Hi Tomas, On Tue, Aug 27, 2024 at 4:41 PM Tomas Paukrt <[email protected]> wrote:
> Hi Fabio, > > you are correct that the existing code will work if the SION bit is set, but > this is not always possible or desirable. For example, if you use the command > "gpio set" to set the state of a pin that is not configured in DTS then you > will get the error message "Warning: value of pin is still 0". Also the > command "gpio status -a" shows wrong states of some output pins without this > patch. This happens due to an incorrect devicetree description, i.e, the lack of setting the SION bit. > Please see the chapters "GPIO data register (GPIOx_DR)" and "GPIO pad status > register (GPIOx_PSR)" in the document IMX6ULLRM.pdf which show that it is > possible to use the DR register instead of the PSR register in this case. > > I also found the exactly same modification in NXP version of U-Boot > (https://github.com/nxp-imx/uboot-imx/commit/4afc3f90943c6b117f79b66d2cd04e64f437b0c2) > made by an NXP employee. Adding Ye Li on Cc. There were many attempts to fix this in both U-Boot and the kernel, but the recommendation has always been: "Set the SION bit if you need to read the output state". Regards, Fabio Estevam
