Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [RFC] ravb: Add support for optional txc_refclk
To:     Adam Ford <aford173@gmail.com>, linux-renesas-soc@vger.kernel.org
Cc:     aford@beaconembedded.com, charles.stevens@logicpd.com,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20201212165648.166220-1-aford173@gmail.com>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Organization: Brain-dead Software
Message-ID: <7f5f8ef2-3e4f-5076-0558-26b48e75b674@gmail.com>
Date:   Sat, 12 Dec 2020 20:54:58 +0300
User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.5.1
MIME-Version: 1.0
In-Reply-To: <20201212165648.166220-1-aford173@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hello!

On 12.12.2020 19:56, Adam Ford wrote:

> The SoC expects the txv_refclk is provided, but if it is provided
> by a programmable clock, there needs to be a way to get and enable
> this clock to operate.  It needs to be optional since it's only
> necessary for those with programmable clocks.
> 
> Signed-off-by: Adam Ford <aford173@gmail.com>
[...]
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index bd30505fbc57..4c3f95923ef2 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
>   		goto out_release;
>   	}
>   
> +	priv->ref_clk = devm_clk_get(&pdev->dev, "txc_refclk");

    Why not devm_clk_get_optional()?

> +	if (IS_ERR(priv->ref_clk)) {
> +		if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> +			/* for Probe defer return error */
> +			error = PTR_ERR(priv->ref_clk);
> +			goto out_release;
> +		}
> +		/* Ignore other errors since it's optional */
> +	} else {
> +		(void)clk_prepare_enable(priv->ref_clk);
> +	}
> +
>   	ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
>   	ndev->min_mtu = ETH_MIN_MTU;
>   

MBR, Sergei