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README
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README
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Introduction
============
This directory contains Device Tree overlays. Device Tree makes it possible
to support many hardware configurations with a single kernel and without the
need to explicitly load or blacklist kernel modules. Note that this isn't a
"pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
are still configured by the board support code, but the intention is to
eventually reach that goal.
On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
default, the Raspberry Pi kernel boots with device tree enabled. You can
completely disable DT usage (for now) by adding:
device_tree=
to your config.txt, which should cause your Pi to revert to the old way of
doing things after a reboot.
In /boot you will find a .dtb for each base platform. This describes the
hardware that is part of the Raspberry Pi board. The loader (start.elf and its
siblings) selects the .dtb file appropriate for the platform by name, and reads
it into memory. At this point, all of the optional interfaces (i2c, i2s, spi)
are disabled, but they can be enabled using Device Tree parameters:
dtparam=i2c=on,i2s=on,spi=on
However, this shouldn't be necessary in many use cases because loading an
overlay that requires one of those interfaces will cause it to be enabled
automatically, and it is advisable to only enable interfaces if they are
needed.
Configuring additional, optional hardware is done using Device Tree overlays
(see below).
GPIO numbering uses the hardware pin numbering scheme (aka BCM scheme) and
not the physical pin numbers.
raspi-config
============
The Advanced Options section of the raspi-config utility can enable and disable
Device Tree use, as well as toggling the I2C and SPI interfaces. Note that it
is possible to both enable an interface and blacklist the driver, if for some
reason you should want to defer the loading.
Modules
=======
As well as describing the hardware, Device Tree also gives enough information
to allow suitable driver modules to be located and loaded, with the corollary
that unneeded modules are not loaded. As a result it should be possible to
remove lines from /etc/modules, and /etc/modprobe.d/raspi-blacklist.conf can
have its contents deleted (or commented out).
Using Overlays
==============
Overlays are loaded using the "dtoverlay" config.txt setting. As an example,
consider I2C Real Time Clock drivers. In the pre-DT world these would be loaded
by writing a magic string comprising a device identifier and an I2C address to
a special file in /sys/class/i2c-adapter, having first loaded the driver for
the I2C interface and the RTC device - something like this:
modprobe i2c-bcm2835
modprobe rtc-ds1307
echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
With DT enabled, this becomes a line in config.txt:
dtoverlay=i2c-rtc,ds1307
This causes the file /boot/overlays/i2c-rtc.dtbo to be loaded and a "node"
describing the DS1307 I2C device to be added to the Device Tree for the Pi. By
default it usees address 0x68, but this can be modified with an additional DT
parameter:
dtoverlay=i2c-rtc,ds1307,addr=0x68
Parameters usually have default values, although certain parameters are
mandatory. See the list of overlays below for a description of the parameters
and their defaults.
Making new Overlays based on existing Overlays
==============================================
Recent overlays have been designed in a more general way, so that they can be
adapted to hardware by changing their parameters. When you have additional
hardware with more than one device of a kind, you end up using the same overlay
multiple times with other parameters, e.g.
# 2 CAN FD interfaces on spi but with different pins
dtoverlay=mcp251xfd,spi0-0,interrupt=25
dtoverlay=mcp251xfd,spi0-1,interrupt=24
# a realtime clock on i2c
dtoverlay=i2c-rtc,pcf85063
While this approach does work, it requires knowledge about the hardware design.
It is more feasible to simplify things for the end user by providing a single
overlay as it is done the traditional way.
A new overlay can be generated by using ovmerge utility.
https://github.com/raspberrypi/utils/blob/master/ovmerge/ovmerge
To generate an overlay for the above configuration we pass the configuration
to ovmerge and add the -c flag.
ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
i2c-rtc-overlay.dts,pcf85063 \
>> merged-overlay.dts
The -c option writes the command above as a comment into the overlay as
a marker that this overlay is generated and how it was generated.
After compiling the overlay it can be loaded in a single line.
dtoverlay=merged
It does the same as the original configuration but without parameters.
The Overlay and Parameter Reference
===================================
N.B. When editing this file, please preserve the indentation levels to make it
simple to parse programmatically. NO HARD TABS.
Name: <The base DTB>
Info: Configures the base Raspberry Pi hardware
Load: <loaded automatically>
Params:
act_led_trigger Choose which activity the LED tracks.
Use "heartbeat" for a nice load indicator.
(default "mmc")
act_led_activelow Set to "on" to invert the sense of the LED
(default "off")
N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led
overlay.
act_led_gpio Set which GPIO to use for the activity LED
(in case you want to connect it to an external
device)
(default "16" on a non-Plus board, "47" on a
Plus or Pi 2)
N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led
overlay.
ant1 Select antenna 1 (default). CM4/5 only.
ant2 Select antenna 2. CM4/5 only.
noant Disable both antennas. CM4/5 only.
audio Set to "on" to enable the onboard ALSA audio
interface (default "off")
axiperf Set to "on" to enable the AXI bus performance
monitors.
