linux-kernel - Re: [PATCH] net: fec: add post PHY reset delay DT property

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Message-ID: <f667da6e-d300-ec79-cc49-3808d9758a99@free-electrons.com>
Date:   Mon, 22 May 2017 16:00:47 +0200
From:   Quentin Schulz <quentin.schulz@...e-electrons.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     fugang.duan@....com, robh+dt@...nel.org, mark.rutland@....com,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, thomas.petazzoni@...e-electrons.com
Subject: Re: [PATCH] net: fec: add post PHY reset delay DT property

Hi Andrew

On 22/05/2017 15:57, Andrew Lunn wrote:
> On Mon, May 22, 2017 at 11:15:17AM +0200, Quentin Schulz wrote:
>> Some PHY require to wait for a bit after the reset GPIO has been
>> toggled. This adds support for the DT property `phy-reset-post-delay`
>> which gives the delay in milliseconds to wait after reset.
>>
>> If the DT property is not given, no delay is observed. Post reset delay
>> greater than 1000ms are invalid and are default to 1ms.
> 
> Hi Quentin
> 
> If it is invalid, please return -EINVAL.
> 

Just copying the wording and behavior of phy-reset-duration. Should we
then change the behavior of phy-reset-duration as well to return -EINVAL
in that case or I just leave both as is?

Quentin

>> Signed-off-by: Quentin Schulz <quentin.schulz@...e-electrons.com>
>> ---
>>  Documentation/devicetree/bindings/net/fsl-fec.txt |  5 +++++
>>  drivers/net/ethernet/freescale/fec_main.c         | 17 +++++++++++++++--
>>  2 files changed, 20 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
>> index a1e3693cca16..8795e8ca5793 100644
>> --- a/Documentation/devicetree/bindings/net/fsl-fec.txt
>> +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
>> @@ -15,6 +15,11 @@ Optional properties:
>>  - phy-reset-active-high : If present then the reset sequence using the GPIO
>>    specified in the "phy-reset-gpios" property is reversed (H=reset state,
>>    L=operation state).
>> +- phy-reset-post-delay : Post reset delay in milliseconds. If present then
>> +  a delay of phy-reset-post-delay milliseconds will be observed after the
>> +  phy-reset-gpios has been toggled. Can be omitted thus no delay is
>> +  observed. Delay is in range of 1ms to 1000ms. If given delay is higher
>> +  than 1000ms, 1ms delay is done instead.
>>  - phy-supply : regulator that powers the Ethernet PHY.
>>  - phy-handle : phandle to the PHY device connected to this device.
>>  - fixed-link : Assume a fixed link. See fixed-link.txt in the same directory.
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
>> index 56a563f90b0b..00a7fd0bcd59 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -3192,7 +3192,7 @@ static int fec_reset_phy(struct platform_device *pdev)
>>  {
>>  	int err, phy_reset;
>>  	bool active_high = false;
>> -	int msec = 1;
>> +	int msec = 1, phy_post_delay = 0;
>>  	struct device_node *np = pdev->dev.of_node;
>>  
>>  	if (!np)
>> @@ -3210,7 +3210,6 @@ static int fec_reset_phy(struct platform_device *pdev)
>>  		return 0;
>>  
>>  	active_high = of_property_read_bool(np, "phy-reset-active-high");
>> -
>>  	err = devm_gpio_request_one(&pdev->dev, phy_reset,
>>  			active_high ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
>>  			"phy-reset");
> 
> No white space changes please.
> 
>    Andrew
> 

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com