Re: [PATCH 1/3] mfd: Add realtek USB card reader driver

[Roger <rogerable@realtek.com>]

On 01/16/2014 05:35 PM, Lee Jones wrote:
>>>> +static int rtsx_usb_bulk_transfer_sglist(struct rtsx_ucr *ucr,
>>>> +             unsigned int pipe, struct scatterlist *sg, int num_sg,
>>>> +             unsigned int length, unsigned int *act_len, int timeout)
>>>> +{
>>>> +     int ret;
>>>> +
>>>> +     dev_dbg(&ucr->pusb_intf->dev, "%s: xfer %u bytes, %d entries\n",
>>>> +                     __func__, length, num_sg);
>>>> +     ret = usb_sg_init(&ucr->current_sg, ucr->pusb_dev, pipe, 0,
>>>> +                     sg, num_sg, length, GFP_NOIO);
>>>> +     if (ret)
>>>> +             return ret;
>>>> +
>>>> +     ucr->sg_timer.expires = jiffies + msecs_to_jiffies(timeout);
>>>> +     add_timer(&ucr->sg_timer);
>>>> +     usb_sg_wait(&ucr->current_sg);
>>>> +     del_timer(&ucr->sg_timer);
>>>> +
>>>> +     if (act_len)
>>>> +             *act_len = ucr->current_sg.bytes;
>>>> +
>>>> +     return ucr->current_sg.status;
>>>> +}
>>>
>>> Code looks fine, but shouldn't this live in a USB driver?
>>>
>> We have studied drivers in usb/storage, the place that most likely
>> to put the driver. All of them are for STANDARD usb mass storage
>> class(something like USB_CLASS_MASS_STORAGE). But this is not the
>> same case. This driver is for our vendor-class device with
>> completely different protocol. It is really an USB interfaced flash
>> card command converter(or channel) device rather than a real
>> storage. It also has two derived modules(rtsx_usb_sdmmc,
>> rtsx_usb_memstick) for other two subsystems.
>>
>> We also have another driver: rtsx_pcr.c resident in mfd/ for similar
>> devices but of PCIe interface. It is nature for us to choose the
>> same place for this variant.
>
> Very well, as long as it truly does not fit in drivers/usb. It would
> be good to have one of the USB folk give the nod though.
>
I found Greg K-H is exactly one of the maintainers of USB subsystem as I 
read the MAINTAINERS document.

Greg, would you please comment this subsystem concern or introduce 
other members? Thanks.