netdev - Re: [PATCH] net: ftgmac100: Request clock and set speed

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Date:   Tue, 10 Oct 2017 14:38:09 +0930
From:   Joel Stanley <joel@....id.au>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        netdev@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH] net: ftgmac100: Request clock and set speed

On Tue, Oct 10, 2017 at 2:34 PM, Florian Fainelli <f.fainelli@...il.com> wrote:
>
>
> On 10/09/2017 09:49 PM, Joel Stanley wrote:
>> According to the ASPEED datasheet, gigabit speeds require a clock of
>> 100MHz or higher. Other speeds require 25MHz or higher.
>>
>> Signed-off-by: Joel Stanley <joel@....id.au>
>> ---
>
>> @@ -161,6 +170,9 @@ static int ftgmac100_reset_and_config_mac(struct ftgmac100 *priv)
>>               break;
>>       }
>>
>> +     if (freq && priv->clk)
>> +             clk_set_rate(priv->clk, freq);
>
> Checking for priv->clk should not be necessary all public clk APIs can
> deal with a NULL clock pointer.

The intention was to set ->clk to NULL to indicate that there was no
clk, and therefore there is no reason to attempt to set the rate or
call prepare/unprepare.

If the we prefer to call the clk apis unconditionally I will send a v2
with the checks removed.

Thanks for the review.

Cheers,

Joel