linux-kernel - Re: [PATCH RFT 1/2] phylib: add device reset GPIO support

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Message-ID: <570BFACF.30507@cogentembedded.com>
Date:	Mon, 11 Apr 2016 22:28:15 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Rob Herring <robh@...nel.org>
Cc:	grant.likely@...aro.org, devicetree@...r.kernel.org,
	f.fainelli@...il.com, netdev@...r.kernel.org,
	frowand.list@...il.com, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFT 1/2] phylib: add device reset GPIO support

On 04/11/2016 10:25 PM, Rob Herring wrote:

>> The PHY  devices sometimes do have their reset signal (maybe even power
>> supply?) tied to some GPIO and sometimes it also does happen that a boot
>> loader does not leave it deasserted. So far this issue has been attacked
>> from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
>> the GPIO in question;  that solution, when  applied to the device trees,
>> led to adding the PHY reset GPIO properties to the MAC device node, with
>> one exception: Cadence MACB driver which could handle the "reset-gpios"
>> prop  in a PHY device  subnode.  I believe that the correct approach is to
>> teach the 'phylib' to get the MDIO device reset GPIO from the device tree
>> node corresponding to this device -- which this patch is doing...
>>
>> Note that I had to modify the  AT803x PHY driver as it would stop working
>> otherwise as it made use of the reset GPIO for its own purposes...
>
> Lots of double spaces in here. Please fix.

    Oh, it's you again! :-D

>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
>>
>> ---
>>   Documentation/devicetree/bindings/net/phy.txt |    2 +
>>   drivers/net/phy/at803x.c                      |   19 ++------------
>>   drivers/net/phy/mdio_bus.c                    |    4 +++
>>   drivers/net/phy/mdio_device.c                 |   27 +++++++++++++++++++--
>>   drivers/net/phy/phy_device.c                  |   33 ++++++++++++++++++++++++--
>>   drivers/of/of_mdio.c                          |   16 ++++++++++++
>>   include/linux/mdio.h                          |    3 ++
>>   include/linux/phy.h                           |    5 +++
>>   8 files changed, 89 insertions(+), 20 deletions(-)
>
> [...]
>
>> Index: net-next/drivers/of/of_mdio.c
>> ===================================================================
>> --- net-next.orig/drivers/of/of_mdio.c
>> +++ net-next/drivers/of/of_mdio.c
>> @@ -44,6 +44,7 @@ static int of_get_phy_id(struct device_n
>>   static int of_mdiobus_register_phy(struct mii_bus *mdio, struct device_node *child,
>>   				   u32 addr)
>>   {
>> +	struct gpio_desc *gpiod;
>>   	struct phy_device *phy;
>>   	bool is_c45;
>>   	int rc;
>> @@ -52,10 +53,17 @@ static int of_mdiobus_register_phy(struc
>>   	is_c45 = of_device_is_compatible(child,
>>   					 "ethernet-phy-ieee802.3-c45");
>>
>> +	gpiod = fwnode_get_named_gpiod(&child->fwnode, "reset-gpios");
>
> Calling fwnode_* functions in a DT specific file/function? That doesn't
> make sense.

    Really?! 8-)
    Where is a DT-only analog I wonder...

MBR, Sergei