linux-kernel - Re: [PATCH v2] soc/lapis: add machine driver

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Date:	Mon, 5 Dec 2011 18:33:03 +0900
From:	Tomoya MORINAGA <tomoya.rohm@...il.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Liam Girdwood <lrg@...com>, Jaroslav Kysela <perex@...ex.cz>,
	Takashi Iwai <tiwai@...e.de>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>,
	Mike Frysinger <vapier@...too.org>,
	Daniel Mack <zonque@...il.com>, alsa-devel@...a-project.org,
	linux-kernel@...r.kernel.org, qi.wang@...el.com,
	yong.y.wang@...el.com, joel.clark@...el.com, kok.howg.ewe@...el.com
Subject: Re: [PATCH v2] soc/lapis: add machine driver

2011/12/3 Mark Brown <broonie@...nsource.wolfsonmicro.com>:
> On Fri, Dec 02, 2011 at 06:45:15PM +0900, Tomoya MORINAGA wrote:
>
>> +#define CODEC_DEV_ADDR 0x1A
>> +static struct i2c_board_info ioh_hwmon_info[] = {
>> +     {I2C_BOARD_INFO("ioh_i2c-0", CODEC_DEV_ADDR + 1)},
>> +     {I2C_BOARD_INFO("ioh_i2c-1", CODEC_DEV_ADDR + 2)},
>> +     {I2C_BOARD_INFO("ioh_i2c-2", CODEC_DEV_ADDR + 3)},
>> +     {I2C_BOARD_INFO("ioh_i2c-3", CODEC_DEV_ADDR + 4)},
>> +     {I2C_BOARD_INFO("ioh_i2c-4", CODEC_DEV_ADDR + 5)},
>> +     {I2C_BOARD_INFO("ioh_i2c-5", CODEC_DEV_ADDR + 0)},
>
> This looks completely wrong.  I'd not expect to see any I2C_BOARD_INFO
> usage at all in a machine driver (that should be done by whatever
> enumerates the system as a whole)
Do you mean machine driver must not use I2C_BOARD_INFO ? Is this true ?
Grepping I2C_BOARD_INFO at sound/soc,  the following drivers use
I2C_BOARD_INFO.
pxa/raumfeld.c: I2C_BOARD_INFO("max9485", 0x63),
pxa/magician.c:         I2C_BOARD_INFO("uda1380", 0x18),
s6000/s6105-ipcam.c:    { I2C_BOARD_INFO("tlv320aic33", 0x18), }

> and I'm not clear what the intended
> effect of the above is - the names look like the names of I2C
> controllers...
You are right.
"ioh_i2c-0" must be "ml26124".


>
>> +static int ml7213_startup(struct snd_pcm_substream *substream)
>> +{
>> +     struct snd_soc_pcm_runtime *rtd = substream->private_data;
>> +     struct snd_soc_codec *codec = rtd->codec;
>> +     struct i2c_client *i2c;
>> +     struct i2c_adapter *adapter;
>> +
>> +     mutex_lock(&codec->mutex);
>> +
>> +     adapter = i2c_get_adapter(1);
>> +     if (!adapter)
>> +             return -ENODEV;
>> +
>> +     i2c = i2c_new_device(adapter, &ioh_hwmon_info[substream->number]);
>> +     if (!i2c) {
>> +             mutex_unlock(&codec->mutex);
>> +             return -1;
>> +     }
>> +     i2c_put_adapter(adapter);
>> +     mutex_unlock(&codec->mutex);
>
> No, this is definitely wrong - we certainly shouldn't be registering new
> devices whenever someone starts an audio stream.  I'm struggling to
> understand what the intended effect is though.
Do you mean this registering must be at xx_init processing ?
OK, I'll move this processing into init().

>> +     ret = snd_soc_dai_set_fmt(codec_dai, SND_SOC_DAIFMT_I2S |
>> +                             SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBS_CFS);
>> +     if (ret < 0)
>> +             return ret;
>
> Use the dai_fmt field in the dai_link to set this.
Sorry, I can't understand your saying.
Let me know in more detail.

>
>> +MODULE_AUTHOR("Tomoya MORINAGA <tomoya.rohm@...il.com>");
>> +MODULE_DESCRIPTION("LAPIS Semiconductor ML7213 IOH ALSA SoC machine driver");
>> +MODULE_LICENSE("GPL");
>
> Should have MODULE_ALIAS too.
Do you mean machine driver should have MODULE_ALIAS ?
Grepping  MODULE_ALIAS at sound/soc, it seems MODULE_ALIAS is used in
platform driver only like below.
pxa/pxa2xx-i2s.c:MODULE_ALIAS("platform:pxa2xx-i2s");

Does machine driver need like "MODULE_ALIAS("machine:ml7213CRB")" ?

Thanks in advance

tomoya
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