linux-kernel - Re: [PATCH net-next] net: dsa: lan9303: lan9303_csr_reg

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Message-ID: <87efnwjbb4.fsf@weeman.i-did-not-set--mail-host-address--so-tickle-me>
Date:   Fri, 15 Dec 2017 09:49:35 -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: lan9303_csr_reg_wait cleanups

Hi Egil,

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

> Non-functional cleanups in lan9303_csr_reg_wait():
>  - Change type of param 'mask' from int to u32.
>  - Remove param 'value' (will probably never be used)
>  - Reduced retries from 1000 to 25, consistent with lan9303_read_wait.
>  - Corrected comments
>
> Signed-off-by: Egil Hjelmeland <privat@...l-hjelmeland.no>
> ---
>  drivers/net/dsa/lan9303-core.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
> index f412aad58253..209882075e3b 100644
> --- a/drivers/net/dsa/lan9303-core.c
> +++ b/drivers/net/dsa/lan9303-core.c
> @@ -249,7 +249,7 @@ static int lan9303_read(struct regmap *regmap, unsigned int offset, u32 *reg)
>  	return -EIO;
>  }
>  
> -/* Wait a while until mask & reg == value. Otherwise return timeout. */
> +/* Wait a while until mask & reg == 0. Otherwise return timeout. */

I'd remove this comment completely. The related code below is quite
explicit and speaks for itself, no need for an extra comment IMO.

    for (...)
        if (!(mask & reg))
            return 0;
    return -ETIMEOUT;

>  static int lan9303_read_wait(struct lan9303 *chip, int offset, u32 mask)
>  {
>  	int i;
> @@ -541,20 +541,20 @@ lan9303_alr_cache_find_mac(struct lan9303 *chip, const u8 *mac_addr)
>  	return NULL;
>  }
>  
> -/* Wait a while until mask & reg == value. Otherwise return timeout. */
> -static int lan9303_csr_reg_wait(struct lan9303 *chip, int regno,
> -				int mask, char value)
> +/* Wait a while until mask & reg == 0. Otherwise return timeout. */

Same here, no need to add some code in a comment.

> +static int lan9303_csr_reg_wait(struct lan9303 *chip, int regno, u32 mask)
>  {
>  	int i;
>  
> -	for (i = 0; i < 0x1000; i++) {
> +	for (i = 0; i < 25; i++) {
>  		u32 reg;
>  
>  		lan9303_read_switch_reg(chip, regno, &reg);
> -		if ((reg & mask) == value)
> +		if (!(reg & mask))
>  			return 0;
>  		usleep_range(1000, 2000);
>  	}
> +
>  	return -ETIMEDOUT;
>  }
>  
> @@ -564,8 +564,7 @@ static int lan9303_alr_make_entry_raw(struct lan9303 *chip, u32 dat0, u32 dat1)
>  	lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_WR_DAT_1, dat1);
>  	lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_CMD,
>  				 LAN9303_ALR_CMD_MAKE_ENTRY);
> -	lan9303_csr_reg_wait(chip, LAN9303_SWE_ALR_CMD_STS, ALR_STS_MAKE_PEND,
> -			     0);
> +	lan9303_csr_reg_wait(chip, LAN9303_SWE_ALR_CMD_STS, ALR_STS_MAKE_PEND);
>  	lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_CMD, 0);

The rest of the patch makes sense.

Thanks,

        Vivien