Re: [PATCH v4 1/5] mfd: Add support for Intel LJCA device

[Ye, Xiang]

On Thu, Mar 09, 2023 at 08:52:24AM +0100, Greg Kroah-Hartman wrote:
> On Thu, Mar 09, 2023 at 03:10:56PM +0800, Ye Xiang wrote:
> > +static int ljca_mng_get_version(struct ljca_stub *stub, char *buf)
> > +{
> > +	struct fw_version version = {};
> > +	unsigned int len = sizeof(version);
> > +	int ret;
> > +
> > +	ret = ljca_stub_write(stub, LJCA_MNG_GET_VERSION, NULL, 0, &version, &len, true,
> > +			      LJCA_USB_WRITE_ACK_TIMEOUT_MS);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (len != sizeof(version)) {
> > +		dev_err(&stub->intf->dev, "get version failed, len:%d\n", len);
> > +		return -EINVAL;
> > +	}
> > +
> > +	return sysfs_emit(buf, "%d.%d.%d.%d\n", version.major, version.minor,
> > +			  le16_to_cpu(version.patch), le16_to_cpu(version.build));
> > +}
> 
> You have sysfs files, yet no Documentation/ABI/ entries?  That's not
> allowed, you know this :(
The Documentation/ABI/ entries is added for the sysfs on patch 5 of this series.
https://patchwork.kernel.org/project/linux-usb/patch/20230309071100.2856899-6-xiang.ye@xxxxxxxxx/
> 
> > +static ssize_t cmd_store(struct device *dev, struct device_attribute *attr, const char *buf,
> > +			 size_t count)
> > +{
> > +	struct usb_interface *intf = to_usb_interface(dev);
> > +	struct ljca_dev *ljca_dev = usb_get_intfdata(intf);
> > +	struct ljca_stub *mng_stub = ljca_stub_find(ljca_dev, LJCA_MNG_STUB);
> > +	struct ljca_stub *diag_stub = ljca_stub_find(ljca_dev, LJCA_DIAG_STUB);
> > +
> > +	if (sysfs_streq(buf, "dfu"))
> > +		ljca_mng_set_dfu_mode(mng_stub);
> > +	else if (sysfs_streq(buf, "debug"))
> > +		ljca_diag_set_trace_level(diag_stub, 3);
> 
> Sorry, but no, you can't do this in a sysfs file.
Do you mean that we can't use sysfs to send "debug" command to device?
Could you provide some detail or hints?
> 
> > +
> > +	return count;
> > +}
> > +
> > +static ssize_t cmd_show(struct device *dev, struct device_attribute *attr, char *buf)
> > +{
> > +	return sysfs_emit(buf, "%s\n", "supported cmd: [dfu, debug]");
> 
> sysfs files do not show "help text".
Ok. I can remove this for this has been described in
Documentation/ABI/testing/sysfs-bus-usb-devices-ljca (added in patch 5
of this series).
> 
> thanks,
> 
> greg k-h

--
Thanks
Ye Xiang