On Thu, Jun 18, 2015 at 8:55 AM, Ellen Wang <el...@cumulusnetworks.com> wrote: > ... > > Since the the long-read fix is less controversial, I've split it out and > sent it as a separate patch.
Hi Ellen, got it, will check soon > As for repeated start, it's not that easy for me to check it. The chip is > in a rack-mounted network switch. However, if you really want me to verify > it, I can pull the box out and hook it up on a bench. > > The Silabs datasheet clearly states that the device is supposed to issue a > repeated start (rev 1.2, > http://www.silabs.com/Support%20Documents/TechnicalDocs/CP2112.pdf, figure 8 > on page 15). > > Is your chip an older rev? Mine is rev 2 (but as you said, there would have > been an erratum if they fixed a hardware bug). > > usb 1-1.2.3: New USB device found, idVendor=10c4, idProduct=ea90 > usb 1-1.2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 > usb 1-1.2.3: Product: CP2112 HID USB-to-SMBus Bridge > usb 1-1.2.3: Manufacturer: Silicon Laboratories > usb 1-1.2.3: SerialNumber: 00343E9A > cp2112 0003:10C4:EA90.0001: hidraw0: USB HID v1.01 Device [Silicon > Laboratories > CP2112 HID USB-to-SMBus Bridge] on usb-0000:00:16.0-1.2.3/input0 > cp2112 0003:10C4:EA90.0001: Part Number: 0x0C Device Version: 0x02 Mine is rev 1 !!! Found also that in the datasheet chapter 12 reports the differences between the two revisions. In 12.1 it states that revision 1 does not implement repeated start. Perfect! I will try to replace my device with a newer one. In mean time, feel free to send the patch for write-read. I will check and test it ignoring the lack of repeated start on my obsolete HW. Thanks, Antonio -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
