ST1633 Touch screen on PB(ish) board.

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1

Trying to get an ST1633 touch screen working with a PB derived board.
I had to jump to Linux 5.1-rc3 (cross building with bb-kernel) to get the sitronix driver patched with st1633 support.

I have CONFIG_TOUCHSCREEN_ST1232 enabled in .config.

I have I2C2 working on the board - I can use
i2cdetect -y -r 2
to find i2c devices that I breadboard onto I2C2 for testing

I can not seem to detect the ST1633 when connected to the PB board,
But I can detect it if I bread board it to another Linux box.
I am guessing at the moment that the st1633 reset line may be in the wrong state.

I am trying to make sure I have the TS.RES set correctly.

I have verified that I have the right pin by setting it to a gpio_led in the device tree overlay, breadboarding an LED to it and I can toggle the LED from /sys/

Currently I have the devicetree pinctl as

pinctrl_st1633: pinmux_pinctrl_st1633 {

pinctrl-single,pins = <

/* (B13) mcasp0_fsx GPIO111 GPIO3_15 LCD.TS.INT */
AM33XX_IOPAD(0x0994, PIN_INPUT_PULLDOWN | MUX_MODE7)

/* (A13) mcasp0_aclkx GPIO110 GPIO3_14 LCD.TS.RES */

AM33XX_IOPAD(0x0990, PIN_OUTPUT_PULLUP | MUX_MODE7)

;

I have the st1633 setup as

fragment@6 {
target = <&i2c2>;
overlay {
status = “okay”;
pinctrl-names = “default”;
pinctrl-0 = <&pb_i2c2_pins>;

/* this is the configuration part */
clock-frequency = <100000>;

#address-cells = <1>;
#size-cells = <0>;

sitronix_ts@55 {
status = “okay”;
compatible = “sitronix,st1633”;
reg = <0x55>;

pinctrl-names = “default”;
pinctrl-0 = <&pinctrl_st1633>;

interrupt-parent = <&gpio3>;
interrupts = <15 0>;

reset-gpios = <&gpio3 14 GPIO_ACTIVE_LOW>;

touchscreen-size-x = <272>;
touchscreen-size-y = <480>;
touchscreen-swapped-x-y;
};
};
};

But when linux boots I am not seeing anything in the logs that suggested in even tried to load the sitronix driver.

Any ideas ?

2

is CONFIG_TOUCHSCREEN_ST1232 configured as built in or a module of linux,
if it’s a module, then use modprobe and see if it loads

3

Built-in
But I will change it.
I might get more messages as a module.

4

I am building st1232.c as a module
it is now getting loaded correctly by the device tree above.
It completes the st1232_probe without error.

but the touch screen is not working
I beleive I am not getting any interrupts when I touch the display.

I am assuming that

interrupt-parent = <&gpio3>;
interrupts = <15 0>;

is correct for gpio3_15

I am also presuming that INPUT_PULLDOWN is the correct configuration for GPIO3_15

5

I was able to get this working - it required using the Linux 5.1 Kernel.

6

Just curious how is the PB talking to display controller? spi?