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Add clock changes and mute gpios (#1938)
[mirror_ubuntu-zesty-kernel.git] / arch / arm / boot / dts / overlays / README
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56d745a1 1Introduction
2============
3
4This directory contains Device Tree overlays. Device Tree makes it possible
5to support many hardware configurations with a single kernel and without the
6need to explicitly load or blacklist kernel modules. Note that this isn't a
7"pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
8are still configured by the board support code, but the intention is to
9eventually reach that goal.
10
11On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
12default, the Raspberry Pi kernel boots with device tree enabled. You can
13completely disable DT usage (for now) by adding:
14
15 device_tree=
16
17to your config.txt, which should cause your Pi to revert to the old way of
18doing things after a reboot.
19
20In /boot you will find a .dtb for each base platform. This describes the
21hardware that is part of the Raspberry Pi board. The loader (start.elf and its
22siblings) selects the .dtb file appropriate for the platform by name, and reads
23it into memory. At this point, all of the optional interfaces (i2c, i2s, spi)
24are disabled, but they can be enabled using Device Tree parameters:
25
26 dtparam=i2c=on,i2s=on,spi=on
27
28However, this shouldn't be necessary in many use cases because loading an
29overlay that requires one of those interfaces will cause it to be enabled
30automatically, and it is advisable to only enable interfaces if they are
31needed.
32
33Configuring additional, optional hardware is done using Device Tree overlays
34(see below).
35
36raspi-config
37============
38
39The Advanced Options section of the raspi-config utility can enable and disable
40Device Tree use, as well as toggling the I2C and SPI interfaces. Note that it
41is possible to both enable an interface and blacklist the driver, if for some
42reason you should want to defer the loading.
43
44Modules
45=======
46
47As well as describing the hardware, Device Tree also gives enough information
48to allow suitable driver modules to be located and loaded, with the corollary
49that unneeded modules are not loaded. As a result it should be possible to
50remove lines from /etc/modules, and /etc/modprobe.d/raspi-blacklist.conf can
51have its contents deleted (or commented out).
52
53Using Overlays
54==============
55
56Overlays are loaded using the "dtoverlay" directive. As an example, consider
57the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
58pre-DT world this would be loaded from /etc/modules, with an explicit
59"modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled,
60this becomes a line in config.txt:
61
62 dtoverlay=lirc-rpi
63
64This causes the file /boot/overlays/lirc-rpi.dtbo to be loaded. By
65default it will use GPIOs 17 (out) and 18 (in), but this can be modified using
66DT parameters:
67
68 dtoverlay=lirc-rpi,gpio_out_pin=17,gpio_in_pin=13
69
70Parameters always have default values, although in some cases (e.g. "w1-gpio")
71it is necessary to provided multiple overlays in order to get the desired
72behaviour. See the list of overlays below for a description of the parameters
73and their defaults.
74
75The Overlay and Parameter Reference
76===================================
77
78N.B. When editing this file, please preserve the indentation levels to make it
79simple to parse programmatically. NO HARD TABS.
80
81
82Name: <The base DTB>
83Info: Configures the base Raspberry Pi hardware
84Load: <loaded automatically>
85Params:
86 audio Set to "on" to enable the onboard ALSA audio
87 interface (default "off")
88
89 i2c_arm Set to "on" to enable the ARM's i2c interface
90 (default "off")
91
92 i2c_vc Set to "on" to enable the i2c interface
93 usually reserved for the VideoCore processor
94 (default "off")
95
96 i2c An alias for i2c_arm
97
98 i2c_arm_baudrate Set the baudrate of the ARM's i2c interface
99 (default "100000")
100
101 i2c_vc_baudrate Set the baudrate of the VideoCore i2c interface
102 (default "100000")
103
104 i2c_baudrate An alias for i2c_arm_baudrate
105
106 i2s Set to "on" to enable the i2s interface
107 (default "off")
108
109 spi Set to "on" to enable the spi interfaces
110 (default "off")
111
112 random Set to "on" to enable the hardware random
113 number generator (default "on")
114
115 sd_overclock Clock (in MHz) to use when the MMC framework
116 requests 50MHz
117
118 sd_force_pio Disable DMA support for SD driver (default off)
119
120 sd_pio_limit Number of blocks above which to use DMA for
121 SD card (default 1)
122
123 sd_debug Enable debug output from SD driver (default off)
124
125 uart0 Set to "off" to disable uart0 (default "on")
126
127 uart1 Set to "on" or "off" to enable or disable uart1
128 (default varies)
129
130 watchdog Set to "on" to enable the hardware watchdog
131 (default "off")
132
133 act_led_trigger Choose which activity the LED tracks.
134 Use "heartbeat" for a nice load indicator.
135 (default "mmc")
136
137 act_led_activelow Set to "on" to invert the sense of the LED
138 (default "off")
139 N.B. For Pi3 see pi3-act-led overlay.
140
141 act_led_gpio Set which GPIO to use for the activity LED
142 (in case you want to connect it to an external
143 device)
144 (default "16" on a non-Plus board, "47" on a
145 Plus or Pi 2)
146 N.B. For Pi3 see pi3-act-led overlay.
147
148 pwr_led_trigger
149 pwr_led_activelow
150 pwr_led_gpio
151 As for act_led_*, but using the PWR LED.
152 Not available on Model A/B boards.
153
154 N.B. It is recommended to only enable those interfaces that are needed.
155 Leaving all interfaces enabled can lead to unwanted behaviour (i2c_vc
156 interfering with Pi Camera, I2S and SPI hogging GPIO pins, etc.)
157 Note also that i2c, i2c_arm and i2c_vc are aliases for the physical
158 interfaces i2c0 and i2c1. Use of the numeric variants is still possible
159 but deprecated because the ARM/VC assignments differ between board
160 revisions. The same board-specific mapping applies to i2c_baudrate,
161 and the other i2c baudrate parameters.
162
163
164Name: adau1977-adc
165Info: Overlay for activation of ADAU1977 ADC codec over I2C for control
166 and I2S for data.
167Load: dtoverlay=adau1977-adc
168Params: <None>
169
170
40ef6193 171Name: adau7002-simple
172Info: Overlay for the activation of ADAU7002 stereo PDM to I2S converter.
173Load: dtoverlay=adau7002-simple,<param>=<val>
174Params: card-name Override the default, "adau7002", card name.
175
176
56d745a1 177Name: ads1015
178Info: Overlay for activation of Texas Instruments ADS1015 ADC over I2C
179Load: dtoverlay=ads1015,<param>=<val>
180Params: addr I2C bus address of device. Set based on how the
181 addr pin is wired. (default=0x48 assumes addr
182 is pulled to GND)
183 cha_enable Enable virtual channel a. (default=true)
184 cha_cfg Set the configuration for virtual channel a.
185 (default=4 configures this channel for the
186 voltage at A0 with respect to GND)
187 cha_datarate Set the datarate (samples/sec) for this channel.
