linux-kernel - Re: [PATCH v4 3/3] mfd: arizona: Refactor arizona_poll

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Message-ID: <20170323105434.wr27jfutuqdnrs7y@dell>
Date:   Thu, 23 Mar 2017 10:54:34 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc:     linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com
Subject: Re: [PATCH v4 3/3] mfd: arizona: Refactor arizona_poll_reg

On Wed, 15 Mar 2017, Charles Keepax wrote:

> Currently, we specify the timeout in terms of the number of polls but it
> is more clear from a user of the functions perspective to specify the
> timeout directly in milliseconds, as such update the function to these new
> semantics.
> 
> Additionally, arizona_poll_reg essentially hard-codes
> regmap_read_poll_timeout, update the implementation to use
> regmap_read_poll_timeout. We still keep arizona_poll_reg around as
> regmap_read_poll_timeout is a macro so rather than expand this for each
> caller keep it wrapped in arizona_poll_reg.
> 
> Whilst we are doing this make the timeouts a little more generous as
> the previous system had a bit more slack as it was done as a delay per
> iteration of the loop whereas regmap_read_poll_timeout compares ktime's.
> 
> Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> ---
> 
> Changes since v3:
>  - Squashed together patches 3/4 from the v3 chain.
> 
> Thanks,
> Charles
> 
>  drivers/mfd/arizona-core.c | 36 ++++++++++++++++--------------------
>  1 file changed, 16 insertions(+), 20 deletions(-)

Much better, thanks.

Applied, thanks.

> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> index 4cb34c3..75488e6 100644
> --- a/drivers/mfd/arizona-core.c
> +++ b/drivers/mfd/arizona-core.c
> @@ -235,29 +235,25 @@ static irqreturn_t arizona_overclocked(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> +#define ARIZONA_REG_POLL_DELAY_US 7500
> +
>  static int arizona_poll_reg(struct arizona *arizona,
> -			    int timeout, unsigned int reg,
> +			    int timeout_ms, unsigned int reg,
>  			    unsigned int mask, unsigned int target)
>  {
>  	unsigned int val = 0;
> -	int ret, i;
> -
> -	for (i = 0; i < timeout; i++) {
> -		ret = regmap_read(arizona->regmap, reg, &val);
> -		if (ret != 0) {
> -			dev_err(arizona->dev, "Failed to read reg 0x%x: %d\n",
> -				reg, ret);
> -			continue;
> -		}
> -
> -		if ((val & mask) == target)
> -			return 0;
> +	int ret;
>  
> -		usleep_range(1000, 5000);
> -	}
> +	ret = regmap_read_poll_timeout(arizona->regmap,
> +				       ARIZONA_INTERRUPT_RAW_STATUS_5, val,
> +				       ((val & mask) == target),
> +				       ARIZONA_REG_POLL_DELAY_US,
> +				       timeout_ms * 1000);
> +	if (ret)
> +		dev_err(arizona->dev, "Polling reg 0x%x timed out: %x\n",
> +			reg, val);
>  
> -	dev_err(arizona->dev, "Polling reg 0x%x timed out: %x\n", reg, val);
> -	return -ETIMEDOUT;
> +	return ret;
>  }
>  
>  static int arizona_wait_for_boot(struct arizona *arizona)
> @@ -269,7 +265,7 @@ static int arizona_wait_for_boot(struct arizona *arizona)
>  	 * we won't race with the interrupt handler as it'll be blocked on
>  	 * runtime resume.
>  	 */
> -	ret = arizona_poll_reg(arizona, 5, ARIZONA_INTERRUPT_RAW_STATUS_5,
> +	ret = arizona_poll_reg(arizona, 30, ARIZONA_INTERRUPT_RAW_STATUS_5,
>  			       ARIZONA_BOOT_DONE_STS, ARIZONA_BOOT_DONE_STS);
>  
>  	if (!ret)
> @@ -339,7 +335,7 @@ static int arizona_enable_freerun_sysclk(struct arizona *arizona,
>  			ret);
>  		return ret;
>  	}
> -	ret = arizona_poll_reg(arizona, 25, ARIZONA_INTERRUPT_RAW_STATUS_5,
> +	ret = arizona_poll_reg(arizona, 180, ARIZONA_INTERRUPT_RAW_STATUS_5,
>  			       ARIZONA_FLL1_CLOCK_OK_STS,
>  			       ARIZONA_FLL1_CLOCK_OK_STS);
>  	if (ret)
> @@ -403,7 +399,7 @@ static int wm5102_apply_hardware_patch(struct arizona *arizona)
>  		goto err;
>  	}
>  
> -	ret = arizona_poll_reg(arizona, 5, ARIZONA_WRITE_SEQUENCER_CTRL_1,
> +	ret = arizona_poll_reg(arizona, 30, ARIZONA_WRITE_SEQUENCER_CTRL_1,
>  			       ARIZONA_WSEQ_BUSY, 0);
>  	if (ret)
>  		regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_0,

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