Initial GPi Case support

This is for the original GPi Case but specifically for the following Pi models:

- Raspberry Pi Zero 2 W
- Raspberry Pi Compute Module 3 via GPi Mate
- Raspberry Pi Compute Module 4 via GPi Mate+

This work in progress as the current issues are know:

- All have no OpenGL hardware acceleration. I think a KMS device tree overlay is required for the screen.
 - CM3 has no sound

case/gpicase/cmdline.txt

@@ -0,0 +1 @@
+zswap.enabled=1 zswap.zpool=z3fold zswap.compressor=lz4 dwc_otg.lpm_enable=0 console=tty2 root=LABEL=writable rootfstype=ext4 rootwait fixrtc quiet loglevel=0 rd.systemd.show_status=false udev.log_level=0 udev.log_priority=0 rd.plymouth=0 plymouth.enable=0 plymouth.ignore-serial-consoles consoleblank=0 vt.global_cursor_default=0 snd_bcm2835.enable_compat_alsa=1 snd_bcm2835.enable_hdmi=0

case/gpicase/config.txt

@@ -0,0 +1,76 @@
+[all]
+kernel=vmlinuz
+cmdline=cmdline.txt
+initramfs initrd.img followkernel
+
+[pi4]
+max_framebuffers=1
+arm_boost=1
+
+[all]
+# Enable the audio output, I2C and SPI interfaces on the GPIO header. As these
+# parameters related to the base device-tree they must appear *before* any
+# other dtoverlay= specification
+dtparam=audio=on
+dtparam=i2c_arm=on
+dtparam=spi=on
+
+# Enable the serial pins
+enable_uart=1
+
+# RetroFlag GPi Case with Pi Zero 2, GPi Mate and GPi Mate Plus
+
+# Video
+cec_osd_name=retrohome
+display_rotate=1
+dtoverlay=dpi24-gpi
+overscan_left=0
+overscan_right=0
+overscan_top=0
+overscan_bottom=0
+framebuffer_width=320
+framebuffer_height=240
+enable_dpi_lcd=1
+display_default_lcd=1
+dpi_group=2
+dpi_mode=87
+dpi_output_format=0x6016
+hdmi_timings=240 1 38 10 20 320 1 20 4 4 0 0 0 60 0 6400000 1
+disable_audio_dither=1
+
+[pi0]
+dtoverlay=pwm-2chan,pin=18,func=2,pin2=19,func2=2
+dtoverlay=pwm-audio-pi-zero
+audio_pwm_mode=2
+
+# Pi Zero 2 stabilization
+arm_freq=1000
+gpu_freq=500
+core_freq=500
+sdram_freq=500
+sdram_schmoo=0x02000020
+# 6 is default
+over_voltage=6
+sdram_over_voltage=2
+
+[cm3]
+dtoverlay=pwm-2chan,pin=18,func=2,pin2=19,func2=2
+dtoverlay=pwm-audio-pi-zero
+audio_pwm_mode=0
+
+[cm4]
+dtoverlay=disable-pcie
+dtoverlay=sdtweak,overclock_50=100
+dtoverlay=dwc2,dr_mode=host
+dtoverlay=audremap,pins_18_19
+audio_pwm_mode=2
+hdmi_ignore_hotplug=1
+hdmi_ignore_edid=0xa5000080
+hdmi_edid_file=1
+
+[all]
+camera_auto_detect=0
+
+# disable activity leds
+dtparam=act_led_trigger=none
+dtparam=act_led_activelow=on

case/retroflag/config.txt

@@ -52,6 +52,8 @@ camera_auto_detect=1
 display_auto_detect=1
 
 # RetroFlag cases - https://www.retroflag.com/
+# https://gitlab.com/recalbox/recalbox/-/tree/master/projects/recalbox-hardware/case/installers/retroflags
+# https://github.com/kristijandraca/GPi_Case_patch
 
