Messages in this thread | | | From | Songhee Baek <> | Date | Fri, 28 Mar 2014 11:10:06 -0700 | Subject | RE: [alsa-devel] [PATCH] ASoC: Add support for multi register mux |
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> > On 03/26/2014 11:41 PM, Songhee Baek wrote: > > >> On 03/26/2014 01:02 AM, Arun Shamanna Lakshmi wrote: > > >> > > >> The way you describe this it seems to me that a value array for > > >> this kind of mux would look like. > > >> > > >> 0x00000000, 0x00000000, 0x00000001 > > >> 0x00000000, 0x00000000, 0x00000002 > > >> 0x00000000, 0x00000000, 0x00000003 > > >> 0x00000000, 0x00000000, 0x00000004 > > >> 0x00000000, 0x00000000, 0x00000008 > > >> ... > > >> > > >> That seems to be extremely tedious. If the MUX uses a one hot > > >> encoding how about storing the index of the bit in the values array > > >> and use (1 << value) when writing the value to the register? > > > > > > If we store the index of the bit, the value will be duplicated for > > > each > > registers inputs since register has 0 to 31bits to shift, then we need > > to decode the index to interpret value for which registers to set. If > > we need to interpret the decoded value of index, it is better to have > > custom put/get function in our driver, isn't it? > > > > > > > I'm not sure I understand. If you use (val / 32) to pick the register > > and (val % > > 32) to pick the bit in the register this should work just fine. Maybe > > I'm missing something. Do you have a real world code example of of the > > this type of enum is used? > > > > I can use val/32 and val%32 for this multi register mux.
With this logic, put function would be easy however get function becomes tedious due to looping on each bit per register for 3 of them in our case. Rather, it would be easy to identify a unique MUX_OFFSET to distinguish between the 3 registers as shown in the code below.
#define MULTI_MUX_INPUT_OFFSET(n) (5 * n)
int snd_soc_dapm_get_enum_double(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol) { struct snd_soc_codec *codec = snd_soc_dapm_kcontrol_codec(kcontrol); struct soc_enum *e = (struct soc_enum *)kcontrol->private_value; unsigned int reg_val, val, reg_idx;
if (e->reg[0] != SND_SOC_NOPM) { for (reg_idx = 0; reg_idx < e->num_regs; reg_idx) { reg_val = snd_soc_read(codec, e->reg[reg_idx]); val = (reg_val >> e->shift_l) & e->mask[reg_idx]; if (val) val += MULTI_MUX_INPUT_OFFSET(reg_idx); } } else { reg_val = dapm_kcontrol_get_value(kcontrol); val = (reg_val >> e->shift_l) & e->mask[0]; }
ucontrol->value.enumerated.item[0] = snd_soc_enum_val_to_item(e, val); if (e->shift_l != e->shift_r) { val = (reg_val >> e->shift_r) & e->mask[0]; val = snd_soc_enum_val_to_item(e, val); ucontrol->value.enumerated.item[1] = val; }
return 0; }
int snd_soc_dapm_put_enum_double(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol) { struct snd_soc_codec *codec = snd_soc_dapm_kcontrol_codec(kcontrol); struct snd_soc_card *card = codec->card; struct soc_enum *e = (struct soc_enum *)kcontrol->private_value; unsigned int *item = ucontrol->value.enumerated.item; unsigned int change, i, value, update_idx = 0; unsigned int mask; struct snd_soc_dapm_update update; int ret = 0, reg_val;
if (item[0] >= e->items) return -EINVAL;
value = snd_soc_enum_item_to_val(e, item[0]) << e->shift_l; mask = e->mask[0] << e->shift_l; if (e->shift_l != e->shift_r) { if (item[1] > e->items) return -EINVAL; value |= snd_soc_enum_item_to_val(e, item[1]) << e->shift_l; mask |= e->mask[0] << e->shift_r; }
if (e->num_regs < 2) { goto update_reg; }
for (i = 0; i < e->num_regs; i++) { reg_val = value - MULTI_MUX_INPUT_OFFSET(i);
/* checking reg_val is power of 2 : one-hot code */ /* if reg_val after subtract MULTI_MUX_INPUT_OFFSET is not power of 2, reg[i] should be zero */ if (reg_val & (reg_val - 1)) { /* clear the current input register */ snd_soc_write(codec, e->reg[i], 0); } else { /* reg_val is power of 2, store updated info */ value = reg_val; mask = e->mask[i]; update_idx = i; } }
update_reg: mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
if (e->reg[update_idx] != SND_SOC_NOPM) change = snd_soc_test_bits(codec, e->reg[update_idx], mask, value); else change = dapm_kcontrol_set_value(kcontrol, value);
if (change) { if (e->reg[update_idx] != SND_SOC_NOPM) { update.kcontrol = kcontrol; update.reg = e->reg[update_idx]; update.mask= mask; update.val = value; card->update = &update; } ret = soc_dapm_mux_update_power(card, kcontrol, item[0], e);
card->update = NULL; } mutex_unlock(&card->dapm_mutex);
if (ret > 0) soc_dpcm_runtime_update(card);
return change; }
> > >>> - int reg; > > >>> + int reg[SOC_ENUM_MAX_REGS]; > > >>> unsigned char shift_l; > > >>> unsigned char shift_r; > > >>> unsigned int items; > > >>> - unsigned int mask; > > >>> + unsigned int mask[SOC_ENUM_MAX_REGS]; > > >> > > >> If you make mask and reg pointers instead of arrays this should be > > >> much more flexible and not be limited to 3 registers.
We will make reg* and mask* instead of arrays and since we use the same structure, the plan is to share the get and put function code.
Thanks. Songhee.
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