From e121ecd8963f0621898858efe9fb4e98728640a5 Mon Sep 17 00:00:00 2001
From: Valentin Ochs <a@0au.de>
Date: Fri, 16 Jul 2021 21:21:54 +0200
Subject: [PATCH] Make encoder setup easier to change

---
 encoder.c | 74 +++++++++++++++++++++++++++++++++----------------------
 1 file changed, 44 insertions(+), 30 deletions(-)

diff --git a/encoder.c b/encoder.c
index f0e0f61..afc7a65 100644
--- a/encoder.c
+++ b/encoder.c
@@ -10,23 +10,25 @@ static volatile int pos;
 
 static void check(void);
 
-#define PIN1 GPIO4
-#define PIN1_IRQ NVIC_EXTI4_IRQ
-#define PIN2 GPIO5
-#define PIN2_IRQ NVIC_EXTI9_5_IRQ
+#define PIN_OPEN GPIO1
+#define PIN_OPEN_IRQ NVIC_EXTI1_IRQ
+#define PIN_CLOSE GPIO2
+#define PIN_CLOSE_IRQ NVIC_EXTI2_IRQ
+
+#define PIN_PORT GPIOC
+#define PIN_RCC RCC_GPIOC
 
 void encoder_setup(void) {
-        rcc_periph_clock_enable(RCC_GPIOA);
+        rcc_periph_clock_enable(PIN_RCC);
 
-        gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, PIN1 | PIN2);
+        gpio_mode_setup(PIN_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, PIN_OPEN | PIN_CLOSE);
 
-        /* Set up exti on A0 & A1 */
-        exti_select_source(PIN1 | PIN2, GPIOA);
-        exti_set_trigger(PIN1 | PIN2, EXTI_TRIGGER_BOTH);
-        exti_enable_request(PIN1 | PIN2);
+        exti_select_source(PIN_OPEN | PIN_CLOSE, PIN_PORT);
+        exti_set_trigger(PIN_OPEN | PIN_CLOSE, EXTI_TRIGGER_BOTH);
+        exti_enable_request(PIN_OPEN | PIN_CLOSE);
 
-        nvic_enable_irq(PIN1_IRQ);
-        nvic_enable_irq(PIN2_IRQ);
+        nvic_enable_irq(PIN_OPEN_IRQ);
+        nvic_enable_irq(PIN_CLOSE_IRQ);
 }
 
 int encoder_get() {
@@ -36,27 +38,39 @@ int encoder_get() {
 static int prev = 0;
 void check(void) {
         int pp = pos;
-        int now = GPIO_IDR(GPIOA);
-        now = (!!(now & PIN1))<<0 | (!!(now & PIN2)) << 1;
+        int now = GPIO_IDR(PIN_PORT);
+        now = (!!(now & PIN_OPEN))<<0 | (!!(now & PIN_CLOSE)) << 1;
 
-        switch (prev << 2 | now) {
-        case 0 * 4 + 2:
-        case 1 * 4 + 0:
-        case 2 * 4 + 3:
-        case 3 * 4 + 1:
-                pos++;
-                break;
-        case 0 * 4 + 1:
-        case 1 * 4 + 3:
-        case 2 * 4 + 0:
-        case 3 * 4 + 2:
+#define NEITHER 0
+#define JUST_OPEN 1
+#define JUST_CLOSE 2
+#define BOTH 3
+#define WAS(x) ((x)<<2)
+#define IS(x) (x)
+
+        switch (WAS(prev) + IS(now)) {
+        case WAS(NEITHER)    + IS(JUST_CLOSE):
+        case WAS(JUST_OPEN)  + IS(NEITHER):
+        case WAS(JUST_CLOSE) + IS(BOTH):
+        case WAS(BOTH)       + IS(JUST_OPEN):
                 pos--;
                 break;
+        case WAS(NEITHER)    + IS(JUST_OPEN):
+        case WAS(JUST_OPEN)  + IS(BOTH):
+        case WAS(BOTH)       + IS(JUST_CLOSE):
+        case WAS(JUST_CLOSE) + IS(NEITHER):
+                pos++;
+                break;
         default:
                 prev = now;
                 return;
         }
-
+#undef NEITHER
+#undef JUST_OPEN
+#undef JUST_CLOSE
+#undef BOTH
+#undef WAS
+#undef IS
         prev = now;
         if (pos < MIN_POS)
                 pos = MIN_POS;
@@ -64,11 +78,11 @@ void check(void) {
                 pos = MAX_POS;
 }
 
-void exti4_isr(void) {
-        exti_reset_request(EXTI4);
+void exti1_isr(void) {
+        exti_reset_request(EXTI1);
         check();
 }
-void exti9_5_isr(void) {
-        exti_reset_request(EXTI5);
+void exti2_isr(void) {
+        exti_reset_request(EXTI2);
         check();
 }