See /sys/kernel/debug/raspberrypi_axi_monitor
for the results.
bdaddr Set an alternative Bluetooth address (BDADDR).
The value should be a 6-byte hexadecimal value,
with or without colon separators, written least-
significant-byte first. For example,
bdaddr=06:05:04:03:02:01
will set the BDADDR to 01:02:03:04:05:06.
button_debounce Set the debounce delay (in ms) on the power/
shutdown button (default 50ms)
cam0_reg Enables CAM 0 regulator.
Only required on CM1 & 3.
cam0_reg_gpio Set GPIO for CAM 0 regulator.
Default 31 on CM1, 3, and 4S.
Default of GPIO expander 5 on CM4, but override
switches to normal GPIO.
cam1_reg Enables CAM 1 regulator.
Only required on CM1 & 3.
cam1_reg_gpio Set GPIO for CAM 1 regulator.
Default 3 on CM1, 3, and 4S.
Default of GPIO expander 5 on CM4, but override
switches to normal GPIO.
cam0_sync Enable a GPIO to reflect frame sync from CSI0,
going high on frame start, and low on frame end.
cam0_sync_inverted Enable a GPIO to reflect frame sync from CSI0
going low on frame start, and high on frame end.
cam1_sync Enable a GPIO to reflect frame sync from CSI1,
going high on frame start, and low on frame end.
cam1_sync_inverted Enable a GPIO to reflect frame sync from CSI1
going low on frame start, and high on frame end.
cooling_fan Enables the Pi 5 cooling fan (enabled
automatically by the firmware)
drm_fb0_rp1_dpi Assign /dev/fb0 to the RP1 DPI output
drm_fb0_rp1_dsi0 Assign /dev/fb0 to the RP1 DSI0 output
drm_fb0_rp1_dsi1 Assign /dev/fb0 to the RP1 DSI1 output
drm_fb0_vc4 Assign /dev/fb0 to the vc4 outputs
drm_fb1_rp1_dpi Assign /dev/fb1 to the RP1 DPI output
drm_fb1_rp1_dsi0 Assign /dev/fb1 to the RP1 DSI0 output
drm_fb1_rp1_dsi1 Assign /dev/fb1 to the RP1 DSI1 output
drm_fb1_vc4 Assign /dev/fb1 to the vc4 outputs
drm_fb2_rp1_dpi Assign /dev/fb2 to the RP1 DPI output
drm_fb2_rp1_dsi0 Assign /dev/fb2 to the RP1 DSI0 output
drm_fb2_rp1_dsi1 Assign /dev/fb2 to the RP1 DSI1 output
drm_fb2_vc4 Assign /dev/fb2 to the vc4 outputs
eee Enable Energy Efficient Ethernet support for
compatible devices (default "on"). See also
"tx_lpi_timer". Pi3B+ 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
0 means never downshift (default 2). Pi3B+ only.
eth_led0 Set mode of LED0 - amber on Pi3B+ (default "1"),
green on Pi4/5 (default "0").
The legal values are:
Pi3B+
0=link/activity 1=link1000/activity
2=link100/activity 3=link10/activity
4=link100/1000/activity 5=link10/1000/activity
6=link10/100/activity 14=off 15=on
Pi4/5
0=Speed/Activity 1=Speed
2=Flash activity 3=FDX
4=Off 5=On
6=Alt 7=Speed/Flash
8=Link 9=Activity
eth_led1 Set mode of LED1 - green on Pi3B+ (default "6"),
amber on Pi4/5 (default "8"). See eth_led0 for
legal values.
eth_max_speed Set the maximum speed a link is allowed
to negotiate. Legal values are 10, 100 and
1000 (default 1000). Pi3B+ only.
fan_temp0 Temperature threshold (in millicelcius) for
1st cooling level (default 50000). Pi5 only.
fan_temp0_hyst Temperature hysteresis (in millicelcius) for
1st cooling level (default 5000). Pi5 only.
fan_temp0_speed Fan PWM setting for 1st cooling level (0-255,
default 75). Pi5 only.
fan_temp1 Temperature threshold (in millicelcius) for
2nd cooling level (default 60000). Pi5 only.
fan_temp1_hyst Temperature hysteresis (in millicelcius) for
2nd cooling level (default 5000). Pi5 only.
fan_temp1_speed Fan PWM setting for 2nd cooling level (0-255,
default 125). Pi5 only.
fan_temp2 Temperature threshold (in millicelcius) for
3rd cooling level (default 67500). Pi5 only.
