On 2024-12-19 08:06, J. Neuschäfer wrote:
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.ne@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.
yes please do, thanks.
Reviewed-by: Sinan Akman sinan@writeme.com
I did not test it on MPC85xx, though.
-- jn