Commit 74fe7b55 authored by Crestez Dan Leonard's avatar Crestez Dan Leonard Committed by Mark Brown

regmap: Add regmap_noinc_read API

The regmap API usually assumes that bulk read operations will read a
range of registers but some I2C/SPI devices have certain registers for
which a such a read operation will return data from an internal FIFO
instead. Add an explicit API to support bulk read without range semantics.

Some linux drivers use regmap_bulk_read or regmap_raw_read for such
registers, for example mpu6050 or bmi150 from IIO. This only happens to
work because when caching is disabled a single regmap read op will map
to a single bus read op (as desired). This breaks if caching is enabled and
reg+1 happens to be a cacheable register.

Without regmap support refactoring a driver to enable regmap caching
requires separate I2C and SPI paths. This is exactly what regmap is
supposed to help avoid.
Suggested-by: default avatarJonathan Cameron <jic23@kernel.org>
Signed-off-by: default avatarCrestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: default avatarStefan Popa <stefan.popa@analog.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent ce397d21
...@@ -94,10 +94,12 @@ struct regmap { ...@@ -94,10 +94,12 @@ struct regmap {
bool (*readable_reg)(struct device *dev, unsigned int reg); bool (*readable_reg)(struct device *dev, unsigned int reg);
bool (*volatile_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); bool (*precious_reg)(struct device *dev, unsigned int reg);
bool (*readable_noinc_reg)(struct device *dev, unsigned int reg);
const struct regmap_access_table *wr_table; const struct regmap_access_table *wr_table;
const struct regmap_access_table *rd_table; const struct regmap_access_table *rd_table;
const struct regmap_access_table *volatile_table; const struct regmap_access_table *volatile_table;
const struct regmap_access_table *precious_table; const struct regmap_access_table *precious_table;
const struct regmap_access_table *rd_noinc_table;
int (*reg_read)(void *context, unsigned int reg, unsigned int *val); int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
int (*reg_write)(void *context, unsigned int reg, unsigned int val); int (*reg_write)(void *context, unsigned int reg, unsigned int val);
...@@ -181,6 +183,7 @@ bool regmap_writeable(struct regmap *map, unsigned int reg); ...@@ -181,6 +183,7 @@ bool regmap_writeable(struct regmap *map, unsigned int reg);
bool regmap_readable(struct regmap *map, unsigned int reg); bool regmap_readable(struct regmap *map, unsigned int reg);
bool regmap_volatile(struct regmap *map, unsigned int reg); bool regmap_volatile(struct regmap *map, unsigned int reg);
bool regmap_precious(struct regmap *map, unsigned int reg); bool regmap_precious(struct regmap *map, unsigned int reg);
bool regmap_readable_noinc(struct regmap *map, unsigned int reg);
int _regmap_write(struct regmap *map, unsigned int reg, int _regmap_write(struct regmap *map, unsigned int reg,
unsigned int val); unsigned int val);
......
...@@ -168,6 +168,17 @@ bool regmap_precious(struct regmap *map, unsigned int reg) ...@@ -168,6 +168,17 @@ bool regmap_precious(struct regmap *map, unsigned int reg)
return false; return false;
} }
bool regmap_readable_noinc(struct regmap *map, unsigned int reg)
{
if (map->readable_noinc_reg)
return map->readable_noinc_reg(map->dev, reg);
if (map->rd_noinc_table)
return regmap_check_range_table(map, reg, map->rd_noinc_table);
return true;
}
static bool regmap_volatile_range(struct regmap *map, unsigned int reg, static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
size_t num) size_t num)
{ {
...@@ -766,10 +777,12 @@ struct regmap *__regmap_init(struct device *dev, ...@@ -766,10 +777,12 @@ struct regmap *__regmap_init(struct device *dev,
map->rd_table = config->rd_table; map->rd_table = config->rd_table;
map->volatile_table = config->volatile_table; map->volatile_table = config->volatile_table;
map->precious_table = config->precious_table; map->precious_table = config->precious_table;
map->rd_noinc_table = config->rd_noinc_table;
map->writeable_reg = config->writeable_reg; map->writeable_reg = config->writeable_reg;
map->readable_reg = config->readable_reg; map->readable_reg = config->readable_reg;
map->volatile_reg = config->volatile_reg; map->volatile_reg = config->volatile_reg;
map->precious_reg = config->precious_reg; map->precious_reg = config->precious_reg;
map->readable_noinc_reg = config->readable_noinc_reg;
map->cache_type = config->cache_type; map->cache_type = config->cache_type;
spin_lock_init(&map->async_lock); spin_lock_init(&map->async_lock);
...@@ -1285,6 +1298,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config) ...@@ -1285,6 +1298,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
map->readable_reg = config->readable_reg; map->readable_reg = config->readable_reg;
map->volatile_reg = config->volatile_reg; map->volatile_reg = config->volatile_reg;
map->precious_reg = config->precious_reg; map->precious_reg = config->precious_reg;
map->readable_noinc_reg = config->readable_noinc_reg;
map->cache_type = config->cache_type; map->cache_type = config->cache_type;
regmap_debugfs_init(map, config->name); regmap_debugfs_init(map, config->name);
...@@ -2564,7 +2578,70 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, ...@@ -2564,7 +2578,70 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
EXPORT_SYMBOL_GPL(regmap_raw_read); EXPORT_SYMBOL_GPL(regmap_raw_read);
/** /**
* regmap_field_read() - Read a value to a single register field * regmap_noinc_read(): Read data from a register without incrementing the
* register number
*
* @map: Register map to read from
* @reg: Register to read from
* @val: Pointer to data buffer
* @val_len: Length of output buffer in bytes.
*
* The regmap API usually assumes that bulk bus read operations will read a
