netdev - Re: [PATCH 3/4] net: mvmdio: print warning when orion-mdio has too many clocks

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Date:   Sat, 6 Jul 2019 18:09:25 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     josua@...id-run.com
Cc:     netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH 3/4] net: mvmdio: print warning when orion-mdio has too
 many clocks

On Sat, Jul 06, 2019 at 05:18:59PM +0200, josua@...id-run.com wrote:
> From: Josua Mayer <josua@...id-run.com>
> 
> Print a warning when device tree specifies more than the maximum of four
> clocks supported by orion-mdio. Because reading from mdio can lock up
> the Armada 8k when a required clock is not initialized, it is important
> to notify the user when a specified clock is ignored.
> 
> Signed-off-by: Josua Mayer <josua@...id-run.com>
> ---
>  drivers/net/ethernet/marvell/mvmdio.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c
> index e17d563e97a6..89a99bf8e87b 100644
> --- a/drivers/net/ethernet/marvell/mvmdio.c
> +++ b/drivers/net/ethernet/marvell/mvmdio.c
> @@ -326,6 +326,10 @@ static int orion_mdio_probe(struct platform_device *pdev)
>  		clk_prepare_enable(dev->clk[i]);
>  	}
>  
> +	if (!IS_ERR(of_clk_get(pdev->dev.of_node, i)))
> +		dev_warn(dev, "unsupported number of clocks, limiting to the first "
> +			 __stringify(ARRAY_SIZE(dev->clk)) "\n");
> +

Hi Josua

Humm. Say getting clock 0 returned -EINVAL, or some other error code.
We break out of the loop, since such errors are being ignored. We then
hit this new code. Getting clock 1 works, and then we incorrectly
print this message.

Rather than getting the i'th clock, get ARRAY_SIZE(dev->clk)'th clock.

       Andrew