mpsl: Use direct GPIO register access in coex

The Zephyr GPIO driver cannot be used from a Zero Latency Interrupt
context, as its power management functions,
e.g. pm_device_runtime_get attempt to take a semaphore.
This can lead to system deadlocks when GPIOs are used from the ZLI.

Signed-off-by: Aleksandr Mirlenko <[email protected]>

Author: Mirlenko

subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x.c

@@ -65,6 +65,14 @@ static const struct gpio_dt_spec req_spec     = GPIO_DT_SPEC_GET(CX_NODE, req_gp
 static const struct gpio_dt_spec status0_spec = GPIO_DT_SPEC_GET(CX_NODE, status0_gpios);
 static const struct gpio_dt_spec grant_spec   = GPIO_DT_SPEC_GET(CX_NODE, grant_gpios);
 
+/* Direct register access pointers for ISR-safe GPIO control from DT */
+static NRF_GPIO_Type *req_port =
+	((NRF_GPIO_Type *)DT_REG_ADDR(DT_GPIO_CTLR(CX_NODE, req_gpios)));
+static NRF_GPIO_Type *status0_port =
+	((NRF_GPIO_Type *)DT_REG_ADDR(DT_GPIO_CTLR(CX_NODE, status0_gpios)));
+static uint32_t req_pin_mask = BIT(DT_GPIO_PIN(CX_NODE, req_gpios));
+static uint32_t status0_pin_mask = BIT(DT_GPIO_PIN(CX_NODE, status0_gpios));
+
 static mpsl_cx_cb_t callback;
 static struct gpio_callback grant_cb;
 static uint32_t grant_abs_pin;
@@ -166,7 +174,18 @@ static int sig_dir_level_calc(mpsl_cx_op_map_t ops)
  */
 static int32_t gpio_drive_status0_to_dir(mpsl_cx_op_map_t ops)
 {
-	return gpio_pin_set_dt(&status0_spec, sig_dir_level_calc(ops));
+	if (status0_port == NULL) {
+		return -NRF_EINVAL;
+	}
+
+	int level = sig_dir_level_calc(ops);
+
+	if (level) {
+		nrf_gpio_port_out_set(status0_port, status0_pin_mask);
+	} else {
+		nrf_gpio_port_out_clear(status0_port, status0_pin_mask);
+	}
+	return 0;
 }
 
 /**
@@ -177,7 +196,16 @@ static int32_t gpio_drive_status0_to_dir(mpsl_cx_op_map_t ops)
  */
 static int32_t gpio_drive_request(int active)
 {
-	return gpio_pin_set_dt(&req_spec, active);
+	if (req_port == NULL) {
+		return -NRF_EINVAL;
+	}
+
+	if (active) {
+		nrf_gpio_port_out_set(req_port, req_pin_mask);
+	} else {
+		nrf_gpio_port_out_clear(req_port, req_pin_mask);
+	}
+	return 0;
 }
 
 static int32_t request(const mpsl_cx_request_t *req_params)