* range of registers. Some devices have certain registers for which a read
* operation read will read from an internal FIFO.
*
* The target register must be volatile but registers after it can be
* completely unrelated cacheable registers.
*
* This will attempt multiple reads as required to read val_len bytes.
*
* A value of zero will be returned on success, a negative errno will be
* returned in error cases.
*/
int regmap_noinc_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len)
{
size_t read_len;
int ret;
if (!map->bus)
return -EINVAL;
if (!map->bus->read)
return -ENOTSUPP;
if (val_len % map->format.val_bytes)
return -EINVAL;
if (!IS_ALIGNED(reg, map->reg_stride))
return -EINVAL;
if (val_len == 0)
return -EINVAL;
map->lock(map->lock_arg);
if (!regmap_volatile(map, reg) || !regmap_readable_noinc(map, reg)) {
ret = -EINVAL;
goto out_unlock;
}
while (val_len) {
if (map->max_raw_read && map->max_raw_read < val_len)
read_len = map->max_raw_read;
else
read_len = val_len;
ret = _regmap_raw_read(map, reg, val, read_len);
if (ret)
goto out_unlock;
val = ((u8 *)val) + read_len;
val_len -= read_len;
}
out_unlock:
map->unlock(map->lock_arg);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_noinc_read);
/**
* regmap_field_read(): Read a value to a single register field
* *
* @field: Register field to read from * @field: Register field to read from
* @val: Pointer to store read value * @val: Pointer to store read value
......
...@@ -268,6 +268,13 @@ typedef void (*regmap_unlock)(void *); ...@@ -268,6 +268,13 @@ typedef void (*regmap_unlock)(void *);
* field is NULL but precious_table (see below) is not, the * field is NULL but precious_table (see below) is not, the
* check is performed on such table (a register is precious if * check is performed on such table (a register is precious if
* it belongs to one of the ranges specified by precious_table). * it belongs to one of the ranges specified by precious_table).
* @readable_noinc_reg: Optional callback returning true if the register
* supports multiple read operations without incrementing
* the register number. If this field is NULL but
* rd_noinc_table (see below) is not, the check is
* performed on such table (a register is no increment
* readable if it belongs to one of the ranges specified
* by rd_noinc_table).
* @disable_locking: This regmap is either protected by external means or * @disable_locking: This regmap is either protected by external means or
* is guaranteed not be be accessed from multiple threads. * is guaranteed not be be accessed from multiple threads.
* Don't use any locking mechanisms. * Don't use any locking mechanisms.
...@@ -295,6 +302,7 @@ typedef void (*regmap_unlock)(void *); ...@@ -295,6 +302,7 @@ typedef void (*regmap_unlock)(void *);
* @rd_table: As above, for read access. * @rd_table: As above, for read access.
* @volatile_table: As above, for volatile registers. * @volatile_table: As above, for volatile registers.
* @precious_table: As above, for precious registers. * @precious_table: As above, for precious registers.
* @rd_noinc_table: As above, for no increment readable registers.
* @reg_defaults: Power on reset values for registers (for use with * @reg_defaults: Power on reset values for registers (for use with
* register cache support). * register cache support).
* @num_reg_defaults: Number of elements in reg_defaults. * @num_reg_defaults: Number of elements in reg_defaults.
...@@ -344,6 +352,7 @@ struct regmap_config { ...@@ -344,6 +352,7 @@ struct regmap_config {
bool (*readable_reg)(struct device *dev, unsigned int reg); bool (*readable_reg)(struct device *dev, unsigned int reg);
bool (*volatile_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); bool (*precious_reg)(struct device *dev, unsigned int reg);
bool (*readable_noinc_reg)(struct device *dev, unsigned int reg);
bool disable_locking; bool disable_locking;
regmap_lock lock; regmap_lock lock;
...@@ -360,6 +369,7 @@ struct regmap_config { ...@@ -360,6 +369,7 @@ struct regmap_config {
const struct regmap_access_table *rd_table; const struct regmap_access_table *rd_table;
const struct regmap_access_table *volatile_table; const struct regmap_access_table *volatile_table;
const struct regmap_access_table *precious_table; const struct regmap_access_table *precious_table;
const struct regmap_access_table *rd_noinc_table;
const struct reg_default *reg_defaults; const struct reg_default *reg_defaults;
unsigned int num_reg_defaults; unsigned int num_reg_defaults;
enum regcache_type cache_type; enum regcache_type cache_type;
...@@ -946,6 +956,8 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg, ...@@ -946,6 +956,8 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val); int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
int regmap_raw_read(struct regmap *map, unsigned int reg, int regmap_raw_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len); void *val, size_t val_len);
int regmap_noinc_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len);
int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
size_t val_count); size_t val_count);
int regmap_update_bits_base(struct regmap *map, unsigned int reg, int regmap_update_bits_base(struct regmap *map, unsigned int reg,
...@@ -1196,6 +1208,13 @@ static inline int regmap_raw_read(struct regmap *map, unsigned int reg, ...@@ -1196,6 +1208,13 @@ static inline int regmap_raw_read(struct regmap *map, unsigned int reg,
return -EINVAL; return -EINVAL;
} }
static inline int regmap_noinc_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len)
{
WARN_ONCE(1, "regmap API is disabled");
return -EINVAL;
}
static inline int regmap_bulk_read(struct regmap *map, unsigned int reg, static inline int regmap_bulk_read(struct regmap *map, unsigned int reg,
void *val, size_t val_count) void *val, size_t val_count)
{ {
......
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