linux-kernel - Re: [PATCH v2 1/4] mfd: arizona: Factor out SYSCLK enable from wm5102 hardware patch

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Message-ID: <20150323135213.GH24804@x1>
Date:	Mon, 23 Mar 2015 13:52:13 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc:	broonie@...nel.org, sameo@...ux.intel.com, lgirdwood@...il.com,
	patches@...nsource.wolfsonmicro.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/4] mfd: arizona: Factor out SYSCLK enable from
 wm5102 hardware patch

On Tue, 17 Mar 2015, Charles Keepax wrote:

> wm5102 applies a custom hardware boot sequence, for this the SYSCLK
> needs to be enabled. This patch factors out the code that enables
> SYSCLK for this sequence such that it can be used for other boot time
> operations that require SYSCLK.
> 
> Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> ---
> 
> Changes since v1:
>  - Added some comments in patch 4 to explain the exact regulator voltage
>    ranges
>  - Removed the reset patch, whilst I work on the suggestions by Mark, the
>    rest of the series is useful in its own right and doesn't need to be
>    blocked by that
> 
> Thanks,
> Charles
> 
>  drivers/mfd/arizona-core.c |   48 ++++++++++++++++++++++++++++---------------
>  1 files changed, 31 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> index 6ca6dfa..ef1f8aa 100644
> --- a/drivers/mfd/arizona-core.c
> +++ b/drivers/mfd/arizona-core.c
> @@ -250,7 +250,8 @@ static int arizona_wait_for_boot(struct arizona *arizona)
>  	return ret;
>  }
>  
> -static int arizona_apply_hardware_patch(struct arizona* arizona)
> +static int arizona_exec_with_sysclk(struct arizona *arizona,
> +				    int (*exec)(struct arizona *))
>  {
>  	unsigned int fll, sysclk;
>  	int ret, err;
> @@ -292,23 +293,8 @@ static int arizona_apply_hardware_patch(struct arizona* arizona)
>  		goto err_fll;
>  	}
>  
> -	/* Start the write sequencer and wait for it to finish */
> -	ret = regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
> -			ARIZONA_WSEQ_ENA | ARIZONA_WSEQ_START | 160);
> -	if (ret != 0) {
> -		dev_err(arizona->dev, "Failed to start write sequencer: %d\n",
> -			ret);
> -		goto err_sysclk;
> -	}
> -	ret = arizona_poll_reg(arizona, 5, ARIZONA_WRITE_SEQUENCER_CTRL_1,
> -			       ARIZONA_WSEQ_BUSY, 0);
> -	if (ret != 0) {
> -		regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
> -				ARIZONA_WSEQ_ABORT);
> -		ret = -ETIMEDOUT;
> -	}
> +	ret = exec(arizona);
>  
> -err_sysclk:
>  	err = regmap_write(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1, sysclk);
>  	if (err != 0) {
>  		dev_err(arizona->dev,
> @@ -330,6 +316,34 @@ err_fll:
>  		return err;
>  }
>  
> +static int arizona_hardware_patch_wseq(struct arizona *arizona)
> +{
> +	int ret;
> +
> +	/* Start the write sequencer and wait for it to finish */
> +	ret = regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
> +			ARIZONA_WSEQ_ENA | ARIZONA_WSEQ_START | 160);
> +	if (ret != 0) {
> +		dev_err(arizona->dev, "Failed to start write sequencer: %d\n",
> +			ret);
> +		return ret;
> +	}
> +	ret = arizona_poll_reg(arizona, 5, ARIZONA_WRITE_SEQUENCER_CTRL_1,
> +			       ARIZONA_WSEQ_BUSY, 0);
> +	if (ret != 0) {
> +		regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
> +				ARIZONA_WSEQ_ABORT);
> +		ret = -ETIMEDOUT;
> +	}
> +
> +	return ret;
> +}
> +
> +static inline int arizona_apply_hardware_patch(struct arizona *arizona)
> +{
> +	return arizona_exec_with_sysclk(arizona, arizona_hardware_patch_wseq);

Not sure I like this much.

What's the reason for over-complicating this?  Can you just:

arizona_exec_with_sysclk(arizona);
arizona_hardware_patch_wseq(arizona); 

... or if you need that call to be in the middle, split the calls up
further.

> +}
> +
>  #ifdef CONFIG_PM
>  static int arizona_runtime_resume(struct device *dev)
>  {

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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