On Wed, Dec 18, 2024 at 02:20:21PM -0500, Sinan Akman wrote: > Hi > > On 2024-12-15 10:18, J. Neuschäfer via B4 Relay wrote: > > From: "J. Neuschäfer"<j...@posteo.net> > > > > The mpc8xxx_gpio driver contains a workaround for certain chips > > where the previously written state of outputs cannot be read back > > from the GPIO data (GPDAT) register (MPC8572/MPC8536). This workaround > > consists of tracking the state of GPDAT in a "shadow register" (i.e. a > > software variable). The shadow register is initialized to zero. > > > > This results in a problem w.r.t. outputs that are configured to a > > high (1) state before U-Boot runs, but not touched by U-Boot itself: > > Due to the zero-initialization, these GPIOs end up being set to zero, > > the first time that any other output is set. > > > > To avoid such issues initialize the GPDAT shadow register to the value > > previously held by any outputs, if possible. On MPC8572/MPC8536 this > > should make no difference, > > Did you test this on a MPC83xx board ?
Yes, on MPC8314E. I'll mention it in the commit message. I did not test it on MPC85xx, though. -- jn
