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BB-LCD-ADAFRUIT-18-SPI1: add pwm backlight on P9.14 #75

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merged 1 commit into from
Mar 22, 2018
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BB-LCD-ADAFRUIT-18-SPI1: add pwm backlight on P9.14 #75

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95 changes: 78 additions & 17 deletions src/arm/BB-LCD-ADAFRUIT-18-SPI1-00A0.dts
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Original file line number Diff line number Diff line change
Expand Up @@ -21,8 +21,9 @@
* It should be connected to BeagleBone SPI1 bus:
*
* P9.12 <--> reset
* P9.14 <--> lite (pwm) [OPTIONAL]
* P9.15 <--> dc
* P9.23 <--> lite (OPTIONAL)
* P9.23 <--> lite (gpio) [OPTIONAL]
* P9.28 <--> tft_cs
* P9.30 <--> mosi
* P9.31 <--> clk
Expand Down Expand Up @@ -51,31 +52,21 @@

#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/pinctrl/am33xx.h>
#include <dt-bindings/board/am335x-bbw-bbb-base.h>

/dts-v1/;
/plugin/;

/ {
fragment@0 {
target-path = "/";
__overlay__ {
/* backlight is optional */
backlight_gpio: backlight_gpio {
compatible = "gpio-backlight";
gpios = <&gpio1 17 GPIO_ACTIVE_HIGH>;
// connect lcd lite pin to P9.23 which is gpio1[17]
// refer to https://elinux.org/Beagleboard:Cape_Expansion_Headers
};
};
};

/*
* Free up the pins used by the cape from the pinmux helpers.
*/
fragment@1 {
fragment@0 {
target = <&ocp>;
__overlay__ {
P9_12_pinmux { status = "disabled"; }; /* lcd reset */
P9_14_pinmux { status = "disabled"; }; /* lcd pwm backlight (OPTIONAL) */
P9_15_pinmux { status = "disabled"; }; /* lcd dc */
P9_23_pinmux { status = "disabled"; }; /* lcd gpio backlight (OPTIONAL) */
P9_28_pinmux { status = "disabled"; }; /* spi1_cs0 */
Expand All @@ -85,7 +76,7 @@
};
};

fragment@2 {
fragment@1 {
target = <&am33xx_pinmux>;
__overlay__ {
/* default state has all gpios released and mode set to uart1 */
Expand All @@ -98,10 +89,79 @@
// 0x164 0x12 /* eCAP0_in_PWM0_out.spi1_cs1 OUTPUT_PULLUP | MODE2 */
>;
};

backlight_pwm_pins: pinmux_backlight_pwm_pins {
pinctrl-single,pins = <
BONE_P9_14 0x06 /* gpmc_a2.ehrpwm1a, OMAP_MUX_MODE6 | AM33XX_PIN_OUTPUT */
>;
}; /* gpmc_a2.ehrpwm1a */
};
};

fragment@2 {
target = <&epwmss1>;
__overlay__ {
status = "okay";
};
};

fragment@3 {
target = <&ehrpwm1>;
__overlay__ {
pinctrl-names = "default";
pinctrl-0 = <&backlight_pwm_pins>;
status = "okay";
};
};

fragment@4 {
target-path = "/";
__overlay__ {

bl_reg: backlight-regulator {
compatible = "regulator-fixed";
regulator-name = "backlight";
regulator-always-on;
regulator-boot-on;
};

/* backlight is optional */
backlight_gpio: backlight_gpio {
compatible = "gpio-backlight";
gpios = <&gpio1 17 GPIO_ACTIVE_HIGH>;
// connect lcd lite pin to P9.23 which is gpio1[17]
// refer to https://elinux.org/Beagleboard:Cape_Expansion_Headers
};

/*
* Turn the PWM backlight on by setting bl_power to 0:
* echo 0 > /sys/devices/platform/backlight_pwm/backlight/backlight_pwm/bl_power
*/
backlight_pwm: backlight_pwm {
// P9.14 <--> lite (pwm-backlight EHRPWM1A)
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>;
power-supply = <&bl_reg>;
};
};
};

fragment@5 {
target = <&spi1>;
__overlay__ {
#address-cells = <1>;
Expand All @@ -119,12 +179,13 @@
dc-gpios = <&gpio1 16 0>; // lcd dc P9.15 gpio1[16]
reset-gpios = <&gpio1 28 0>; // lcd reset P9.12 gpio1[28]
// backlight is optional
backlight = <&backlight_gpio>; // lcd lite P9.23 gpio1[17]
// choose either pwm or gpio control
//backlight = <&backlight_gpio>; // lcd lite P9.23 gpio1[17]
backlight = <&backlight_pwm>; // lcd lite P9.14 gpmc_a2.ehrpwm1a
// refer to https://elinux.org/Beagleboard:Cape_Expansion_Headers
// rotation is optional
// rotation = <270>;
};

};
};
};