dts: bcm2711-rpi-cm4s: add enable_eeprom dtparam for onboard bootloader EEPROM

Add a GPIO hog on GPIO 57 (active high, output-low) to enable the onboard
bootloader EEPROM on CM4S. The hog is disabled by default and can be
activated via dtparam=enable_eeprom=on in config.txt.

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>

Author: nbuchwitz

arch/arm/boot/dts/broadcom/bcm2711-rpi-cm4s.dts

@@ -255,6 +255,13 @@
 		brcm,pins = <>;
 		brcm,function = <>;
 	};
+
+	enable_eeprom_hog: enable_eeprom_hog {
+		gpio-hog;
+		gpios = <57 GPIO_ACTIVE_HIGH>;
+		output-low;
+		status = "disabled";
+	};
 };
 
 /* Permanently disable HDMI1 */
@@ -301,5 +308,7 @@ i2c_csi_dsi0: &i2c0 {
 		act_led_gpio = <&led_act>,"gpios:4";
 		act_led_activelow = <&led_act>,"gpios:8";
 		act_led_trigger = <&led_act>,"linux,default-trigger";
+
+		enable_eeprom = <&enable_eeprom_hog>,"status";
 	};
 };

arch/arm/boot/dts/overlays/README

@@ -236,6 +236,10 @@ Params:
                                 compatible devices (default "on"). See also
                                 "tx_lpi_timer". Pi3B+ only.
 
+        enable_eeprom           Set to "on" to enable the onboard bootloader
+                                EEPROM by driving GPIO 57 low
+                                (default "off"). CM4S only.
+
         eth_downshift_after     Set the number of auto-negotiation failures
                                 after which the 1000Mbps modes are disabled.
                                 Legal values are 2, 3, 4, 5 and 0, where