mux init with multiple signal paths.

mux init with multiple signal paths.

[Silesh C V]

Hi,

What is the best way to mux signals which are available on multiple pins ?
For example on omap4, gpio 103 can be muxed on

1.gpmc_ncs6.
2.sdmmc_dat1.

omap_mux_init_gpio and omap_mux_init_signal on these pins will now
return with -EINVAL without modifying the mux register and the pin
will be left in the state in which the x-loader/u-boot left it at. So
is it true that the mux framework does not support muxing pins which
have multiple paths and they have to muxed by accessing the registers
directly ? Or am I missing something ?

Thanks for your time,
Silesh.

RE: mux init with multiple signal paths.

[Anand Gadiyar]

Silesh C V wrote:
> Hi,
>
> What is the best way to mux signals which are available on
> multiple pins ?
> For example on omap4, gpio 103 can be muxed on
>
> 1.gpmc_ncs6.
> 2.sdmmc_dat1.
>

Specify the signal as pad.signal:
gpmc_ncs6.sdmmc_dat1

(where, pad is the signal name on mode0, and
signal is the signal name for the mode you are interested in).

> omap_mux_init_gpio and omap_mux_init_signal on these pins will now
> return with -EINVAL without modifying the mux register and the pin
> will be left in the state in which the x-loader/u-boot left it at. So
> is it true that the mux framework does not support muxing pins which
> have multiple paths and they have to muxed by accessing the registers
> directly ? Or am I missing something ?
>

The technique above works at least with omap_mux_init_signal.

I'm not so sure about omap_mux_init_gpio.

- Anand

Re: mux init with multiple signal paths.

[Silesh C V]

Hi Anand,

On Thu, Jan 27, 2011 at 1:40 PM, Anand Gadiyar <gadiyar@ti.com> wrote:
> Silesh C V wrote:
>> Hi,
>>
>> What is the best way to mux signals which are available on
>> multiple pins ?
>> For example on omap4, gpio 103 can be muxed on
>>
>> 1.gpmc_ncs6.
>> 2.sdmmc_dat1.
>>
>
> Specify the signal as pad.signal:
> gpmc_ncs6.sdmmc_dat1

Thanks. This works. In my case I had to use sdmmc.dat1.gpio_103 to
configure the pin .

>
> (where, pad is the signal name on mode0, and
> signal is the signal name for the mode you are interested in).
>
>> omap_mux_init_gpio and omap_mux_init_signal on these pins will now
>> return with -EINVAL without modifying the mux register and the pin
>> will be left in the state in which the x-loader/u-boot left it at. So
>> is it true that the mux framework does not support muxing pins which
>> have multiple paths and they have to muxed by accessing the registers
>> directly ? Or am I missing something ?
>>
>
> The technique above works at least with omap_mux_init_signal.
>
> I'm not so sure about omap_mux_init_gpio.

If a gpio is available in multiple pins, you have to use
omap_mux_init_signal to configure the pin as gpio_mux_init_gpio takes
only the gpio number and the value as the input and it returns without
altering the mux setting.

Thanks,
Silesh.