Commits on Aug 8, 2023

1. drivers: pinctrl: nrf: Add support for setting initial pin state …

   The nRF pinctrl driver did not allow for setting the initial state
   of the pins. This issue specifically affected the SPI SPIM driver,
   which caused an invalid SCK state when configured with CPOL
   (Clock Polarity).
   
   With the introduction of the power-optimized SPIM driver,
   it disables the peripheral instance once the transfer is completed.
   As a result, the GPIO takes control over the SCK pin and drive it
   based on its own configuration. However, the pinctrl configures pins
   for SPIM incorrectly when CPOL is set. This causes that GPIO
   sets the SCK pin to 0 instead of the expected 1 when idle after SPI
   transaction is finished.
   
   To address this issue, a patch was introduced.
   Now, when an SPIM instance is configured with CPOL,
   the pinctrl node must have the 'output-high' property set
   to ensure the correct initial pin state.
   
   Example devicetree fragment:
   
       spi1_default: spi1_default {
           group1 {
               psels = <NRF_PSEL(SPIM_SCK, 0, 5)>;
               output-high;
           };
           group2 {
               psels = <NRF_PSEL(SPIM_MISO, 0, 6)>,
                       <NRF_PSEL(SPIM_MOSI, 0, 7)>;
           };
       };
   
   Signed-off-by: Adam Wojasinski <adam.wojasinski@nordicsemi.no>

   Adam Wojasinski committed Aug 8, 2023
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