drivers: gpio: silabs: add lookup table documentation

This commit only adds documentation. It will help a user to translate
pinout from the reference manual to a device tree gpio (HP and ULP).

Signed-off-by: Martin Hoff <[email protected]>

Author: Martinhoff-maker

drivers/gpio/gpio_silabs_siwx91x.c

@@ -27,6 +27,13 @@
 	CONFIG_GPIO_INIT_PRIORITY.
 #endif
 
+/* Lookup table:  Port-Pin (dts) -> SoC Pin (HP Pin from reference manual)              */
+/*                                                                                      */
+/* Port: A  A  A  A  B  B  B  B  B  B  B  C  C  C  C  C  D  D  D  D  D  D  D  D  D  D   */
+/* Pin : 10 11 12 15 09 10 11 12 13 14 15 00 01 02 14 15 00 01 02 03 04 05 06 07 08 09  */
+/*                                                                                      */
+/* HP  : 10 11 12 15 25 26 27 28 29 30 31 32 33 34 46 47 48 49 50 51 52 53 54 55 56 57  */
+
 #define MAX_PORT_COUNT  4
 #define MAX_PIN_COUNT   16
 #define INVALID_PORT    0xFF

drivers/gpio/gpio_silabs_siwx91x_uulp.c

@@ -20,6 +20,12 @@
 #include <zephyr/drivers/gpio.h>
 #include <zephyr/drivers/gpio/gpio_utils.h>
 
+/* Lookup table: Pin (dts) -> SoC Pin (ULP Pin from reference manual)             */
+/*                                                                                */
+/* Pin : 0  1  2  3  4                                                            */
+/*                                                                                */
+/* ULP : 0  1  2  3  4                                                            */
+
 #define UULP_GPIO_COUNT           5
 #define UULP_REG_INTERRUPT_CONFIG 0x10