188 (default=4 sets 1600 sps)
189 cha_gain Set the gain of the Programmable Gain
190 Amplifier for this channel. (default=2 sets the
191 full scale of the channel to 2.048 Volts)
192
193 Channel (ch) parameters can be set for each enabled channel.
194 A maximum of 4 channels can be enabled (letters a thru d).
195 For more information refer to the device datasheet at:
196 http://www.ti.com/lit/ds/symlink/ads1015.pdf
197
198
8940ce4e
SE		 199Name: ads1115
200Info: Texas Instruments ADS1115 ADC
201Load: dtoverlay=ads1115,<param>[=<val>]
202Params: addr I2C bus address of device. Set based on how the
203 addr pin is wired. (default=0x48 assumes addr
204 is pulled to GND)
205 cha_enable Enable virtual channel a.
206 cha_cfg Set the configuration for virtual channel a.
207 (default=4 configures this channel for the
208 voltage at A0 with respect to GND)
209 cha_datarate Set the datarate (samples/sec) for this channel.
210 (default=7 sets 860 sps)
211 cha_gain Set the gain of the Programmable Gain
212 Amplifier for this channel. (Default 1 sets the
213 full scale of the channel to 4.096 Volts)
214
215 Channel parameters can be set for each enabled channel.
216 A maximum of 4 channels can be enabled (letters a thru d).
217 For more information refer to the device datasheet at:
218 http://www.ti.com/lit/ds/symlink/ads1115.pdf
219
220
56d745a1 221Name: ads7846
222Info: ADS7846 Touch controller
223Load: dtoverlay=ads7846,<param>=<val>
224Params: cs SPI bus Chip Select (default 1)
225 speed SPI bus speed (default 2MHz, max 3.25MHz)
226 penirq GPIO used for PENIRQ. REQUIRED
227 penirq_pull Set GPIO pull (default 0=none, 2=pullup)
228 swapxy Swap x and y axis
229 xmin Minimum value on the X axis (default 0)
230 ymin Minimum value on the Y axis (default 0)
231 xmax Maximum value on the X axis (default 4095)
232 ymax Maximum value on the Y axis (default 4095)
233 pmin Minimum reported pressure value (default 0)
234 pmax Maximum reported pressure value (default 65535)
235 xohms Touchpanel sensitivity (X-plate resistance)
236 (default 400)
237
238 penirq is required and usually xohms (60-100) has to be set as well.
239 Apart from that, pmax (255) and swapxy are also common.
240 The rest of the calibration can be done with xinput-calibrator.
241 See: github.com/notro/fbtft/wiki/FBTFT-on-Raspian
242 Device Tree binding document:
243 www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt
244
245
246Name: akkordion-iqdacplus
247Info: Configures the Digital Dreamtime Akkordion Music Player (based on the
248 OEM IQAudIO DAC+ or DAC Zero module).
249Load: dtoverlay=akkordion-iqdacplus,<param>=<val>
250Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
251 Digital volume control. Enable with
252 dtoverlay=akkordion-iqdacplus,24db_digital_gain
253 (The default behaviour is that the Digital
254 volume control is limited to a maximum of
255 0dB. ie. it can attenuate but not provide
256 gain. For most users, this will be desired
257 as it will prevent clipping. By appending
258 the 24db_digital_gain parameter, the Digital
259 volume control will allow up to 24dB of
260 gain. If this parameter is enabled, it is the
261 responsibility of the user to ensure that
262 the Digital volume control is set to a value
263 that does not result in clipping/distortion!)
264
265
5bdc2c16
B		 266Name: allo-boss-dac-pcm512x-audio
267Info: Configures the Allo Boss DAC audio cards.
268Load: dtoverlay=allo-boss-dac-pcm512x-audio,<param>
269Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
270 Digital volume control. Enable with
271 "dtoverlay=allo-boss-dac-pcm512x-audio,
272 24db_digital_gain"
273 (The default behaviour is that the Digital
274 volume control is limited to a maximum of
275 0dB. ie. it can attenuate but not provide
276 gain. For most users, this will be desired
277 as it will prevent clipping. By appending
278 the 24db_digital_gain parameter, the Digital
279 volume control will allow up to 24dB of
280 gain. If this parameter is enabled, it is the
281 responsibility of the user to ensure that
282 the Digital volume control is set to a value
283 that does not result in clipping/distortion!)
284 slave Force Boss DAC into slave mode, using Pi a
285 master for bit clock and frame clock. Enable
286 with "dtoverlay=allo-boss-dac-pcm512x-audio,
287 slave"
288
289
56d745a1 290Name: allo-piano-dac-pcm512x-audio
291Info: Configures the Allo Piano DAC (2.0/2.1) audio cards.
292 (NB. This initial support is for 2.0 channel audio ONLY! ie. stereo.
293 The subwoofer outputs on the Piano 2.1 are not currently supported!)
294Load: dtoverlay=allo-piano-dac-pcm512x-audio,<param>
bcf425d0
RM		 295Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
296 Digital volume control.
297 (The default behaviour is that the Digital
298 volume control is limited to a maximum of
299 0dB. ie. it can attenuate but not provide
300 gain. For most users, this will be desired
301 as it will prevent clipping. By appending
302 the 24db_digital_gain parameter, the Digital
303 volume control will allow up to 24dB of
304 gain. If this parameter is enabled, it is the
305 responsibility of the user to ensure that
306 the Digital volume control is set to a value
307 that does not result in clipping/distortion!)
308
309
310Name: allo-piano-dac-plus-pcm512x-audio
311Info: Configures the Allo Piano DAC (2.1) audio cards.
312Load: dtoverlay=allo-piano-dac-plus-pcm512x-audio,<param>
56d745a1 313Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
314 Digital volume control.
315 (The default behaviour is that the Digital
316 volume control is limited to a maximum of
317 0dB. ie. it can attenuate but not provide
318 gain. For most users, this will be desired
319 as it will prevent clipping. By appending
320 the 24db_digital_gain parameter, the Digital
321 volume control will allow up to 24dB of
322 gain. If this parameter is enabled, it is the
323 responsibility of the user to ensure that
324 the Digital volume control is set to a value
325 that does not result in clipping/distortion!)
8b012fc5
B		 326 glb_mclk This option is only with Kali board. If enabled,
327 MCLK for Kali is used and PLL is disabled for
328 better voice quality. (default Off)
56d745a1 329
330
331Name: at86rf233
332Info: Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver,
333 connected to spi0.0
334Load: dtoverlay=at86rf233,<param>=<val>
335Params: interrupt GPIO used for INT (default 23)
336 reset GPIO used for Reset (default 24)
337 sleep GPIO used for Sleep (default 25)
338 speed SPI bus speed in Hz (default 3000000)
339 trim Fine tuning of the internal capacitance
340 arrays (0=+0pF, 15=+4.5pF, default 15)
341
342
13b6aff5
MF		 343Name: audioinjector-addons
344Info: Configures the audioinjector.net audio add on soundcards
345Load: dtoverlay=audioinjector-addons
346Params: <None>
347
348
56d745a1 349Name: audioinjector-wm8731-audio
350Info: Configures the audioinjector.net audio add on soundcard
351Load: dtoverlay=audioinjector-wm8731-audio
352Params: <None>
353
354
355Name: audremap
356Info: Switches PWM sound output to pins 12 (Right) & 13 (Left)
357Load: dtoverlay=audremap,<param>=<val>
358Params: swap_lr Reverse the channel allocation, which will also
359 swap the audio jack outputs (default off)
360 enable_jack Don't switch off the audio jack output
361 (default off)
362
363
364Name: bmp085_i2c-sensor
365Info: This overlay is now deprecated - see i2c-sensor
366Load: dtoverlay=bmp085_i2c-sensor
367Params: <None>
368
369
370Name: dht11
371Info: Overlay for the DHT11/DHT21/DHT22 humidity/temperature sensors
372 Also sometimes found with the part number(s) AM230x.
373Load: dtoverlay=dht11,<param>=<val>
374Params: gpiopin GPIO connected to the sensor's DATA output.
