Hello Mark, Liam,
I'm facing the following problem with the TWL4030 codec: The order of DAPM register write order different in case, when I start a capture operation after setting up the routing, and when I change the routing during active capture. This is really visible, when I want to record from the digital microphone interface. Because of this ordering problem, when during active capture I switch to the digital mic from analog path, the codec would enable analog bias (2.2 volts) to the digital mic for a moment, and than later it will switch to the correct digital mic bias (1.8 volts). Since the twl4030 codec needs several bits in different registers to be changed, when I change between analog and digital input it is not that obvious how to get the correct ordering all the time.
I have two different ways to fix this: A: by reordering how DAPM would handle control changes (patch 1) B: by changing TWL4030 internal DAPM widgets (patch 2)
Obviously only one of the two patch is needed, and I'm really not sure if the change in soc-dapm is a correct one, since it will affect all codec driver, and could potentially cause unexpected glitches.
Some more thoughts.. A: Reordering in soc-dapm. Currently this is how it works: A.1 Route setup, followed by capture - User selects the digimic0 interface (DAPM_MUX_E) ADCMICSEL: TX1IN_SEL->1 MUX_E(TX1 Capture Route) enum register selects digital path MICBIAS_CTL: MICBIAS1_CTL->1 MUX_E(TX1 Capture Route) POST_REG select digimic bias (1.8 volts) - Capture starts MICBIAS_CTL: MICBIAS1_EN->1 MICBIAS(Mic Bias 1) power enables the micbias1/digimic0 bias (1.8 volts) ADCMICSEL: DIGIMIC0_EN->1 PGA_E(Digimic0 Enable) power enable the digimic0 interface
A.2 Changing from analog path to digital path during capture - User selects the digimic0 interface from analog source AVADC_CTL: ADCL_EN->0 PGA(ADC Physical Left) power turn off ADC left ANAMICL: MICAMPL_EN->0 MIXER(Analog Left) power turn off mic amp on analog path MICBIAS_CTL: MICBIAS1_EN->1 MICBIAS(Mic Bias 1) power enables the micbias1/digimic0 bias (2.2 volts) ADCMICSEL: DIGIMIC0_EN->1 PGA(Digimic0 Enable) power enable the digimic0 interface ADCMICSEL: TX1IN_SEL->1 MUX_E(TX1 Capture Route) enum register selects digital path MICBIAS_CTL: MICBIAS1_CTL->1 MUX_E(TX1 Capture Route) POST_REG select digimic bias (1.8 volts)
With the reordering in soc-dapm, only the runtime order is going to change: A.2 ADCMICSEL: TX1IN_SEL->1 MUX_E(TX1 Capture Route) enum register selects digital path MICBIAS_CTL: MICBIAS1_CTL->1 MUX_E(TX1 Capture Route) POST_REG select digimic bias (1.8 volts) AVADC_CTL: ADCL_EN->0 PGA(ADC Physical Left) power turn off ADC left ANAMICL: MICAMPL_EN->0 MIXER(Analog Left) power turn off mic amp on analog path MICBIAS_CTL: MICBIAS1_EN->1 MICBIAS(Mic Bias 1) power enables the micbias1/digimic0 bias (1.8 volts) ADCMICSEL: DIGIMIC0_EN->1 PGA(Digimic0 Enable) power enable the digimic0 interface
So first DAPM would do the change in the register, than goes on and check the needed things to be done in the DAPM tree. This works with the TWL codec, but I'm not sure what are the implication on other codecs. But from the ordering point of view now there is no difference between 'cold start' or runtime change in DAPM write sequence.
B: Reordering in TWL4030 codec driver The sequence will look like this: B.1 Route setup, followed by capture - User selects the digimic0 interface (DAPM_MUX_E) ADCMICSEL: TX1IN_SEL->1 MUX(TX1 Capture Route) enum register selects digital path - Capture starts MICBIAS_CTL: MICBIAS1_CTL->1 SUPPLY(micbias1 select) power select digimic bias (1.8 volts) MICBIAS_CTL: MICBIAS1_EN->1 MICBIAS(Mic Bias 1) power enables the micbias1/digimic0 bias (1.8 volts) ADCMICSEL: DIGIMIC0_EN->1 PGA_E(Digimic0 Enable) power enable the digimic0 interface
B.2 Changing from analog path to digital path during capture - User selects the digimic0 interface from analog source AVADC_CTL: ADCL_EN->0 PGA(ADC Physical Left) power turn off ADC left ANAMICL: MICAMPL_EN->0 MIXER(Analog Left) power turn off mic amp on analog path MICBIAS_CTL: MICBIAS1_CTL->1 SUPPLY(micbias1 select) power select digimic bias (1.8 volts) MICBIAS_CTL: MICBIAS1_EN->1 MICBIAS(Mic Bias 1) power enables the micbias1/digimic0 bias (1.8 volts) ADCMICSEL: DIGIMIC0_EN->1 PGA(Digimic0 Enable) power enable the digimic0 interface ADCMICSEL: TX1IN_SEL->1 MUX(TX1 Capture Route) enum register selects digital path
In this case the order is still not the same, but at least I avoid feeding wrong bias to the digimic interface.
I need either the soc-dapm.c patch _or_ the patch against twl4030 codec to solve my problem. Do you see another way to actually solve this problem? Which approach is acceptable for you?
The series generated on top of (needs th previous TWL DAPM fix): git://git.kernel.org/pub/scm/linux/kernel/git/lrg/asoc-2.6.git:for-2.6.36
Thank you, Peter
--- Peter Ujfalusi (2): ASoC: soc-dapm: Reorder DAPM register write sequence ASoC: TWL4030: Capture route runtime DAPM ordering fix
sound/soc/codecs/twl4030.c | 48 +++++++++++--------------------------------- sound/soc/soc-dapm.c | 41 ++++++++++++++++++++++-------------- 2 files changed, 37 insertions(+), 52 deletions(-)
-- 1.7.2