It's often the case that we would write or read a particular field in register. With the current soc_component apis, reading a particular field in register would involve first read the register and then perform shift operations.
Ex: to read from a field mask of 0xf0
val = snd_soc_component_read(component, reg); field = ((val & 0xf0) >> 0x4);
This is sometimes prone to errors and code become less readable!
With this new api we could just do field = snd_soc_component_read_field(component, reg, 0xf0);
this makes it bit simple, easy to write and less error prone!
This also applies to writing!
There are various places in kernel which provides such field interfaces however soc_component seems to be missing this.
This patch is inspired by FIELD_GET/FIELD_PREP macros in include/linux/bitfield.h
Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org ---
Changes since v1: - removed open coding and call read and update_bits - made soc_component_field_shift an inline function
include/sound/soc-component.h | 6 ++++ sound/soc/soc-component.c | 53 +++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+)
diff --git a/include/sound/soc-component.h b/include/sound/soc-component.h index 0bce41fefd30..5b47768222b7 100644 --- a/include/sound/soc-component.h +++ b/include/sound/soc-component.h @@ -353,6 +353,12 @@ int snd_soc_component_test_bits(struct snd_soc_component *component, unsigned int reg, unsigned int mask, unsigned int value);
+unsigned int snd_soc_component_read_field(struct snd_soc_component *component, + unsigned int reg, unsigned int mask); +int snd_soc_component_write_field(struct snd_soc_component *component, + unsigned int reg, unsigned int mask, + unsigned int val); + /* component wide operations */ int snd_soc_component_set_sysclk(struct snd_soc_component *component, int clk_id, int source, diff --git a/sound/soc/soc-component.c b/sound/soc/soc-component.c index 760523382f3c..361a79d655e3 100644 --- a/sound/soc/soc-component.c +++ b/sound/soc/soc-component.c @@ -34,6 +34,18 @@ static inline int _soc_component_ret(struct snd_soc_component *component, return ret; }
+static inline int soc_component_field_shift(struct snd_soc_component *component, + unsigned int mask) +{ + if (!mask) { + dev_err(component->dev, "ASoC: error field mask is zero for %s\n", + component->name); + return 0; + } + + return (__builtin_ffs(mask) - 1); +} + /* * We might want to check substream by using list. * In such case, we can update these macros. @@ -839,6 +851,47 @@ int snd_soc_component_update_bits_async(struct snd_soc_component *component, } EXPORT_SYMBOL_GPL(snd_soc_component_update_bits_async);
+/** + * snd_soc_component_read_field() - Read register field value + * @component: Component to read from + * @reg: Register to read + * @mask: mask of the register field + * + * Return: read value of register field. + */ +unsigned int snd_soc_component_read_field(struct snd_soc_component *component, + unsigned int reg, unsigned int mask) +{ + unsigned int val; + + val = snd_soc_component_read(component, reg); + + val = (val & mask) >> soc_component_field_shift(component, mask); + + return val; +} +EXPORT_SYMBOL_GPL(snd_soc_component_read_field); + +/** + * snd_soc_component_write_field() - write to register field + * @component: Component to write to + * @reg: Register to write + * @mask: mask of the register field to update + * @val: value of the field to write + * + * Return: 1 for change, otherwise 0. + */ +int snd_soc_component_write_field(struct snd_soc_component *component, + unsigned int reg, unsigned int mask, + unsigned int val) +{ + + val = (val << soc_component_field_shift(component, mask)) & mask; + + return snd_soc_component_update_bits(component, reg, mask, val); +} +EXPORT_SYMBOL_GPL(snd_soc_component_write_field); + /** * snd_soc_component_async_complete() - Ensure asynchronous I/O has completed * @component: Component for which to wait