This issue was found while the customer was migrating his Xilinx Zynq 7000 based project. The customer uses the GPIO driver from the PL (i.e. " Xilinx gpio driver for xps/axi_gpio IP") The corresponding driver source in the linux kernel is drivers/gpio/gpio-xilinx.c This driver which worked in WRL9 has now a bug into the probe routine in LTS18 and always returns an error. The following test is wrong, the driver returns always "input clock not found": if (IS_ERR(chip->clk)) { if ((PTR_ERR(chip->clk) != -ENOENT) || (PTR_ERR(chip->clk) != -EPROBE_DEFER)) { dev_err(&pdev->dev, "Input clock not found\n"); return PTR_ERR(chip->clk); }