Re: [PATCH v2 2/5] rtc: gamecube: Report low battery as invalid data

From: Alexandre Belloni
Date: Tue Nov 30 2021 - 17:45:37 EST


Hello,

On 28/10/2021 00:35:12+0200, Emmanuel Gil Peyrot wrote:
> I haven’t been able to test this patch as all of my consoles have a
> working RTC battery, but according to the documentation it should work
> like that.
>
> Signed-off-by: Emmanuel Gil Peyrot <linkmauve@xxxxxxxxxxxx>
> ---
> drivers/rtc/rtc-gamecube.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/drivers/rtc/rtc-gamecube.c b/drivers/rtc/rtc-gamecube.c
> index e8260c82c07d..1932c6fe1301 100644
> --- a/drivers/rtc/rtc-gamecube.c
> +++ b/drivers/rtc/rtc-gamecube.c
> @@ -83,6 +83,10 @@
> #define RTC_CONTROL0 0x21000c
> #define RTC_CONTROL1 0x21000d
>
> +/* RTC flags */
> +#define RTC_CONTROL0_UNSTABLE_POWER 0x00000800
> +#define RTC_CONTROL0_LOW_BATTERY 0x00000200
> +
> struct priv {
> struct regmap *regmap;
> void __iomem *iob;
> @@ -182,9 +186,35 @@ static int gamecube_rtc_set_time(struct device *dev, struct rtc_time *t)
> return regmap_write(d->regmap, RTC_COUNTER, timestamp - d->rtc_bias);
> }
>
> +static int gamecube_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
> +{
> + struct priv *d = dev_get_drvdata(dev);
> + int value;
> + int control0;
> + int ret;
> +
> + switch (cmd) {
> + case RTC_VL_READ:
> + ret = regmap_read(d->regmap, RTC_CONTROL0, &control0);
> + if (ret)
> + return ret;
> +
> + value = 0;
> + if (control0 & RTC_CONTROL0_UNSTABLE_POWER)
> + value |= RTC_VL_DATA_INVALID;
> + if (control0 & RTC_CONTROL0_LOW_BATTERY)
> + value |= RTC_VL_DATA_INVALID;

Shouldn't that one be RTC_VL_BACKUP_LOW?

Else, the driver is great, I'm ready to apply it.

> + return put_user(value, (unsigned int __user *)arg);
> +
> + default:
> + return -ENOIOCTLCMD;
> + }
> +}
> +
> static const struct rtc_class_ops gamecube_rtc_ops = {
> .read_time = gamecube_rtc_read_time,
> .set_time = gamecube_rtc_set_time,
> + .ioctl = gamecube_rtc_ioctl,
> };
>
> static int gamecube_rtc_read_offset_from_sram(struct priv *d)
> --
> 2.33.1
>

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com