375 (default 4)
376
377
378Name: dionaudio-loco
379Info: Configures the Dion Audio LOCO DAC-AMP
380Load: dtoverlay=dionaudio-loco
381Params: <None>
382
383
f3c86139
M		 384Name: dionaudio-loco-v2
385Info: Configures the Dion Audio LOCO-V2 DAC-AMP
386Load: dtoverlay=dionaudio-loco-v2,<param>=<val>
387Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
388 Digital volume control. Enable with
389 "dtoverlay=hifiberry-dacplus,24db_digital_gain"
390 (The default behaviour is that the Digital
391 volume control is limited to a maximum of
392 0dB. ie. it can attenuate but not provide
393 gain. For most users, this will be desired
394 as it will prevent clipping. By appending
395 the 24dB_digital_gain parameter, the Digital
396 volume control will allow up to 24dB of
397 gain. If this parameter is enabled, it is the
398 responsibility of the user to ensure that
399 the Digital volume control is set to a value
400 that does not result in clipping/distortion!)
401
402
56d745a1 403Name: dpi18
404Info: Overlay for a generic 18-bit DPI display
405 This uses GPIOs 0-21 (so no I2C, uart etc.), and activates the output
406 2-3 seconds after the kernel has started.
407Load: dtoverlay=dpi18
408Params: <None>
409
410
411Name: dpi24
412Info: Overlay for a generic 24-bit DPI display
413 This uses GPIOs 0-27 (so no I2C, uart etc.), and activates the output
414 2-3 seconds after the kernel has started.
415Load: dtoverlay=dpi24
416Params: <None>
417
418
419Name: dwc-otg
420Info: Selects the dwc_otg USB controller driver which has fiq support. This
421 is the default on all except the Pi Zero which defaults to dwc2.
422Load: dtoverlay=dwc-otg
423Params: <None>
424
425
426Name: dwc2
427Info: Selects the dwc2 USB controller driver
428Load: dtoverlay=dwc2,<param>=<val>
429Params: dr_mode Dual role mode: "host", "peripheral" or "otg"
430
431 g-rx-fifo-size Size of rx fifo size in gadget mode
432
433 g-np-tx-fifo-size Size of non-periodic tx fifo size in gadget
434 mode
435
56d745a1 436
437[ The ds1307-rtc overlay has been deleted. See i2c-rtc. ]
438
439
440Name: enc28j60
441Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI0
442Load: dtoverlay=enc28j60,<param>=<val>
443Params: int_pin GPIO used for INT (default 25)
444
445 speed SPI bus speed (default 12000000)
446
447
448Name: enc28j60-spi2
449Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI2
450Load: dtoverlay=enc28j60-spi2,<param>=<val>
451Params: int_pin GPIO used for INT (default 39)
452
453 speed SPI bus speed (default 12000000)
454
455
24d04290
FP		 456Name: fe-pi-audio
457Info: Configures the Fe-Pi Audio Sound Card
458Load: dtoverlay=fe-pi-audio
459Params: <None>
460
461
c53839f9
PM		 462Name: googlevoicehat-soundcard
463Info: Configures the Google voiceHAT soundcard
464Load: dtoverlay=googlevoicehat-soundcard
465Params: <None>
466
467
56d745a1 468Name: gpio-ir
469Info: Use GPIO pin as rc-core style infrared receiver input. The rc-core-
470 based gpio_ir_recv driver maps received keys directly to a
471 /dev/input/event* device, all decoding is done by the kernel - LIRC is
472 not required! The key mapping and other decoding parameters can be
473 configured by "ir-keytable" tool.
474Load: dtoverlay=gpio-ir,<param>=<val>
475Params: gpio_pin Input pin number. Default is 18.
476
477 gpio_pull Desired pull-up/down state (off, down, up)
478 Default is "down".
479
480 rc-map-name Default rc keymap (can also be changed by
481 ir-keytable), defaults to "rc-rc6-mce"
482
483
484Name: gpio-poweroff
485Info: Drives a GPIO high or low on poweroff (including halt)
486Load: dtoverlay=gpio-poweroff,<param>=<val>
487Params: gpiopin GPIO for signalling (default 26)
488
489 active_low Set if the power control device requires a
490 high->low transition to trigger a power-down.
491 Note that this will require the support of a
492 custom dt-blob.bin to prevent a power-down
493 during the boot process, and that a reboot
494 will also cause the pin to go low.
495
496
497Name: hifiberry-amp
498Info: Configures the HifiBerry Amp and Amp+ audio cards
499Load: dtoverlay=hifiberry-amp
500Params: <None>
501
502
503Name: hifiberry-dac
504Info: Configures the HifiBerry DAC audio card
505Load: dtoverlay=hifiberry-dac
506Params: <None>
507
508
509Name: hifiberry-dacplus
510Info: Configures the HifiBerry DAC+ audio card
511Load: dtoverlay=hifiberry-dacplus,<param>=<val>
512Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
513 Digital volume control. Enable with
514 "dtoverlay=hifiberry-dacplus,24db_digital_gain"
515 (The default behaviour is that the Digital
516 volume control is limited to a maximum of
517 0dB. ie. it can attenuate but not provide
518 gain. For most users, this will be desired
519 as it will prevent clipping. By appending
520 the 24dB_digital_gain parameter, the Digital
521 volume control will allow up to 24dB of
522 gain. If this parameter is enabled, it is the
523 responsibility of the user to ensure that
524 the Digital volume control is set to a value
525 that does not result in clipping/distortion!)
526 slave Force DAC+ Pro into slave mode, using Pi as
527 master for bit clock and frame clock.
528
529
530Name: hifiberry-digi
531Info: Configures the HifiBerry Digi and Digi+ audio card
532Load: dtoverlay=hifiberry-digi
533Params: <None>
534
535
536Name: hifiberry-digi-pro
537Info: Configures the HifiBerry Digi+ Pro audio card
538Load: dtoverlay=hifiberry-digi-pro
539Params: <None>
540
541
542Name: hy28a
543Info: HY28A - 2.8" TFT LCD Display Module by HAOYU Electronics
544 Default values match Texy's display shield
545Load: dtoverlay=hy28a,<param>=<val>
546Params: speed Display SPI bus speed
547
548 rotate Display rotation {0,90,180,270}
549
550 fps Delay between frame updates
551
552 debug Debug output level {0-7}
553
554 xohms Touchpanel sensitivity (X-plate resistance)
555
556 resetgpio GPIO used to reset controller
557
558 ledgpio GPIO used to control backlight
559
560
561Name: hy28b
562Info: HY28B - 2.8" TFT LCD Display Module by HAOYU Electronics
563 Default values match Texy's display shield
564Load: dtoverlay=hy28b,<param>=<val>
565Params: speed Display SPI bus speed
566
567 rotate Display rotation {0,90,180,270}
568
569 fps Delay between frame updates
570
571 debug Debug output level {0-7}
572
573 xohms Touchpanel sensitivity (X-plate resistance)
574
575 resetgpio GPIO used to reset controller
576
577 ledgpio GPIO used to control backlight
578
579
580Name: i2c-bcm2708
581Info: Fall back to the i2c_bcm2708 driver for the i2c_arm bus.
