diff options
author | Mario Six <mario.six@gdsys.cc> | 2018-10-15 09:24:15 +0200 |
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committer | Simon Glass <sjg@chromium.org> | 2018-11-14 09:16:27 -0800 |
commit | a6d4b0608b79023c703ca2ad1cbdfa784160449b (patch) | |
tree | 099051d33acc0fc8692302fcbd75c5da1848fa98 /include/regmap.h | |
parent | 9b77fe3b80b038af7114f7dae4934773bb026f8e (diff) |
regmap: Add overview documentation
Add some overview documentation that explains the purpose and some of
the features and limitations of the regmap interface.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Diffstat (limited to 'include/regmap.h')
-rw-r--r-- | include/regmap.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/regmap.h b/include/regmap.h index 98860c2732..b2b733fda6 100644 --- a/include/regmap.h +++ b/include/regmap.h @@ -8,6 +8,33 @@ #define __REGMAP_H /** + * DOC: Overview + * + * Regmaps are an abstraction mechanism that allows device drivers to access + * register maps irrespective of the underlying bus architecture. This entails + * that for devices that support multiple busses (e.g. I2C and SPI for a GPIO + * expander chip) only one driver has to be written. This driver will + * instantiate a regmap with a backend depending on the bus the device is + * attached to, and use the regmap API to access the register map through that + * bus transparently. + * + * Read and write functions are supplied, which can read/write data of + * arbitrary length from/to the regmap. + * + * The endianness of regmap accesses is selectable for each map through device + * tree settings via the boolean "little-endian", "big-endian", and + * "native-endian" properties. + * + * Furthermore, the register map described by a regmap can be split into + * multiple disjoint areas called ranges. In this way, register maps with + * "holes", i.e. areas of addressable memory that are not part of the register + * map, can be accessed in a concise manner. + * + * Currently, only a bare "mem" backend for regmaps is supported, which + * accesses the register map as regular IO-mapped memory. + */ + +/** * enum regmap_size_t - Access sizes for regmap reads and writes * * @REGMAP_SIZE_8: 8-bit read/write access size |