SDMMC peripheral driver, SD protocol driver, FATFS library, VFS integration
This MR contains:
- SDMMC host peripheral driver
- SD protocol driver in sdmmc component (can be extended to support MMC/eMMC and SPI based hosts)
- ChaN's FATFS library v0.12b
- VFS integration
- FAT access via VFS is thread-safe (unless same file is read/written/unlinked/renamed from different tasks)
- Support for POSIX directory-related functions in VFS (and in vfs_fatfs.c)
- unit test for the above
- Example
- API documentation
Will be done in other MRs:
- Support for spi_flash IO driver for FatFs
- SPI host driver and support for SPI mode commands in sdmmc component
- MMC/eMMC support in sdmmc component
- Support for slightly higher 53/26.6MHz clocks (currently I'm using 20MHz for DS and 40MHz for HS, instead of 25MHz/50MHz per standard), and arbitrary low clocks (e.g. 4MHz).
See merge request !353