drivers: wifi: Hook RPU power off

The API to power off RPU was unused, hook it to the higher level APIs
and tie to QSPI bus removal.

This reduces current consumption on interface down from ~13uA to ~2uA.

Implements SHEL-1672.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>

drivers/wifi/nrf700x/osal/bus_if/bus/qspi/src/qspi.c

@@ -114,6 +114,9 @@ static void wifi_nrf_bus_qspi_dev_rem(void *bus_dev_ctx)
 	wifi_nrf_osal_bus_qspi_dev_intr_unreg(qspi_dev_ctx->qspi_priv->opriv,
 					      qspi_dev_ctx->os_qspi_dev_ctx);
 
+	wifi_nrf_osal_bus_qspi_dev_rem(qspi_dev_ctx->qspi_priv->opriv,
+					       qspi_dev_ctx->os_qspi_dev_ctx);
+
 	wifi_nrf_osal_mem_free(qspi_dev_ctx->qspi_priv->opriv,
 			       qspi_dev_ctx);
 }

drivers/wifi/nrf700x/zephyr/src/qspi/inc/rpu_hw_if.h

@@ -39,6 +39,7 @@ int rpu_write(unsigned int addr, const void *data, int len);
 
 int rpu_gpio_config(void);
 int rpu_pwron(void);
+int rpu_pwroff(void);
 int  rpu_qspi_init(void);
 int rpu_sleep(void);
 int rpu_wakeup(void);

drivers/wifi/nrf700x/zephyr/src/qspi/src/rpu_hw_if.c

@@ -223,6 +223,14 @@ int rpu_pwron(void)
 	return 0;
 }
 
+int rpu_pwroff(void)
+{
+	gpio_pin_set_dt(&bucken_spec, 0); /* BUCKEN = 0 */
+	gpio_pin_set_dt(&iovdd_ctrl_spec, 0); /* IOVDD CNTRL = 0 */
+
+	return 0;
+}
+
 #if defined(CONFIG_BOARD_NRF7002DK_NRF7001_NRF5340_CPUAPP) || \
 	defined(CONFIG_BOARD_NRF7002DK_NRF5340_CPUAPP)
 int ble_ant_switch(unsigned int ant_switch)
@@ -351,7 +359,7 @@ int rpu_enable(void)
 
 int rpu_disable(void)
 {
-	gpio_pin_set_dt(&bucken_spec, 0); /* BUCKEN = 0 */
-	gpio_pin_set_dt(&iovdd_ctrl_spec, 0); /* IOVDD CNTRL = 0 */
+	rpu_pwroff();
+
 	return 0;
 }

drivers/wifi/nrf700x/zephyr/src/shim.c

@@ -567,6 +567,7 @@ static void zep_shim_bus_qspi_dev_rem(void *os_qspi_dev_ctx)
 	dev = os_qspi_dev_ctx;
 
 	/* TODO: Make qspi_dev a dynamic instance and remove it here */
+	rpu_disable();
 }
 
 static void *zep_shim_bus_qspi_init(void)