I'm using an "adafruitts" touchscreen with a raspi to control a usb peripheral.
The full raspbian kernel takes forever to boot (50 seconds), and part of that is due to the touchscreen driver loading (by modprobe/udev) and initializing.
During the first 20-30 seconds of boot, the display is not loaded, so it is blank. I need this to be a user-friendly item that cannot be blank for 30 seconds each time it is turned on, so I've used buildroot to build a small kernel with the touchscreen driver built-in. (I am on a steep learning curve with buildroot and kernel building in general).
The display driver is fbtft_device.c patched to include the adafruitts display. This patch defines the "touch" half:
/* Touch device spi-half of adafruit touchscreen */
.name = "adafruitts",
.spi = &(struct spi_board_info) {
.modalias = "stmpe610",
.max_speed_hz = 500000,
.mode = SPI_MODE_0,
.chip_select = 1,
.platform_data = &(struct stmpe_platform_data) {
.blocks = STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_GPIO,
.irq_over_gpio = 1,
.irq_gpio = 24,
.irq_trigger = IRQF_TRIGGER_FALLING,
.irq_base = GPIO_IRQ_START + GPIO_IRQS,
.ts = &(struct stmpe_ts_platform_data) {
.sample_time = 4,
.mod_12b = 1,
.ref_sel = 0,
.adc_freq = 2,
.ave_ctrl = 3,
.touch_det_delay = 4,
.settling = 2,
.fraction_z = 7,
.i_drive = 0,
},
}
},
.is_support = 1,
.gpio_settings = (struct gpio_setting []) {
{
.gpio = 24,
.pull = pull_up,
}
},
.gpio_num_settings = 1,
},
and the LCD half:
}, {
/* LCD component of adafruit touchscreen */
.name = "adafruitts",
.spi = &(struct spi_board_info) {
.modalias = "fb_ili9340",
.max_speed_hz = 16000000,
.mode = SPI_MODE_0,
.chip_select = 0,
.platform_data = &(struct fbtft_platform_data) {
.display = {
.buswidth = 8,
.backlight = 1,
},
.bgr = true,
.gpios = (const struct fbtft_gpio []) {
{ "dc", 25 },
{},
},
}
}
}, {
by including:
fbtft_device.name=adafruitts
in the cmdline.txt for the boot loader, I've gotten the display half of the system to work (it boots in ~ 5 seconds :) ) with tinyX/matchbox desktop showing the desktop, but I cannot get the touchscreen part to work (the cursor does not move when I touch the screeen).
Somehow I have to bind the touch part of the touchscreen to tinyX, but I have not been able to figure out how to do this.
I have tried to specify the keyboard (and mouse) when launching tinyX:
X -keybd smpte610 (for example)
but X reports it cannot find the driver.
How can I verify the touch screen input device was successfully loaded?
The boot log has these messages about fbtft_device:
fbtft_device: SPI devices registered:
fbtft_device: spidev spi0.0 500kHz 8 bits mode=0x00
fbtft_device: spidev spi0.1 500kHz 8 bits mode=0x00
fbtft_device: 'fb' Platform devices registered:
fbtft_device: bcm2708_fb id=-1 pdata? no
fbtft_device: Deleting spi0.1 (spi0.1)
fbtft_device: Looking at item 0
fbtft_device: Setting pin 24 to 2
stmpe-spi: probe of spi0.1 failed with error -22
fbtft_device: Deleting spi0.0 (spi0.0)
Console: switching to colour frame buffer device 40x30
graphics fb0: fb_ili9340 frame buffer, 320x240, 150 KiB video memory, 16 KiB buffer memory, fps=20, spi0.0 at 16 MHz
fbtft_device: GPIOS used by 'adafruitts':
fbtft_device: 'dc' = GPIO25
fbtft_device: SPI devices registered:
fbtft_device: stmpe610 spi0.1 48000kHz 8 bits mode=0x00
fbtft_device: fb_ili9340 spi0.0 16000kHz 8 bits mode=0x00
kgdb: Registered I/O driver kgdboc.
Is the kgdb message associated with fbtft_device or something else?
If I look in /dev/input I see: event0, event1, and mice. event0 and event1 are associated with an attached keyboard (according to the boot log) and I have no mouse attached. Should there be some other items in input?
If the touch screen input device IS loaded, how to I specify the correct driver for tinyX?
Thanks
