Re: [PATCH v2] rtc: rs5c372: Add RTC_VL_READ, RTC_VL_CLR ioctls

[Camel Guo]

On 11/10/21 3:14 PM, Camel Guo wrote:
> From: Camel Guo <camelg@xxxxxxxx>
>
> In order to make it possible to get battery voltage status, this commit
> adds RTC_VL_READ, RTC_VL_CLR ioctl commands to rtc-rs5c372.
>
> Signed-off-by: Camel Guo <camelg@xxxxxxxx>
> ---
>
> v2: Set RTC_VL_BACKUP_LOW if VDET is set. Do not clear PON, XSTP in
> RTC_VL_CLR ioctl
>
>   drivers/rtc/rtc-rs5c372.c | 60 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 60 insertions(+)
>
> diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
> index 80980414890c..4ab8718d9360 100644
> --- a/drivers/rtc/rtc-rs5c372.c
> +++ b/drivers/rtc/rtc-rs5c372.c
> @@ -485,6 +485,65 @@ static int rs5c372_rtc_proc(struct device *dev, 
> struct seq_file *seq)
>   #define rs5c372_rtc_proc        NULL
>   #endif
>
> +#ifdef CONFIG_RTC_INTF_DEV
> +static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned 
> long arg)
> +{
> +       struct rs5c372  *rs5c = i2c_get_clientdata(to_i2c_client(dev));
> +       unsigned char   ctrl2;
> +       int             addr;
> +       unsigned int    flags;
> +
> +       dev_dbg(dev, "%s: cmd=%x\n", __func__, cmd);
> +
> +       addr = RS5C_ADDR(RS5C_REG_CTRL2);
> +       ctrl2 = i2c_smbus_read_byte_data(rs5c->client, addr);
> +
> +       switch (cmd) {
> +       case RTC_VL_READ:
> +               flags = 0;
> +
> +               switch (rs5c->type) {
> +               case rtc_r2025sd:
> +               case rtc_r2221tl:
> +                       if ((rs5c->type == rtc_r2025sd && !(ctrl2 & 
> R2x2x_CTRL2_XSTP)) ||
> +                               (rs5c->type == rtc_r2221tl &&  (ctrl2 & 
> R2x2x_CTRL2_XSTP))) {
> +                               flags |= RTC_VL_DATA_INVALID;
> +                       }
> +                       if (ctrl2 & R2x2x_CTRL2_VDET)
> +                               flags |= RTC_VL_BACKUP_LOW;
> +                       break;
> +               default:
> +                       if (ctrl2 & RS5C_CTRL2_XSTP)
> +                               flags |= RTC_VL_DATA_INVALID;
> +                       break;
> +               }
> +
> +               return put_user(flags, (unsigned int __user *)arg);
> +       case RTC_VL_CLR:
> +               /* clear VDET bit */
> +               switch (rs5c->type) {
> +               case rtc_r2025sd:
> +               case rtc_r2221tl:
> +                       ctrl2 &= ~R2x2x_CTRL2_VDET;
> +               default:
> +                       break;
> +               }
> +
> +               if (i2c_smbus_write_byte_data(rs5c->client, addr, ctrl2) 
> < 0) {
> +                       dev_dbg(&rs5c->client->dev, "%s: write error in 
> line %i\n",
> +                                       __func__, __LINE__);
> +                       return -EIO;
> +               }
> +               return 0;
> +       default:
> +               return -ENOIOCTLCMD;
> +       }
> +       return 0;
> +}
> +#else
> +#define rs5c372_ioctl  NULL
> +#endif
> +
>   static const struct rtc_class_ops rs5c372_rtc_ops = {
>           .proc           = rs5c372_rtc_proc,
>           .read_time      = rs5c372_rtc_read_time,
> @@ -492,6 +551,7 @@ static const struct rtc_class_ops rs5c372_rtc_ops = {
>           .read_alarm     = rs5c_read_alarm,
>           .set_alarm      = rs5c_set_alarm,
>           .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
> +       .ioctl          = rs5c372_ioctl,
>   };
>
>   #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
> --
> 2.20.1

PATCH v3 is uploaded with the fix of avoiding setting ctrl2 register 
when unnecessary.  Please review v3 instead.