[1/2] rtc: rx8025: implement RX-8035 support

The RX-8035 is a newer RTC from EPSON that is very
similar to the RX-8025.

The key difference is in the oscillation stop (XSTP)
bit which is inverted on the RX-8035.

Signed-off-by: Mathew McBride <matt@traverse.com.au>
---
 drivers/rtc/rtc-rx8025.c | 59 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 53 insertions(+), 6 deletions(-)

Hi,

2021年7月7日(水) 16:17 Mathew McBride <matt@traverse.com.au>:
>
> The RX-8035 is a newer RTC from EPSON that is very
> similar to the RX-8025.
>
> The key difference is in the oscillation stop (XSTP)
> bit which is inverted on the RX-8035.
>
> Signed-off-by: Mathew McBride <matt@traverse.com.au>
> ---
>  drivers/rtc/rtc-rx8025.c | 59 ++++++++++++++++++++++++++++++++++++----
>  1 file changed, 53 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rtc/rtc-rx8025.c b/drivers/rtc/rtc-rx8025.c
> index c914091819ba..1a33ec402f4a 100644
> --- a/drivers/rtc/rtc-rx8025.c
> +++ b/drivers/rtc/rtc-rx8025.c
> @@ -60,14 +60,24 @@
>  #define RX8025_ADJ_DATA_MAX    62
>  #define RX8025_ADJ_DATA_MIN    -62
>
> +enum rx_model {
> +       model_rx_unknown,
> +       model_rx_8025,
> +       model_rx_8035,
> +       model_last
> +};
> +
>  static const struct d rx8025_id[] = {
> -       { "rx8025", 0 },
> +       { "rx8025", model_rx_8025 },
> +       { "rx8035", model_rx_8035 },
>         { }
>  };
> +
>  MODULE_DEVICE_TABLE(i2c, rx8025_id);
>
>  struct rx8025_data {
>         struct rtc_device *rtc;
> +       enum rx_model type;

I think 'model' is easier to understand than 'type'.

>         u8 ctrl1;
>  };
>
> @@ -100,10 +110,26 @@ static s32 rx8025_write_regs(const struct i2c_client *client,
>                                               length, values);
>  }
>
> +static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
> +{
> +       int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
> +       /* XSTP bit has different polarity on RX-8025 vs RX-8035.
> +        * RX-8025: 0 == oscillator stopped
> +        * RX-8035: 1 == oscillator stopped
> +        */
> +
> +       if (model == model_rx_8025)
> +               xstp = !xstp;
> +
> +       return xstp;
> +}
> +
>  static int rx8025_check_validity(struct device *dev)
>  {
>         struct i2c_client *client = to_i2c_client(dev);
> +       struct rx8025_data *drvdata = dev_get_drvdata(dev);
>         int ctrl2;
> +       int xstp;
>
>         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
>         if (ctrl2 < 0)
> @@ -117,7 +143,8 @@ static int rx8025_check_validity(struct device *dev)
>                 return -EINVAL;
>         }
>
> -       if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
> +       xstp = rx8025_is_osc_stopped(drvdata->type, ctrl2);
> +       if (xstp) {
>                 dev_warn(dev, "crystal stopped, date is invalid\n");
>                 return -EINVAL;
>         }
> @@ -125,7 +152,7 @@ static int rx8025_check_validity(struct device *dev)
>         return 0;
>  }
>
> -static int rx8025_reset_validity(struct i2c_client *client)
> +static int rx8025_reset_validity(enum rx_model model, struct i2c_client *client)

We can get the struct rx8025_data by using i2c_get_clientdata().
Therefore, I think that it can be updated without increasing the arguments.

```
struct rx8025_data *rx8025 = i2c_get_clientdata(client);

if (rx8025->type == model_rx_8025)
```

>  {
>         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
>
> @@ -134,8 +161,13 @@ static int rx8025_reset_validity(struct i2c_client *client)
>
>         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
>
> +       if (model == model_rx_8025)
> +               ctrl2 |= RX8025_BIT_CTRL2_XST;
> +       else
> +               ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
> +
>         return rx8025_write_reg(client, RX8025_REG_CTRL2,
> -                               ctrl2 | RX8025_BIT_CTRL2_XST);
> +                               ctrl2);
>  }
>
>  static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
> @@ -149,7 +181,7 @@ static irqreturn_t (int irq, void *dev_id)
>         if (status < 0)
>                 goto out;
>
> -       if (!(status & RX8025_BIT_CTRL2_XST))
> +       if (rx8025_is_osc_stopped(rx8025->type, status))

In rx8025_check_validity(), the return value is put in xstp and confirmed.
I thought it would be better to unify to either one.

>                 dev_warn(&client->dev, "Oscillation stop was detected,"
>                          "you may have to readjust the clock\n");
>
> @@ -241,7 +273,7 @@ static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
>         if (ret < 0)
>                 return ret;
>
> -       return rx8025_reset_validity(client);
> +       return rx8025_reset_validity(rx8025->type, client);
>  }
>
>  static int rx8025_init_client(struct i2c_client *client)
> @@ -519,6 +551,21 @@ static int rx8025_probe(struct i2c_client *client,
>
>         i2c_set_clientdata(client, rx8025);
>
> +       if (id) {
> +               rx8025->type = id->driver_data;
> +               switch (rx8025->type) {
> +               case model_rx_8025:
> +                       dev_info(&client->dev, "Type RX-8025");
> +               break;

Please fix indent.

> +               case model_rx_8035:
> +                       dev_info(&client->dev, "Type RX-8035");
> +                       break;
> +               default:
> +                       dev_warn(&client->dev, "Unknown type: %d\n", rx8025->type);
> +               break;

ditto.

> +               }
> +       }
> +
>         err = rx8025_init_client(client);
>         if (err)
>                 return err;
> --
> 2.30.1
>

Best regards,
  Nobuhiro