Use ECPM to reduce power usage

src/board/system76/galp3-c/ecpm.c

@@ -0,0 +1,10 @@
+#include <board/ecpm.h>
+
+void ecpm_init(void) {
+    // Clock gate EGPC, CIR, and SWUC
+    CGCTRL2 |= (1 << 6) | (1 << 5) | (1 << 4);
+    // Clock gate UART, SSPI, and DBGR
+    CGCTRL3 |= (1 << 2) | (1 << 1) | (1 << 0);
+    // Clock gate CEC
+    CGCTRL4 |= (1 << 0);
+}

src/board/system76/galp3-c/include/board/ecpm.h

@@ -0,0 +1,8 @@
+#ifndef _BOARD_ECPM_H
+#define _BOARD_ECPM_H
+
+#include <ec/ecpm.h>
+
+void ecpm_init(void);
+
+#endif // _BOARD_ECPM_H

src/board/system76/galp3-c/main.c

@@ -7,6 +7,7 @@
 #include <arch/delay.h>
 #include <arch/time.h>
 #include <board/battery.h>
+#include <board/ecpm.h>
 #include <board/gpio.h>
 #include <board/gctrl.h>
 #include <board/kbc.h>
@@ -33,17 +34,19 @@ void timer_2(void) __interrupt(5) {}
 uint8_t main_cycle = 0;
 
 void init(void) {
+    // Must happen first
     arch_init();
-
-    gpio_init();
     gctrl_init();
-    pwm_init();
+    gpio_init();
 
+    // Can happen in any order
+    ecpm_init();
     kbc_init();
     kbled_init();
     kbscan_init();
-    pmc_init();
     peci_init();
+    pmc_init();
+    pwm_init();
     smbus_init();
 
     //TODO: INTC