From b6822b86ac2627bb85df6fce5344a2078507d366 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Wed, 25 Jul 2018 22:25:18 +0200
Subject: [PATCH] busio/I2C: Split out samd_i2c_get_sercom()

It will be shared with I2CSlave.
---
 ports/atmel-samd/common-hal/busio/I2C.c | 54 +++++++++++++------------
 ports/atmel-samd/common-hal/busio/I2C.h |  3 ++
 2 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/ports/atmel-samd/common-hal/busio/I2C.c b/ports/atmel-samd/common-hal/busio/I2C.c
index 8bfa8ddd28..c0643865d6 100644
--- a/ports/atmel-samd/common-hal/busio/I2C.c
+++ b/ports/atmel-samd/common-hal/busio/I2C.c
@@ -39,39 +39,41 @@
 // Number of times to try to send packet if failed.
 #define ATTEMPTS 2
 
+Sercom *samd_i2c_get_sercom(const mcu_pin_obj_t* scl, const mcu_pin_obj_t* sda,
+                            uint8_t *sercom_index, uint32_t *sda_pinmux, uint32_t *scl_pinmux) {
+    *sda_pinmux = 0;
+    *scl_pinmux = 0;
+    for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
+        *sercom_index = sda->sercom[i].index;
+        if (*sercom_index >= SERCOM_INST_NUM) {
+            continue;
+        }
+        Sercom* potential_sercom = sercom_insts[*sercom_index];
+        if (potential_sercom->I2CM.CTRLA.bit.ENABLE != 0 ||
+            sda->sercom[i].pad != 0) {
+            continue;
+        }
+        *sda_pinmux = PINMUX(sda->number, (i == 0) ? MUX_C : MUX_D);
+        for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
+            if (*sercom_index == scl->sercom[j].index &&
+                scl->sercom[j].pad == 1) {
+                *scl_pinmux = PINMUX(scl->number, (j == 0) ? MUX_C : MUX_D);
+                return potential_sercom;
+            }
+        }
+    }
+    return NULL;
+}
+
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
         const mcu_pin_obj_t* scl, const mcu_pin_obj_t* sda, uint32_t frequency, uint32_t timeout) {
     #ifdef PIRKEY_M0
     mp_raise_NotImplementedError(translate("Not enough pins available"));
     return;
     #endif
-    Sercom* sercom = NULL;
     uint8_t sercom_index;
-    uint32_t sda_pinmux = 0;
-    uint32_t scl_pinmux = 0;
-    for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
-        sercom_index = sda->sercom[i].index;
-        if (sercom_index >= SERCOM_INST_NUM) {
-            continue;
-        }
-        Sercom* potential_sercom = sercom_insts[sercom_index];
-        if (potential_sercom->I2CM.CTRLA.bit.ENABLE != 0 ||
-            sda->sercom[i].pad != 0) {
-            continue;
-        }
-        sda_pinmux = PINMUX(sda->number, (i == 0) ? MUX_C : MUX_D);
-        for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
-            if (sercom_index == scl->sercom[j].index &&
-                scl->sercom[j].pad == 1) {
-                scl_pinmux = PINMUX(scl->number, (j == 0) ? MUX_C : MUX_D);
-                sercom = potential_sercom;
-                break;
-            }
-        }
-        if (sercom != NULL) {
-            break;
-        }
-    }
+    uint32_t sda_pinmux, scl_pinmux;
+    Sercom* sercom = samd_i2c_get_sercom(scl, sda, &sercom_index, &sda_pinmux, &scl_pinmux);
     if (sercom == NULL) {
         mp_raise_ValueError(translate("Invalid pins"));
     }
diff --git a/ports/atmel-samd/common-hal/busio/I2C.h b/ports/atmel-samd/common-hal/busio/I2C.h
index 2401d92471..366c6c469d 100644
--- a/ports/atmel-samd/common-hal/busio/I2C.h
+++ b/ports/atmel-samd/common-hal/busio/I2C.h
@@ -41,4 +41,7 @@ typedef struct {
     uint8_t sda_pin;
 } busio_i2c_obj_t;
 
+extern Sercom *samd_i2c_get_sercom(const mcu_pin_obj_t* scl, const mcu_pin_obj_t* sda,
+                                   uint8_t *sercom_index, uint32_t *sda_pinmux, uint32_t *scl_pinmux);
+
 #endif // MICROPY_INCLUDED_ATMEL_SAMD_COMMON_HAL_BUSIO_I2C_H