Re: [PATCH v2] hwmon: (sun4i-lradc) Add driver for LRADC found on Allwinner A13/A20 SoC

From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Ruslan Zalata <rz@fabmicro.ru>, Jean Delvare <jdelvare@suse.com>,
	"Chen-Yu Tsai" <wens@csie.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	"Samuel Holland" <samuel@sholland.org>,
	<linux-kernel@vger.kernel.org>, <linux-hwmon@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-sunxi@lists.linux.dev>
Subject: Re: [PATCH v2] hwmon: (sun4i-lradc) Add driver for LRADC found on Allwinner A13/A20 SoC
Date: Fri, 29 Apr 2022 14:24:12 +0100	[thread overview]
Message-ID: <20220429142412.00001e43@Huawei.com> (raw)
In-Reply-To: <f79a8edf-36d4-02af-da8f-32b4e491bd47@roeck-us.net>

On Thu, 28 Apr 2022 14:30:06 -0700
Guenter Roeck <linux@roeck-us.net> wrote:

> On 4/28/22 14:09, Ruslan Zalata wrote:
> > Some Allwinner SoCs like A13, A20 or T2 are equipped with two-channel
> > low rate (6 bit) ADC that is often used for extra keys. There's a driver
> > for that already implementing standard input device, but it has these
> > limitations: 1) it cannot be used for general ADC data equisition, and  
> 
> acquisition
> 
> > 2) it uses only one LRADC channel of two available.
> > 
> > This driver provides basic hwmon interface to both channels of LRADC on
> > such Allwinner SoCs.
> > 
> > Signed-off-by: Ruslan Zalata <rz@fabmicro.ru>  
> 
> Ok, next phase of review.
> 

One thing noticed whilst randomly glancing at this patch.

> > +#ifdef CONFIG_PM
> > +static int sun4i_lradc_resume(struct device *dev)
> > +{
> > +	struct sun4i_lradc_data *lradc = dev_get_drvdata(dev);
> > +
> > +	return sun4i_lradc_start(lradc);
> > +}
> > +
> > +static int sun4i_lradc_suspend(struct device *dev)
> > +{
> > +	struct sun4i_lradc_data *lradc = dev_get_drvdata(dev);
> > +
> > +	sun4i_lradc_stop(lradc);
> > +	return 0;
> > +}
> > +
> > +#define SUN4I_LRADC_DEV_PM_OPS	(&sun4i_lradc_dev_pm_ops)
> > +#else
> > +#define SUN4I_LRADC_DEV_PM_OPS	NULL
> > +#endif /* CONFIG_PM */
> > +
> > +static const struct dev_pm_ops sun4i_lradc_dev_pm_ops = {

We have much better infrastructure for this these days.

Take a look at DEFINE_SIMPLE_DEV_PM_OPS()
and pm_sleep_ptr()

Those two in combination will let you get rid of all the ifdef stuff
here by letting the compiler remove the unused code automatically.

> > +	.suspend = sun4i_lradc_suspend,
> > +	.resume = sun4i_lradc_resume,
> > +};
> > +
> > +static const struct of_device_id sun4i_lradc_of_match[] = {
> > +	{ .compatible = "allwinner,sun4i-a10-lradc-keys", .data = &variant_sun4i_a10_lradc},
> > +	{ /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
> > +
> > +static struct platform_driver sun4i_lradc_driver = {
> > +	.driver = {
> > +		.name	= "sun4i-lradc-hwmon",
> > +		.of_match_table = of_match_ptr(sun4i_lradc_of_match),
> > +		.pm = SUN4I_LRADC_DEV_PM_OPS,
> > +	},
> > +	.probe	= sun4i_lradc_probe,
> > +};
> > +
> > +module_platform_driver(sun4i_lradc_driver);
> > +
> > +MODULE_DESCRIPTION("Allwinner A13/A20 LRADC hwmon driver");
> > +MODULE_AUTHOR("Ruslan Zalata <rz@fabmicro.ru>");
> > +MODULE_LICENSE("GPL");
> > +No empty line at end, please  
> 
> 
> _______________________________________________
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> linux-arm-kernel@lists.infradead.org
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