netdev - Re: [PATCH] phy: add support for a reset-gpio specification

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Message-ID: <57348D05.905@ti.com>
Date:	Thu, 12 May 2016 17:02:45 +0300
From:	Roger Quadros <rogerq@...com>
To:	Nishanth Menon <nm@...com>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	<netdev@...r.kernel.org>, <devicetree@...r.kernel.org>,
	Florian Fainelli <f.fainelli@...il.com>
CC:	<kernel@...gutronix.de>, "Andrew F . Davis" <afd@...com>,
	Sekhar Nori <nsekhar@...com>, Suman Anna <s-anna@...com>
Subject: Re: [PATCH] phy: add support for a reset-gpio specification

Hi,

On 12/05/16 16:50, Nishanth Menon wrote:
> On 05/12/2016 05:00 AM, Uwe Kleine-König wrote:
>> The framework only asserts (for now) that the reset gpio is not active.
>>
>> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
>> ---
>>  Documentation/devicetree/bindings/net/phy.txt | 3 +++
>>  drivers/net/phy/phy_device.c                  | 8 ++++++++
>>  2 files changed, 11 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
>> index bc1c3c8bf8fa..c00a9a894547 100644
>> --- a/Documentation/devicetree/bindings/net/phy.txt
>> +++ b/Documentation/devicetree/bindings/net/phy.txt
>> @@ -35,6 +35,8 @@ Optional Properties:
>>  - broken-turn-around: If set, indicates the PHY device does not correctly
>>    release the turn around line low at the end of a MDIO transaction.
>>  
>> +- reset-gpios: Reference to a GPIO used to reset the phy.
>> +
>>  Example:
>>  
>>  ethernet-phy@0 {
>> @@ -42,4 +44,5 @@ ethernet-phy@0 {
>>  	interrupt-parent = <40000>;
>>  	interrupts = <35 1>;
>>  	reg = <0>;
>> +	reset-gpios = <&gpio1 17 GPIO_ACTIVE_LOW>;
>>  };
>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
>> index e551f3a89cfd..7d666ab47271 100644
>> --- a/drivers/net/phy/phy_device.c
>> +++ b/drivers/net/phy/phy_device.c
>> @@ -34,6 +34,7 @@
>>  #include <linux/io.h>
>>  #include <linux/uaccess.h>
>>  #include <linux/of.h>
>> +#include <linux/gpio/consumer.h>
>>  
>>  #include <asm/irq.h>
>>  
>> @@ -1569,9 +1570,16 @@ static int phy_probe(struct device *dev)
>>  	struct device_driver *drv = phydev->mdio.dev.driver;
>>  	struct phy_driver *phydrv = to_phy_driver(drv);
>>  	int err = 0;
>> +	struct gpio_descs *reset_gpios;
>>  
>>  	phydev->drv = phydrv;
>>  
>> +	/* take phy out of reset */
>> +	reset_gpios = devm_gpiod_get_array_optional(dev, "reset",
>> +						    GPIOD_OUT_LOW);
>> +	if (IS_ERR(reset_gpios))
>> +		return PTR_ERR(reset_gpios);
>> +
>>  	/* Disable the interrupt if the PHY doesn't support it
>>  	 * but the interrupt is still a valid one
>>  	 */
>>
> 
> This looks like the right approach to me at least: I see that TI EVMs
> will also benefit with this approach.
> 

Agreed. Although on some of our boards we actually need a RESET pulse
to get the PHY in a sane state. I can send a patch on top for that.

Reviewed-by: Roger Quadros <rogerq@...com>

--
cheers,
-roger