linux-kernel - Re: [PATCH v2 2/4] hwrng: stm32 - implement support for STM32MP25x platforms

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Message-ID: <8c13b0aa-7fb1-493c-9abc-5e5cfd982855@denx.de>
Date: Mon, 14 Oct 2024 10:52:38 +0200
From: Marek Vasut <marex@...x.de>
To: Gatien CHEVALLIER <gatien.chevallier@...s.st.com>,
 Olivia Mackall <olivia@...enic.com>, Herbert Xu
 <herbert@...dor.apana.org.au>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Maxime Coquelin <mcoquelin.stm32@...il.com>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Lionel Debieve <lionel.debieve@...s.st.com>
Cc: linux-crypto@...r.kernel.org, devicetree@...r.kernel.org,
 linux-stm32@...md-mailman.stormreply.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] hwrng: stm32 - implement support for STM32MP25x
 platforms

On 10/14/24 10:38 AM, Gatien CHEVALLIER wrote:
> 
> 
> On 10/11/24 18:17, Marek Vasut wrote:
>> On 10/11/24 5:41 PM, Gatien Chevallier wrote:
>>
>> [...]
>>
>>> @@ -551,6 +565,41 @@ static int stm32_rng_probe(struct 
>>> platform_device *ofdev)
>>>       priv->rng.read = stm32_rng_read;
>>>       priv->rng.quality = 900;
>>> +    if (!priv->data->nb_clock || priv->data->nb_clock > 2)
>>> +        return -EINVAL;
>>> +
>>> +    priv->clk_bulk = devm_kzalloc(dev, priv->data->nb_clock * 
>>> sizeof(*priv->clk_bulk),
>>> +                      GFP_KERNEL);
>>> +    if (!priv->clk_bulk)
>>> +        return -ENOMEM;
>>
>> Try this:
>>
>> ret = devm_clk_bulk_get(dev, priv->data->nb_clock, priv->clk_bulk);
>> ...
>> // Swap the clock if they are not in the right order:
>> if (priv->data->nb_clock == 2 &&
>>      strcmp(__clk_get_name(priv->clk_bulk[0].clk), "core"))
>> {
>>   const char *id = priv->clk_bulk[1].id;
>>   struct clk *clk = priv->clk_bulk[1].clk;
>>   priv->clk_bulk[1].id = priv->clk_bulk[0].id;
>>   priv->clk_bulk[1].clk = priv->clk_bulk[0].clk;
>>   priv->clk_bulk[0].id = id;
>>   priv->clk_bulk[0].clk = clk;
>> }
>>
> 
> Hi Marek,
> 
> This won't work as the name returned by this API is clk->core->name.
> AFAICT, it doesn't correspond to the names present in the device tree
> under the "clock-names" property.
> Any other idea or are you fine with what's below?
Hmmm, it is not great, but at least it reduces the changes throughout 
the driver, so that is an improvement.

I guess one could do some of_clk_get() and clk_is_match() in probe to 
look up the clock in OF by name and then compare which clock is which 
before swapping them in clk_bulk[] array, but that might be too convoluted?