[adding linux-gpio + Linus W.] On 10/10/18 9:13 AM, wzab wrote: > Hi, > > The function of_get_named_gpiod_flags in older versions of the kernel > (up to 4.7.10 - > https://elixir.bootlin.com/linux/v4.7.10/source/drivers/gpio/gpiolib-of.c#L75 > ) > contained an important workaround: > > /* .of_xlate might decide to not fill in the flags, so clear it. */if (flags) > *flags = 0; Unfortunately, newer kernels do not contain it. Therefore if > the > "xlat" function in the gpiochip driver does not set flags, (like e.g. > the Xilinx AXI GPIO driver: > https://github.com/Xilinx/linux-xlnx/blob/c2ba891326bb472da59b6a2da29aca218d337687/drivers/gpio/gpio-xilinx.c#L262 > ) > the random, unitialized value from the stack in of_find_gpio > ( > https://elixir.bootlin.com/linux/v4.18.13/source/drivers/gpio/gpiolib-of.c#L228 > ) > is used, which results in random settings of e.g., OPEN DRAIN or OPEN SOURCE > mode. > > I have also reported the problem in the Xilinx forum: > https://forums.xilinx.com/t5/Embedded-Linux/Bug-in-of-get-named-gpiod-flags-function-in-the-kernel-random/td-p/897695 > > With best regards, > Wojciech Zabolotny > > >
-- ~Randy