fan_temp2_hyst Temperature hysteresis (in millicelcius) for
3rd cooling level (default 5000). Pi5 only.
fan_temp2_speed Fan PWM setting for 3rd cooling level (0-255,
default 175). Pi5 only.
fan_temp3 Temperature threshold (in millicelcius) for
4th cooling level (default 75000). Pi5 only.
fan_temp3_hyst Temperature hysteresis (in millicelcius) for
4th cooling level (default 5000). Pi5 only.
fan_temp3_speed Fan PWM setting for 4th cooling level (0-255,
default 250). Pi5 only.
hdmi Set to "off" to disable the HDMI interface
(default "on")
i2c An alias for i2c_arm
i2c_arm Set to "on" to enable the ARM's i2c interface
(default "off")
i2c_arm_baudrate Set the baudrate of the ARM's i2c interface
(default "100000")
i2c_baudrate An alias for i2c_arm_baudrate
i2c_csi_dsi Set to "on" to enable the i2c_csi_dsi interface
i2c_csi_dsi0 Set to "on" to enable the i2c_csi_dsi0 interface
i2c_csi_dsi1 Set to "on" to enable the i2c_csi_dsi1 interface
i2c_vc Set to "on" to enable the i2c interface
usually reserved for the VideoCore processor
(default "off")
i2c_vc_baudrate Set the baudrate of the VideoCore i2c interface
(default "100000")
i2s Set to "on" to enable the i2s interface
(default "off")
i2s_dma4 Use to enable 40-bit DMA on the i2s interface
(the assigned value doesn't matter)
(2711 only)
krnbt Set to "off" to disable autoprobing of Bluetooth
driver without need of hciattach/btattach
(default "on")
krnbt_baudrate Set the baudrate of the PL011 UART when used
with krnbt=on
nvme Alias for "pciex1" (2712 only)
nvmem_cust_rw Allow read/write access to customer otp
nvmem_mac_rw Allow read/write access to mac addresses otp
nvmem_priv_rw Allow read/write access to customer private otp
pcie Set to "off" to disable the PCIe interface
(default "on")
(2711 only, but not applicable on CM4S)
N.B. USB-A ports on 4B are subsequently disabled
pcie_tperst_clk_ms Add N milliseconds between PCIe reference clock
activation and PERST# deassertion
(CM4 and 2712, default "0")
pciex1 Set to "on" to enable the external PCIe link
(2712 only, default "off")
pciex1_gen Sets the PCIe "GEN"/speed for the external PCIe
link (2712 only, default "2")
pciex1_no_l0s Set to "on" to disable ASPM L0s on the external
PCIe link for devices that have broken
implementations (2712 only, default "off")
pciex1_tperst_clk_ms Alias for pcie_tperst_clk_ms
(2712 only, default "0")
pwr_led_trigger
pwr_led_activelow
pwr_led_gpio
As for act_led_*, but using the PWR LED.
Not available on Model A/B boards.
random Set to "on" to enable the hardware random
number generator (default "on")
rtc Set to "off" to disable the onboard Real Time
Clock (2712 only, default "on")
rtc_bbat_vchg Set the RTC backup battery charging voltage in
microvolts. If set to 0 or not specified, the
trickle charger is disabled.
(2712 only, default "0")
sd Set to "off" to disable the SD card (or eMMC on
non-lite SKU of CM4).
(default "on")
sd_cqe Use to enable Command Queueing on the SD
interface for faster Class A2 card performance
(Pi 5 only, default "off")
sd_overclock Clock (in MHz) to use when the MMC framework
requests 50MHz
sd_poll_once Looks for a card once after booting. Useful
for network booting scenarios to avoid the
overhead of continuous polling. N.B. Using
this option restricts the system to using a
single card per boot (or none at all).
(default off)
sd_force_pio Disable DMA support for SD driver (default off)
sd_pio_limit Number of blocks above which to use DMA for
SD card (default 1)
sd_debug Enable debug output from SD driver (default off)
sdio_overclock Clock (in MHz) to use when the MMC framework
requests 50MHz for the SDIO/WLAN interface.
spi Set to "on" to enable the spi interfaces
(default "off")
spi_dma4 Use to enable 40-bit DMA on spi interfaces
(the assigned value doesn't matter)
(2711 only)
strict_gpiod Return GPIOs to inputs when they are released.
If using the gpiod utilities, it is necessary
to keep a gpioset running (e.g. with
--mode=wait) in order for an output value to
persist.
suspend Make the power button trigger a suspend rather
than a power-off (2712 only, default "off")
tx_lpi_timer Set the delay in microseconds between going idle
and entering the low power state (default 600).
