Re: [PATCH] base: add sysfs socs info

From: Greg KH
Date: Tue Dec 14 2010 - 11:19:46 EST


On Tue, Dec 14, 2010 at 01:40:17PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> this provide an easy way to register soc information
>
> arch, family, model, id, revision
>
> as this for at91sam9g20
>
> $ cat /sys/devices/system/soc/soc0/arch
> current
> $ cat /sys/devices/system/soc/soc0/family
> at91
> $ cat /sys/devices/system/soc/soc0/id
> at91sam9g20
> $ cat /sys/devices/system/soc/soc0/model
> 0x00000000019905a0
> $ cat /sys/devices/system/soc/soc0/revision
> 1.1

What is this for? When you add sysfs files, you are required to add
entries to the Documentation/ABI/ files as well, please always provide
this so we are able to review the code easier.

> +/*
> + * register_soc - Setup a sysfs device for a SOC.
> + *
> + * Initialize and register the SOC device.
> + */
> +int register_soc(struct soc *soc)
> +{
> + int err;
> +
> + if (!soc)
> + return -EINVAL;
> +
> + soc->sysdev.id = nb_socs;
> + soc->sysdev.cls = &soc_sysdev_class;
> +
> + if (!soc->arch)
> + soc->arch = arch_current;
> +
> + err = sysdev_register(&soc->sysdev);
> +
> + if (err)
> + return err;
> +
> + err = sysdev_create_file(&soc->sysdev, &attr_arch);
> +
> + if (err)
> + goto end;

<snip>

Please use an attribute group, it makes the code simpler and easier to
read.

> +struct soc {
> + u64 id;
> + char *arch;
> + char *family;
> + char *model;
> + char *revision;
> + struct sys_device sysdev;
> +};

What is a "SOC"? A "Small Ordinary Creature"?

And does every system have one of these? Just one? Not multiple? We
need a whole lot more information here as to why this code is needed,
and who will be using it.

Also, isn't this information already in /proc/cpu/ today?

thanks,

greg k-h
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