linux-kernel - Re: [PATCH v2 2/2] spi: amlogic-spifc-a1: add support for max_speed

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Date:   Thu, 20 Jul 2023 18:41:11 +0300
From:   Martin Kurbanov <mmkurbanov@...rdevices.ru>
To:     Jerome Brunet <jbrunet@...libre.com>,
        Mark Brown <broonie@...nel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>
CC:     <linux-spi@...r.kernel.org>, <linux-amlogic@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <kernel@...rdevices.ru>
Subject: Re: [PATCH v2 2/2] spi: amlogic-spifc-a1: add support for
 max_speed_hz



On 11.07.2023 10:25, Jerome Brunet wrote:
>>  
>> +static int amlogic_spifc_a1_set_freq(struct amlogic_spifc_a1 *spifc, u32 freq)
>> +{
>> +	int ret;
>> +
>> +	if (freq == spifc->curr_speed_hz)
>> +		return 0;
>> +
>> +	ret = clk_set_rate(spifc->clk, freq);
>> +	if (ret)
>> +		return ret;
>> +
>> +	spifc->curr_speed_hz = freq;
> 
> There is no guarantee that clk_set_rate() has set the rate you have
> requested, at least not precisely. You should call clk_get_rate() here.
> 

Hello Jerome, thank you for the feedback.
Are you referring to a situation where there is a change in the rate due
to a request from another client, such as a sibling driver with the same
parent clock?

-- 
Best Regards,
Martin Kurbanov