Requires EEE to be enabled - see "eee".
uart0 Set to "off" to disable uart0 (default "on")
uart0_console Move the kernel boot console to UART0 on pins
6, 8 and 10 of the 40-way header (2712 only,
default "off")
uart1 Set to "on" or "off" to enable or disable uart1
(default varies)
watchdog Set to "on" to enable the hardware watchdog
(default "off")
wifiaddr Set an alternative WiFi MAC address.
The value should be a 6-byte hexadecimal value,
with or without colon separators, written in the
natural (big-endian) order.
N.B. It is recommended to only enable those interfaces that are needed.
Leaving all interfaces enabled can lead to unwanted behaviour (i2c_vc
interfering with Pi Camera, I2S and SPI hogging GPIO pins, etc.)
Note also that i2c, i2c_arm and i2c_vc are aliases for the physical
interfaces i2c0 and i2c1. Use of the numeric variants is still possible
but deprecated because the ARM/VC assignments differ between board
revisions. The same board-specific mapping applies to i2c_baudrate,
and the other i2c baudrate parameters.
Name: act-led
Info: Pi 3B, 3B+, 3A+ and 4B use a GPIO expander to drive the LEDs which can
only be accessed from the VPU. There is a special driver for this with a
separate DT node, which has the unfortunate consequence of breaking the
act_led_gpio and act_led_activelow dtparams.
This overlay changes the GPIO controller back to the standard one and
restores the dtparams.
Load: dtoverlay=act-led,<param>=<val>
Params: activelow Set to "on" to invert the sense of the LED
(default "off")
gpio Set which GPIO to use for the activity LED
(in case you want to connect it to an external
device)
REQUIRED
Name: adafruit-st7735r
Info: Overlay for the SPI-connected Adafruit 1.8" 160x128 or 128x128 displays,
based on the ST7735R chip.
This overlay uses the newer DRM/KMS "Tiny" driver.
Load: dtoverlay=adafruit-st7735r,<param>=<val>
Params: 128x128 Select the 128x128 driver (default 160x128)
rotate Display rotation {0,90,180,270} (default 90)
speed SPI bus speed in Hz (default 4000000)
dc_pin GPIO pin for D/C (default 24)
reset_pin GPIO pin for RESET (default 25)
led_pin GPIO used to control backlight (default 18)
Name: adafruit18
Info: Overlay for the SPI-connected Adafruit 1.8" display (based on the
ST7735R chip). It includes support for the "green tab" version.
This overlay uses the older fbtft driver.
Load: dtoverlay=adafruit18,<param>=<val>
Params: green Use the adafruit18_green variant.
rotate Display rotation {0,90,180,270}
speed SPI bus speed in Hz (default 4000000)
fps Display frame rate in Hz
bgr Enable BGR mode (default off)
debug Debug output level {0-7}
dc_pin GPIO pin for D/C (default 24)
reset_pin GPIO pin for RESET (default 25)
led_pin GPIO used to control backlight (default 18)
Name: adau1977-adc
Info: Overlay for activation of ADAU1977 ADC codec over I2C for control
and I2S for data.
Load: dtoverlay=adau1977-adc
Params: <None>
Name: adau7002-simple
Info: Overlay for the activation of ADAU7002 stereo PDM to I2S converter.
Load: dtoverlay=adau7002-simple,<param>=<val>
Params: card-name Override the default, "adau7002", card name.
Name: ads1015
Info: Overlay for activation of Texas Instruments ADS1015 ADC over I2C
Load: dtoverlay=ads1015,<param>=<val>
Params: addr I2C bus address of device. Set based on how the
addr pin is wired. (default=0x48 assumes addr
is pulled to GND)
cha_enable Enable virtual channel a. (default=true)
cha_cfg Set the configuration for virtual channel a.
(default=4 configures this channel for the
voltage at A0 with respect to GND)
cha_datarate Set the datarate (samples/sec) for this channel.
(default=4 sets 1600 sps)
cha_gain Set the gain of the Programmable Gain
Amplifier for this channel. (default=2 sets the
full scale of the channel to 2.048 Volts)
Channel (ch) parameters can be set for each enabled channel.
A maximum of 4 channels can be enabled (letters a thru d).
For more information refer to the device datasheet at:
http://www.ti.com/lit/ds/symlink/ads1015.pdf
Name: ads1115
Info: Texas Instruments ADS1115 ADC
Load: dtoverlay=ads1115,<param>[=<val>]
Params: addr I2C bus address of device. Set based on how the
addr pin is wired. (default=0x48 assumes addr
is pulled to GND)
cha_enable Enable virtual channel a.
cha_cfg Set the configuration for virtual channel a.
(default=4 configures this channel for the
voltage at A0 with respect to GND)
cha_datarate Set the datarate (samples/sec) for this channel.
