netdev - Re: [PATCH 1/4] net: ethernet: dwmac: add Ethernet glue logic for stm32 chip

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Date:	Mon, 22 Feb 2016 22:52:17 +0100
From:	Joachim Eastwood <manabian@...il.com>
To:	Alexandre Torgue <alexandre.torgue@...il.com>
Cc:	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Giuseppe Cavallaro <peppe.cavallaro@...com>,
	netdev <netdev@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/4] net: ethernet: dwmac: add Ethernet glue logic for
 stm32 chip

On 22 February 2016 at 15:50, Alexandre Torgue
<alexandre.torgue@...il.com> wrote:
> 2016-02-13 14:48 GMT+01:00 Joachim  Eastwood <manabian@...il.com>:
>> On 3 February 2016 at 15:54, Alexandre TORGUE
>> <alexandre.torgue@...il.com> wrote:
>>> +       plat_dat->bsp_priv = dwmac;
>>> +       plat_dat->init = stm32_dwmac_init;
>>> +       plat_dat->exit = stm32_dwmac_exit;
>>
>> Instead of using these callbacks could you rather implement the PM
>> callbacks directly in this driver?
>> I don't think it should add much code and it will make it look more
>> like standard driver. This will also give you some more control and
>> flexibility in your code.
>
> I prefer to keep the code as it is. Glue layer is directly linked to
> stmmac driver and I don't want to brake the link between the glue and
> the stmmac driver.

What do you mean by break the link?

There has been numerous of patch sets to make the stmmac "glue"
drivers into more standard platform drivers.
http://marc.info/?l=linux-netdev&m=143159850631093&w=2
http://marc.info/?l=linux-netdev&m=143708560009851&w=2
http://marc.info/?l=linux-netdev&m=143812136600541&w=2

Do you see any advantage by using the init and exit hooks in your
driver instead of using the standard driver PM callbacks and remove
function?
The only "cost" I see is slightly more boilerplate code. But since you
already have init/exit functions you could easily make them into PM
resume/suspend so I doubt there would be much increase in code size.

One other thing;
Do you need to have the PHY mode setup code in the init function which
is called each time on resume?
If you could move it to probe you could drop the interface priv data
member and use plat_dat->interface as stmmac_probe_config_dt() has
already done of_get_phy_mode().

regards,
Joachim Eastwood