmem_register(&config); } -Users of board files can define and register nvmem cells using the -nvmem_cell_table struct:: +Device drivers can define and register an nvmem cell using the nvmem_cell_info +struct:: - static struct nvmem_cell_info foo_nvmem_cells[] = { + static const struct nvmem_cell_info foo_nvmem_cell = { { .name = "macaddr", .offset = 0x7f00, @@ -70,13 +70,7 @@ nvmem_cell_table struct:: } }; - static struct nvmem_cell_table foo_nvmem_cell_table = { - .nvmem_name = "i2c-eeprom", - .cells = foo_nvmem_cells, - .ncells = ARRAY_SIZE(foo_nvmem_cells), - }; - - nvmem_add_cell_table(&foo_nvmem_cell_table); + int nvmem_add_one_cell(nvmem, &foo_nvmem_cell); Additionally it is possible to create nvmem cell lookup entries and register them with the nvmem framework from machine code as shown in the example below:: @@ -185,3 +179,24 @@ ex:: ===================== See Documentation/devicetree/bindings/nvmem/nvmem.txt + +8. NVMEM layouts +================ + +NVMEM layouts are yet another mechanism to create cells. With the device +tree binding it is possible to specify simple cells by using an offset +and a length. Sometimes, the cells doesn't have a static offset, but +the content is still well defined, e.g. tag-length-values. In this case, +the NVMEM device content has to be first parsed and the cells need to +be added accordingly. Layouts let you read the content of the NVMEM device +and let you add cells dynamically. + +Another use case for layouts is the post processing of cells. With layouts, +it is possible to associate a custom post processing hook to a cell. It +even possible to add this hook to cells not created by the layout itself. + +9. Internal kernel API +====================== + +.. kernel-doc:: drivers/nvmem/core.c + :export: |