From: Thomas Preston <thomas.preston@codethink.co.uk>
To: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
Marco Felsch <m.felsch@pengutronix.de>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Kirill Marinushkin <kmarinushkin@birdec.tech>,
Cheng-Yi Chiang <cychiang@chromium.org>,
linux-kernel@vger.kernel.org, Nate Case <ncase@tesla.com>,
Takashi Iwai <tiwai@suse.com>, Rob Herring <robh+dt@kernel.org>,
Liam Girdwood <lgirdwood@gmail.com>,
Paul Cercueil <paul@crapouillou.net>,
Vinod Koul <vkoul@kernel.org>, Mark Brown <broonie@kernel.org>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Annaliese McDermond <nh6z@nh6z.net>,
Rob Duncan <rduncan@tesla.com>,
Patrick Glaser <pglaser@tesla.com>,
Jerome Brunet <jbrunet@baylibre.com>
Subject: Re: [alsa-devel] [PATCH v2 2/3] ASoC: Add codec driver for ST TDA7802
Date: Tue, 30 Jul 2019 16:49:32 +0100 [thread overview]
Message-ID: <4285701d-ae61-208b-8f38-ac44e77ad9b5@codethink.co.uk> (raw)
In-Reply-To: <20190730123825.GG54126@ediswmail.ad.cirrus.com>
On 30/07/2019 13:38, Charles Keepax wrote:
> On Tue, Jul 30, 2019 at 01:09:36PM +0100, Thomas Preston wrote:
>> Add an I2C based codec driver for ST TDA7802 amplifier. The amplifier
>> supports 4 audio channels but can support up to 16 with multiple
>> devices.
>>
>> Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
>> Cc: Patrick Glaser <pglaser@tesla.com>
>> Cc: Rob Duncan <rduncan@tesla.com>
>> Cc: Nate Case <ncase@tesla.com>
>> ---
>> Changes since v1:
>> - Use ALSA kcontrol interface to expose device controls to userland
>> - Gain
>> - Channel diagnostic mode
>> - Impedance efficiency optimiser. I decided against setting this
>> as a DT property since it seems like something that can be
>> changed on the fly.
>> - Add regmap default values
>> - Channel unmute by default is added in a downstream patch.
>> - I'm not sure if I should keep this since they're all zero,
>> although there are other drivers will all-zero reg_defaults.
>> - I believe the "//" style is used for SPDX headers in normal C source files.
>> https://lwn.net/Articles/739183/
>> - Drop the "enable" sysfs device attribute.
>> - Don't set TDM format using magic numbers.
>> - Set sample rate using hw_params.
>> - Remove unecessary defines.
>> - Use DAPM to handle AMP_ON.
>> - Cosmetic fixups
>>
>> sound/soc/codecs/Kconfig | 6 +
>> sound/soc/codecs/Makefile | 2 +
>> sound/soc/codecs/tda7802.c | 509 +++++++++++++++++++++++++++++++++++++
>> 3 files changed, 517 insertions(+)
>> create mode 100644 sound/soc/codecs/tda7802.c
>>
>> +++ b/sound/soc/codecs/tda7802.c
>> @@ -0,0 +1,509 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * tda7802.c -- codec driver for ST TDA7802
>> + *
>> + * Copyright (C) 2016-2019 Tesla Motors, Inc.
>> + */
>
> Better to make the whole comment // see something like
> sound/soc/codecs/cs47l35.c for an example.
>
I will update to "//" style. Is this a new standard? There aren't many
comments like that in 4.14 (my target kernel) - I can see a lot more
in 5.3.
