As stated in 'TLV320AIC3254 Application Reference Guide' ([1]):
3.2 Device Startup Lockout Times After the TLV320AIC3254 initializes through hardware reset at power-up or software reset, the internal registers initialize to default values. This initialization takes place within 1ms after pulling the RESET signal high. During this initialization phase, no register-read or register-write operation should be performed on ADC or DAC coefficient buffers. Also, no block within the codec should be powered up during the initialization phase.
[1] http://www.ti.com/lit/an/slaa408a/slaa408a.pdf
Signed-off-by: Peter Seiderer ps.report@gmx.net --- Changes v1 -> v2: - call mdelay only in case the reset gpio was toggled (suggested by Mark Brown)
Note: This came up after the electronic departement took a deeper look at the i2c-bus/vcc/reset pins with a logic analyzer and the documentation because of a vcc/reset timing problem (now fixed on custom board). Not 100% sure if the 1 ms is needed (as restricted to ADC/DAC coefficent and codec block power up). --- sound/soc/codecs/tlv320aic32x4.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c index e1bfba62fc08..96f1526cb258 100644 --- a/sound/soc/codecs/tlv320aic32x4.c +++ b/sound/soc/codecs/tlv320aic32x4.c @@ -970,6 +970,7 @@ static int aic32x4_component_probe(struct snd_soc_component *component) if (gpio_is_valid(aic32x4->rstn_gpio)) { ndelay(10); gpio_set_value(aic32x4->rstn_gpio, 1); + mdelay(1); }
snd_soc_component_write(component, AIC32X4_RESET, 0x01);