Am Dienstag, den 01.09.2020, 18:02 +0000 schrieb John Robertson:
GPIO state cannot be changed via the device tree (e.g. with gpio-hog) or using the 'gpio' command from the console.
The root cause is a discrepancy between the driver and the device tree: the driver code expects an absolute I/O address in the <reg> property, while the device tree defines the address relative to a declaration in the parent pinctrl node.
Changing the device tree to fix a driver issue would normally be wrong, however:
- I have run the first version of U-Boot in which this driver appears (v2016.03) and the same problem exists, so this is not a regression;
- There is no code that references a parent device tree node that might suggest the intent of the author was to parse the DT as it exists now;
- The equivalent Linux PIC32 GPIO driver also uses absolute addresses for the GPIO <reg> property. This change brings the U-Boot DT more into line with Linux.
Additionally, the data sheet (Microchip ref. 60001361H) shows that the register set to control a GPIO bank spans 0xE0 bytes, but the device tree specified size is only 0x48 bytes.
Signed-off-by: John Robertson john.robertson@simiatec.com
Changes in v2
- Split patch
- Document change more fully
arch/mips/dts/pic32mzda.dtsi | 45 ++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 23 deletions(-)
applied to u-boot-mips/fixes, thanks.