582Load: dtoverlay=i2c-bcm2708
583Params: <None>
584
585
586Name: i2c-gpio
587Info: Adds support for software i2c controller on gpio pins
588Load: dtoverlay=i2c-gpio,<param>=<val>
589Params: i2c_gpio_sda GPIO used for I2C data (default "23")
590
591 i2c_gpio_scl GPIO used for I2C clock (default "24")
592
593 i2c_gpio_delay_us Clock delay in microseconds
594 (default "2" = ~100kHz)
595
596
597Name: i2c-mux
598Info: Adds support for a number of I2C bus multiplexers on i2c_arm
599Load: dtoverlay=i2c-mux,<param>=<val>
600Params: pca9542 Select the NXP PCA9542 device
601
602 pca9545 Select the NXP PCA9545 device
603
604 pca9548 Select the NXP PCA9548 device
605
606 addr Change I2C address of the device (default 0x70)
607
608
609[ The i2c-mux-pca9548a overlay has been deleted. See i2c-mux. ]
610
611
612Name: i2c-pwm-pca9685a
613Info: Adds support for an NXP PCA9685A I2C PWM controller on i2c_arm
614Load: dtoverlay=i2c-pwm-pca9685a,<param>=<val>
615Params: addr I2C address of PCA9685A (default 0x40)
616
617
618Name: i2c-rtc
619Info: Adds support for a number of I2C Real Time Clock devices
620Load: dtoverlay=i2c-rtc,<param>=<val>
621Params: abx80x Select one of the ABx80x family:
622 AB0801, AB0803, AB0804, AB0805,
623 AB1801, AB1803, AB1804, AB1805
624
625 ds1307 Select the DS1307 device
626
627 ds1339 Select the DS1339 device
628
629 ds3231 Select the DS3231 device
630
631 mcp7940x Select the MCP7940x device
632
633 mcp7941x Select the MCP7941x device
634
635 pcf2127 Select the PCF2127 device
636
637 pcf8523 Select the PCF8523 device
638
639 pcf8563 Select the PCF8563 device
640
641 trickle-diode-type Diode type for trickle charge - "standard" or
642 "schottky" (ABx80x only)
643
644 trickle-resistor-ohms Resistor value for trickle charge (DS1339,
645 ABx80x)
646
647 wakeup-source Specify that the RTC can be used as a wakeup
648 source
649
650
651Name: i2c-sensor
652Info: Adds support for a number of I2C barometric pressure and temperature
653 sensors on i2c_arm
654Load: dtoverlay=i2c-sensor,<param>=<val>
655Params: bmp085 Select the Bosch sensortronic BMP085
656
657 bmp280 Select the Bosch sensortronic BMP280
658
d4a2386b
PE		 659 lm75 Select the Maxim LM75 temperature sensor
660
661 lm75addr Choose the address for the LM75 (0x48-0x4f -
662 default 0x4f)
663
1c99d0ed
PE		 664 si7020 Select the Silicon Labs Si7013/20/21 humidity/
665 temperature sensor
666
56d745a1 667
668Name: i2c0-bcm2708
669Info: Enable the i2c_bcm2708 driver for the i2c0 bus. Not all pin combinations
670 are usable on all platforms.
671Load: dtoverlay=i2c0-bcm2708,<param>=<val>
672Params: sda0_pin GPIO pin for SDA0 (deprecated - use pins_*)
673 scl0_pin GPIO pin for SCL0 (deprecated - use pins_*)
674 pins_0_1 Use pins 0 and 1 (default)
675 pins_28_29 Use pins 28 and 29
676 pins_44_45 Use pins 44 and 45
677 pins_46_47 Use pins 46 and 47
678
679
680Name: i2c1-bcm2708
681Info: Enable the i2c_bcm2708 driver for the i2c1 bus
682Load: dtoverlay=i2c1-bcm2708,<param>=<val>
683Params: sda1_pin GPIO pin for SDA1 (2 or 44 - default 2)
684 scl1_pin GPIO pin for SCL1 (3 or 45 - default 3)
685 pin_func Alternative pin function (4 (alt0), 6 (alt2) -
686 default 4)
687
688
689Name: i2s-gpio28-31
690Info: move I2S function block to GPIO 28 to 31
691Load: dtoverlay=i2s-gpio28-31
692Params: <None>
693
694
695Name: iqaudio-dac
696Info: Configures the IQaudio DAC audio card
697Load: dtoverlay=iqaudio-dac,<param>
698Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
699 Digital volume control. Enable with
700 "dtoverlay=iqaudio-dac,24db_digital_gain"
701 (The default behaviour is that the Digital
702 volume control is limited to a maximum of
703 0dB. ie. it can attenuate but not provide
704 gain. For most users, this will be desired
705 as it will prevent clipping. By appending
706 the 24db_digital_gain parameter, the Digital
707 volume control will allow up to 24dB of
708 gain. If this parameter is enabled, it is the
709 responsibility of the user to ensure that
710 the Digital volume control is set to a value
711 that does not result in clipping/distortion!)
712
713
714Name: iqaudio-dacplus
715Info: Configures the IQaudio DAC+ audio card
716Load: dtoverlay=iqaudio-dacplus,<param>=<val>
717Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
718 Digital volume control. Enable with
719 "dtoverlay=iqaudio-dacplus,24db_digital_gain"
720 (The default behaviour is that the Digital
721 volume control is limited to a maximum of
722 0dB. ie. it can attenuate but not provide
723 gain. For most users, this will be desired
724 as it will prevent clipping. By appending
725 the 24db_digital_gain parameter, the Digital
726 volume control will allow up to 24dB of
727 gain. If this parameter is enabled, it is the
728 responsibility of the user to ensure that
729 the Digital volume control is set to a value
730 that does not result in clipping/distortion!)
731 auto_mute_amp If specified, unmute/mute the IQaudIO amp when
732 starting/stopping audio playback.
733 unmute_amp If specified, unmute the IQaudIO amp once when
734 the DAC driver module loads.
735
736
737Name: iqaudio-digi-wm8804-audio
738Info: Configures the IQAudIO Digi WM8804 audio card
739Load: dtoverlay=iqaudio-digi-wm8804-audio,<param>=<val>
740Params: card_name Override the default, "IQAudIODigi", card name.
741 dai_name Override the default, "IQAudIO Digi", dai name.
742 dai_stream_name Override the default, "IQAudIO Digi HiFi",
743 dai stream name.
