linux-kernel - Re: [PATCH v6 2/2] clk: wpcm450: Add Nuvoton WPCM450 clock/reset controller driver

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Date:   Thu, 20 Apr 2023 07:32:07 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     j.neuschaefer@....net
Cc:     avifishman70@...il.com, benjaminfair@...gle.com,
        daniel.lezcano@...aro.org, devicetree@...r.kernel.org,
        krzk+dt@...nel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux@...ck-us.net, mturquette@...libre.com,
        openbmc@...ts.ozlabs.org, p.zabel@...gutronix.de,
        robh+dt@...nel.org, sboyd@...nel.org, tali.perry1@...il.com,
        tglx@...utronix.de, tmaimon77@...il.com, venture@...gle.com,
        wim@...ux-watchdog.org, yuenn@...gle.com
Subject: Re: [PATCH v6 2/2] clk: wpcm450: Add Nuvoton WPCM450 clock/reset
 controller driver

Le 19/04/2023 à 23:52, Jonathan Neuschäfer a écrit :
> Hello Christophe,
> 
> On Sat, Apr 15, 2023 at 02:16:09PM +0200, Christophe JAILLET wrote:
>> Le 15/04/2023 à 13:13, Jonathan Neuschäfer a écrit :
>>> This driver implements the following features w.r.t. the clock and reset
>>> controller in the WPCM450 SoC:
>>>
>>> - It calculates the rates for all clocks managed by the clock controller
>>> - It leaves the clock tree mostly unchanged, except that it enables/
>>>     disables clock gates based on usage.
>>> - It exposes the reset lines managed by the controller using the
>>>     Generic Reset Controller subsystem
>>>
>>> NOTE: If the driver and the corresponding devicetree node are present,
>>>         the driver will disable "unused" clocks. This is problem until
>>>         the clock relations are properly declared in the devicetree (in a
>>>         later patch). Until then, the clk_ignore_unused kernel parameter
>>>         can be used as a workaround.
>>>
>>> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer-hi6Y0CQ0nG0@...lic.gmane.org>
>>> ---
> [...]
>>> +	// Enables/gates
>>> +	for (i = 0; i < ARRAY_SIZE(clken_data); i++) {
>>> +		const struct wpcm450_clken_data *data = &clken_data[i];
>>> +
>>> +		hw = clk_hw_register_gate_parent_data(NULL, data->name, &data->parent, data->flags,
>>> +						      clk_base + REG_CLKEN, data->bitnum,
>>> +						      data->flags, &wpcm450_clk_lock);
>>
>> If an error occures in the 'for' loop or after it, should this be
>> clk_hw_unregister_gate()'ed somewhere?
> 
> Ideally yes —
> 
> in this case, if the clock driver fails, the system is arguably in such
> a bad state that there isn't much point in bothering.
> 

Ok, but below we care about freeing clk_data->hws in the error handling 
path.

Why do we handle just half of the resources?
Shouldn't it be all (to be clean, if it makes sense) or nothing (to 
reduce the LoC and have a smaller driver)?

CJ

> 
>>
>> CJ
>>
>>> +		if (IS_ERR(hw)) {
>>> +			pr_err("Failed to register gate: %pe\n", hw);
>>> +			goto err_free;
>>> +		}
>>> +		clk_data->hws[data->bitnum] = hw;
>>> +	}
> 
> 
> 
> Best regards,
> Jonathan