On Thu, May 21, 2020 at 10:09:26PM +0200, Drew Fustini wrote: > The BeagleBone Black has P8 and P9 headers [0] which expose many of the > AM3358 ZCZ SoC balls to stacking expansion boards called "capes", or to > other external connections like jumper wires connected to a breadboard. > BeagleBone users will often refer to the "Cape Exanpsion Headers" pin > diagram [1] as it is in the "Bone101" getting started tutorial. [2] > > Most of the P8 and P9 header pins can muxed to a GPIO line. The > gpio-line-names describe which P8 or P9 pin that line goes to and the > default mux for that P8 or P9 pin if it is not GPIO. > > For example, gpiochip 1 line 0 is connected to P8 header pin 25 (P8_25) > however the default device tree has the corresponding BGA ball (ZCZ U7) > muxed to mmc1_dat0 as it is used for the on-board eMMC chip. For that > GPIO line to be used, one would need to modify the device tree to > disable the eMMC and change the pin mux for that ball to GPIO mode. > > Some of the AM3358 ZCZ balls corresponding to GPIO lines are not routed > to a P8 or P9 header, but are instead wired to some peripheral device > like on-board eMMC, HDMI framer IC, or status LEDs. Those names are in > brackets to denote those GPIO lines can not be used. > > Some GPIO lines are named "[NC]" as the corresponding balls are not > routed to anything on the PCB. > > The goal for these names is to make it easier for a user viewing the > output of gpioinfo to determine which P8 or P9 pin is connected to a > GPIO line. The output of gpioinfo on a BeagleBone Black would be: > > gpiochip0 - 32 lines: > line 0: "[ethernet]" unused input active-high > line 1: "[ethernet]" unused input active-high > line 2: "P9_22 [spi0_sclk]" unused input active-high > line 3: "P9_21 [spi0_d0]" unused input active-high > line 4: "P9_18 [spi0_d1]" unused input active-high > line 5: "P9_17 [spi0_cs0]" unused input active-high > line 6: "[sd card]" "cd" input active-low [used] > line 7: "P9_42A [ecappwm0]" unused input active-high > line 8: "P8_35 [hdmi]" unused input active-high > line 9: "P8_33 [hdmi]" unused input active-high > line 10: "P8_31 [hdmi]" unused input active-high > line 11: "P8_32 [hdmi]" unused input active-high > line 12: "P9_20 [i2c2_sda]" unused input active-high > line 13: "P9_19 [i2c2_scl]" unused input active-high > line 14: "P9_26 [uart1_rxd]" unused input active-high > line 15: "P9_24 [uart1_txd]" unused input active-high > line 16: "[ethernet]" unused input active-high > line 17: "[ethernet]" unused input active-high > line 18: "[usb]" unused input active-high > line 19: "[hdmi]" unused input active-high > line 20: "P9_41B" unused input active-high > line 21: "[ethernet]" unused input active-high > line 22: "P8_19 [ehrpwm2a]" unused input active-high > line 23: "P8_13 [ehrpwm2b]" unused input active-high > line 24: "[NC]" unused input active-high > line 25: "[NC]" unused input active-high > line 26: "P8_14" unused input active-high > line 27: "P8_17" unused input active-high > line 28: "[ethernet]" unused input active-high > line 29: "[ethernet]" unused input active-high > line 30: "P9_11 [uart4_rxd]" unused input active-high > line 31: "P9_13 [uart4_txd]" unused input active-high > gpiochip1 - 32 lines: > line 0: "P8_25 [emmc]" unused input active-high > line 1: "[emmc]" unused input active-high > line 2: "P8_5 [emmc]" unused input active-high > line 3: "P8_6 [emmc]" unused input active-high > line 4: "P8_23 [emmc]" unused input active-high > line 5: "P8_22 [emmc]" unused input active-high > line 6: "P8_3 [emmc]" unused input active-high > line 7: "P8_4 [emmc]" unused input active-high > line 8: "[NC]" unused input active-high > line 9: "[NC]" unused input active-high > line 10: "[NC]" unused input active-high > line 11: "[NC]" unused input active-high > line 12: "P8_12" unused input active-high > line 13: "P8_11" unused input active-high > line 