drivers/base/regmap/regcache-flat.c

Source file repositories/reference/linux-study-clean/drivers/base/regmap/regcache-flat.c

File Facts

System
Linux kernel
Corpus path
drivers/base/regmap/regcache-flat.c
Extension
.c
Size
4167 bytes
Lines
178
Domain
Driver Families
Bucket
drivers/base
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct regcache_flat_data {
	unsigned long *valid;
	unsigned int data[];
};

static int regcache_flat_init(struct regmap *map)
{
	unsigned int cache_size;
	struct regcache_flat_data *cache;

	if (!map || map->reg_stride_order < 0 || !map->max_register_is_set)
		return -EINVAL;

	cache_size = regcache_flat_get_index(map, map->max_register) + 1;
	cache = kzalloc_flex(*cache, data, cache_size, map->alloc_flags);
	if (!cache)
		return -ENOMEM;

	cache->valid = bitmap_zalloc(cache_size, map->alloc_flags);
	if (!cache->valid)
		goto err_free;

	map->cache = cache;

	return 0;

err_free:
	kfree(cache);
	return -ENOMEM;
}

static int regcache_flat_exit(struct regmap *map)
{
	struct regcache_flat_data *cache = map->cache;

	if (cache)
		bitmap_free(cache->valid);

	kfree(cache);
	map->cache = NULL;

	return 0;
}

static int regcache_flat_populate(struct regmap *map)
{
	struct regcache_flat_data *cache = map->cache;
	unsigned int i;

	for (i = 0; i < map->num_reg_defaults; i++) {
		unsigned int reg = map->reg_defaults[i].reg;
		unsigned int index = regcache_flat_get_index(map, reg);

		cache->data[index] = map->reg_defaults[i].def;
		__set_bit(index, cache->valid);
	}

	if (map->reg_default_cb) {
		dev_dbg(map->dev,
			"Populating regcache_flat using reg_default_cb callback\n");

		for (i = 0; i <= map->max_register; i += map->reg_stride) {
			unsigned int index = regcache_flat_get_index(map, i);
			unsigned int value;

			if (test_bit(index, cache->valid))
				continue;

			if (map->reg_default_cb(map->dev, i, &value))
				continue;

			cache->data[index] = value;
			__set_bit(index, cache->valid);
		}
	}

	return 0;
}

static int regcache_flat_read(struct regmap *map,
			      unsigned int reg, unsigned int *value)
{
	struct regcache_flat_data *cache = map->cache;
	unsigned int index = regcache_flat_get_index(map, reg);

	/* legacy behavior: ignore validity, but warn the user */
	if (unlikely(!test_bit(index, cache->valid)))
		dev_warn_once(map->dev,
			"using zero-initialized flat cache, this may cause unexpected behavior");

Annotation

Implementation Notes