Beaglebone Black pinmuxing

[O'Connor, Daniel]

> On 17 Aug 2018, at 11:16, O'Connor, Daniel <darius at dons.net.au> wrote:
> OK, I'll go back to trying an overlay once I get it working by editing am335x-boneblack.dts

So, I got it working (without an overlay as yet) with this diff..

--- am335x-boneblack-orig.dts   2018-08-11 12:27:38.000000000 +0000
+++ am335x-boneblack.dts        2018-08-12 10:10:24.000000000 +0000
@@ -785,6 +785,13 @@
                                                pinctrl-single,pins = <0x170 0x30 0x174 0x0>;
                                                phandle = <0x4f>;
                                        };
+                                       pinmux_uart4_pins {
+                                               pinctrl-single,pins = <
+                                        0x070 0x2e      // P9_11 gpmc_wait0.uart4_rxd_mux2 -> mode 6
+                                        0x074 0x06      // P9_13 gpmc_wpn.uart4_txd_mux2 -> mode 6
+                                               >;
+                                               phandle = <0xce>;
+                                       };
                                        pinmux_clkout2_pin {

                                                pinctrl-single,pins = <0x1b4 0x3>;
@@ -1153,8 +1160,10 @@
                        clock-frequency = <0x2dc6c00>;
                        reg = <0x481a8000 0x2000>;
                        interrupts = <0x2d>;
-                       status = "disabled";
+                       status = "okay";
                        phandle = <0x7a>;
+                       pinctrl-names = "default";
+                       pinctrl-0 = <0xce>;
                };
                serial at 481aa000 {

@@ -2189,6 +2198,7 @@
                hdmi_0 = "/ocp/i2c at 44e0b000/tda19988/ports/port at 0/endpoint at 0";
                gpio1 = "/ocp/gpio at 4804c000";
                uart0_pins = "/ocp/l4_wkup at 44c00000/scm at 210000/pinmux at 800/pinmux_uart0_pins";
+               uart4_pins = "/ocp/l4_wkup at 44c00000/scm at 210000/pinmux at 800/pinmux_uart4_pins";
                i2c2_pins = "/ocp/l4_wkup at 44c00000/scm at 210000/pinmux at 800/pinmux_i2c2_pins";
                pm_sram_data = "/ocp/ocmcram at 40300000/pm-sram-data at 1000";
                sha0_fck = "/ocp/l4_wkup at 44c00000/scm at 210000/scm_conf at 0/clocks/sha0_fck";

Next step is to make an overlay version - hopefully I can look at that tonight :)

--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
 -- Andrew Tanenbaum