.. _lfs:

========
littlefs
========

**littlefs** is a little fail-safe filesystem library designed for microcontrollers.

The lv_fs_littlefs extension is an interface to the littlefs library.

For a detailed introduction, see:  https://github.com/littlefs-project/littlefs .



Usage
*****

Set :c:macro:`LV_USE_FS_LITTLEFS` in ``lv_conf.h`` to ``1`` and define an upper-case
letter (as a C character type) for :c:macro:`LV_FS_LITTLEFS_LETTER` in the range
['A'..'Z'].

When enabled :cpp:func:`lv_littlefs_set_handler` can be used to set up a mount point.

Example
*******

.. code-block:: c

    #include "lfs.h"

    // configuration of the filesystem is provided by this struct
    const struct lfs_config cfg = {
        // block device operations
        .read  = user_provided_block_device_read,
        .prog  = user_provided_block_device_prog,
        .erase = user_provided_block_device_erase,
        .sync  = user_provided_block_device_sync,

        // block device configuration
        .read_size = 16,
        .prog_size = 16,
        .block_size = 4096,
        .block_count = 128,
        .cache_size = 16,
        .lookahead_size = 16,
        .block_cycles = 500,
    };

    // mount the filesystem
    int err = lfs_mount(&lfs, &cfg);

    // reformat if we can't mount the filesystem
    // this should only happen on the first boot
    if (err) {
        lfs_format(&lfs, &cfg);
        lfs_mount(&lfs, &cfg);
    }

    lv_littlefs_set_handler(&lfs);


API
***

:ref:`lv_fsdrv_h`

See also:  `lvgl/src/libs/fsdrv/lv_fs_littlefs.c <https://github.com/lvgl/lvgl/blob/master/src/libs/fsdrv/lv_fs_littlefs.c>`__