 enable_uart=1
 dtoverlay=RetroFlag_pw_io.dtbo

retro-home-image

@@ -539,24 +539,16 @@ dtoverlay=dwc2" >> "${B}/config.txt"
         gpicase)
             nspawn apt-get -y install --no-install-recommends python3-gpiozero python3-lgpio python3-psutil python3-setproctitle
             CASE_SUPPORT="gpi.py"
-            # https://support.retroflag.com/
-            # https://github.com/tsoliman/Retroflag-GPi-case
-            # https://github.com/CrashCortez/gpi-case/blob/master/config.txt
-            # .dts source from https://github.com/kristijandraca/GPi_Case_patch
-            #
             #dtc -W no-unit_address_vs_reg -I dts -O dtb -o "${B}/overlays/dpi24-gpi.dtbo" case/${REMIX}/boot/overlays/dpi24-gpi-overlay.dts
             #dtc -W no-unit_address_vs_reg -I dts -O dtb -o "${B}/overlays/pwm-audio-pi-zero-gpi.dtbo" case/${REMIX}/boot/overlays/pwm-audio-pi-zero-gpi-overlay.dts
             ;;
         gpimate)
             nspawn apt-get -y install --no-install-recommends python3-gpiozero python3-lgpio python3-psutil python3-setproctitle
             CASE_SUPPORT="gpi.py"
-            # https://forum.batocera.org/d/4097-support-for-gpimate/5
             ;;
         gpimateplus)
             nspawn apt-get -y install --no-install-recommends python3-gpiozero python3-lgpio python3-psutil python3-setproctitle
             CASE_SUPPORT="gpi.py"
-            # https://github.com/martinx72/GPiMatePlusHowTo
-
             #dtc -W no-unit_address_vs_reg -I dts -O dtb -o "${B}/overlays/dpi24-gpi.dtbo" case/${REMIX}/boot/overlays/dpi24-gpi-overlay.dts
             #dtc -W no-unit_address_vs_reg -I dts -O dtb -o "${B}/overlays/disable-pcie.dtbo" case/${REMIX}/boot/overlays/disable-pcie-overlay.dts
             ;;
@@ -779,8 +771,26 @@ case "${REMIX}" in
         echo "[+] Specified Waveshare GamePi43"
         not_implemented
         shift;;
-    gpicase)
-        echo "[+] Specified RetroFlag GPi Case with Raspberry Pi Zero 2 W"
+    gpicase|gpimate*)
+        # GPi Case
+        # https://support.retroflag.com/
+        # https://github.com/tsoliman/Retroflag-GPi-case
+        # https://github.com/kristijandraca/GPi_Case_patch - Re-eng device tree source
+        # https://gitlab.com/recalbox/recalbox/-/tree/master/projects/recalbox-hardware/case/installers/gpi
+
+        # GPi Mate
+        # https://retrogamerestore.com/store/gpimate/
+
+        # GPi Mate+
+        # https://retrogamerestore.com/store/gpimateplus/
+        # https://github.com/martinx72/GPiMatePlusHowTo
+
+        # KMS
+        # https://forums.raspberrypi.com/viewtopic.php?t=322556 - Possible device tree KMS overylay for the GPi Case screen
+        echo "[+] Specified RetroFlag GPi Case with:"
+        echo "      - Raspberry Pi Zero 2 W"
+        echo "      - GPiMatePlus and CM3+Lite"
+        echo "      - GPiMatePlus and CM4+Lite"
         SIZE_FB="320x240"
         SIZE_LOGO="128"
         SIZE_FRAME="192"
@@ -790,22 +800,6 @@ case "${REMIX}" in
         SIZE_FB="640x480"
         not_implemented
         shift;;
-    gpimate)
-        # https://retrogamerestore.com/store/gpimate/
-        echo "[+] Specified RetroFlag GPi Case with GPiMate for CM3+Lite"
-        SIZE_FB="320x240"
-        SIZE_LOGO="128"
-        SIZE_FRAME="192"
-        shift;;
-    gpimateplus)
-        # https://retrogamerestore.com/store/gpimateplus/
-        # https://github.com/martinx72/GPiMatePlusHowTo
-        echo "[+] Specified RetroFlag GPi Case with GPiMatePlus for CM4+Lite"
-        SIZE_FB="320x240"
-        SIZE_LOGO="128"
-        SIZE_FRAME="192"
-        REMIX="gpicase"
-        shift;;
     gpm2803)
         # https://www.waveshare.com/wiki/GPM280
         echo "[+] Specified Waveshare GPM2803 with CM3+Lite"