linux-kernel - Re: [PATCH v3] net: phy: mdio-gpio: Fix working over slow can

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Date:   Wed, 14 Nov 2018 14:03:51 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     Martin Schiller <ms@....tdt.de>, andrew@...n.ch,
        f.fainelli@...il.com
Cc:     davem@...emloft.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] net: phy: mdio-gpio: Fix working over slow can_sleep
 GPIOs

On 11/14/2018 01:12 PM, Martin Schiller wrote:

> This commit re-enables support for slow GPIO pins. It was initially
> introduced by commit 2d6c9091ab76 ("net: mdio-gpio: support access that
> may sleep") and got lost by commit 7e5fbd1e0700 ("net: mdio-gpio:
> Convert to use gpiod functions where possible").
> 
> Also add a warning about slow GPIO pins like it is done in i2c-gpio.
> 
> Signed-off-by: Martin Schiller <ms@....tdt.de>
> ---
> v3:
>  - modified commit summary
>  - fixed commit cites in commit message
>  - fixed line continuation
>  
> v2:
>  - fixed copy/paste bug in warning about slow GPIO pins
> ---
>  drivers/net/phy/mdio-gpio.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/phy/mdio-gpio.c b/drivers/net/phy/mdio-gpio.c
> index 33265747bf39..e1c305089172 100644
> --- a/drivers/net/phy/mdio-gpio.c
> +++ b/drivers/net/phy/mdio-gpio.c
[...]
> @@ -162,6 +162,11 @@ static int mdio_gpio_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	if (gpiod_cansleep(bitbang->mdc) || gpiod_cansleep(bitbang->mdio) ||
> +	    gpiod_cansleep(bitbang->mdo))
> +		dev_warn(&pdev->dev, "Slow GPIO pins might wreak havoc into"
> +				     "MDIO bus timing");

   Oops, missed this in the 1st review: you don't need to break the kernel messages
like that, they may violate the 80-column limit (to facilitate searching)...

[...]

MBR, Sergei