Re: Powering OMAP's pins

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On Wed, 2012-09-26 at 11:59 -0700, Tony Lindgren wrote:
> * Tomi Valkeinen <tomi.valkeinen@ti.com> [120926 00:06]:

> > So if I want to use parallel dss output, which uses dss_data0 pin,
> > omapdss driver needs to enable vdda_dsi on omap3430, even though there's
> > no other use for vdda_dsi in the parallel output case. But on omap4430
> > data0 pins seems to be powered by vdds_1p8v. On AM35xx something else.
> > So either I need to program all those into the omapdss driver, which is
> > not the right way as they are platform specific things, or I need to
> > pass some kind of pin data from platform data to omapdss driver, giving
> > the required regulator for each pin.
> 
> Pass the device tree regulators to the DSS driver and enable the
> ones with runtime PM in the DSS driver? I guess you have the names
> for those regulatros?

Well, yes, I could create a pin->regulator mapping for dss that is
filled in the DT data.

I just feel this is something that the omapdss driver shouldn't care
about. The powers for the pins are in no way related to dss.
 
> > And how about the uart1_cts or gpio_70 pins on 3430? Do both uart and
> > gpio drivers need to have similar kind of platform data, giving the
> > required regulator so that the pin can be enabled?
> 
> Hmm aren't those always enabled with VIO_18?

No, 3430 datamanual (OMAP34xx_ES2.0_ES2.1_POP_DM_V_K.pdf) says some uart
and gpio pins are powered by vdds_dsi, some by vdds_sdi, some gpio pins
are powered by vdds_csi2, etc.

I could be mistaken how to HW works (but it does work like that for
dss), but sounds to me that uart and gpio drivers (and perhaps some
others, I didn't go through all the pins) need similar pin->regulator
mapping as you suggested for omapdss.

 Tomi


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