A: No. Q: Should I include quotations after my reply? http://daringfireball.net/2007/07/on_top On Thu, Oct 15, 2015 at 02:56:48PM +0100, John Tapsell wrote: > Hi Greg, > > I'm trying to write a driver for this specific usb-to-i2c chip > (mcp2221). It only offers an In and Out Interrupt Endpoint. To do a > single i2c read I need to: > > 1. Send a packet saying "I want to read from i2c" > 2. Wait for a reply saying 'okay'. > 3. Send another packet saying "Please now send me the data that you read" > 4. Wait for that reply. > > This means a delay of 2x8ms = 16ms to get a single bit of data. For > the specific case that I want to use the chip for, this means I'm > reading from my i2c sensor at 62 hz. I'd really like to do better if > it at all possible. > > Any suggestions? For a horrid protocol like this, no, there isn't any way to make it go faster, sorry. That is designed in such a way to make it the worst possible thing for a USB system, go kick the person who designed such a thing (hint, they have no idea how USB works...) I strongly suggest going and getting a different sensor chip, don't encourage such behaviour by actually buying their hardware. sorry, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