(default=7 sets 860 sps)
cha_gain Set the gain of the Programmable Gain
Amplifier for this channel. (Default 1 sets the
full scale of the channel to 4.096 Volts)
i2c0 Choose the I2C0 bus on GPIOs 0&1
i2c_csi_dsi Choose the I2C0 bus on GPIOs 44&45
i2c3 Choose the I2C3 bus (configure with the i2c3
overlay - BCM2711 only)
i2c4 Choose the I2C4 bus (configure with the i2c4
overlay - BCM2711 only)
i2c5 Choose the I2C5 bus (configure with the i2c5
overlay - BCM2711 only)
i2c6 Choose the I2C6 bus (configure with the i2c6
overlay - BCM2711 only)
Channel parameters can be set for each enabled channel.
A maximum of 4 channels can be enabled (letters a thru d).
For more information refer to the device datasheet at:
http://www.ti.com/lit/ds/symlink/ads1115.pdf
Name: ads7846
Info: ADS7846 Touch controller
Load: dtoverlay=ads7846,<param>=<val>
Params: cs SPI bus Chip Select (default 1)
speed SPI bus speed (default 2MHz, max 3.25MHz)
penirq GPIO used for PENIRQ. REQUIRED
penirq_pull Set GPIO pull (default 0=none, 2=pullup)
swapxy Swap x and y axis
xmin Minimum value on the X axis (default 0)
ymin Minimum value on the Y axis (default 0)
xmax Maximum value on the X axis (default 4095)
ymax Maximum value on the Y axis (default 4095)
pmin Minimum reported pressure value (default 0)
pmax Maximum reported pressure value (default 65535)
xohms Touchpanel sensitivity (X-plate resistance)
(default 400)
penirq is required and usually xohms (60-100) has to be set as well.
Apart from that, pmax (255) and swapxy are also common.
The rest of the calibration can be done with xinput-calibrator.
See: github.com/notro/fbtft/wiki/FBTFT-on-Raspian
Device Tree binding document:
www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt
Name: adv7282m
Info: Analog Devices ADV7282M analogue video to CSI2 bridge.
Uses Unicam1, which is the standard camera connector on most Pi
variants.
Load: dtoverlay=adv7282m,<param>=<val>
Params: addr Overrides the I2C address (default 0x21)
media-controller Configure use of Media Controller API for
configuring the sensor (default off)
Name: adv728x-m
Info: Analog Devices ADV728[0|1|2]-M analogue video to CSI2 bridges.
This is a wrapper for adv7282m, and defaults to ADV7282M.
Load: dtoverlay=adv728x-m,<param>=<val>
Params: addr Overrides the I2C address (default 0x21)
adv7280m Select ADV7280-M.
adv7281m Select ADV7281-M.
adv7281ma Select ADV7281-MA.
media-controller Configure use of Media Controller API for
configuring the sensor (default off)
Name: akkordion-iqdacplus
Info: Configures the Digital Dreamtime Akkordion Music Player (based on the
OEM IQAudIO DAC+ or DAC Zero module).
Load: dtoverlay=akkordion-iqdacplus,<param>=<val>
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
Digital volume control. Enable with
dtoverlay=akkordion-iqdacplus,24db_digital_gain
(The default behaviour is that the Digital
volume control is limited to a maximum of
0dB. ie. it can attenuate but not provide
gain. For most users, this will be desired
as it will prevent clipping. By appending
the 24db_digital_gain parameter, the Digital
volume control will allow up to 24dB of
gain. If this parameter is enabled, it is the
responsibility of the user to ensure that
the Digital volume control is set to a value
that does not result in clipping/distortion!)
Name: allo-boss-dac-pcm512x-audio
Info: Configures the Allo Boss DAC audio cards.
Load: dtoverlay=allo-boss-dac-pcm512x-audio,<param>
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
Digital volume control. Enable with
"dtoverlay=allo-boss-dac-pcm512x-audio,
24db_digital_gain"
(The default behaviour is that the Digital
volume control is limited to a maximum of
0dB. ie. it can attenuate but not provide
gain. For most users, this will be desired
as it will prevent clipping. By appending
the 24db_digital_gain parameter, the Digital
volume control will allow up to 24dB of
gain. If this parameter is enabled, it is the
responsibility of the user to ensure that
the Digital volume control is set to a value
that does not result in clipping/distortion!)
slave Force Boss DAC into slave mode, using Pi a
master for bit clock and frame clock. Enable
with "dtoverlay=allo-boss-dac-pcm512x-audio,
slave"
Name: allo-boss2-dac-audio
Info: Configures the Allo Boss2 DAC audio card
Load: dtoverlay=allo-boss2-dac-audio
Params: <None>
Name: allo-digione
Info: Configures the Allo Digione audio card
Load: dtoverlay=allo-digione
Params: <None>
Name: allo-katana-dac-audio
Info: Configures the Allo Katana DAC audio card
Load: dtoverlay=allo-katana-dac-audio
Params: <None>
Name: allo-piano-dac-pcm512x-audio
Info: Configures the Allo Piano DAC (2.0/2.1) audio cards.
