linux-kernel - Re: [PATCH v3 2/3] pwm: sophgo: add driver for Sophgo SG2042 PWM

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Message-ID:
 <MA0P287MB2822E1F15C9C2FD25847316AFE7A2@MA0P287MB2822.INDP287.PROD.OUTLOOK.COM>
Date: Sat, 12 Oct 2024 10:34:24 +0800
From: Chen Wang <unicorn_wang@...look.com>
To: Sean Young <sean@...s.org>
Cc: ukleinek@...nel.org, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, inochiama@...look.com, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
 linux-riscv@...ts.infradead.org, chao.wei@...hgo.com,
 haijiao.liu@...hgo.com, xiaoguang.xing@...hgo.com, chunzhi.lin@...hgo.com
Subject: Re: [PATCH v3 2/3] pwm: sophgo: add driver for Sophgo SG2042 PWM


On 2024/10/8 16:24, Sean Young wrote:
> On Tue, Oct 08, 2024 at 11:04:14AM +0800, Chen Wang wrote:
>> From: Chen Wang <unicorn_wang@...look.com>
>>
>> Add a PWM driver for PWM controller in Sophgo SG2042 SoC.
[......]
>> +static int pwm_sg2042_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct sg2042_pwm_ddata *ddata;
>> +	struct pwm_chip *chip;
>> +	struct clk *clk;
>> +	int ret;
>> +
>> +	chip = devm_pwmchip_alloc(dev, SG2042_PWM_CHANNELNUM, sizeof(*ddata));
>> +	if (IS_ERR(chip))
>> +		return PTR_ERR(chip);
>> +	ddata = pwmchip_get_drvdata(chip);
>> +
>> +	ddata->base = devm_platform_ioremap_resource(pdev, 0);
>> +	if (IS_ERR(ddata->base))
>> +		return PTR_ERR(ddata->base);
>> +
>> +	clk = devm_clk_get_enabled(dev, "apb");
>> +	if (IS_ERR(clk))
>> +		return dev_err_probe(dev, PTR_ERR(clk), "failed to get base clk\n");
>> +
>> +	ret = devm_clk_rate_exclusive_get(dev, clk);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "failed to get exclusive rate\n");
>> +
>> +	ddata->clk_rate_hz = clk_get_rate(clk);
>> +	if (!ddata->clk_rate_hz || ddata->clk_rate_hz > NSEC_PER_SEC)
>> +		return dev_err_probe(dev, -EINVAL,
>> +				     "Invalid clock rate: %lu\n", ddata->clk_rate_hz);
>> +
>> +	chip->ops = &pwm_sg2042_ops;
> I think you can add here:
>
> 	chip->atomic = true;
>
> As far as I can see, the driver does not do any sleeping operations
> in pwm_sg2042_apply(). This probably should be tested with
> CONFIG_PWM_DEBUG and CONFIG_DEBUG_ATOMIC_SLEEP just to be sure.
>
> Thanks,
> Sean

Thank you Sean. We don't sleep when apply, so atomic should be needed.

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