Re: [PATCH alpha] eeprom: at24: new DT property "address-width"

[Bartosz Golaszewski <brgl@xxxxxxxx>]

2018-01-25 14:40 GMT+01:00 Johannes Poehlmann <johannes.poehlmann@xxxxxxxxxxx>:
> Hi Bartosz,
>
> The patch was build against recent linus master
>    commit 5b7d27967dabfb17c21b0d98b29153b9e3ee71e5
>    Merge: f165495 624ca9c
>    Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>    Date:   Wed Jan 24 17:24:30 2018 -0800
>
> checkpatch.pl run to 0 Errors
> tested on powerpc 32bit
>
> Any recommendations/comments ?
>
>
> -------------------------------------------------------------------
>
> Signed-off-by: Johannes Poehlmann <johannes.poehlmann@xxxxxxxxxxx>
>
> needed with some eeprom chips
> modelled after at25
> ---
>  .../devicetree/bindings/eeprom/eeprom.txt          |  3 +++
>  drivers/misc/eeprom/at24.c                         | 24 ++++++++++++++++++++--
>  2 files changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt b/Documentation/devicetree/bindings/eeprom/eeprom.txt
> index 27f2bc1..8f3293c 100644
> --- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
> +++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
> @@ -38,10 +38,13 @@ Optional properties:
>
>    - size: total eeprom size in bytes
>
> +  - address-width : number of address bits (8 or 16)
> +
>  Example:
>
>  eeprom@52 {
>         compatible = "atmel,24c32";
>         reg = <0x52>;
>         pagesize = <32>;
> +       address-width = <16>;
>  };
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 4d63ac8..2a6d476 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -651,11 +651,27 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>         return 0;
>  }
>
> -static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
> +static int at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>  {
>         int err;
>         u32 val;
>
> +       if (device_property_read_u32(dev, "address-width", &val) == 0) {
> +               switch (val) {
> +               case 8:
> +                       chip->flags &= ~AT24_FLAG_ADDR16;
> +                       break;
> +               case 16:
> +                       chip->flags |= AT24_FLAG_ADDR16;
> +                       break;
> +               default:
> +                       dev_err(dev,
> +                               "Error: bad \"address-width\" property: %u\n",
> +                               val);
> +                       return -ENODEV;
> +               }
> +       }
> +
>         if (device_property_present(dev, "read-only"))
>                 chip->flags |= AT24_FLAG_READONLY;
>
> @@ -674,6 +690,7 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>                  */
>                 chip->page_size = 1;
>         }
> +       return 0;
>  }
>
>  static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
> @@ -716,7 +733,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>                 magic >>= AT24_SIZE_BYTELEN;
>                 chip.flags = magic & AT24_BITMASK(AT24_SIZE_FLAGS);
>
> -               at24_get_pdata(&client->dev, &chip);
> +               err = at24_get_pdata(&client->dev, &chip);
> +               if (err)
> +                       return err;
> +
>
>                 chip.setup = NULL;
>                 chip.context = NULL;
> --
> 2.1.4
>

What EEPROM model do you need that for? Is it not covered by all the
standard types we already support in the driver?

Thanks,
Bartosz