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--- en:bpi-r4:start [2024/04/21 12:48] – [thermal] frank
+++ en:bpi-r4:start [2024/04/21 13:25] – [GPIO] frank
@@ Line 125: / Line 125: @@
 {{ :en:bpi-r4:bpi-r4-gpio.png?direct&400 |}}
+===== eeprom =====
+BPI-R4 has an eeprom on i2c-mux channel 0
+  [ 1.515672] at24 2-0057: 256 byte 24c02 EEPROM, writable, 1 bytes/write
+write-mode (wp-gpio is linked to green led):
+<code>
+# echo 0 > /sys/devices/platform/gpio-leds/leds/green:status/brightness
+root@bpi-r4-v11:~
+# echo "test" > /sys/bus/i2c/devices/2-0057/eeprom
+root@bpi-r4-v11:~
+# hexdump -C /sys/bus/i2c/devices/2-0057/eeprom
+00000000  74 65 73 74 0a ff ff ff  ff ff ff ff ff ff ff ff  |test............|
+00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
+*
+00000100
+root@bpi-r4-v11:~
+# echo 1 > /sys/devices/platform/gpio-leds/leds/green:status/brightness
+root@bpi-r4-v11:~
+</code>
 ===== uboot/ATF =====