linux-kernel - Re: [PATCH net-next] net: dsa: lan9303: Introduce lan9303_read

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Date:   Tue, 12 Dec 2017 13:08:24 -0500
From:   Vivien Didelot <vivien.didelot@...oirfairelinux.com>
To:     Egil Hjelmeland <privat@...l-hjelmeland.no>, andrew@...n.ch,
        f.fainelli@...il.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Egil Hjelmeland <privat@...l-hjelmeland.no>
Subject: Re: [PATCH net-next] net: dsa: lan9303: Introduce lan9303_read_wait

Hi Egil,

Egil Hjelmeland <privat@...l-hjelmeland.no> writes:

> Simplify lan9303_indirect_phy_wait_for_completion()
> and lan9303_switch_wait_for_completion() by using a new function
> lan9303_read_wait()
>
> Signed-off-by: Egil Hjelmeland <privat@...l-hjelmeland.no>
> ---
>  drivers/net/dsa/lan9303-core.c | 59 +++++++++++++++++++-----------------------
>  1 file changed, 27 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
> index c1b004fa64d9..96ccce0939d3 100644
> --- a/drivers/net/dsa/lan9303-core.c
> +++ b/drivers/net/dsa/lan9303-core.c
> @@ -249,6 +249,29 @@ static int lan9303_read(struct regmap *regmap, unsigned int offset, u32 *reg)
>  	return -EIO;
>  }
>  
> +/* Wait a while until mask & reg == value. Otherwise return timeout. */
> +static int lan9303_read_wait(struct lan9303 *chip, int offset, int mask,
> +			     char value)
> +{
> +	int i;
> +
> +	for (i = 0; i < 25; i++) {
> +		u32 reg;
> +		int ret;
> +
> +		ret = lan9303_read(chip->regmap, offset, &reg);
> +		if (ret) {
> +			dev_err(chip->dev, "%s failed to read offset %d: %d\n",
> +				__func__, offset, ret);
> +			return ret;
> +		}
> +		if ((reg & mask) == value)
> +			return 0;

That is weird to mix int, u32 and char for mask checking. I suggest you
to use the u32 type as well for both mask and value.

Looking at how lan9303_read_wait is called, the value argument doesn't
seem necessary. You can directly return 0 if (!(reg & mask)).

> +		usleep_range(1000, 2000);
> +	}
> +	return -ETIMEDOUT;

A newline before the return statment would be appreciated.

> +}
> +
>  static int lan9303_virt_phy_reg_read(struct lan9303 *chip, int regnum)
>  {
>  	int ret;
> @@ -274,22 +297,8 @@ static int lan9303_virt_phy_reg_write(struct lan9303 *chip, int regnum, u16 val)
>  
>  static int lan9303_indirect_phy_wait_for_completion(struct lan9303 *chip)
>  {
> -	int ret, i;
> -	u32 reg;
> -
> -	for (i = 0; i < 25; i++) {
> -		ret = lan9303_read(chip->regmap, LAN9303_PMI_ACCESS, &reg);
> -		if (ret) {
> -			dev_err(chip->dev,
> -				"Failed to read pmi access status: %d\n", ret);
> -			return ret;
> -		}
> -		if (!(reg & LAN9303_PMI_ACCESS_MII_BUSY))
> -			return 0;
> -		usleep_range(1000, 2000);
> -	}
> -
> -	return -EIO;
> +	return lan9303_read_wait(chip, LAN9303_PMI_ACCESS,
> +				 LAN9303_PMI_ACCESS_MII_BUSY, 0);
>  }
>  
>  static int lan9303_indirect_phy_read(struct lan9303 *chip, int addr, int regnum)
> @@ -366,22 +375,8 @@ EXPORT_SYMBOL_GPL(lan9303_indirect_phy_ops);
>  
>  static int lan9303_switch_wait_for_completion(struct lan9303 *chip)
>  {
> -	int ret, i;
> -	u32 reg;
> -
> -	for (i = 0; i < 25; i++) {
> -		ret = lan9303_read(chip->regmap, LAN9303_SWITCH_CSR_CMD, &reg);
> -		if (ret) {
> -			dev_err(chip->dev,
> -				"Failed to read csr command status: %d\n", ret);
> -			return ret;
> -		}
> -		if (!(reg & LAN9303_SWITCH_CSR_CMD_BUSY))
> -			return 0;
> -		usleep_range(1000, 2000);
> -	}
> -
> -	return -EIO;
> +	return lan9303_read_wait(chip, LAN9303_SWITCH_CSR_CMD,
> +				 LAN9303_SWITCH_CSR_CMD_BUSY, 0);
>  }
>  
>  static int lan9303_write_switch_reg(struct lan9303 *chip, u16 regnum, u32 val)


Thanks,

        Vivien