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regmap: make lock/unlock functions customizable
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It is sometimes convenient for a regmap user to override the standard
regmap lock/unlock functions with custom functions.
For instance this can be useful in case an already existing spinlock
or mutex has to be used for locking a set of registers instead of the
internal regmap spinlock/mutex.
Note that the fast_io field of struct regmap_bus is ignored in case
custom locking functions are used.

Signed-off-by: Davide Ciminaghi <ciminaghi@gnudd.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Davide Ciminaghi authored and Mark Brown committed Oct 17, 2012
1 parent ddffeb8 commit 0d4529c
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Showing 3 changed files with 54 additions and 31 deletions.
4 changes: 1 addition & 3 deletions drivers/base/regmap/internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,14 +31,12 @@ struct regmap_format {
unsigned int (*parse_val)(void *buf);
};

typedef void (*regmap_lock)(struct regmap *map);
typedef void (*regmap_unlock)(struct regmap *map);

struct regmap {
struct mutex mutex;
spinlock_t spinlock;
regmap_lock lock;
regmap_unlock unlock;
void *lock_arg; /* This is passed to lock/unlock functions */

struct device *dev; /* Device we do I/O on */
void *work_buf; /* Scratch buffer used to format I/O */
Expand Down
65 changes: 38 additions & 27 deletions drivers/base/regmap/regmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -214,23 +214,27 @@ static unsigned int regmap_parse_32_native(void *buf)
return *(u32 *)buf;
}

static void regmap_lock_mutex(struct regmap *map)
static void regmap_lock_mutex(void *__map)
{
struct regmap *map = __map;
mutex_lock(&map->mutex);
}

static void regmap_unlock_mutex(struct regmap *map)
static void regmap_unlock_mutex(void *__map)
{
struct regmap *map = __map;
mutex_unlock(&map->mutex);
}

static void regmap_lock_spinlock(struct regmap *map)
static void regmap_lock_spinlock(void *__map)
{
struct regmap *map = __map;
spin_lock(&map->spinlock);
}

static void regmap_unlock_spinlock(struct regmap *map)
static void regmap_unlock_spinlock(void *__map)
{
struct regmap *map = __map;
spin_unlock(&map->spinlock);
}

Expand Down Expand Up @@ -335,14 +339,21 @@ struct regmap *regmap_init(struct device *dev,
goto err;
}

if (bus->fast_io) {
spin_lock_init(&map->spinlock);
map->lock = regmap_lock_spinlock;
map->unlock = regmap_unlock_spinlock;
if (config->lock && config->unlock) {
map->lock = config->lock;
map->unlock = config->unlock;
map->lock_arg = config->lock_arg;
} else {
mutex_init(&map->mutex);
map->lock = regmap_lock_mutex;
map->unlock = regmap_unlock_mutex;
if (bus->fast_io) {
spin_lock_init(&map->spinlock);
map->lock = regmap_lock_spinlock;
map->unlock = regmap_unlock_spinlock;
} else {
mutex_init(&map->mutex);
map->lock = regmap_lock_mutex;
map->unlock = regmap_unlock_mutex;
}
map->lock_arg = map;
}
map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
map->format.pad_bytes = config->pad_bits / 8;
Expand Down Expand Up @@ -939,11 +950,11 @@ int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
if (reg % map->reg_stride)
return -EINVAL;

map->lock(map);
map->lock(map->lock_arg);

ret = _regmap_write(map, reg, val);

map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand Down Expand Up @@ -975,11 +986,11 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
if (reg % map->reg_stride)
return -EINVAL;

map->lock(map);
map->lock(map->lock_arg);

ret = _regmap_raw_write(map, reg, val, val_len);

map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand Down Expand Up @@ -1011,7 +1022,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
if (reg % map->reg_stride)
return -EINVAL;

map->lock(map);
map->lock(map->lock_arg);

/* No formatting is require if val_byte is 1 */
if (val_bytes == 1) {
Expand Down Expand Up @@ -1047,7 +1058,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
kfree(wval);

out:
map->unlock(map);
map->unlock(map->lock_arg);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_bulk_write);
Expand Down Expand Up @@ -1137,11 +1148,11 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
if (reg % map->reg_stride)
return -EINVAL;

map->lock(map);
map->lock(map->lock_arg);

ret = _regmap_read(map, reg, val);

map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand Down Expand Up @@ -1171,7 +1182,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
if (reg % map->reg_stride)
return -EINVAL;

map->lock(map);
map->lock(map->lock_arg);

if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass ||
map->cache_type == REGCACHE_NONE) {
Expand All @@ -1193,7 +1204,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
}

out:
map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand Down Expand Up @@ -1300,9 +1311,9 @@ int regmap_update_bits(struct regmap *map, unsigned int reg,
bool change;
int ret;

map->lock(map);
map->lock(map->lock_arg);
ret = _regmap_update_bits(map, reg, mask, val, &change);
map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand All @@ -1326,9 +1337,9 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
{
int ret;

map->lock(map);
map->lock(map->lock_arg);
ret = _regmap_update_bits(map, reg, mask, val, change);
map->unlock(map);
map->unlock(map->lock_arg);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits_check);
Expand Down Expand Up @@ -1357,7 +1368,7 @@ int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
if (map->patch)
return -EBUSY;

map->lock(map);
map->lock(map->lock_arg);

bypass = map->cache_bypass;

Expand Down Expand Up @@ -1385,7 +1396,7 @@ int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
out:
map->cache_bypass = bypass;

map->unlock(map);
map->unlock(map->lock_arg);

return ret;
}
Expand Down
16 changes: 15 additions & 1 deletion include/linux/regmap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,9 @@ enum regmap_endian {
REGMAP_ENDIAN_NATIVE,
};

typedef void (*regmap_lock)(void *);
typedef void (*regmap_unlock)(void *);

/**
* Configuration for the register map of a device.
*
Expand All @@ -75,6 +78,12 @@ enum regmap_endian {
* @precious_reg: Optional callback returning true if the rgister
* should not be read outside of a call from the driver
* (eg, a clear on read interrupt status register).
* @lock: Optional lock callback (overrides regmap's default lock
* function, based on spinlock or mutex).
* @unlock: As above for unlocking.
* @lock_arg: this field is passed as the only argument of lock/unlock
* functions (ignored in case regular lock/unlock functions
* are not overridden).
*
* @max_register: Optional, specifies the maximum valid register index.
* @reg_defaults: Power on reset values for registers (for use with
Expand Down Expand Up @@ -116,6 +125,9 @@ struct regmap_config {
bool (*readable_reg)(struct device *dev, unsigned int reg);
bool (*volatile_reg)(struct device *dev, unsigned int reg);
bool (*precious_reg)(struct device *dev, unsigned int reg);
regmap_lock lock;
regmap_unlock unlock;
void *lock_arg;

unsigned int max_register;
const struct reg_default *reg_defaults;
Expand Down Expand Up @@ -181,7 +193,9 @@ typedef void (*regmap_hw_free_context)(void *context);
* Description of a hardware bus for the register map infrastructure.
*
* @fast_io: Register IO is fast. Use a spinlock instead of a mutex
* to perform locking.
* to perform locking. This field is ignored if custom lock/unlock
* functions are used (see fields lock/unlock of
* struct regmap_config).
* @write: Write operation.
* @gather_write: Write operation with split register/value, return -ENOTSUPP
* if not implemented on a given device.
Expand Down

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