14: "P8_16" unused input active-high > line 15: "P8_15" unused input active-high > line 16: "P9_15A" unused input active-high > line 17: "P9_23" unused input active-high > line 18: "P9_14 [ehrpwm1a]" unused input active-high > line 19: "P9_16 [ehrpwm1b]" unused input active-high > line 20: "[emmc]" unused input active-high > line 21: "[usr0 led]" "beaglebone:green:heartbeat" output active-high [used] > line 22: "[usr1 led]" "beaglebone:green:mmc0" output active-high [used] > line 23: "[usr2 led]" "beaglebone:green:usr2" output active-high [used] > line 24: "[usr3 led]" "beaglebone:green:usr3" output active-high [used] > line 25: "[hdmi]" "interrupt" input active-high [used] > line 26: "[usb]" unused input active-high > line 27: "[hdmi audio]" "enable" output active-high [used] > line 28: "P9_12" unused input active-high > line 29: "P8_26" unused input active-high > line 30: "P8_21 [emmc]" unused input active-high > line 31: "P8_20 [emmc]" unused input active-high > gpiochip2 - 32 lines: > line 0: "P9_15B" unused input active-high > line 1: "P8_18" unused input active-high > line 2: "P8_7" unused input active-high > line 3: "P8_8" unused input active-high > line 4: "P8_10" unused input active-high > line 5: "P8_9" unused input active-high > line 6: "P8_45 [hdmi]" unused input active-high > line 7: "P8_46 [hdmi]" unused input active-high > line 8: "P8_43 [hdmi]" unused input active-high > line 9: "P8_44 [hdmi]" unused input active-high > line 10: "P8_41 [hdmi]" unused input active-high > line 11: "P8_42 [hdmi]" unused input active-high > line 12: "P8_39 [hdmi]" unused input active-high > line 13: "P8_40 [hdmi]" unused input active-high > line 14: "P8_37 [hdmi]" unused input active-high > line 15: "P8_38 [hdmi]" unused input active-high > line 16: "P8_36 [hdmi]" unused input active-high > line 17: "P8_34 [hdmi]" unused input active-high > line 18: "[ethernet]" unused input active-high > line 19: "[ethernet]" unused input active-high > line 20: "[ethernet]" unused input active-high > line 21: "[ethernet]" unused input active-high > line 22: "P8_27 [hdmi]" unused input active-high > line 23: "P8_29 [hdmi]" unused input active-high > line 24: "P8_28 [hdmi]" unused input active-high > line 25: "P8_30 [hdmi]" unused input active-high > line 26: "[emmc]" unused input active-high > line 27: "[emmc]" unused input active-high > line 28: "[emmc]" unused input active-high > line 29: "[emmc]" unused input active-high > line 30: "[emmc]" unused input active-high > line 31: "[emmc]" unused input active-high > gpiochip3 - 32 lines: > line 0: "[ethernet]" unused input active-high > line 1: "[ethernet]" unused input active-high > line 2: "[ethernet]" unused input active-high > line 3: "[ethernet]" unused input active-high > line 4: "[ethernet]" unused input active-high > line 5: "[i2c0]" unused input active-high > line 6: "[i2c0]" unused input active-high > line 7: "[emu]" unused input active-high > line 8: "[emu]" unused input active-high > line 9: "[ethernet]" unused input active-high > line 10: "[ethernet]" unused input active-high > line 11: "[NC]" unused input active-high > line 12: "[NC]" unused input active-high > line 13: "[usb]" unused input active-high > line 14: "P9_31 [spi1_sclk]" unused input active-high > line 15: "P9_29 [spi1_d0]" unused input active-high > line 16: "P9_30 [spi1_d1]" unused input active-high > line 17: "P9_28 [spi1_cs0]" unused input active-high > line 18: "P9_42B [ecappwm0]" unused input active-high > line 19: "P9_27" unused input active-high > line 20: "P9_41A" unused input active-high > line 21: "P9_25" unused input active-high > line 22: "[NC]" unused input active-high > line 23: "[NC]" unused input active-high > line 24: "[NC]" unused input active-high > line 25: "[NC]" unused input active-high > line 26: "[NC]" unused input active-high > line 27: "[NC]" unused input active-high > line 28: "[NC]" unused input