drivers: stepper: adi_tmc: diag0 interrupt support for tmc51xx

Add support for using the diag0 pin as an interrupt source. This
allows event detection via diag0 interrupts instead of polling rampstat.
The driver now:
- Configures diag0 when the GPIO is available
- Sets up GPIO interrupt handling for rising edge transitions for
rampstat reading
- Falls back to polling only when diag0 is not available

Signed-off-by: Dipak Shetty <shetty.dipak@gmx.com>

Author: dipakgmx

drivers/stepper/adi_tmc/adi_tmc_reg.h

@@ -145,9 +145,10 @@ extern "C" {
 
 #ifdef CONFIG_STEPPER_ADI_TMC51XX
 
-#define TMC51XX_GCONF_EN_PWM_MODE_SHIFT	2
-#define TMC51XX_GCONF_SHAFT_SHIFT	4
-#define TMC51XX_GCONF_TEST_MODE_SHIFT	17
+#define TMC51XX_GCONF_EN_PWM_MODE_SHIFT        2
+#define TMC51XX_GCONF_SHAFT_SHIFT              4
+#define TMC51XX_GCONF_DIAG0_INT_PUSHPULL_SHIFT 12
+#define TMC51XX_GCONF_TEST_MODE_SHIFT          17
 
 #define TMC51XX_IHOLD_IRUN	0x10
 #define TMC51XX_TPOWER_DOWN	0x11