Messages in this thread |  | | | Date | Mon, 17 Oct 2011 09:16:16 -0700 | | From | Greg KH <> | | Subject | Re: [PATCH 2/6] drivers/base: add bus for System-on-Chip devices |
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On Mon, Oct 17, 2011 at 12:52:54PM +0100, Lee Jones wrote: > Traditionally, any System-on-Chip based platform creates a flat list > of platform_devices directly under /sys/devices/platform. > > In order to give these some better structure, this introduces a new > bus type for soc_devices that are registered with the new > soc_device_register() function. All devices that are on the same > chip should then be registered as child devices of the soc device. > > The soc bus also exports a few standardised device attributes which > allow user space to query the specific type of soc. > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
The code is much better, and smaller, but there's still some issues with it:
> +static ssize_t soc_info_get(struct device *dev, > + struct device_attribute *attr, > + char *buf); > + > +static DEVICE_ATTR(machine, S_IRUGO, soc_info_get, NULL); > +static DEVICE_ATTR(family, S_IRUGO, soc_info_get, NULL); > +static DEVICE_ATTR(soc_id, S_IRUGO, soc_info_get, NULL); > +static DEVICE_ATTR(revision, S_IRUGO, soc_info_get, NULL); > + > +static ssize_t soc_info_get(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct soc_device *soc_dev = > + container_of(dev, struct soc_device, dev); > + > + if (attr == &dev_attr_machine) > + return sprintf(buf, "%s\n", soc_dev->attr->machine); > + if (attr == &dev_attr_family) > + return sprintf(buf, "%s\n", soc_dev->attr->family); > + if (attr == &dev_attr_revision) > + return sprintf(buf, "%s\n", soc_dev->attr->revision); > + if (attr == &dev_attr_soc_id) > + return sprintf(buf, "%s\n", soc_dev->attr->soc_id); > + > + return -EINVAL; > + > +}
If you move around things a bit here, you can save 4 lines of code, please do so.
> + > +struct bus_type soc_bus_type = { > + .name = "soc", > +}; > + > +static int __init soc_bus_register(void) > +{ > + return bus_register(&soc_bus_type); > +} > +core_initcall(soc_bus_register);
No unregister?
> +struct attribute *soc_attr[] = { > + &dev_attr_machine.attr, > + &dev_attr_family.attr, > + &dev_attr_soc_id.attr, > + &dev_attr_revision.attr, > + NULL, > +}; > + > +struct attribute_group soc_attr_group = { > + .attrs = soc_attr, > +}; > + > +struct device *soc_device_register(struct soc_device_attribute *soc_dev_attr) > +{ > + struct soc_device *soc_dev; > + static atomic_t soc_device_num = ATOMIC_INIT(0);
No, please don't do this, use the proper kernel interface to dynamically handle numbering devices (hint, if you unload a SOC device, you will never reclaim that device number, which isn't that nice.)
> +struct soc_device_attribute { > + const char *machine; > + const char *family; > + const char *revision; > + const char *soc_id; > +};
What happens if one of these attributes is NULL? Please check for that when you create the attributes so that you don't create an attribute you don't want to.
> + > +struct soc_device { > + struct device dev; > + struct soc_device_attribute *attr; > +};
Why is this needed to be defined here? It should be in the .c file as no external code needs to know what it looks like.
thanks,
greg k-h
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