active-high > line 29: "[NC]" unused input active-high > line 30: "[NC]" unused input active-high > line 31: "[NC]" unused input active-high > > [0] https://git.io/JfgOd > [1] https://beagleboard.org/capes > [1] https://beagleboard.org/Support/bone101 > [2] https://beagleboard.org/static/images/cape-headers.png > > Reviewed-by: Jason Kridner <jason@xxxxxxxxxxxxxxx> > Reviewed-by: Robert Nelson <robertcnelson@xxxxxxxxx> > Signed-off-by: Drew Fustini <drew@xxxxxxxxxxxxxxx> > --- > V2 change: > - include output of gpioinfo to illustrate how the gpio-line-names > will appear. My apologies for forgetting to include in V1. > > V1 note: > I had posted a patch with these line names for am335x-bone-common.dtsi > but Grygorii Strashko pointed out that the names are not applicable to > all BeagleBone models. Thus I have created this patch to add these > names just for the BeagleBone Black. > > arch/arm/boot/dts/am335x-boneblack.dts | 144 +++++++++++++++++++++++++ > 1 file changed, 144 insertions(+) > > diff --git a/arch/arm/boot/dts/am335x-boneblack.dts b/arch/arm/boot/dts/am335x-boneblack.dts > index d3928662aed4..5f31e832eb82 100644 > --- a/arch/arm/boot/dts/am335x-boneblack.dts > +++ b/arch/arm/boot/dts/am335x-boneblack.dts > @@ -23,3 +23,147 @@ oppnitro-1000000000 { > opp-supported-hw = <0x06 0x0100>; > }; > }; > + > +&gpio0 { > + gpio-line-names = > + "[ethernet]", > + "[ethernet]", > + "P9_22 [spi0_sclk]", > + "P9_21 [spi0_d0]", > + "P9_18 [spi0_d1]", > + "P9_17 [spi0_cs0]", > + "[sd card]", > + "P9_42A [ecappwm0]", > + "P8_35 [hdmi]", > + "P8_33 [hdmi]", > + "P8_31 [hdmi]", > + "P8_32 [hdmi]", > + "P9_20 [i2c2_sda]", > + "P9_19 [i2c2_scl]", > + "P9_26 [uart1_rxd]", > + "P9_24 [uart1_txd]", > + "[ethernet]", > + "[ethernet]", > + "[usb]", > + "[hdmi]", > + "P9_41B", > + "[ethernet]", > + "P8_19 [ehrpwm2a]", > + "P8_13 [ehrpwm2b]", > + "[NC]", > + "[NC]", > + "P8_14", > + "P8_17", > + "[ethernet]", > + "[ethernet]", > + "P9_11 [uart4_rxd]", > + "P9_13 [uart4_txd]"; > +}; > + > +&gpio1 { > + gpio-line-names = > + "P8_25 [emmc]", > + "[emmc]", > + "P8_5 [emmc]", > + "P8_6 [emmc]", > + "P8_23 [emmc]", > + "P8_22 [emmc]", > + "P8_3 [emmc]", > + "P8_4 [emmc]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "P8_12", > + "P8_11", > + "P8_16", > + "P8_15", > + "P9_15A", > + "P9_23", > + "P9_14 [ehrpwm1a]", > + "P9_16 [ehrpwm1b]", > + "[emmc]", > + "[usr0 led]", > + "[usr1 led]", > + "[usr2 led]", > + "[usr3 led]", > + "[hdmi]", > + "[usb]", > + "[hdmi audio]", > + "P9_12", > + "P8_26", > + "P8_21 [emmc]", > + "P8_20 [emmc]"; > +}; > + > +&gpio2 { > + gpio-line-names = > + "P9_15B", > + "P8_18", > + "P8_7", > + "P8_8", > + "P8_10", > + "P8_9", > + "P8_45 [hdmi]", > + "P8_46 [hdmi]", > + "P8_43 [hdmi]", > + "P8_44 [hdmi]", > + "P8_41 [hdmi]", > + "P8_42 [hdmi]", > + "P8_39 [hdmi]", > + "P8_40 [hdmi]", > + "P8_37 [hdmi]", > + "P8_38 [hdmi]", > + "P8_36 [hdmi]", > + "P8_34 [hdmi]", > + "[ethernet]", > + "[ethernet]", > + "[ethernet]", > + "[ethernet]", > + "P8_27 [hdmi]", > + "P8_29 [hdmi]", > + "P8_28 [hdmi]", > + "P8_30 [hdmi]", > + "[emmc]", > + "[emmc]", > + "[emmc]", > + "[emmc]", > + "[emmc]", > + "[emmc]"; > +}; > + > +&gpio3 { > + gpio-line-names = > + "[ethernet]", > + "[ethernet]", > + "[ethernet]", > + "[ethernet]", > + "[ethernet]", > + "[i2c0]", > + "[i2c0]", > + "[emu]", > + "[emu]", > + "[ethernet]", > + "[ethernet]", > + "[NC]", > + "[NC]", > + "[usb]", > + "P9_31 [spi1_sclk]", > + "P9_29 [spi1_d0]", > + "P9_30 [spi1_d1]", > + "P9_28 [spi1_cs0]", > + "P9_42B [ecappwm0]", > + "P9_27", > + "P9_41A", > + "P9_25", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]", > + "[NC]"; > +}; > -- > 2.25.1 > FYI - Linus W. provided an Acked-by in related thread [0]. Anyone else have any review comments? thank you, drew [0] https://lore.kernel.org/linux-devicetree/CACRpkdZLRjcE0FGwVR-Q7a50aEmpB=xO4q6H8_EaV199fGr0OA@xxxxxxxxxxxxxx/