My intention was:
1. Apply the SPDX rules to SPDX bit. Documentation/process/license-rules.rst
2. Use multi-line comments for the rest. Documentation/process/coding-style.rst
>> +static int tda7802_set_bias_level(struct snd_soc_component *component,
>> + enum snd_soc_bias_level level)
>> +{
>> + const struct tda7802_priv *tda7802 =
>> + snd_soc_component_get_drvdata(component);
>> + struct snd_soc_dapm_context *dapm_context =
>> + snd_soc_component_get_dapm(component);
>> + const enum snd_soc_bias_level oldlevel =
>> + snd_soc_dapm_get_bias_level(dapm_context);
>> + int err = 0;
>> +
>> + dev_dbg(component->dev, "%s level %d\n", __func__, level);
>> +
>> + switch (level) {
>> + case SND_SOC_BIAS_ON:
>> + break;
>> + case SND_SOC_BIAS_PREPARE:
>> + break;
>> + 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);
>> +
>> + if (oldlevel == SND_SOC_BIAS_OFF) {
>> + dev_dbg(component->dev, "Syncing regcache\n");
>> + err = regcache_sync(component->regmap);
>> + if (err < 0)
>> + dev_err(component->dev,
>> + "Could not sync regcache, %d\n", err);
>
> If your doing a regcache_sync I would probably have expected to
> see calls to regcache_cache_only.
>
> If the device needs syncing that implies the hardware registers
> have lost state, so there is little point in writing to them
> if they are unavailable/about to loose their state.
>
Ah, from the comments I thought I only needed to call regcache_mark_dirty...
>> + }
>> + break;
>> + case SND_SOC_BIAS_OFF:
>> + regcache_mark_dirty(component->regmap);
>> + err = regulator_disable(tda7802->enable_reg);
>> + if (err < 0)
>> + dev_err(component->dev, "Could not disable.\n");
>> + break;
>> + }
>> +
>> + return err;
>> +}
So I think the correct order is:
device_off:
regcache_cache_only
power-off (enable)
regcache_mark_dirty
device_on:
power-on (enable)
regcache_sync
I will double-check the register state is actually lost too. Fiddling
with the cache might be completely unnecessary.
Many thanks
next prev parent reply other threads:[~2019-07-30 15:49 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 12:09 [PATCH v2 0/3] ASoC: Codecs: Add TDA7802 codec Thomas Preston
2019-07-30 12:09 ` [PATCH v2 1/3] dt-bindings: ASoC: Add TDA7802 amplifier Thomas Preston
2019-07-30 12:27 ` Charles Keepax
2019-07-30 13:12 ` Marco Felsch
2019-07-30 14:12 ` [alsa-devel] " Thomas Preston
2019-07-30 14:33 ` Mark Brown
2019-07-30 14:10 ` Thomas Preston
2019-07-30 12:09 ` [PATCH v2 2/3] ASoC: Add codec driver for ST TDA7802 Thomas Preston
2019-07-30 12:38 ` Charles Keepax
2019-07-30 15:49 ` Thomas Preston [this message]
2019-07-30 14:58 ` Mark Brown
2019-07-30 17:26 ` [alsa-devel] " Thomas Preston
2019-07-31 6:06 ` Marco Felsch
2019-07-31 8:57 ` Thomas Preston
2019-07-30 12:09 ` [PATCH v2 3/3] ASoC: TDA7802: Add turn-on diagnostic routine Thomas Preston
2019-07-30 12:41 ` Charles Keepax
2019-07-30 14:04 ` [alsa-devel] " Thomas Preston
2019-07-30 14:18 ` Charles Keepax
2019-07-30 14:20 ` [alsa-devel] " Mark Brown
2019-07-30 15:27 ` Thomas Preston
2019-07-30 14:19 ` Mark Brown
2019-07-30 15:25 ` [alsa-devel] " Thomas Preston
2019-07-30 15:50 ` Mark Brown
2019-07-30 16:28 ` Thomas Preston
2019-07-31 8:03 ` Charles Keepax
2019-08-01 23:42 ` Mark Brown
2019-08-02 8:32 ` Thomas Preston
2019-08-02 11:10 ` Mark Brown
2019-08-02 14:51 ` Thomas Preston
2019-08-02 17:27 ` Mark Brown
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