diff --git a/drivers/mailbox/stm32-ipcc.c b/drivers/mailbox/stm32-ipcc.c
index 533b0da..5c2d1e1 100644
--- a/drivers/mailbox/stm32-ipcc.c
+++ b/drivers/mailbox/stm32-ipcc.c
@@ -8,9 +8,9 @@
 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/interrupt.h>
+#include <linux/io.h>
 #include <linux/mailbox_controller.h>
 #include <linux/module.h>
-#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/pm_wakeirq.h>
 
@@ -50,6 +50,7 @@
 	void __iomem *reg_base;
 	void __iomem *reg_proc;
 	struct clk *clk;
+	spinlock_t lock; /* protect access to IPCC registers */
 	int irqs[IPCC_IRQ_NUM];
 	int wkp;
 	u32 proc_id;
@@ -58,14 +59,24 @@
 	u32 xmr;
 };
 
-static inline void stm32_ipcc_set_bits(void __iomem *reg, u32 mask)
+static inline void stm32_ipcc_set_bits(spinlock_t *lock, void __iomem *reg,
+				       u32 mask)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
 	writel_relaxed(readl_relaxed(reg) | mask, reg);
+	spin_unlock_irqrestore(lock, flags);
 }
 
-static inline void stm32_ipcc_clr_bits(void __iomem *reg, u32 mask)
+static inline void stm32_ipcc_clr_bits(spinlock_t *lock, void __iomem *reg,
+				       u32 mask)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
 	writel_relaxed(readl_relaxed(reg) & ~mask, reg);
+	spin_unlock_irqrestore(lock, flags);
 }
 
 static irqreturn_t stm32_ipcc_rx_irq(int irq, void *data)
@@ -92,7 +103,7 @@
 
 		mbox_chan_received_data(&ipcc->controller.chans[chan], NULL);
 
-		stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XSCR,
+		stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
 				    RX_BIT_CHAN(chan));
 
 		ret = IRQ_HANDLED;
@@ -121,7 +132,7 @@
 		dev_dbg(dev, "%s: chan:%d tx\n", __func__, chan);
 
 		/* mask 'tx channel free' interrupt */
-		stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR,
+		stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 				    TX_BIT_CHAN(chan));
 
 		mbox_chan_txdone(&ipcc->controller.chans[chan], 0);
@@ -141,10 +152,12 @@
 	dev_dbg(ipcc->controller.dev, "%s: chan:%d\n", __func__, chan);
 
 	/* set channel n occupied */
-	stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XSCR, TX_BIT_CHAN(chan));
+	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
+			    TX_BIT_CHAN(chan));
 
 	/* unmask 'tx channel free' interrupt */
-	stm32_ipcc_clr_bits(ipcc->reg_proc + IPCC_XMR, TX_BIT_CHAN(chan));
+	stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
+			    TX_BIT_CHAN(chan));
 
 	return 0;
 }
@@ -163,7 +176,8 @@
 	}
 
 	/* unmask 'rx channel occupied' interrupt */
-	stm32_ipcc_clr_bits(ipcc->reg_proc + IPCC_XMR, RX_BIT_CHAN(chan));
+	stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
+			    RX_BIT_CHAN(chan));
 
 	return 0;
 }
@@ -175,7 +189,7 @@
 					       controller);
 
 	/* mask rx/tx interrupt */
-	stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR,
+	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 			    RX_BIT_CHAN(chan) | TX_BIT_CHAN(chan));
 
 	clk_disable_unprepare(ipcc->clk);
@@ -208,6 +222,8 @@
 	if (!ipcc)
 		return -ENOMEM;
 
+	spin_lock_init(&ipcc->lock);
+
 	/* proc_id */
 	if (of_property_read_u32(np, "st,proc-id", &ipcc->proc_id)) {
 		dev_err(dev, "Missing st,proc-id\n");
@@ -240,9 +256,11 @@
 
 	/* irq */
 	for (i = 0; i < IPCC_IRQ_NUM; i++) {
-		ipcc->irqs[i] = of_irq_get_byname(dev->of_node, irq_name[i]);
+		ipcc->irqs[i] = platform_get_irq_byname(pdev, irq_name[i]);
 		if (ipcc->irqs[i] < 0) {
-			dev_err(dev, "no IRQ specified %s\n", irq_name[i]);
+			if (ipcc->irqs[i] != -EPROBE_DEFER)
+				dev_err(dev, "no IRQ specified %s\n",
+					irq_name[i]);
 			ret = ipcc->irqs[i];
 			goto err_clk;
 		}
@@ -257,27 +275,27 @@
 	}
 
 	/* mask and enable rx/tx irq */
-	stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XMR,
+	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
 			    RX_BIT_MASK | TX_BIT_MASK);
-	stm32_ipcc_set_bits(ipcc->reg_proc + IPCC_XCR, XCR_RXOIE | XCR_TXOIE);
+	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR,
+			    XCR_RXOIE | XCR_TXOIE);
 
 	/* wakeup */
 	if (of_property_read_bool(np, "wakeup-source")) {
-		ipcc->wkp = of_irq_get_byname(dev->of_node, "wakeup");
+		ipcc->wkp = platform_get_irq_byname(pdev, "wakeup");
 		if (ipcc->wkp < 0) {
-			dev_err(dev, "could not get wakeup IRQ\n");
+			if (ipcc->wkp != -EPROBE_DEFER)
+				dev_err(dev, "could not get wakeup IRQ\n");
 			ret = ipcc->wkp;
 			goto err_clk;
 		}
 
-		device_init_wakeup(dev, true);
+		device_set_wakeup_capable(dev, true);
 		ret = dev_pm_set_dedicated_wake_irq(dev, ipcc->wkp);
 		if (ret) {
 			dev_err(dev, "Failed to set wake up irq\n");
 			goto err_init_wkp;
 		}
-	} else {
-		device_init_wakeup(dev, false);
 	}
 
 	/* mailbox controller */
@@ -299,7 +317,7 @@
 	for (i = 0; i < ipcc->controller.num_chans; i++)
 		ipcc->controller.chans[i].con_priv = (void *)i;
 
-	ret = mbox_controller_register(&ipcc->controller);
+	ret = devm_mbox_controller_register(dev, &ipcc->controller);
 	if (ret)
 		goto err_irq_wkp;
 
@@ -329,8 +347,6 @@
 {
 	struct stm32_ipcc *ipcc = platform_get_drvdata(pdev);
 
-	mbox_controller_unregister(&ipcc->controller);
-
 	if (ipcc->wkp)
 		dev_pm_clear_wake_irq(&pdev->dev);