Commit f227b88f authored by Markus Pargmann's avatar Markus Pargmann Committed by Mark Brown
Browse files

ASoC: core: Add signed register volume control logic 



Some codecs use signed volume control representation with non standard
register sizes, e.g. 6 or 7 bit signed integers.

This patch adds generic signed register volume control logic to
soc-core. Instead of a fixed width signed register control, this
implementation uses a 'min' value and the signed bit location to translate
it to an absolute volume. Using the 'sign_bit' we can calculate a
correct mask for the register values and translate it back into signed
integers of standard size.

Signed-off-by: default avatarMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 38dbfb59

include/sound/soc.h

+1 −0
Original line number Diff line number Diff line
@@ -1067,6 +1067,7 @@ struct soc_mixer_control { 
	int min, max, platform_max;

	int reg, rreg;

	unsigned int shift, rshift;

	unsigned int sign_bit;

	unsigned int invert:1;

	unsigned int autodisable:1;

};

sound/soc/soc-core.c

+61 −7
Original line number Diff line number Diff line
@@ -2715,6 +2715,48 @@ int snd_soc_put_value_enum_double(struct snd_kcontrol *kcontrol, 
}

EXPORT_SYMBOL_GPL(snd_soc_put_value_enum_double);



/**

 * snd_soc_read_signed - Read a codec register and interprete as signed value

 * @codec: codec

 * @reg: Register to read

 * @mask: Mask to use after shifting the register value

 * @shift: Right shift of register value

 * @sign_bit: Bit that describes if a number is negative or not.

 *

 * This functions reads a codec register. The register value is shifted right

 * by 'shift' bits and masked with the given 'mask'. Afterwards it translates

 * the given registervalue into a signed integer if sign_bit is non-zero.

 *

 * Returns the register value as signed int.

 */

static int snd_soc_read_signed(struct snd_soc_codec *codec, unsigned int reg,

		unsigned int mask, unsigned int shift, unsigned int sign_bit)

{

	int ret;

	unsigned int val;



	val = (snd_soc_read(codec, reg) >> shift) & mask;



	if (!sign_bit)

		return val;



	/* non-negative number */

	if (!(val & BIT(sign_bit)))

		return val;



	ret = val;



	/*

	 * The register most probably does not contain a full-sized int.

	 * Instead we have an arbitrary number of bits in a signed

	 * representation which has to be translated into a full-sized int.

	 * This is done by filling up all bits above the sign-bit.

	 */

	ret |= ~((int)(BIT(sign_bit) - 1));



	return ret;

}



/**

 * snd_soc_info_volsw - single mixer info callback

 * @kcontrol: mixer control
@@ -2743,7 +2785,7 @@ int snd_soc_info_volsw(struct snd_kcontrol *kcontrol, 


	uinfo->count = snd_soc_volsw_is_stereo(mc) ? 2 : 1;

	uinfo->value.integer.min = 0;

	uinfo->value.integer.max = platform_max;

	uinfo->value.integer.max = platform_max - mc->min;

	return 0;

}

EXPORT_SYMBOL_GPL(snd_soc_info_volsw);
@@ -2769,11 +2811,16 @@ int snd_soc_get_volsw(struct snd_kcontrol *kcontrol, 
	unsigned int shift = mc->shift;

	unsigned int rshift = mc->rshift;

	int max = mc->max;

	int min = mc->min;

	int sign_bit = mc->sign_bit;

	unsigned int mask = (1 << fls(max)) - 1;

	unsigned int invert = mc->invert;



	ucontrol->value.integer.value[0] =

		(snd_soc_read(codec, reg) >> shift) & mask;

	if (sign_bit)

		mask = BIT(sign_bit + 1) - 1;



	ucontrol->value.integer.value[0] = snd_soc_read_signed(codec, reg, mask,

			shift, sign_bit) - min;

	if (invert)

		ucontrol->value.integer.value[0] =

			max - ucontrol->value.integer.value[0];
@@ -2781,10 +2828,12 @@ int snd_soc_get_volsw(struct snd_kcontrol *kcontrol, 
	if (snd_soc_volsw_is_stereo(mc)) {

		if (reg == reg2)

			ucontrol->value.integer.value[1] =

				(snd_soc_read(codec, reg) >> rshift) & mask;

				snd_soc_read_signed(codec, reg, mask, rshift,

						sign_bit) - min;

		else

			ucontrol->value.integer.value[1] =

				(snd_soc_read(codec, reg2) >> shift) & mask;

				snd_soc_read_signed(codec, reg2, mask, shift,

						sign_bit) - min;

		if (invert)

			ucontrol->value.integer.value[1] =

				max - ucontrol->value.integer.value[1];
@@ -2815,6 +2864,8 @@ int snd_soc_put_volsw(struct snd_kcontrol *kcontrol, 
	unsigned int shift = mc->shift;

	unsigned int rshift = mc->rshift;

	int max = mc->max;

	int min = mc->min;

	unsigned int sign_bit = mc->sign_bit;

	unsigned int mask = (1 << fls(max)) - 1;

	unsigned int invert = mc->invert;

	int err;
@@ -2822,13 +2873,16 @@ int snd_soc_put_volsw(struct snd_kcontrol *kcontrol, 
	unsigned int val2 = 0;

	unsigned int val, val_mask;



	val = (ucontrol->value.integer.value[0] & mask);

	if (sign_bit)

		mask = BIT(sign_bit + 1) - 1;



	val = ((ucontrol->value.integer.value[0] + min) & mask);

	if (invert)

		val = max - val;

	val_mask = mask << shift;

	val = val << shift;

	if (snd_soc_volsw_is_stereo(mc)) {

		val2 = (ucontrol->value.integer.value[1] & mask);

		val2 = ((ucontrol->value.integer.value[1] + min) & mask);

		if (invert)

			val2 = max - val2;

		if (reg == reg2) {

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