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

From: Ruslan Zalata
Date: Mon May 02 2022 - 19:23:03 EST


Hi Jonathan,

Thank you for pointing to DEFINE_SIMPLE_DEV_PM_OPS macros, will use it.

---
Regards,
Ruslan.

Fabmicro, LLC.

On 2022-04-29 18:24, Jonathan Cameron wrote:
On Thu, 28 Apr 2022 14:30:06 -0700
Guenter Roeck <linux@xxxxxxxxxxxx> 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@xxxxxxxxxxx>

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@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> +No empty line at end, please


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