linux-kernel - Re: [PATCH] ASoC: wm8962: Let CODEC driver enable and disable its own MCLK

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Date:	Mon, 28 Jul 2014 19:23:24 +0800
From:	Nicolin Chen <Guangyu.Chen@...escale.com>
To:	Nicolin Chen <nicoleotsuka@...il.com>
CC:	<broonie@...nel.org>, <alsa-devel@...a-project.org>,
	<patches@...nsource.wolfsonmicro.com>,
	<linux-kernel@...r.kernel.org>, <b42378@...escale.com>,
	<b02247@...escale.com>
Subject: Re: [PATCH] ASoC: wm8962: Let CODEC driver enable and disable its
 own MCLK

PLEASE IGNORE THIS VERSION

On Mon, Jul 28, 2014 at 06:56:01PM +0800, Nicolin Chen wrote:
> snd_soc_open() will trigger pm_runtime resume() which will then enable
> the regulator and initialization. So we should make sure the MCLK is
> enabled before this resume().
> 
> Previously we let the machine driver get the clock and enable it in
> its probe(). However, considering about power saving, it'll be better
> to enable it when it's going to be used and disable it after using.
> 
> So this patch just simply adds clk_get() and clk_enable() to WM8962
> driver. Meanwhile, it marks clock pointer to NULL if no clock assigned
> to it so it will not break any current function.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@...il.com>

Sorry, the patch has some problem. I'll send v2 to fix it.

Please ignore this version.

Thank you,
Nicolin

> ---
>  include/sound/wm8962.h    |  1 +
>  sound/soc/codecs/wm8962.c | 11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/include/sound/wm8962.h b/include/sound/wm8962.h
> index 79e6d42..0af7c16 100644
> --- a/include/sound/wm8962.h
> +++ b/include/sound/wm8962.h
> @@ -37,6 +37,7 @@
>  #define WM8962_GPIO_FN_MICSCD          22
>  
>  struct wm8962_pdata {
> +	struct clk *mclk;
>  	int gpio_base;
>  	u32 gpio_init[WM8962_MAX_GPIO];
>  
> diff --git a/sound/soc/codecs/wm8962.c b/sound/soc/codecs/wm8962.c
> index ca2fda9..256ae51 100644
> --- a/sound/soc/codecs/wm8962.c
> +++ b/sound/soc/codecs/wm8962.c
> @@ -14,6 +14,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/init.h>
> +#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/pm.h>
>  #include <linux/gcd.h>
> @@ -3541,6 +3542,8 @@ static int wm8962_set_pdata_from_of(struct i2c_client *i2c,
>  				pdata->gpio_init[i] = 0x0;
>  		}
>  
> +	pdata->mclk = devm_clk_get(&i2c->dev, NULL);
> +
>  	return 0;
>  }
>  
> @@ -3572,6 +3575,10 @@ static int wm8962_i2c_probe(struct i2c_client *i2c,
>  			return ret;
>  	}
>  
> +	/* Mark the mclk pointer to NULL if no mclk assigned */
> +	if (IS_ERR(pdata->mclk))
> +		pdata->mclk = NULL;
> +
>  	for (i = 0; i < ARRAY_SIZE(wm8962->supplies); i++)
>  		wm8962->supplies[i].supply = wm8962_supply_names[i];
>  
> @@ -3780,6 +3787,8 @@ static int wm8962_runtime_resume(struct device *dev)
>  	struct wm8962_priv *wm8962 = dev_get_drvdata(dev);
>  	int ret;
>  
> +	clk_prepare_enable(wm8962->pdata.mclk);
> +
>  	ret = regulator_bulk_enable(ARRAY_SIZE(wm8962->supplies),
>  				    wm8962->supplies);
>  	if (ret != 0) {
> @@ -3839,6 +3848,8 @@ static int wm8962_runtime_suspend(struct device *dev)
>  	regulator_bulk_disable(ARRAY_SIZE(wm8962->supplies),
>  			       wm8962->supplies);
>  
> +	clk_disable_unprepare(wm8962->pdata.mclk);
> +
>  	return 0;
>  }
>  #endif
> -- 
> 1.8.4
> 
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