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Last active January 8, 2023 16:59
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src/arm/BB-SPIDEV1-00A0.dts modify to add tinydrm st7735r for Adafruit 1.8" TFT LCD connected to BeagleBone Black running 4.16.0-rc2-bone3 kernel. More info: https://groups.google.com/d/msg/beagleboard/GuMQIP_XCW0/b3lxbx_8AwAJ
/*
* Copyright (C) 2013 CircuitCo
*
* Virtual cape for SPI1 on connector pins P9.29 P9.31 P9.30 P9.28
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <dt-bindings/pinctrl/am33xx.h>
/dts-v1/;
/plugin/;
/ {
compatible = "ti,beaglebone", "ti,beaglebone-black", "ti,beaglebone-green";
/* identification */
part-number = "BB-SPIDEV1";
version = "00A0";
/* state the resources this cape uses */
exclusive-use =
/* the pin header uses */
"P9.31", /* spi1_sclk */
"P9.29", /* spi1_d0 */
"P9.30", /* spi1_d1 */
"P9.28", /* spi1_cs0 */
// "P9.42", /* spi1_cs1 */
/* the hardware ip uses */
"spi1";
fragment@0 {
target = <&am33xx_pinmux>;
__overlay__ {
/* default state has all gpios released and mode set to uart1 */
bb_spi1_pins: pinmux_bb_spi1_pins {
pinctrl-single,pins = <
0x190 0x33 /* mcasp0_aclkx.spi1_sclk, INPUT_PULLUP | MODE3 */
0x194 0x33 /* mcasp0_fsx.spi1_d0, INPUT_PULLUP | MODE3 */
0x198 0x13 /* mcasp0_axr0.spi1_d1, OUTPUT_PULLUP | MODE3 */
0x19c 0x13 /* mcasp0_ahclkr.spi1_cs0, OUTPUT_PULLUP | MODE3 */
// 0x164 0x12 /* eCAP0_in_PWM0_out.spi1_cs1 OUTPUT_PULLUP | MODE2 */
>;
};
};
};
fragment@1 {
target = <&spi1>;
__overlay__ {
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&bb_spi1_pins>;
ti,pio-mode; /* disable dma when used as an overlay, dma gets stuck at 160 bits... */
/*channel@0 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "spidev";
reg = <0>;
spi-max-frequency = <16000000>;
spi-cpha;
};
channel@1 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "spidev";
reg = <1>;
spi-max-frequency = <16000000>;
};*/
display@0{
status = "okay";
compatible = "jianda,jd-t18003-t01", "sitronix,st7735r";
reg = <0>;
spi-max-frequency = <16000000>;
/* https://elinux.org/Beagleboard:Cape_Expansion_Headers */
dc-gpios = <&gpio1 16 0>; /* dc:48 P9.15 GPIO1_16 */
reset-gpios = <&gpio1 28 0>; /* reset:60 P9.12 GPIO1_28 */
/* rotation = <270>; */
};
};
};
};
@pdp7
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pdp7 commented Feb 22, 2018

debian@beaglebone:~/libdrm/tests/modetest$ ./modetest -M st7735r |head
Encoders:
id	crtc	type	possible crtcs	possible clones	
31	30	none	0x00000001	0x00000000

Connectors:
id	encoder	status		name		size (mm)	modes	encoders
28	31	connected	Virtual-1      	35x28		1	31
  modes:
	name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
  160x128 0 160 160 160 160 128 128 128 128 1 flags: ; type: preferred, driver

debian@beaglebone:~/libdrm/tests/modetest$ sudo ./modetest -M st7735r -s 28:160x128 
setting mode 160x128-0Hz@XR24 on connectors 28, crtc 30

debian@beaglebone:~/libdrm/tests/modetest$ find |grep modetest^C
debian@beaglebone:~/libdrm/tests/modetest$ sudo ./modetest -M st7735r -s 28:160x128 -v
setting mode 160x128-0Hz@XR24 on connectors 28, crtc 30
freq: 37.50Hz
freq: 37.43Hz

For anyone interested, here is a discussion thread about using this Adafruit 1.8" TFT LCD with tinydrm on BeagleBone.

@pdp7
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pdp7 commented Feb 25, 2018

PWM backlight example in BB-BONE-4D4C-01-00A1.dts:

        fragment@1 {
                target = <&am33xx_pinmux>;
                __overlay__ {

                        bb_lcd_pwm_backlight_pins: pinmux_bb_lcd_pwm_backlight_pins {
                                pinctrl-single,pins = <
                                        BONE_P9_14 0x06 /* gpmc_a2.ehrpwm1a, OMAP_MUX_MODE6 | AM33XX_PIN_OUTPUT */
                                >;
                        };
        fragment@6 {
                target-path="/";
                __overlay__ {

                        /* avoid stupid warning */
                        #address-cells = <1>;
                        #size-cells = <1>;

                        backlight {
                                status = "okay";
                                compatible = "pwm-backlight";
                                pwms = <&ehrpwm1 0 500000 0>;
                                brightness-levels = <
                                        0  1  2  3  4  5  6  7  8  9
                                        10 11 12 13 14 15 16 17 18 19
                                        20 21 22 23 24 25 26 27 28 29
                                        30 31 32 33 34 35 36 37 38 39
                                        40 41 42 43 44 45 46 47 48 49
                                        50 51 52 53 54 55 56 57 58 59
                                        60 61 62 63 64 65 66 67 68 69
                                        70 71 72 73 74 75 76 77 78 79
                                        80 81 82 83 84 85 86 87 88 89
                                        90 91 92 93 94 95 96 97 98 99
                                        100
                                >;
                                default-brightness-level = <100>;
                        };

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