Re: [PATCH v7 2/4] ARM: dts: am437x-gp-evm: add support for parallel NAND flash

[Tony Lindgren <tony@atomide.com>]

* Gupta, Pekon <pekon@ti.com> [140519 21:07]:
> From: Tony Lindgren [mailto:tony@atomide.com]
> >* Pekon Gupta <pekon@ti.com> [140519 02:16]:
> >> Adds pinmux and DT node for Micron (MT29F4G08AB) x8 NAND device present on
> >> am437x-gp-evm board.
> >> (1) As NAND Flash data lines are muxed with eMMC, Thus at a given time either
> >>     eMMC or NAND can be enabled. Selection between eMMC and NAND is controlled:
> >>     (a) By dynamically driving following GPIO pin from software
> >>         SPI2_CS0(GPIO) == 0 NAND is selected (default)
> >>         SPI2_CS0(GPIO) == 1 eMMC is selected
> >>     (b) By statically using Jumper (J89) on the board
> >
> >So which MMC controller has eMMC then? How do we select which one we
> >have enabled in the am437x-gp-evm.dts by default?
> >
> If there is no Jumper on the board, then driving SPI2_CS0 before device
> probe decides the selection between NAND and eMMC. Therefore NAND
> pin-mux also includes SPI2_CS0 and enables PULLDOWN on it to select NAND.

So do they share lines outside omap, not inside omap?

The reason I'm asking is I'm worried about the conflicting
pinctrl settings if we try to use both. And I guess that's
not an issue if the muxing of lines is done outside the
omap?

Regards,

Tony