linux-kernel - Re: [PATCH v5 2/2] pwm: Add clock based PWM output driver

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Message-ID: <170305a686280ed44a5d3e49dee3176f@trvn.ru>
Date:   Sat, 19 Feb 2022 11:48:50 +0500
From:   Nikita Travkin <nikita@...n.ru>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Cc:     thierry.reding@...il.com, lee.jones@...aro.org,
        u.kleine-koenig@...gutronix.de, robh+dt@...nel.org,
        sboyd@...nel.org, linus.walleij@...aro.org, masneyb@...tation.org,
        sean.anderson@...o.com, linux-pwm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht
Subject: Re: [PATCH v5 2/2] pwm: Add clock based PWM output driver

Hi,

Krzysztof Kozlowski писал(а) 14.02.2022 16:19:
> On 12/02/2022 17:23, Nikita Travkin wrote:
>> Some systems have clocks exposed to external devices. If the clock
>> controller supports duty-cycle configuration, such clocks can be used as
>> pwm outputs. In fact PWM and CLK subsystems are interfaced with in a
>> similar way and an "opposite" driver already exists (clk-pwm). Add a
>> driver that would enable pwm devices to be used via clk subsystem.
>>
>> Signed-off-by: Nikita Travkin <nikita@...n.ru>
>> --
>>
> 
> (...)
> 
>> +
>> +static int pwm_clk_probe(struct platform_device *pdev)
>> +{
>> +	struct pwm_clk_chip *chip;
>> +	int ret;
>> +
>> +	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
>> +	if (!chip)
>> +		return -ENOMEM;
>> +
>> +	chip->clk = devm_clk_get(&pdev->dev, NULL);
>> +	if (IS_ERR(chip->clk))
>> +		return dev_err_probe(&pdev->dev, PTR_ERR(chip->clk),
>> +				     "Failed to get clock\n");
>> +
>> +	chip->chip.dev = &pdev->dev;
>> +	chip->chip.ops = &pwm_clk_ops;
>> +	chip->chip.npwm = 1;
>> +
>> +	ret = clk_prepare(chip->clk);
>> +	if (ret < 0)
>> +		return dev_err_probe(&pdev->dev, ret, "Failed to prepare clock\n");
>> +
>> +	ret = pwmchip_add(&chip->chip);
>> +	if (ret < 0)
>> +		return dev_err_probe(&pdev->dev, ret, "Failed to add pwm chip\n");
> 
> You need to cleanup - unprepare the clock.
> 

Oops, I will add unprepare in v6, Thanks!

Nikita

>> +
>> +	platform_set_drvdata(pdev, chip);
>> +	return 0;
>> +}
>> +
> 
> 
> Best regards,
> Krzysztof