Hi Thomas,
again sorry for jumping in..
On 19-07-30 18:26, Thomas Preston wrote:
> On 30/07/2019 15:58, Mark Brown wrote:
> > On Tue, Jul 30, 2019 at 01:09:36PM +0100, Thomas Preston wrote:
> >
> >> index 000000000000..0f82a88bc1a4
> >> --- /dev/null
> >> +++ b/sound/soc/codecs/tda7802.c
> >> @@ -0,0 +1,509 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * tda7802.c -- codec driver for ST TDA7802
> >
> > Please make the entire comment a C++ one so this looks intentional.
> >
>
> Ok thanks.
>
> >> +static int tda7802_digital_mute(struct snd_soc_dai *dai, int mute)
> >> +{
> >> + const u8 mute_disabled = mute ? 0 : IB2_DIGITAL_MUTE_DISABLED;
> >
> > Please write normal conditional statements to make the code easier to
> > read.
> >
>
> On it.
>
> >> + case SND_SOC_BIAS_STANDBY:
> >> + err = regulator_enable(tda7802->enable_reg);
> >> + if (err < 0) {
> >> + dev_err(component->dev, "Could not enable.\n");
> >> + return err;
> >> + }
> >> + dev_dbg(component->dev, "Regulator enabled\n");
> >> + msleep(ENABLE_DELAY_MS);
> >
> > Is this delay needed by the device or is it for the regulator to ramp?
> > If it's for the regulator to ramp then the regulator should be doing it.
> >
>
> According to the datasheet the device itself takes 10ms to rise from 0V
> after PLLen is enabled. There are additional rise times but they are
> negligible with default capacitor configuration (which we have).
>
> Good to know about the regulator rising configuration though. Thanks.
Isn't it the regulator we mentioned to not use that because it is a
GPIO?
Regards,
Marco
> >> + case SND_SOC_BIAS_OFF:
> >> + regcache_mark_dirty(component->regmap);
> >
> > If the regulator is going off you should really be marking the device as
> > cache only.
> >
>
> Got it, thanks.
>
> >> + err = regulator_disable(tda7802->enable_reg);
> >> + if (err < 0)
> >> + dev_err(component->dev, "Could not disable.\n");
> >
> > Any non-zero value from regulator_disable() is an error, there's similar
> > error checking issues in other places.
> >
>
> I return the error at the end of the function, but I'll bring it back here
> for consistency.
>
> >> +static const struct snd_kcontrol_new tda7802_snd_controls[] = {
> >> + SOC_SINGLE("Channel 4 Tristate", TDA7802_IB0, 7, 1, 0),
> >> + SOC_SINGLE("Channel 3 Tristate", TDA7802_IB0, 6, 1, 0),
> >> + SOC_SINGLE("Channel 2 Tristate", TDA7802_IB0, 5, 1, 0),
> >> + SOC_SINGLE("Channel 1 Tristate", TDA7802_IB0, 4, 1, 0),
> >
> > These look like simple on/off switches so should have Switch at the end
> > of the control name. It's also not clear to me why this is exported to
> > userspace - why would this change at runtime and won't any changes need
> > to be coordinated with whatever else is connected to the signal?
> >
> >> + SOC_ENUM("Mute time", mute_time),
> >> + SOC_SINGLE("Unmute channels 1 & 3", TDA7802_IB2, 4, 1, 0),
> >> + SOC_SINGLE("Unmute channels 2 & 4", TDA7802_IB2, 3, 1, 0),
> >
> > These are also Switch controls. There are *lots* of problems with
> > control names, see control-names.rst.
> >
>
> Ok thanks, I didn't know about the "Switch" suffix, I will read
> control-names.rst.
>
> I will move Tristate to DT properties. I was also unsure about the
> Impedance Efficiency Optimiser but the datasheet doesn't go into much
> detail about this so I left it exposed.
>
> They both seemed like user configurable options in the context of a
> test rig, but I agree - who knows what this output might be connected
> to in other systems. I will lock them down in DT. Thanks.
>
> >> +static const struct snd_soc_component_driver tda7802_component_driver = {
> >> + .set_bias_level = tda7802_set_bias_level,
> >> + .idle_bias_on = 1,
> >
> > Any reason to keep the device powered up? It looks like the power on
> > process is just powering things up and writing the register cache out
> > and there's not that many registers so the delay is trivial.
> >
>
> Ah no, I think that's a mistake. I want the PLLen to switch off in
> idle/suspend and the device should restore on wake.
>
> >> + tda7802->enable_reg = devm_regulator_get(dev, "enable");
> >> + if (IS_ERR(tda7802->enable_reg)) {
> >> + dev_err(dev, "Failed to get enable regulator\n");
> >
> > It's better to print error codes if you have them and are printing a
> > diagnostic so people have more to go on when debugging problems.
>
> Yep on it.
>
> Many thanks, I appreciate the feedback.
>
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