From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH] i2c-mux-pca954x: allow downstream bus numbers to be specified
 in the dts
Date: Thu, 17 Apr 2014 23:30:21 +0530
Message-ID: <535016B5.7060006@nvidia.com>
References: <532A1B12.8080400@yahoo.com> <1511928.3cA2QKoAZt@avalon> <534FF708.7040409@yahoo.com> <1736074.QFiloDzhqn@avalon>
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To: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>, Frank Bormann <fbormann-/E1597aS9LQAvxtiuMwx3w@public.gmane.org>
Cc: Rodolfo Giometti <giometti-k2GhghHVRtY@public.gmane.org>, Linux I2C List <linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
List-Id: linux-i2c@vger.kernel.org

On Thursday 17 April 2014 09:16 PM, Laurent Pinchart wrote:
> +       u32 fixed_bus_numbers[PCA954X_MAX_NCHANS] = { 0 };
>           int ret;
>
>           if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
> @@ -214,6 +215,17 @@ static int pca954x_probe(struct i2c_client *client,
>                           if (ret < 0)
>                                   return ret;
>                   }
> +
> +               /* Get fixed bus numbers */
> +               ret = of_property_read_u32_array(np, "fixed-bus-numbers",
> +                       fixed_bus_numbers, chips[id->driver_data].nchans);
> +               if (ret == -EINVAL)
> +                       ret = 0;        /* missing dtb node is not an error
> */ +               if (ret < 0) {
> +                       dev_err(&client->dev, "fixed-bus-numbers: "
> +                       "invalid format\n");
> +                       return ret;
> +               }
>           }
>

Hi Frank,
Why not you use aliases on DTS instead of changing driver?
You can alias the bus number with the child node name. On the following, 
the bus will be registerd as 6, 7, 8 and 9.
i2c-core already support this.

         aliases {
                 i2c6 = &pca9546_i2c0;
                 i2c7 = &pca9546_i2c1;
                 i2c8 = &pca9546_i2c2;
                 i2c9 = &pca9546_i2c3;
         };


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