Re: [PATCH v3 1/4] mfd: arizona: Factor out SYSCLK enable from wm5102 hardware patch

[Lee Jones <lee.jones@linaro.org>]

On Mon, 23 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@opensource.wolfsonmicro.com>
> ---
> 
> Changes since v3:
>  - Split out enable and disable for the freerunning SYSCLK instead
>    of having a single function that takes a function pointer.
>  - Improve some naming for the sake of clarity
>  - Update error handling to use if (err) rather than if (err != 0)
>  - Added comment on register patch
> 
> Thanks,
> Charles
> 
>  drivers/mfd/arizona-core.c |  103 ++++++++++++++++++++++++++++++-------------
>  1 files changed, 72 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> index 6ca6dfa..695c68e 100644
> --- a/drivers/mfd/arizona-core.c
> +++ b/drivers/mfd/arizona-core.c
> @@ -250,20 +250,26 @@ static int arizona_wait_for_boot(struct arizona *arizona)
>  	return ret;
>  }
>  
> -static int arizona_apply_hardware_patch(struct arizona* arizona)
> +struct arizona_sysclk_state {
> +	unsigned int fll;
> +	unsigned int sysclk;
> +};
> +
> +static int arizona_enable_freerun_sysclk(struct arizona *arizona,
> +					 struct arizona_sysclk_state *state)
>  {
> -	unsigned int fll, sysclk;
>  	int ret, err;
>  
>  	/* Cache existing FLL and SYSCLK settings */
> -	ret = regmap_read(arizona->regmap, ARIZONA_FLL1_CONTROL_1, &fll);
> -	if (ret != 0) {
> +	ret = regmap_read(arizona->regmap, ARIZONA_FLL1_CONTROL_1, &state->fll);
> +	if (ret) {
>  		dev_err(arizona->dev, "Failed to cache FLL settings: %d\n",
>  			ret);
>  		return ret;
>  	}
> -	ret = regmap_read(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1, &sysclk);
> -	if (ret != 0) {
> +	ret = regmap_read(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1,
> +			  &state->sysclk);
> +	if (ret) {
>  		dev_err(arizona->dev, "Failed to cache SYSCLK settings: %d\n",
>  			ret);
>  		return ret;
> @@ -272,7 +278,7 @@ static int arizona_apply_hardware_patch(struct arizona* arizona)
>  	/* Start up SYSCLK using the FLL in free running mode */
>  	ret = regmap_write(arizona->regmap, ARIZONA_FLL1_CONTROL_1,
>  			ARIZONA_FLL1_ENA | ARIZONA_FLL1_FREERUN);
> -	if (ret != 0) {
> +	if (ret) {
>  		dev_err(arizona->dev,
>  			"Failed to start FLL in freerunning mode: %d\n",
>  			ret);
> @@ -281,50 +287,85 @@ static int arizona_apply_hardware_patch(struct arizona* arizona)
>  	ret = arizona_poll_reg(arizona, 25, ARIZONA_INTERRUPT_RAW_STATUS_5,
>  			       ARIZONA_FLL1_CLOCK_OK_STS,
>  			       ARIZONA_FLL1_CLOCK_OK_STS);
> -	if (ret != 0) {
> +	if (ret) {
>  		ret = -ETIMEDOUT;
>  		goto err_fll;
>  	}
>  
>  	ret = regmap_write(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1, 0x0144);
> -	if (ret != 0) {
> +	if (ret) {
>  		dev_err(arizona->dev, "Failed to start SYSCLK: %d\n", ret);
>  		goto err_fll;
>  	}
>  
> +	return 0;
> +
> +err_fll:
> +	err = regmap_write(arizona->regmap, ARIZONA_FLL1_CONTROL_1, state->fll);
> +	if (err)
> +		dev_err(arizona->dev,
> +			"Failed to re-apply old FLL settings: %d\n",
> +			err);

Nit: How is it that the regmap_write() line fit on 80 chars and the
"err);" bit can't?

> +	return ret;
> +}
> +
> +static int arizona_disable_freerun_sysclk(struct arizona *arizona,
> +					  struct arizona_sysclk_state *state)
> +{
> +	int ret = 0;
> +	int err;
> +
> +	err = regmap_write(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1,
> +			   state->sysclk);
> +	if (err) {
> +		dev_err(arizona->dev,
> +			"Failed to re-apply old SYSCLK settings: %d\n",
> +			err);

Same there, this extra linewrap seems unnecessary.

> +		ret = err;
> +	}

Can you explain the resson for using 'err' and and not 'ret'?

> +	err = regmap_write(arizona->regmap, ARIZONA_FLL1_CONTROL_1, state->fll);
> +	if (err) {
> +		dev_err(arizona->dev,
> +			"Failed to re-apply old FLL settings: %d\n",
> +			err);
> +		ret = err;
> +	}
> +
> +	return ret;
> +}
> +
> +static int wm5102_apply_hardware_patch(struct arizona *arizona)
> +{
> +	struct arizona_sysclk_state state;
> +	int err, ret;
> +
> +	ret = arizona_enable_freerun_sysclk(arizona, &state);
> +	if (ret)
> +		return 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) {
> +	if (ret) {
>  		dev_err(arizona->dev, "Failed to start write sequencer: %d\n",
>  			ret);
> -		goto err_sysclk;
> +		goto err;
>  	}
> +
>  	ret = arizona_poll_reg(arizona, 5, ARIZONA_WRITE_SEQUENCER_CTRL_1,
>  			       ARIZONA_WSEQ_BUSY, 0);
> -	if (ret != 0) {
> +	if (ret) {
>  		regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,
> -				ARIZONA_WSEQ_ABORT);
> +			     ARIZONA_WSEQ_ABORT);
>  		ret = -ETIMEDOUT;
>  	}
>  
> -err_sysclk:
> -	err = regmap_write(arizona->regmap, ARIZONA_SYSTEM_CLOCK_1, sysclk);
> -	if (err != 0) {
> -		dev_err(arizona->dev,
> -			"Failed to re-apply old SYSCLK settings: %d\n",
> -			err);
> -	}
> -
> -err_fll:
> -	err = regmap_write(arizona->regmap, ARIZONA_FLL1_CONTROL_1, fll);
> -	if (err != 0) {
> -		dev_err(arizona->dev,
> -			"Failed to re-apply old FLL settings: %d\n",
> -			err);
> -	}
> +err:
> +	err = arizona_disable_freerun_sysclk(arizona, &state);
>  
> -	if (ret != 0)
> +	if (ret)
>  		return ret;
>  	else
>  		return err;

return ret ?: err;

> @@ -366,7 +407,7 @@ static int arizona_runtime_resume(struct device *dev)
>  			goto err;
>  		}
>  
> -		ret = arizona_apply_hardware_patch(arizona);
> +		ret = wm5102_apply_hardware_patch(arizona);
>  		if (ret != 0) {
>  			dev_err(arizona->dev,
>  				"Failed to apply hardware patch: %d\n",
> @@ -891,7 +932,7 @@ int arizona_dev_init(struct arizona *arizona)
>  
>  		switch (arizona->type) {
>  		case WM5102:
> -			ret = arizona_apply_hardware_patch(arizona);
> +			ret = wm5102_apply_hardware_patch(arizona);
>  			if (ret != 0) {
>  				dev_err(arizona->dev,
>  					"Failed to apply hardware patch: %d\n",

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