(NB. This initial support is for 2.0 channel audio ONLY! ie. stereo.
The subwoofer outputs on the Piano 2.1 are not currently supported!)
Load: dtoverlay=allo-piano-dac-pcm512x-audio,<param>
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
Digital volume control.
(The default behaviour is that the Digital
volume control is limited to a maximum of
0dB. ie. it can attenuate but not provide
gain. For most users, this will be desired
as it will prevent clipping. By appending
the 24db_digital_gain parameter, the Digital
volume control will allow up to 24dB of
gain. If this parameter is enabled, it is the
responsibility of the user to ensure that
the Digital volume control is set to a value
that does not result in clipping/distortion!)
Name: allo-piano-dac-plus-pcm512x-audio
Info: Configures the Allo Piano DAC (2.1) audio cards.
Load: dtoverlay=allo-piano-dac-plus-pcm512x-audio,<param>
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
Digital volume control.
(The default behaviour is that the Digital
volume control is limited to a maximum of
0dB. ie. it can attenuate but not provide
gain. For most users, this will be desired
as it will prevent clipping. By appending
the 24db_digital_gain parameter, the Digital
volume control will allow up to 24dB of
gain. If this parameter is enabled, it is the
responsibility of the user to ensure that
the Digital volume control is set to a value
that does not result in clipping/distortion!)
glb_mclk This option is only with Kali board. If enabled,
MCLK for Kali is used and PLL is disabled for
better voice quality. (default Off)
Name: anyspi
Info: Universal device tree overlay for SPI devices
Just specify the SPI address and device name ("compatible" property).
This overlay lacks any device-specific parameter support!
For devices on spi1 or spi2, the interfaces should be enabled
with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
Examples:
1. SPI NOR flash on spi0.1, maximum SPI clock frequency 45MHz:
dtoverlay=anyspi:spi0-1,dev="jedec,spi-nor",speed=45000000
2. MCP3204 ADC on spi1.2, maximum SPI clock frequency 500kHz:
dtoverlay=anyspi:spi1-2,dev="microchip,mcp3204"
Load: dtoverlay=anyspi,<param>=<val>
Params: spi<n>-<m> Configure device at spi<n>, cs<m>
(boolean, required)
dev Set device name to search compatible module
(string, required)
speed Set SPI clock frequency in Hz
(integer, optional, default 500000)
Name: apds9960
Info: Configures the AVAGO APDS9960 digital proximity, ambient light, RGB and
gesture sensor
Load: dtoverlay=apds9960,<param>=<val>
Params: gpiopin GPIO used for INT (default 4)
noints Disable the interrupt GPIO line.
Name: applepi-dac
Info: Configures the Orchard Audio ApplePi-DAC audio card
Load: dtoverlay=applepi-dac
Params: <None>
Name: arducam-64mp
Info: Arducam 64MP camera module.
Uses Unicam 1, which is the standard camera connector on most Pi
variants.
Load: dtoverlay=arducam-64mp,<param>=<val>
Params: rotation Mounting rotation of the camera sensor (0 or
180, default 0)
orientation Sensor orientation (0 = front, 1 = rear,
2 = external, default external)
media-controller Configure use of Media Controller API for
configuring the sensor (default on)
cam0 Adopt the default configuration for CAM0 on a
Compute Module (CSI0, i2c_vc, and cam0_reg).
vcm Select lens driver state. Default is enabled,
but vcm=off will disable.
Name: arducam-pivariety
Info: Arducam Pivariety camera module.
Uses Unicam 1, which is the standard camera connector on most Pi
variants.
Load: dtoverlay=arducam-pivariety,<param>=<val>
Params: rotation Mounting rotation of the camera sensor (0 or
180, default 0)
orientation Sensor orientation (0 = front, 1 = rear,
2 = external, default external)
media-controller Configure use of Media Controller API for
configuring the sensor (default on)
cam0 Adopt the default configuration for CAM0 on a
Compute Module (CSI0, i2c_vc, and cam0_reg).