744
745
746Name: justboom-dac
747Info: Configures the JustBoom DAC HAT, Amp HAT, DAC Zero and Amp Zero audio
748 cards
749Load: dtoverlay=justboom-dac,<param>=<val>
750Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
751 Digital volume control. Enable with
752 "dtoverlay=justboom-dac,24db_digital_gain"
753 (The default behaviour is that the Digital
754 volume control is limited to a maximum of
755 0dB. ie. it can attenuate but not provide
756 gain. For most users, this will be desired
757 as it will prevent clipping. By appending
758 the 24dB_digital_gain parameter, the Digital
759 volume control will allow up to 24dB of
760 gain. If this parameter is enabled, it is the
761 responsibility of the user to ensure that
762 the Digital volume control is set to a value
763 that does not result in clipping/distortion!)
764
765
766Name: justboom-digi
767Info: Configures the JustBoom Digi HAT and Digi Zero audio cards
768Load: dtoverlay=justboom-digi
769Params: <None>
770
771
772Name: lirc-rpi
773Info: Configures lirc-rpi (Linux Infrared Remote Control for Raspberry Pi)
774 Consult the module documentation for more details.
775Load: dtoverlay=lirc-rpi,<param>=<val>
776Params: gpio_out_pin GPIO for output (default "17")
777
778 gpio_in_pin GPIO for input (default "18")
779
780 gpio_in_pull Pull up/down/off on the input pin
781 (default "down")
782
783 sense Override the IR receive auto-detection logic:
784 "0" = force active-high
785 "1" = force active-low
786 "-1" = use auto-detection
787 (default "-1")
788
789 softcarrier Turn the software carrier "on" or "off"
790 (default "on")
791
792 invert "on" = invert the output pin (default "off")
793
794 debug "on" = enable additional debug messages
795 (default "off")
796
797
798Name: mcp23017
799Info: Configures the MCP23017 I2C GPIO expander
800Load: dtoverlay=mcp23017,<param>=<val>
801Params: gpiopin Gpio pin connected to the INTA output of the
802 MCP23017 (default: 4)
803
804 addr I2C address of the MCP23017 (default: 0x20)
805
806
807Name: mcp23s17
808Info: Configures the MCP23S08/17 SPI GPIO expanders.
809 If devices are present on SPI1 or SPI2, those interfaces must be enabled
810 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
811 If interrupts are enabled for a device on a given CS# on a SPI bus, that
812 device must be the only one present on that SPI bus/CS#.
813Load: dtoverlay=mcp23s17,<param>=<val>
814Params: s08-spi<n>-<m>-present 4-bit integer, bitmap indicating MCP23S08
815 devices present on SPI<n>, CS#<m>
816
817 s17-spi<n>-<m>-present 8-bit integer, bitmap indicating MCP23S17
818 devices present on SPI<n>, CS#<m>
819
820 s08-spi<n>-<m>-int-gpio integer, enables interrupts on a single
821 MCP23S08 device on SPI<n>, CS#<m>, specifies
822 the GPIO pin to which INT output of MCP23S08
823 is connected.
824
825 s17-spi<n>-<m>-int-gpio integer, enables mirrored interrupts on a
826 single MCP23S17 device on SPI<n>, CS#<m>,
827 specifies the GPIO pin to which either INTA
828 or INTB output of MCP23S17 is connected.
829
830
831Name: mcp2515-can0
832Info: Configures the MCP2515 CAN controller on spi0.0
833Load: dtoverlay=mcp2515-can0,<param>=<val>
834Params: oscillator Clock frequency for the CAN controller (Hz)
835
836 spimaxfrequency Maximum SPI frequence (Hz)
837
838 interrupt GPIO for interrupt signal
839
840
841Name: mcp2515-can1
842Info: Configures the MCP2515 CAN controller on spi0.1
843Load: dtoverlay=mcp2515-can1,<param>=<val>
844Params: oscillator Clock frequency for the CAN controller (Hz)
845
846 spimaxfrequency Maximum SPI frequence (Hz)
847
848 interrupt GPIO for interrupt signal
849
850
3c179550
SE		 851Name: mcp3008
852Info: Configures MCP3008 A/D converters
853 For devices on spi1 or spi2, the interfaces should be enabled
854 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
855Load: dtoverlay=mcp3008,<param>[=<val>]
856Params: spi<n>-<m>-present boolean, configure device at spi<n>, cs<m>
857 spi<n>-<m>-speed integer, set the spi bus speed for this device
858
859
56d745a1 860Name: midi-uart0
861Info: Configures UART0 (ttyAMA0) so that a requested 38.4kbaud actually gets
862 31.25kbaud, the frequency required for MIDI
863Load: dtoverlay=midi-uart0
864Params: <None>
865
866
867Name: mmc
868Info: Selects the bcm2835-mmc SD/MMC driver, optionally with overclock
869Load: dtoverlay=mmc,<param>=<val>
870Params: overclock_50 Clock (in MHz) to use when the MMC framework
871 requests 50MHz
872
873
874Name: mz61581
875Info: MZ61581 display by Tontec
876Load: dtoverlay=mz61581,<param>=<val>
877Params: speed Display SPI bus speed
878
879 rotate Display rotation {0,90,180,270}
880
881 fps Delay between frame updates
882
883 txbuflen Transmit buffer length (default 32768)
884
885 debug Debug output level {0-7}
886
887 xohms Touchpanel sensitivity (X-plate resistance)
888
889
890[ The pcf2127-rtc overlay has been deleted. See i2c-rtc. ]
891
892
893[ The pcf8523-rtc overlay has been deleted. See i2c-rtc. ]
894
895
896[ The pcf8563-rtc overlay has been deleted. See i2c-rtc. ]
897
898
899Name: pi3-act-led
900Info: Pi3 uses a GPIO expander to drive the LEDs which can only be accessed
901 from the VPU. There is a special driver for this with a separate DT
902 node, which has the unfortunate consequence of breaking the
903 act_led_gpio and act_led_activelow dtparams.
904 This overlay changes the GPIO controller back to the standard one and
905 restores the dtparams.
906Load: dtoverlay=pi3-act-led,<param>=<val>
907Params: activelow Set to "on" to invert the sense of the LED
908 (default "off")
909
910 gpio Set which GPIO to use for the activity LED
911 (in case you want to connect it to an external
912 device)
913 REQUIRED
914
915
916Name: pi3-disable-bt
917Info: Disable Pi3 Bluetooth and restore UART0/ttyAMA0 over GPIOs 14 & 15
918 N.B. To disable the systemd service that initialises the modem so it
919 doesn't use the UART, use 'sudo systemctl disable hciuart'.
920Load: dtoverlay=pi3-disable-bt
921Params: <None>
922
923
2f26294a
PE		 924Name: pi3-disable-wifi
925Info: Disable Pi3 onboard WiFi
926Load: dtoverlay=pi3-disable-wifi
927Params: <None>
928
929
56d745a1 930Name: pi3-miniuart-bt
931Info: Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
932 UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum
933 usable baudrate.
