Part Number: AM4378
Hello,
I'm developing a product using custom am437x board. (Based on am437x-gp-evm)
It almost done but the LCD and LCD backlight don't work.
When I measure the backlight pin with an oscilloscope, it outputs a constant 3.6V high level instead of a PWM signal.
But, The '/sys/class/backlight/backlight' directory contains files such as 'max_brightness' and 'brightness'.
The LCD also does not work.
Below is dts file I write.
// dts //////////////////////////////
/dts-v1/;
#include "am4372.dtsi"
#include <dt-bindings/pinctrl/am43xx.h>
#include <dt-bindings/pwm/pwm.h>
#include <dt-bindings/gpio/gpio.h>
/ {
model = "TI AM437x UPE1";
compatible = "ti,am437x-upe1","ti,am4372","ti,am43";
chosen {
stdout-path = &uart0;
};
aliases {
display0 = &lcd0;
};
evm_v3_3d: fixedregulator-v3_3d {
compatible = "regulator-fixed";
regulator-name = "evm_v3_3d";
regulator-min-microvolt = <3300000>;
regulator-max-microvolt = <3300000>;
enable-active-high;
};
/* TPS51200 */
vtt_fixed: fixedregulator-vtt {
compatible = "regulator-fixed";
regulator-name = "vtt_fixed";
regulator-min-microvolt = <3300000>;
regulator-max-microvolt = <3300000>;
regulator-always-on;
regulator-boot-on;
/*enable-active-high;*/
/*gpio = <&gpio5 7 GPIO_ACTIVE_HIGH>;*/
};
/* Gpio leds */
gpio-leds {
compatible = "gpio-leds";
status_led0 {
label = "status_led0";
gpios = <&gpio1 24 GPIO_ACTIVE_LOW>;
linux,default-trigger = "heartbeat";
};
};
/* LCD Backlight */
lcd_bl: backlight {
compatible = "pwm-backlight";
//50000 => 20kHz
pwms = <&ecap0 0 50000 PWM_POLARITY_INVERTED>;
brightness-levels = <10 35 70 105 140 175 210 245 255>;
default-brightness-level = <3>;
};
/* 1280x800 LCD */
lcd0: display {
compatible = "panel-dpi";
label = "lcd";
backlight = <&lcd_bl>;
panel-timing {
clock-frequency = <70946400>;
hactive = <1280>;
vactive = <800>;
hfront-porch = <52>;
hsync-len = <58>;
hback-porch = <52>;
vfront-porch = <6>;
vsync-len = <10>;
vback-porch = <6>;
hsync-active = <1>;
vsync-active = <1>;
de-active = <1>;
pixelclk-active = <1>;
};
port {
lcd_in: endpoint {
remote-endpoint = <&dpi_out>;
};
};
};
cpus {
cpu@0 {
cpu0-supply = <&dcdc2>;
};
};
};
&am43xx_pinmux {
pinctrl-names = "default";
/* I2C0: PMIC, EEPROM */
i2c0_pins: i2c0_pins {
pinctrl-single,pins = <
AM4372_IOPAD(0x98c, PIN_INPUT_PULLUP | SLEWCTRL_FAST | MUX_MODE0) /* i2c0_sda */
AM4372_IOPAD(0x988, PIN_INPUT_PULLUP | SLEWCTRL_FAST | MUX_MODE0) /* i2c0_scl */
>;
};
.
.
.
/* LCD */
dss_pins: dss_pins {
pinctrl-single,pins = <
AM4372_IOPAD(0x820, PIN_OUTPUT_PULLUP | MUX_MODE1) /*gpmc ad 8 -> DSS DATA 23 */
AM4372_IOPAD(0x824, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x828, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x82c, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x830, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x834, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x838, PIN_OUTPUT_PULLUP | MUX_MODE1)
AM4372_IOPAD(0x83c, PIN_OUTPUT_PULLUP | MUX_MODE1) /*gpmc ad 15 -> DSS DATA 16 */
AM4372_IOPAD(0x8a0, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS DATA 0 */
AM4372_IOPAD(0x8a4, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8a8, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8ac, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8b0, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8b4, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8b8, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8bc, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8c0, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8c4, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8c8, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8cc, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8d0, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8d4, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8d8, PIN_OUTPUT_PULLUP | MUX_MODE0)
AM4372_IOPAD(0x8dc, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS DATA 15 */
AM4372_IOPAD(0x8e0, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS VSYNC */
AM4372_IOPAD(0x8e4, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS HSYNC */
AM4372_IOPAD(0x8e8, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS PCLK */
AM4372_IOPAD(0x8ec, PIN_OUTPUT_PULLUP | MUX_MODE0) /* DSS AC BIAS EN */
>;
};
ecap0_pins: backlight_pins {
pinctrl-single,pins = <
AM4372_IOPAD(0x964, PIN_OUTPUT | MUX_MODE0)
>;
};
};
&i2c0 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&i2c0_pins>;
clock-frequency = <100000>;
tps65218: tps65218@24 {
reg = <0x24>;
compatible = "ti,tps65218";
interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>; /* NMIn */
interrupt-parent = <&gic>;
interrupt-controller;
#interrupt-cells = <2>;
dcdc1: regulator-dcdc1 {
compatible = "ti,tps65218-dcdc1";
regulator-name = "vdd_core";
regulator-min-microvolt = <912000>;
regulator-max-microvolt = <1144000>;
regulator-boot-on;
regulator-always-on;
};
.
.
.
};
.
.
.
&epwmss0 {
status = "okay";
};
&ecap0 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&ecap0_pins>;
//pwm-cells = <3>;
};
&dss {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&dss_pins>;
port {
dpi_out: endpoint@0 {
remote-endpoint = <&lcd_in>;
data-lines = <24>;
};
};
};
////////////Could the issue be related to the device driver or Linux kernel configuration rather than the DTS file?
Please help.