Name: at86rf233
Info: Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver,
connected to spi0.0
Load: dtoverlay=at86rf233,<param>=<val>
Params: interrupt GPIO used for INT (default 23)
reset GPIO used for Reset (default 24)
sleep GPIO used for Sleep (default 25)
speed SPI bus speed in Hz (default 3000000)
trim Fine tuning of the internal capacitance
arrays (0=+0pF, 15=+4.5pF, default 15)
Name: audioinjector-addons
Info: Configures the audioinjector.net audio add on soundcards
Load: dtoverlay=audioinjector-addons,<param>=<val>
Params: non-stop-clocks Keeps the clocks running even when the stream
is paused or stopped (default off)
Name: audioinjector-bare-i2s
Info: Configures the audioinjector.net audio bare i2s soundcard
Load: dtoverlay=audioinjector-bare-i2s
Params: <None>
Name: audioinjector-isolated-soundcard
Info: Configures the audioinjector.net isolated soundcard
Load: dtoverlay=audioinjector-isolated-soundcard
Params: <None>
Name: audioinjector-ultra
Info: Configures the audioinjector.net ultra soundcard
Load: dtoverlay=audioinjector-ultra
Params: <None>
Name: audioinjector-wm8731-audio
Info: Configures the audioinjector.net audio add on soundcard
Load: dtoverlay=audioinjector-wm8731-audio
Params: <None>
Name: audiosense-pi
Info: Configures the audiosense-pi add on soundcard
For more information refer to
https://gitlab.com/kakar0t/audiosense-pi
Load: dtoverlay=audiosense-pi
Params: <None>
Name: audremap
Info: Switches PWM sound output to GPIOs on the 40-pin header
Load: dtoverlay=audremap,<param>=<val>
Params: swap_lr Reverse the channel allocation, which will also
swap the audio jack outputs (default off)
enable_jack Don't switch off the audio jack output. Does
nothing on BCM2711 (default off)
pins_12_13 Select GPIOs 12 & 13 (default)
pins_18_19 Select GPIOs 18 & 19
pins_40_41 Select GPIOs 40 & 41 (not available on CM4, used
for other purposes)
pins_40_45 Select GPIOs 40 & 45 (don't use on BCM2711 - the
pins are on different controllers)
Name: balena-fin
Info: Overlay that enables WLAN, Bluetooth and the GPIO expander on the
balenaFin carrier board for the Raspberry Pi Compute Module 3/3+ Lite.
Load: dtoverlay=balena-fin
Params: <None>
Name: bcm2712d0
Info: Overlay encapsulating the BCM2712 C0->D0 differences
Load: dtoverlay=bcm2712d0
Params: <None>
Name: bmp085_i2c-sensor
Info: This overlay is now deprecated - see i2c-sensor
Load: <Deprecated>
Name: camera-mux-2port
Info: Configures a 2 port camera multiplexer
Note that currently ALL IMX290 modules share a common clock, therefore
all modules will need to have the same clock frequency.
Load: dtoverlay=camera-mux-2port,<param>=<val>
Params: cam0-arducam-64mp Select Arducam64MP for camera on port 0
cam0-imx219 Select IMX219 for camera on port 0
cam0-imx258 Select IMX258 for camera on port 0
cam0-imx290 Select IMX290 for camera on port 0
cam0-imx477 Select IMX477 for camera on port 0
cam0-imx519 Select IMX519 for camera on port 0
cam0-imx708 Select IMX708 for camera on port 0
cam0-ov2311 Select OV2311 for camera on port 0
cam0-ov5647 Select OV5647 for camera on port 0
cam0-ov64a40 Select OV64A40 for camera on port 0
cam0-ov7251 Select OV7251 for camera on port 0
cam0-ov9281 Select OV9281 for camera on port 0
cam0-imx290-clk-freq Set clock frequency for an IMX290 on port 0
cam1-arducam-64mp Select Arducam64MP for camera on port 1
cam1-imx219 Select IMX219 for camera on port 1
cam1-imx258 Select IMX258 for camera on port 1
cam1-imx290 Select IMX290 for camera on port 1
cam1-imx477 Select IMX477 for camera on port 1
cam1-imx519 Select IMX519 for camera on port 1
cam1-imx708 Select IMX708 for camera on port 1
cam1-ov2311 Select OV2311 for camera on port 1
cam1-ov5647 Select OV5647 for camera on port 1
cam1-ov64a40 Select OV64A40 for camera on port 1
cam1-ov7251 Select OV7251 for camera on port 1
cam1-ov9281 Select OV9281 for camera on port 1
cam1-imx290-clk-freq Set clock frequency for an IMX290 on port 1
cam0-sync-source Set camera on port 0 as vsync source
cam0-sync-sink Set camera on port 0 as vsync sink
cam1-sync-source Set camera on port 1 as vsync source
cam1-sync-sink Set camera on port 1 as vsync sink
cam0 Connect the mux to CAM0 port (default is CAM1)
Name: camera-mux-4port
Info: Configures a 4 port camera multiplexer
Note that currently ALL IMX290 modules share a common clock, therefore
all modules will need to have the same clock frequency.