934 N.B. It is also necessary to edit /lib/systemd/system/hciuart.service
935 and replace ttyAMA0 with ttyS0, unless you have a system with udev rules
936 that create /dev/serial0 and /dev/serial1, in which case use
937 /dev/serial1 instead because it will always be correct. Furthermore,
938 you must also set core_freq=250 in config.txt or the miniuart will not
939 work.
940Load: dtoverlay=pi3-miniuart-bt
941Params: <None>
942
943
944Name: piscreen
945Info: PiScreen display by OzzMaker.com
946Load: dtoverlay=piscreen,<param>=<val>
947Params: speed Display SPI bus speed
948
949 rotate Display rotation {0,90,180,270}
950
951 fps Delay between frame updates
952
953 debug Debug output level {0-7}
954
955 xohms Touchpanel sensitivity (X-plate resistance)
956
957
958Name: piscreen2r
959Info: PiScreen 2 with resistive TP display by OzzMaker.com
960Load: dtoverlay=piscreen2r,<param>=<val>
961Params: speed Display SPI bus speed
962
963 rotate Display rotation {0,90,180,270}
964
965 fps Delay between frame updates
966
967 debug Debug output level {0-7}
968
969 xohms Touchpanel sensitivity (X-plate resistance)
970
971
972Name: pisound
973Info: Configures the Blokas Labs pisound card
974Load: dtoverlay=pisound
975Params: <None>
976
977
978Name: pitft22
979Info: Adafruit PiTFT 2.2" screen
980Load: dtoverlay=pitft22,<param>=<val>
981Params: speed Display SPI bus speed
982
983 rotate Display rotation {0,90,180,270}
984
985 fps Delay between frame updates
986
987 debug Debug output level {0-7}
988
989
990Name: pitft28-capacitive
991Info: Adafruit PiTFT 2.8" capacitive touch screen
992Load: dtoverlay=pitft28-capacitive,<param>=<val>
993Params: speed Display SPI bus speed
994
995 rotate Display rotation {0,90,180,270}
996
997 fps Delay between frame updates
998
999 debug Debug output level {0-7}
1000
1001 touch-sizex Touchscreen size x (default 240)
1002
1003 touch-sizey Touchscreen size y (default 320)
1004
1005 touch-invx Touchscreen inverted x axis
1006
1007 touch-invy Touchscreen inverted y axis
1008
1009 touch-swapxy Touchscreen swapped x y axis
1010
1011
1012Name: pitft28-resistive
1013Info: Adafruit PiTFT 2.8" resistive touch screen
1014Load: dtoverlay=pitft28-resistive,<param>=<val>
1015Params: speed Display SPI bus speed
1016
1017 rotate Display rotation {0,90,180,270}
1018
1019 fps Delay between frame updates
1020
1021 debug Debug output level {0-7}
1022
1023
1024Name: pitft35-resistive
1025Info: Adafruit PiTFT 3.5" resistive touch screen
1026Load: dtoverlay=pitft35-resistive,<param>=<val>
1027Params: speed Display SPI bus speed
1028
1029 rotate Display rotation {0,90,180,270}
1030
1031 fps Delay between frame updates
1032
1033 debug Debug output level {0-7}
1034
1035
1036Name: pps-gpio
1037Info: Configures the pps-gpio (pulse-per-second time signal via GPIO).
1038Load: dtoverlay=pps-gpio,<param>=<val>
1039Params: gpiopin Input GPIO (default "18")
1040 assert_falling_edge When present, assert is indicated by a falling
1041 edge, rather than by a rising edge
1042
1043
1044Name: pwm
1045Info: Configures a single PWM channel
1046 Legal pin,function combinations for each channel:
1047 PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
1048 PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
1049 N.B.:
1050 1) Pin 18 is the only one available on all platforms, and
1051 it is the one used by the I2S audio interface.
1052 Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
1053 2) The onboard analogue audio output uses both PWM channels.
1054 3) So be careful mixing audio and PWM.
1055 4) Currently the clock must have been enabled and configured
1056 by other means.
1057Load: dtoverlay=pwm,<param>=<val>
1058Params: pin Output pin (default 18) - see table
1059 func Pin function (default 2 = Alt5) - see above
1060 clock PWM clock frequency (informational)
1061
1062
1063Name: pwm-2chan
1064Info: Configures both PWM channels
1065 Legal pin,function combinations for each channel:
1066 PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
1067 PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
1068 N.B.:
1069 1) Pin 18 is the only one available on all platforms, and
1070 it is the one used by the I2S audio interface.
1071 Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
1072 2) The onboard analogue audio output uses both PWM channels.
1073 3) So be careful mixing audio and PWM.
1074 4) Currently the clock must have been enabled and configured
1075 by other means.
1076Load: dtoverlay=pwm-2chan,<param>=<val>
1077Params: pin Output pin (default 18) - see table
1078 pin2 Output pin for other channel (default 19)
1079 func Pin function (default 2 = Alt5) - see above
1080 func2 Function for pin2 (default 2 = Alt5)
1081 clock PWM clock frequency (informational)
1082
1083
1084Name: qca7000
1085Info: I2SE's Evaluation Board for PLC Stamp micro
1086Load: dtoverlay=qca7000,<param>=<val>
1087Params: int_pin GPIO pin for interrupt signal (default 23)
1088
1089 speed SPI bus speed (default 12 MHz)
1090
1091
1092Name: raspidac3
1093Info: Configures the RaspiDAV Rev.3x audio card
1094Load: dtoverlay=raspidac3
1095Params: <None>
1096
1097
1098Name: rpi-backlight
1099Info: Raspberry Pi official display backlight driver
1100Load: dtoverlay=rpi-backlight
1101Params: <None>
1102
1103
2327debb
MR		 1104Name: rpi-cirrus-wm5102
1105Info: Configures the Cirrus Logic Audio Card
1106Load: dtoverlay=rpi-cirrus-wm5102
1107Params: <None>
1108
1109
56d745a1 1110Name: rpi-dac
1111Info: Configures the RPi DAC audio card
1112Load: dtoverlay=rpi-dac
1113Params: <None>
1114
1115
1116Name: rpi-display
1117Info: RPi-Display - 2.8" Touch Display by Watterott
1118Load: dtoverlay=rpi-display,<param>=<val>
1119Params: speed Display SPI bus speed
1120 rotate Display rotation {0,90,180,270}
1121 fps Delay between frame updates
1122 debug Debug output level {0-7}
1123 xohms Touchpanel sensitivity (X-plate resistance)
1124 swapxy Swap x and y axis
1125
1126
1127Name: rpi-ft5406
1128Info: Official Raspberry Pi display touchscreen
1129Load: dtoverlay=rpi-ft5406
1130Params: <None>
1131
1132
1133Name: rpi-proto
1134Info: Configures the RPi Proto audio card
1135Load: dtoverlay=rpi-proto
1136Params: <None>
1137
1138
1139Name: rpi-sense
1140Info: Raspberry Pi Sense HAT
1141Load: dtoverlay=rpi-sense
1142Params: <None>
1143
1144
1145Name: rra-digidac1-wm8741-audio
1146Info: Configures the Red Rocks Audio DigiDAC1 soundcard
1147Load: dtoverlay=rra-digidac1-wm8741-audio
1148Params: <None>
1149
1150
1151Name: sc16is750-i2c
1152Info: Overlay for the NXP SC16IS750 UART with I2C Interface
1153 Enables the chip on I2C1 at 0x48. To select another address,
1154 please refer to table 10 in reference manual.
