[ts-7000] Re: mmap failing when trying to interface to some DIO; TS-7260

["charliem_1216" <>]

Hi Sean --

--- In  sean machin <> wrote:
>
> Hi All,
> 
> I'm writing a driver which needs to interface to the digital I/O ports 
> on my TS-7260.  The particular physical addresses
> I need access to are 0x80840014 for a data direction register and 
> 0x80840004 for the data register.
> 
> It looks like my call to mmap the address 0x80840014 is failing with 
> errno 22 (invalid argument).  Anyone on the
> list got an idea why the call is failing?  Thanks.

Are you sure that your fd is OK, (opened properly, with O_RDWR|O_SYNC)?

ISTR there are some limits on the granularity of mmap locations.  Can
you do something like:

gpio_reg = mmap( .... fd, 0x80840000);
gpio_data = gpio_reg + 0x04;
gpio_ddr  = gpio_reg + 0x14;

Also, there should be some example code in the files area that does
DIO, I think from Jim Jackson.  (... checking ...)

OK, it's here too:
http://www.comp.leeds.ac.uk/jj/linux/adio.tgz


regards, ....... Charlie

>
--------------------------------------------------------------------------------------------------------------
>     uint8_t* ddr_reg = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, 
> MAP_SHARED, fd, 0x80840014);
>     if (ddr_reg == MAP_FAILED) {
>         syslog(LOG_ERR, "mmap failed with errno %d", errno);
>     }
>




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