From: Tony Lindgren [mailto:tony@xxxxxxxxxxx] >* Pekon Gupta <pekon@xxxxxx> [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. + 0x26c(PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* spi2_cs0.gpio/eMMCorNANDsel */ >Regards, > >Tony > >> (2) As NAND device connnected to this board has page-size=4K and oob-size=224, >> So ROM code expects boot-loaders to be flashed in BCH16 ECC scheme for >> NAND boot. >> >> Signed-off-by: Pekon Gupta <pekon@xxxxxx> >> Reviewed-by: Javier Martinez Canillas <javier@xxxxxxxxxxxx> >> --- >> arch/arm/boot/dts/am437x-gp-evm.dts | 108 ++++++++++++++++++++++++++++++++++++ >> 1 file changed, 108 insertions(+) >> >> diff --git a/arch/arm/boot/dts/am437x-gp-evm.dts b/arch/arm/boot/dts/am437x-gp-evm.dts >> index 30ace1b..f432685 100644 >> --- a/arch/arm/boot/dts/am437x-gp-evm.dts >> +++ b/arch/arm/boot/dts/am437x-gp-evm.dts >> @@ -150,6 +150,27 @@ >> 0x14c (PIN_INPUT_PULLDOWN | MUX_MODE7) >> >; >> }; >> + >> + nand_flash_x8: nand_flash_x8 { >> + pinctrl-single,pins = < >> + 0x26c(PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* <------ >spi2_cs0.gpio/eMMCorNANDsel */ with regards, pekon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
