Unverified Commit 1da0b989 authored by Srinivas Kandagatla's avatar Srinivas Kandagatla Committed by Mark Brown
Browse files

ASoC: soc-component: add snd_soc_component_read/write_field() 



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: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210126171749.1863-1-srinivas.kandagatla@linaro.org


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent ed9ce1ed

include/sound/soc-component.h

+6 −0
Original line number Diff line number Diff line
@@ -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,

sound/soc/soc-component.c

+53 −0
Original line number Diff line number Diff line
@@ -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