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

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Message-ID: <e33175d3-bf03-4b84-3198-0952cb6a0707@egil-hjelmeland.no>
Date:   Tue, 12 Dec 2017 21:59:41 +0100
From:   Egil Hjelmeland <privat@...l-hjelmeland.no>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
        andrew@...n.ch, f.fainelli@...il.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] net: dsa: lan9303: Introduce lan9303_read_wait

Hi Vivien.

Den 12. des. 2017 19:08, skrev Vivien Didelot:
> 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.
> 

Good catch. Will fix that. Same with lan9303_csr_reg_wait() then.


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

The idea was to make in more general usable, in case one need to wait 
for a bit to be set. But I don't have any example from the datasheet 
that needs it, so I could take "value" away.

>> +		usleep_range(1000, 2000);
>> +	}
>> +	return -ETIMEDOUT;
> 
> A newline before the return statment would be appreciated.
> 
Ok.

>> +}
>> +
>>   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
> 

Thanks, Egil