linux-kernel - Re: [PATCH RESEND 4/4] mfd: arizona: Use regmap_read_poll

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Date:   Wed, 8 Feb 2017 10:22:32 +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 RESEND 4/4] mfd: arizona: Use regmap_read_poll_timeout
 instead of hard coding it

On Tue, 31 Jan 2017, Charles Keepax wrote:

> arizona_poll_reg essentially hard-codes regmap_read_poll_timeout, this
> patch updates 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>
> ---
>  drivers/mfd/arizona-core.c | 37 ++++++++++++++-----------------------
>  1 file changed, 14 insertions(+), 23 deletions(-)

Roll this up into 3/4.

> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> index ae4cdc4..75488e6 100644
> --- a/drivers/mfd/arizona-core.c
> +++ b/drivers/mfd/arizona-core.c
> @@ -235,34 +235,25 @@ static irqreturn_t arizona_overclocked(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> -#define ARIZONA_REG_POLL_DELAY_MS 5
> +#define ARIZONA_REG_POLL_DELAY_US 7500
>  
>  static int arizona_poll_reg(struct arizona *arizona,
>  			    int timeout_ms, unsigned int reg,
>  			    unsigned int mask, unsigned int target)
>  {
> -	unsigned int npolls = (timeout_ms + ARIZONA_REG_POLL_DELAY_MS - 1) /
> -			      ARIZONA_REG_POLL_DELAY_MS;
>  	unsigned int val = 0;
> -	int ret, i;
> -
> -	for (i = 0; i < npolls; 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((ARIZONA_REG_POLL_DELAY_MS * 1000) / 2,
> -			     ARIZONA_REG_POLL_DELAY_MS * 1000);
> -	}
> +	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)
> @@ -274,7 +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, 25, 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)
> @@ -344,7 +335,7 @@ static int arizona_enable_freerun_sysclk(struct arizona *arizona,
>  			ret);
>  		return ret;
>  	}
> -	ret = arizona_poll_reg(arizona, 125, 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)
> @@ -408,7 +399,7 @@ static int wm5102_apply_hardware_patch(struct arizona *arizona)
>  		goto err;
>  	}
>  
> -	ret = arizona_poll_reg(arizona, 25, 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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