1155
1156Load: dtoverlay=sc16is750-i2c,<param>=<val>
1157Params: int_pin GPIO used for IRQ (default 24)
1158 addr Address (default 0x48)
1159
1160
1161Name: sc16is752-spi1
1162Info: Overlay for the NXP SC16IS752 Dual UART with SPI Interface
1163 Enables the chip on SPI1.
1164 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
1165 A+, B+, Zero and PI2 B; as well as the Compute Module.
1166
1167Load: dtoverlay=sc16is752-spi1,<param>=<val>
1168Params: int_pin GPIO used for IRQ (default 24)
1169
1170
1171Name: sdhost
1172Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock.
1173 N.B. This overlay is designed for situations where the mmc driver is
1174 the default, so it disables the other (mmc) interface - this will kill
1175 WiFi on a Pi3. If this isn't what you want, either use the sdtweak
1176 overlay or the new sd_* dtparams of the base DTBs.
1177Load: dtoverlay=sdhost,<param>=<val>
1178Params: overclock_50 Clock (in MHz) to use when the MMC framework
1179 requests 50MHz
1180
1181 force_pio Disable DMA support (default off)
1182
1183 pio_limit Number of blocks above which to use DMA
1184 (default 1)
1185
1186 debug Enable debug output (default off)
1187
1188
1189Name: sdio
1190Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
1191 and enables SDIO via GPIOs 22-27.
1192Load: dtoverlay=sdio,<param>=<val>
1193Params: overclock_50 SD Clock (in MHz) to use when the MMC framework
1194 requests 50MHz
1195
1196 sdio_overclock SDIO Clock (in MHz) to use when the MMC
1197 framework requests 50MHz
1198
1199 force_pio Disable DMA support (default off)
1200
1201 pio_limit Number of blocks above which to use DMA
1202 (default 1)
1203
1204 debug Enable debug output (default off)
1205
1206 poll_once Disable SDIO-device polling every second
1207 (default on: polling once at boot-time)
1208
1209 bus_width Set the SDIO host bus width (default 4 bits)
1210
1211
1212Name: sdio-1bit
1213Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
1214 and enables 1-bit SDIO via GPIOs 22-25.
1215Load: dtoverlay=sdio-1bit,<param>=<val>
1216Params: overclock_50 SD Clock (in MHz) to use when the MMC framework
1217 requests 50MHz
1218
1219 sdio_overclock SDIO Clock (in MHz) to use when the MMC
1220 framework requests 50MHz
1221
1222 force_pio Disable DMA support (default off)
1223
1224 pio_limit Number of blocks above which to use DMA
1225 (default 1)
1226
1227 debug Enable debug output (default off)
1228
1229 poll_once Disable SDIO-device polling every second
1230 (default on: polling once at boot-time)
1231
1232
1233Name: sdtweak
1234Info: Tunes the bcm2835-sdhost SD/MMC driver
1235 N.B. This functionality is now available via the sd_* dtparams in the
1236 base DTB.
1237Load: dtoverlay=sdtweak,<param>=<val>
1238Params: overclock_50 Clock (in MHz) to use when the MMC framework
1239 requests 50MHz
1240
1241 force_pio Disable DMA support (default off)
1242
1243 pio_limit Number of blocks above which to use DMA
1244 (default 1)
1245
1246 debug Enable debug output (default off)
1247
1248
1249Name: smi
1250Info: Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
1251Load: dtoverlay=smi
1252Params: <None>
1253
1254
1255Name: smi-dev
1256Info: Enables the userspace interface for the SMI driver
1257Load: dtoverlay=smi-dev
1258Params: <None>
1259
1260
1261Name: smi-nand
1262Info: Enables access to NAND flash via the SMI interface
1263Load: dtoverlay=smi-nand
1264Params: <None>
1265
1266
1267Name: spi-gpio35-39
74fc9f5f 1268Info: Move SPI function block to GPIO 35 to 39
56d745a1 1269Load: dtoverlay=spi-gpio35-39
1270Params: <None>
1271
1272
1273Name: spi-rtc
1274Info: Adds support for a number of SPI Real Time Clock devices
1275Load: dtoverlay=spi-rtc,<param>=<val>
1276Params: pcf2123 Select the PCF2123 device
1277
1278
74fc9f5f
PE		 1279Name: spi0-cs
1280Info: Allows the (software) CS pins for SPI0 to be changed
1281Load: dtoverlay=spi0-cs,<param>=<val>
1282Params: cs0_pin GPIO pin for CS0 (default 8)
1283 cs1_pin GPIO pin for CS1 (default 7)
1284
1285
56d745a1 1286Name: spi0-hw-cs
1287Info: Re-enables hardware CS/CE (chip selects) for SPI0
1288Load: dtoverlay=spi0-hw-cs
1289Params: <None>
1290
1291
1292Name: spi1-1cs
1293Info: Enables spi1 with a single chip select (CS) line and associated spidev
1294 dev node. The gpio pin number for the CS line and spidev device node
1295 creation are configurable.
1296 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
1297 A+, B+, Zero and PI2 B; as well as the Compute Module.
1298Load: dtoverlay=spi1-1cs,<param>=<val>
1299Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
1300 cs0_spidev Set to 'disabled' to stop the creation of a
1301 userspace device node /dev/spidev1.0 (default
1302 is 'okay' or enabled).
1303
1304
1305Name: spi1-2cs
1306Info: Enables spi1 with two chip select (CS) lines and associated spidev
1307 dev nodes. The gpio pin numbers for the CS lines and spidev device node
1308 creation are configurable.
1309 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
1310 A+, B+, Zero and PI2 B; as well as the Compute Module.
1311Load: dtoverlay=spi1-2cs,<param>=<val>
1312Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
1313 cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
1314 cs0_spidev Set to 'disabled' to stop the creation of a
1315 userspace device node /dev/spidev1.0 (default
1316 is 'okay' or enabled).
1317 cs1_spidev Set to 'disabled' to stop the creation of a
1318 userspace device node /dev/spidev1.1 (default
1319 is 'okay' or enabled).
1320
1321
1322Name: spi1-3cs
1323Info: Enables spi1 with three chip select (CS) lines and associated spidev
1324 dev nodes. The gpio pin numbers for the CS lines and spidev device node
1325 creation are configurable.
1326 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
1327 A+, B+, Zero and PI2 B; as well as the Compute Module.
1328Load: dtoverlay=spi1-3cs,<param>=<val>
1329Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
1330 cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
1331 cs2_pin GPIO pin for CS2 (default 16 - BCM SPI1_CE2).
1332 cs0_spidev Set to 'disabled' to stop the creation of a
1333 userspace device node /dev/spidev1.0 (default
1334 is 'okay' or enabled).
1335 cs1_spidev Set to 'disabled' to stop the creation of a
1336 userspace device node /dev/spidev1.1 (default
1337 is 'okay' or enabled).
