* [RFC v1] tlv320aic32x4: delay i2c access by 1 ms after hardware reset
@ 2019-02-10 15:45 Peter Seiderer
2019-02-11 15:04 ` Mark Brown
0 siblings, 1 reply; 3+ messages in thread
From: Peter Seiderer @ 2019-02-10 15:45 UTC (permalink / raw)
To: linux-kernel
Cc: Liam Girdwood, Mark Brown, Jaroslav Kysela, Takashi Iwai, b-ak,
Kuninori Morimoto, alsa-devel
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>
---
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 | 2 ++
1 file changed, 2 insertions(+)
diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c
index e1bfba62fc08..b3beb0ca87c3 100644
--- a/sound/soc/codecs/tlv320aic32x4.c
+++ b/sound/soc/codecs/tlv320aic32x4.c
@@ -972,6 +972,8 @@ static int aic32x4_component_probe(struct snd_soc_component *component)
gpio_set_value(aic32x4->rstn_gpio, 1);
}
+ mdelay(1);
+
snd_soc_component_write(component, AIC32X4_RESET, 0x01);
if (aic32x4->setup)
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RFC v1] tlv320aic32x4: delay i2c access by 1 ms after hardware reset
2019-02-10 15:45 [RFC v1] tlv320aic32x4: delay i2c access by 1 ms after hardware reset Peter Seiderer
@ 2019-02-11 15:04 ` Mark Brown
2019-02-11 21:02 ` Peter Seiderer
0 siblings, 1 reply; 3+ messages in thread
From: Mark Brown @ 2019-02-11 15:04 UTC (permalink / raw)
To: Peter Seiderer
Cc: linux-kernel, Liam Girdwood, Jaroslav Kysela, Takashi Iwai, b-ak,
Kuninori Morimoto, alsa-devel
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On Sun, Feb 10, 2019 at 04:45:19PM +0100, Peter Seiderer wrote:
> @@ -972,6 +972,8 @@ static int aic32x4_component_probe(struct snd_soc_component *component)
> gpio_set_value(aic32x4->rstn_gpio, 1);
> }
>
> + mdelay(1);
> +
Perhaps only do this if we toggled the GPIO? If the device wasn't in
reset then there's no need to wait.
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC v1] tlv320aic32x4: delay i2c access by 1 ms after hardware reset
2019-02-11 15:04 ` Mark Brown
@ 2019-02-11 21:02 ` Peter Seiderer
0 siblings, 0 replies; 3+ messages in thread
From: Peter Seiderer @ 2019-02-11 21:02 UTC (permalink / raw)
To: Mark Brown
Cc: linux-kernel, Liam Girdwood, Jaroslav Kysela, Takashi Iwai, b-ak,
Kuninori Morimoto, alsa-devel
Hello Mark,
On Mon, 11 Feb 2019 15:04:25 +0000, Mark Brown <broonie@kernel.org> wrote:
> On Sun, Feb 10, 2019 at 04:45:19PM +0100, Peter Seiderer wrote:
>
> > @@ -972,6 +972,8 @@ static int aic32x4_component_probe(struct snd_soc_component *component)
> > gpio_set_value(aic32x4->rstn_gpio, 1);
> > }
> >
> > + mdelay(1);
> > +
>
> Perhaps only do this if we toggled the GPIO? If the device wasn't in
> reset then there's no need to wait.
You are absolutely right with this, will re-spin the patch with
the suggested change, thanks for review...
Regards,
Peter
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-02-11 21:03 UTC | newest]
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2019-02-10 15:45 [RFC v1] tlv320aic32x4: delay i2c access by 1 ms after hardware reset Peter Seiderer
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