regmap: Add "no-bus" option for regmap API
This commit adds provision for "no-bus" usage of the regmap API. In
this configuration user can provide API with two callbacks 'reg_read'
and 'reg_write' which are to be called when reads and writes to one of
device's registers is performed. This is useful for devices that
expose registers but whose register access sequence does not fit the 'bus'
abstraction.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 51f0574..b55fde5 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -77,6 +77,8 @@
int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+ bool defer_caching;
+
u8 read_flag_mask;
u8 write_flag_mask;
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 6845a07..9592030 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -379,7 +379,7 @@
enum regmap_endian reg_endian, val_endian;
int i, j;
- if (!bus || !config)
+ if (!config)
goto err;
map = kzalloc(sizeof(*map), GFP_KERNEL);
@@ -393,7 +393,8 @@
map->unlock = config->unlock;
map->lock_arg = config->lock_arg;
} else {
- if (bus->fast_io) {
+ if ((bus && bus->fast_io) ||
+ config->fast_io) {
spin_lock_init(&map->spinlock);
map->lock = regmap_lock_spinlock;
map->unlock = regmap_unlock_spinlock;
@@ -433,11 +434,19 @@
if (config->read_flag_mask || config->write_flag_mask) {
map->read_flag_mask = config->read_flag_mask;
map->write_flag_mask = config->write_flag_mask;
- } else {
+ } else if (bus) {
map->read_flag_mask = bus->read_flag_mask;
}
- map->reg_read = _regmap_bus_read;
+ if (!bus) {
+ map->reg_read = config->reg_read;
+ map->reg_write = config->reg_write;
+
+ map->defer_caching = false;
+ goto skip_format_initialization;
+ } else {
+ map->reg_read = _regmap_bus_read;
+ }
reg_endian = config->reg_format_endian;
if (reg_endian == REGMAP_ENDIAN_DEFAULT)
@@ -584,10 +593,15 @@
goto err_map;
}
- if (map->format.format_write)
+ if (map->format.format_write) {
+ map->defer_caching = false;
map->reg_write = _regmap_bus_formatted_write;
- else if (map->format.format_val)
+ } else if (map->format.format_val) {
+ map->defer_caching = true;
map->reg_write = _regmap_bus_raw_write;
+ }
+
+skip_format_initialization:
map->range_tree = RB_ROOT;
for (i = 0; i < config->num_ranges; i++) {
@@ -790,7 +804,7 @@
regcache_exit(map);
regmap_debugfs_exit(map);
regmap_range_exit(map);
- if (map->bus->free_context)
+ if (map->bus && map->bus->free_context)
map->bus->free_context(map->bus_context);
kfree(map->work_buf);
kfree(map);
@@ -893,6 +907,8 @@
size_t len;
int i;
+ BUG_ON(!map->bus);
+
/* Check for unwritable registers before we start */
if (map->writeable_reg)
for (i = 0; i < val_len / map->format.val_bytes; i++)
@@ -1002,7 +1018,7 @@
struct regmap_range_node *range;
struct regmap *map = context;
- BUG_ON(!map->format.format_write);
+ BUG_ON(!map->bus || !map->format.format_write);
range = _regmap_range_lookup(map, reg);
if (range) {
@@ -1028,7 +1044,7 @@
{
struct regmap *map = context;
- BUG_ON(!map->format.format_val);
+ BUG_ON(!map->bus || !map->format.format_val);
map->format.format_val(map->work_buf + map->format.reg_bytes
+ map->format.pad_bytes, val, 0);
@@ -1039,12 +1055,18 @@
map->format.val_bytes);
}
+static inline void *_regmap_map_get_context(struct regmap *map)
+{
+ return (map->bus) ? map : map->bus_context;
+}
+
int _regmap_write(struct regmap *map, unsigned int reg,
unsigned int val)
{
int ret;
+ void *context = _regmap_map_get_context(map);
- if (!map->cache_bypass && map->format.format_write) {
+ if (!map->cache_bypass && !map->defer_caching) {
ret = regcache_write(map, reg, val);
if (ret != 0)
return ret;
@@ -1061,7 +1083,7 @@
trace_regmap_reg_write(map->dev, reg, val);
- return map->reg_write(map, reg, val);
+ return map->reg_write(context, reg, val);
}
/**
@@ -1112,6 +1134,8 @@
{
int ret;
+ if (!map->bus)
+ return -EINVAL;
if (val_len % map->format.val_bytes)
return -EINVAL;
if (reg % map->reg_stride)
@@ -1148,6 +1172,8 @@
size_t val_bytes = map->format.val_bytes;
void *wval;
+ if (!map->bus)
+ return -EINVAL;
if (!map->format.parse_val)
return -EINVAL;
if (reg % map->reg_stride)
@@ -1201,6 +1227,8 @@
u8 *u8 = map->work_buf;
int ret;
+ BUG_ON(!map->bus);
+
range = _regmap_range_lookup(map, reg);
if (range) {
ret = _regmap_select_page(map, ®, range,
@@ -1252,6 +1280,8 @@
unsigned int *val)
{
int ret;
+ void *context = _regmap_map_get_context(map);
+
BUG_ON(!map->reg_read);
if (!map->cache_bypass) {
@@ -1263,7 +1293,7 @@
if (map->cache_only)
return -EBUSY;
- ret = map->reg_read(map, reg, val);
+ ret = map->reg_read(context, reg, val);
if (ret == 0) {
#ifdef LOG_DEVICE
if (strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
@@ -1325,6 +1355,8 @@
unsigned int v;
int ret, i;
+ if (!map->bus)
+ return -EINVAL;
if (val_len % map->format.val_bytes)
return -EINVAL;
if (reg % map->reg_stride)
@@ -1376,6 +1408,8 @@
size_t val_bytes = map->format.val_bytes;
bool vol = regmap_volatile_range(map, reg, val_count);
+ if (!map->bus)
+ return -EINVAL;
if (!map->format.parse_val)
return -EINVAL;
if (reg % map->reg_stride)
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf..28dde94 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -127,7 +127,18 @@
* @lock_arg: this field is passed as the only argument of lock/unlock
* functions (ignored in case regular lock/unlock functions
* are not overridden).
- *
+ * @reg_read: Optional callback that if filled will be used to perform
+ * all the reads from the registers. Should only be provided for
+ * devices whos read operation cannot be represented as a simple read
+ * operation on a bus such as SPI, I2C, etc. Most of the devices do
+ * not need this.
+ * @reg_write: Same as above for writing.
+ * @fast_io: Register IO is fast. Use a spinlock instead of a mutex
+ * to perform locking. This field is ignored if custom lock/unlock
+ * functions are used (see fields lock/unlock of struct regmap_config).
+ * This field is a duplicate of a similar file in
+ * 'struct regmap_bus' and serves exact same purpose.
+ * Use it only for "no-bus" cases.
* @max_register: Optional, specifies the maximum valid register index.
* @wr_table: Optional, points to a struct regmap_access_table specifying
* valid ranges for write access.
@@ -177,6 +188,11 @@
regmap_unlock unlock;
void *lock_arg;
+ int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
+ int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+
+ bool fast_io;
+
unsigned int max_register;
const struct regmap_access_table *wr_table;
const struct regmap_access_table *rd_table;