1338 cs2_spidev Set to 'disabled' to stop the creation of a
1339 userspace device node /dev/spidev1.2 (default
1340 is 'okay' or enabled).
1341
1342
1343Name: spi2-1cs
1344Info: Enables spi2 with a single chip select (CS) line and associated spidev
1345 dev node. The gpio pin number for the CS line and spidev device node
1346 creation are configurable.
1347 N.B.: spi2 is only accessible with the Compute Module.
1348Load: dtoverlay=spi2-1cs,<param>=<val>
1349Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
1350 cs0_spidev Set to 'disabled' to stop the creation of a
1351 userspace device node /dev/spidev2.0 (default
1352 is 'okay' or enabled).
1353
1354
1355Name: spi2-2cs
1356Info: Enables spi2 with two chip select (CS) lines and associated spidev
1357 dev nodes. The gpio pin numbers for the CS lines and spidev device node
1358 creation are configurable.
1359 N.B.: spi2 is only accessible with the Compute Module.
1360Load: dtoverlay=spi2-2cs,<param>=<val>
1361Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
1362 cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
1363 cs0_spidev Set to 'disabled' to stop the creation of a
1364 userspace device node /dev/spidev2.0 (default
1365 is 'okay' or enabled).
1366 cs1_spidev Set to 'disabled' to stop the creation of a
1367 userspace device node /dev/spidev2.1 (default
1368 is 'okay' or enabled).
1369
1370
1371Name: spi2-3cs
1372Info: Enables spi2 with three chip select (CS) lines and associated spidev
1373 dev nodes. The gpio pin numbers for the CS lines and spidev device node
1374 creation are configurable.
1375 N.B.: spi2 is only accessible with the Compute Module.
1376Load: dtoverlay=spi2-3cs,<param>=<val>
1377Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
1378 cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
1379 cs2_pin GPIO pin for CS2 (default 45 - BCM SPI2_CE2).
1380 cs0_spidev Set to 'disabled' to stop the creation of a
1381 userspace device node /dev/spidev2.0 (default
1382 is 'okay' or enabled).
1383 cs1_spidev Set to 'disabled' to stop the creation of a
1384 userspace device node /dev/spidev2.1 (default
1385 is 'okay' or enabled).
1386 cs2_spidev Set to 'disabled' to stop the creation of a
1387 userspace device node /dev/spidev2.2 (default
1388 is 'okay' or enabled).
1389
1390
1391Name: tinylcd35
1392Info: 3.5" Color TFT Display by www.tinylcd.com
1393 Options: Touch, RTC, keypad
1394Load: dtoverlay=tinylcd35,<param>=<val>
1395Params: speed Display SPI bus speed
1396
1397 rotate Display rotation {0,90,180,270}
1398
1399 fps Delay between frame updates
1400
1401 debug Debug output level {0-7}
1402
1403 touch Enable touch panel
1404
1405 touchgpio Touch controller IRQ GPIO
1406
1407 xohms Touchpanel: Resistance of X-plate in ohms
1408
1409 rtc-pcf PCF8563 Real Time Clock
1410
1411 rtc-ds DS1307 Real Time Clock
1412
1413 keypad Enable keypad
1414
1415 Examples:
1416 Display with touchpanel, PCF8563 RTC and keypad:
1417 dtoverlay=tinylcd35,touch,rtc-pcf,keypad
1418 Old touch display:
1419 dtoverlay=tinylcd35,touch,touchgpio=3
1420
1421
1422Name: uart1
1423Info: Enable uart1 in place of uart0
1424Load: dtoverlay=uart1,<param>=<val>
1425Params: txd1_pin GPIO pin for TXD1 (14, 32 or 40 - default 14)
1426
1427 rxd1_pin GPIO pin for RXD1 (15, 33 or 41 - default 15)
1428
1429
1430Name: vc4-fkms-v3d
1431Info: Enable Eric Anholt's DRM VC4 V3D driver on top of the dispmanx
1432 display stack.
1433Load: dtoverlay=vc4-fkms-v3d,<param>
1434Params: cma-256 CMA is 256MB, 256MB-aligned (needs 1GB)
1435 cma-192 CMA is 192MB, 256MB-aligned (needs 1GB)
1436 cma-128 CMA is 128MB, 128MB-aligned
1437 cma-96 CMA is 96MB, 128MB-aligned
1438 cma-64 CMA is 64MB, 64MB-aligned
1439
1440
1441Name: vc4-kms-v3d
1442Info: Enable Eric Anholt's DRM VC4 HDMI/HVS/V3D driver. Running startx or
1443 booting to GUI while this overlay is in use will cause interesting
1444 lockups.
1445Load: dtoverlay=vc4-kms-v3d,<param>
1446Params: cma-256 CMA is 256MB, 256MB-aligned (needs 1GB)
1447 cma-192 CMA is 192MB, 256MB-aligned (needs 1GB)
1448 cma-128 CMA is 128MB, 128MB-aligned
1449 cma-96 CMA is 96MB, 128MB-aligned
1450 cma-64 CMA is 64MB, 64MB-aligned
1451
1452
1453Name: vga666
1454Info: Overlay for the Fen Logic VGA666 board
1455 This uses GPIOs 2-21 (so no I2C), and activates the output 2-3 seconds
1456 after the kernel has started.
1457Load: dtoverlay=vga666
1458Params: <None>
1459
1460
1461Name: w1-gpio
1462Info: Configures the w1-gpio Onewire interface module.
1463 Use this overlay if you *don't* need a GPIO to drive an external pullup.
1464Load: dtoverlay=w1-gpio,<param>=<val>
1465Params: gpiopin GPIO for I/O (default "4")
1466
1467 pullup Non-zero, "on", or "y" to enable the parasitic
1468 power (2-wire, power-on-data) feature
1469
1470
1471Name: w1-gpio-pullup
1472Info: Configures the w1-gpio Onewire interface module.
1473 Use this overlay if you *do* need a GPIO to drive an external pullup.
1474Load: dtoverlay=w1-gpio-pullup,<param>=<val>
1475Params: gpiopin GPIO for I/O (default "4")
1476
1477 pullup Non-zero, "on", or "y" to enable the parasitic
1478 power (2-wire, power-on-data) feature
1479
1480 extpullup GPIO for external pullup (default "5")
1481
1482
1483Name: wittypi
1484Info: Configures the wittypi RTC module.
1485Load: dtoverlay=wittypi,<param>=<val>
1486Params: led_gpio GPIO for LED (default "17")
1487 led_trigger Choose which activity the LED tracks (default
1488 "default-on")
1489
1490
1491Troubleshooting
1492===============
1493
1494If you are experiencing problems that you think are DT-related, enable DT
1495diagnostic output by adding this to /boot/config.txt:
1496
1497 dtdebug=on
1498
1499and rebooting. Then run:
1500
1501 sudo vcdbg log msg
1502
1503and look for relevant messages.
1504
1505Further reading
1506===============
1507
1508This is only meant to be a quick introduction to the subject of Device Tree on
1509Raspberry Pi. There is a more complete explanation here:
1510
1511http://www.raspberrypi.org/documentation/configuration/device-tree.md
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