Just to confuse things, the checksum byte is available from the chip if required. Reading it involves a slightly different approach to normal message processor reads, in that the host needs to write the 16-bit address of the message processor, with the MSB set. It must then follow these two bytes with another byte consisting of the checksum of the previous two bytes. This functionality was added at a customer's request, although I don't know if any current customers actually use it. Alan Bowens Section Manager / Atmel Corporation Tel: (+44) (0)1489-553-611 alan.bowens@xxxxxxxxx / www.atmel.com The information contained in this email message may be privileged, confidential and/or protected from unauthorized disclosure. If you are not the intended recipient, any dissemination, distribution or copying is strictly prohibited. Please immediately notify the sender by reply if you received this email in error. Thank you for your cooperation. -----Original Message----- From: Nick Dyer [mailto:nick.dyer@xxxxxxxxxxx] Sent: 20 March 2012 15:08 To: Daniel Kurtz Cc: Dmitry Torokhov; Joonyoung Shim; Valkonen, Iiro; Henrik Rydberg; linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Benson Leung; Yufeng Shen; Tiwari, Atul; Bowens, Alan Subject: Re: [PATCH 09/20] Input: atmel_mxt_ts - do not read extra (checksum) byte Daniel Kurtz wrote: > It isn't sent, nor checked anyway, so don't bother reading it. > > Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx> This is fair enough, although IMO the checksum should be checked. -- Nick Dyer Software Engineer, ITDev Ltd Hardware and Software Development Consultancy Website: http://www.itdev.co.uk -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
