The Allwinner SoCs that have an HDMI pin, also have a memory-mapped HDMI-CEC register located at HDMI base 0xf1c16000 plus the offset 0x214. This register provides the following bits
#define CEC_RX 0x0100 /* phys. line value, either high or low */ #define CEC_TX 0x0200 #define CEC_ENABLE 0x0800 Other bits are unused. I asked Allwinner about CEC once but they only replied that A10s doesn't have a hardware CEC core. You can find examples of using the CEC register in some unfinished CEC code in the 3.4 linux-sunxi kernel. --Vladimir On 3 October 2014 07:33, Chen-Yu Tsai <[email protected]> wrote: > Hi, > > On Fri, Oct 3, 2014 at 3:29 AM, [email protected] <[email protected]> > wrote: > > I > > > > On Thu, Oct 2, 2014 at 1:19 PM, Christian Ege <[email protected]> wrote: > >> During a quick search I had not been able to find any HDMI CEC driver. > In > >> the docs available there is only one Register about CEC. > >> > >> I thought about implementation of an driver and libcec support for the > A20. > > > > I believe CEC is just I2C on the HDMI connector. > > > > So maybe --- it is one of the I2C devices. Then that bit enables it > > onto the HDMI pin? Just a guess. > > > > EDID works the same way. How is it implemented? > > You are referring to DDC. The HDMI block has a separate DDC controller. > IIRC, the DDC pins also have standard TWI muxed on them, so you could > use either one. > > But this is entirely irrelevant to the original question. > > As Christian stated, the HDMI block does have a register named > HDMI_HDP_CEC. However it does not contain any useful descriptions. > Also the SoC does have a pin for HDMI CEC. > > Best ask Allwinner for some help. > > > ChenYu > > -- > You received this message because you are subscribed to the Google Groups > "linux-sunxi" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
