On Sat, Mar 23, 2019 at 02:51:52PM +0800, zhuchangchun@xxxxxxxx wrote: > On Fri, Mar 22, 2019 at 11:14:14AM +0800, zhuchangchun@xxxxxxxx wrote: > > From above,you can kown when you export a GPIO ,it will do request, > > > > and there will set TX and RX register at the time same time. > > > > when you try to set direction in and set value, TX register value can > > roll back > > > > the value,but RX register was not set, so who will set RX value back?? > > I think you are looking at some older code. There is now function > __intel_gpio_set_direction() that is supposed to set both buffers > depending on the direction. It was introduced with commit 17fab473693e > ("pinctrl: intel: Set pin direction properly"). > > > --> Yes ,I see the latest master branch, the __intel_gpio_set_direction will > set RX and TX, but I still think we need to implement free function,cause > it will help many other engineers,especailly for some manufactories use some > module,and this modules embeded its own driver but not can be modified, > if they want use the gpio control the module, they may meet the same problem. What problem? Is it reproducible on latest vanilla kernel? -- With Best Regards, Andy Shevchenko