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: Markus Pargmann mpa@pengutronix.de --- include/sound/soc.h | 1 + sound/soc/soc-core.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 62 insertions(+), 7 deletions(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index 1f741cb..5907583 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -1053,6 +1053,7 @@ 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; }; diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index a66783e..de61159 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -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 * @uinfo: control element information @@ -2742,7 +2784,7 @@ 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); @@ -2768,11 +2810,16 @@ 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]; @@ -2780,10 +2827,12 @@ 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]; @@ -2814,6 +2863,8 @@ 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; @@ -2821,13 +2872,16 @@ 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) {