Load: dtoverlay=camera-mux-4port,<param>=<val>
Params: cam0-arducam-64mp Select Arducam64MP for camera on port 0
cam0-imx219 Select IMX219 for camera on port 0
cam0-imx258 Select IMX258 for camera on port 0
cam0-imx290 Select IMX290 for camera on port 0
cam0-imx477 Select IMX477 for camera on port 0
cam0-imx519 Select IMX519 for camera on port 0
cam0-imx708 Select IMX708 for camera on port 0
cam0-ov2311 Select OV2311 for camera on port 0
cam0-ov5647 Select OV5647 for camera on port 0
cam0-ov64a40 Select OV64A40 for camera on port 0
cam0-ov7251 Select OV7251 for camera on port 0
cam0-ov9281 Select OV9281 for camera on port 0
cam0-imx290-clk-freq Set clock frequency for an IMX290 on port 0
cam1-arducam-64mp Select Arducam64MP for camera on port 1
cam1-imx219 Select IMX219 for camera on port 1
cam1-imx258 Select IMX258 for camera on port 1
cam1-imx290 Select IMX290 for camera on port 1
cam1-imx477 Select IMX477 for camera on port 1
cam1-imx519 Select IMX519 for camera on port 1
cam1-imx708 Select IMX708 for camera on port 1
cam1-ov2311 Select OV2311 for camera on port 1
cam1-ov5647 Select OV5647 for camera on port 1
cam1-ov64a40 Select OV64A40 for camera on port 1
cam1-ov7251 Select OV7251 for camera on port 1
cam1-ov9281 Select OV9281 for camera on port 1
cam1-imx290-clk-freq Set clock frequency for an IMX290 on port 1
cam2-arducam-64mp Select Arducam64MP for camera on port 2
cam2-imx219 Select IMX219 for camera on port 2
cam2-imx258 Select IMX258 for camera on port 2
cam2-imx290 Select IMX290 for camera on port 2
cam2-imx477 Select IMX477 for camera on port 2
cam2-imx519 Select IMX519 for camera on port 2
cam2-imx708 Select IMX708 for camera on port 2
cam2-ov2311 Select OV2311 for camera on port 2
cam2-ov5647 Select OV5647 for camera on port 2
cam2-ov64a40 Select OV64A40 for camera on port 2
cam2-ov7251 Select OV7251 for camera on port 2
cam2-ov9281 Select OV9281 for camera on port 2
cam2-imx290-clk-freq Set clock frequency for an IMX290 on port 2
cam3-arducam-64mp Select Arducam64MP for camera on port 3
cam3-imx219 Select IMX219 for camera on port 3
cam3-imx258 Select IMX258 for camera on port 3
cam3-imx290 Select IMX290 for camera on port 3
cam3-imx477 Select IMX477 for camera on port 3
cam3-imx519 Select IMX519 for camera on port 3
cam3-imx708 Select IMX708 for camera on port 3
cam3-ov2311 Select OV2311 for camera on port 3
cam3-ov5647 Select OV5647 for camera on port 3
cam3-ov64a40 Select OV64A40 for camera on port 3
cam3-ov7251 Select OV7251 for camera on port 3
cam3-ov9281 Select OV9281 for camera on port 3
cam3-imx290-clk-freq Set clock frequency for an IMX290 on port 3
cam0-sync-source Set camera on port 0 as vsync source
cam0-sync-sink Set camera on port 0 as vsync sink
cam1-sync-source Set camera on port 1 as vsync source
cam1-sync-sink Set camera on port 1 as vsync sink
cam2-sync-source Set camera on port 2 as vsync source
cam2-sync-sink Set camera on port 2 as vsync sink
cam3-sync-source Set camera on port 3 as vsync source
cam3-sync-sink Set camera on port 3 as vsync sink
cam0 Connect the mux to CAM0 port (default is CAM1)
Name: cap1106
Info: Enables the ability to use the cap1106 touch sensor as a keyboard
Load: dtoverlay=cap1106,<param>=<val>
Params: int_pin GPIO pin for interrupt signal (default 23)
Name: chipdip-dac
Info: Configures Chip Dip audio cards.
Load: dtoverlay=chipdip-dac
Params: <None>
Name: cirrus-wm5102
Info: Configures the Cirrus Logic Audio Card
Load: dtoverlay=cirrus-wm5102
Params: <None>
Name: cm-swap-i2c0
Info: Largely for Compute Modules 1&3 where the original instructions for
adding a camera used GPIOs 0&1 for CAM1 and 28&29 for CAM0, whilst all
other platforms use 28&29 (or 44&45) for CAM1.
The default assignment through using this overlay is for
i2c0 to use 28&29, and i2c10 (aka i2c_csi_dsi) to use 28&29, but the
overrides allow this to be changed.