linux-kernel - Re: [PATCH v1 net-next 4/4] net: stmmac: setup higher frequency clk support for EHL & TGL

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Date:   Tue, 27 Aug 2019 08:08:30 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     "Voon, Weifeng" <weifeng.voon@...el.com>,
        Andrew Lunn <andrew@...n.ch>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Jose Abreu <joabreu@...opsys.com>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        "Ong, Boon Leong" <boon.leong.ong@...el.com>
Subject: Re: [PATCH v1 net-next 4/4] net: stmmac: setup higher frequency clk
 support for EHL & TGL



On 8/27/2019 3:38 AM, Voon, Weifeng wrote:
>>>> +#include <linux/clk-provider.h>
>>>>  #include <linux/pci.h>
>>>>  #include <linux/dmi.h>
>>>>
>>>> @@ -174,6 +175,19 @@ static int intel_mgbe_common_data(struct
>> pci_dev *pdev,
>>>>  	plat->axi->axi_blen[1] = 8;
>>>>  	plat->axi->axi_blen[2] = 16;
>>>>
>>>> +	plat->ptp_max_adj = plat->clk_ptp_rate;
>>>> +
>>>> +	/* Set system clock */
>>>> +	plat->stmmac_clk = clk_register_fixed_rate(&pdev->dev,
>>>> +						   "stmmac-clk", NULL, 0,
>>>> +						   plat->clk_ptp_rate);
>>>> +
>>>> +	if (IS_ERR(plat->stmmac_clk)) {
>>>> +		dev_warn(&pdev->dev, "Fail to register stmmac-clk\n");
>>>> +		plat->stmmac_clk = NULL;
>>>
>>> Don't you need to propagate at least EPROBE_DEFER here?
>>
>> Hi Florian
>>
>> Isn't a fixed rate clock a complete fake. There is no hardware behind it.
>> So can it return EPROBE_DEFER?
>>
>>     Andrew
> 
> Yes, there is no hardware behind it. So, I don't think we need to deferred probe
> and a warning message should be sufficient. Anyhow, please point it out if I miss
> out anything.

Looks good to me, thanks both for clarifying.
-- 
Florian