board: phytec: Add SOM detection for AM6x

Add all functions to read each SOM option from the EEPROM
image and detect whether it's the correct product for this
image.

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
diff --git a/board/phytec/common/am6_som_detection.h b/board/phytec/common/am6_som_detection.h
new file mode 100644
index 0000000..032f9da
--- /dev/null
+++ b/board/phytec/common/am6_som_detection.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2024 PHYTEC Messtechnik GmbH
+ * Author: Daniel Schultz <d.schultz@phytec.de>
+ */
+
+#ifndef _PHYTEC_AM6_SOM_DETECTION_H
+#define _PHYTEC_AM6_SOM_DETECTION_H
+
+#include "phytec_som_detection.h"
+
+#define PHYTEC_AM62X_SOM			71
+#define PHYTEC_AM64X_SOM			72
+#define PHYTEC_EEPROM_VALUE_X			0x21
+#define PHYTEC_EEPROM_NOR_FLASH_64MB_QSPI	0xC
+
+int __maybe_unused phytec_am6_detect(struct phytec_eeprom_data *data);
+u8 __maybe_unused phytec_get_am6_ddr_size(struct phytec_eeprom_data *data);
+u8 __maybe_unused phytec_get_am6_spi(struct phytec_eeprom_data *data);
+u8 __maybe_unused phytec_get_am6_eth(struct phytec_eeprom_data *data);
+u8 __maybe_unused phytec_get_am6_rtc(struct phytec_eeprom_data *data);
+
+static inline int phytec_am6_is_qspi(struct phytec_eeprom_data *data)
+{
+	u8 spi = phytec_get_am6_spi(data);
+
+	if (spi == PHYTEC_EEPROM_VALUE_X)
+		return 0;
+	return spi <= PHYTEC_EEPROM_NOR_FLASH_64MB_QSPI;
+}
+
+static inline int phytec_am6_is_ospi(struct phytec_eeprom_data *data)
+{
+	return phytec_get_am6_spi(data) > PHYTEC_EEPROM_NOR_FLASH_64MB_QSPI;
+}
+#endif /* _PHYTEC_AM6_SOM_DETECTION_H */