Problem with ST7735S

[tbop-R]

I use an OrangePi zero H616.
I bought the following ST7735S LCD.
https://it.aliexpress.com/item/33031122936.html?spm=a2g0o.order_list.order_list_main.32.67b836960mEnKd&gatewayAdapt=glo2ita

I followed the following guide:
https://www.instructables.com/Orange-Pi-Zero-Connect-TFT-SPI-ST7735/

after running the command

sudo modprobe fbtft_device name=adafruit18 gpios=reset:1,dc:0,led:3 speed=16000000 fps=25 rotate=90 busnum=1

I get the following errors:

`[ 78.218500] spidev spi0.0: dh2228fv spi0.0 16777kHz 8 bits mode=0x00
[ 78.218521] spidev spi1.1: dh2228fv spi1.1 16777kHz 8 bits mode=0x00
[ 78.218539] spi spi1.0: fb_st7735r spi1.0 16000kHz 8 bits mode=0x00
[ 78.242713] fb_st7735r: module is from the staging directory, the quality is unknown, you have been warned.
[ 78.364571] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 78.364594] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 78.364614] fb_st7735r spi1.0: fbtft_write_reg8_bus8: write() failed and returned -22
[ 78.514732] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 78.514753] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 78.514775] fb_st7735r spi1.0: fbtft_write_reg8_bus8: write() failed and returned -22
[ 79.014900] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 79.014920] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...
[ 79.014942] fb_st7735r spi1.0: fbtft_write_reg8_bus8: write() failed and returned -22
[ 79.125906] fb_st7735r spi1.0: fbtft_write_reg8_bus8: write() failed and returned -22
[ 79.126359] graphics fb1: fb_st7735r frame buffer, 160x128, 40 KiB video memory, 4 KiB buffer memory, fps=25, spi1.0 at 16 MHz

`
The display remains white with a horizontal red line at the bottom.
What can I do?

Thank you all

[notro]

[ 78.364571] sunxi_spi_xfer_setup()1021 - [spi1] sunxi_spi_check_cs failed! spi_device cs =0 ...

I did a search for sunxi_spi_xfer_setup which gave me these:

https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/drivers/spi/spi-sunxi.c#L833-L837

(the source line 1021 doesn't match so you're using some other version of this driver)

https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/drivers/spi/spi-sunxi.c#L773-L775

It looks like for you CS0 is not in the supported cs_bitmap.
I have never used sunxi so I suggest you try a sunxi forum to get help with this error.

[tbop-R]

Thank you for answering me.
I ran modprobe changing the parameters:
sudo modprobe fbtft_device custom name=fb_st7735r gpios=dc:3,reset:0 speed=16000000 rotate=90
in dmesg I find no errors and the file /dev/fb1 is created.
The screen remains blank.
How can I test it?

Thank you

[notro]

A simple way is to dump some random pixels to the display: cat /dev/urandom > /dev/fb1
(ignore the no space left error)

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