20 files changed, 558 insertions, 139 deletions

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 59f25286befe..3daae8ddd511 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -308,6 +308,19 @@ config HW_RANDOM_HISI
 
 	  If unsure, say Y.
 
+config HW_RANDOM_HISI_V2
+	tristate "HiSilicon True Random Number Generator V2 support"
+	depends on HW_RANDOM && ARM64 && ACPI
+	default HW_RANDOM
+	help
+	  This driver provides kernel-side support for the True Random Number
+	  Generator V2 hardware found on HiSilicon Hi1620 SoC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hisi-trng-v2.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_ST
 	tristate "ST Microelectronics HW Random Number Generator support"
 	depends on HW_RANDOM && ARCH_STI
@@ -440,6 +453,19 @@ config HW_RANDOM_OPTEE
 
 	  If unsure, say Y.
 
+config HW_RANDOM_NPCM
+	tristate "NPCM Random Number Generator support"
+	depends on ARCH_NPCM || COMPILE_TEST
+	default HW_RANDOM
+	help
+ 	  This driver provides support for the Random Number
+	  Generator hardware available in Nuvoton NPCM SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called npcm-rng.
+
+ 	  If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM
@@ -458,7 +484,7 @@ config UML_RANDOM
 	  /dev/hwrng and injects the entropy into /dev/random.
 
 config HW_RANDOM_KEYSTONE
-	depends on ARCH_KEYSTONE
+	depends on ARCH_KEYSTONE || COMPILE_TEST
 	default HW_RANDOM
 	tristate "TI Keystone NETCP SA Hardware random number generator"
 	help
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 7c9ef4a7667f..a7801b49ce6c 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
 obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
 obj-$(CONFIG_HW_RANDOM_HISI)	+= hisi-rng.o
+obj-$(CONFIG_HW_RANDOM_HISI_V2) += hisi-trng-v2.o
 obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
 obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
 obj-$(CONFIG_HW_RANDOM_ST) += st-rng.o
@@ -39,3 +40,4 @@ obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
+obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o
diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c
index e55705745d5e..ecb71c4317a5 100644
--- a/drivers/char/hw_random/atmel-rng.c
+++ b/drivers/char/hw_random/atmel-rng.c
@@ -14,14 +14,22 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/hw_random.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 
 #define TRNG_CR		0x00
+#define TRNG_MR		0x04
 #define TRNG_ISR	0x1c
 #define TRNG_ODATA	0x50
 
 #define TRNG_KEY	0x524e4700 /* RNG */
 
+#define TRNG_HALFR	BIT(0) /* generate RN every 168 cycles */
+
+struct atmel_trng_data {
+	bool has_half_rate;
+};
+
 struct atmel_trng {
 	struct clk *clk;
 	void __iomem *base;
@@ -62,21 +70,31 @@ static void atmel_trng_disable(struct atmel_trng *trng)
 static int atmel_trng_probe(struct platform_device *pdev)
 {
 	struct atmel_trng *trng;
-	struct resource *res;
+	const struct atmel_trng_data *data;
 	int ret;
 
 	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
 	if (!trng)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	trng->base = devm_ioremap_resource(&pdev->dev, res);
+	trng->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(trng->base))
 		return PTR_ERR(trng->base);
 
 	trng->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(trng->clk))
 		return PTR_ERR(trng->clk);
+	data = of_device_get_match_data(&pdev->dev);
+	if (!data)
+		return -ENODEV;
+
+	if (data->has_half_rate) {
+		unsigned long rate = clk_get_rate(trng->clk);
+
+		/* if peripheral clk is above 100MHz, set HALFR */
+		if (rate > 100000000)
+			writel(TRNG_HALFR, trng->base + TRNG_MR);
+	}
 
 	ret = clk_prepare_enable(trng->clk);
 	if (ret)
@@ -141,9 +159,24 @@ static const struct dev_pm_ops atmel_trng_pm_ops = {
 };
 #endif /* CONFIG_PM */
 
+static const struct atmel_trng_data at91sam9g45_config = {
+	.has_half_rate = false,
+};
+
+static const struct atmel_trng_data sam9x60_config = {
+	.has_half_rate = true,
+};
+
 static const struct of_device_id atmel_trng_dt_ids[] = {
-	{ .compatible = "atmel,at91sam9g45-trng" },
-	{ /* sentinel */ }
+	{
+		.compatible = "atmel,at91sam9g45-trng",
+		.data = &at91sam9g45_config,
+	}, {
+		.compatible = "microchip,sam9x60-trng",
+		.data = &sam9x60_config,
+	}, {
+		/* sentinel */
+	}
 };
 MODULE_DEVICE_TABLE(of, atmel_trng_dt_ids);
 
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index f759790c3cdb..d2a5791eb49f 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -142,7 +142,6 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
 	struct device_node *np = dev->of_node;
 	const struct of_device_id *rng_id;
 	struct bcm2835_rng_priv *priv;
-	struct resource *r;
 	int err;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -151,10 +150,8 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-
 	/* map peripheral */
-	priv->base = devm_ioremap_resource(dev, r);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 8d53b8ef545c..d2d7a42d7e0d 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -111,6 +111,14 @@ static void drop_current_rng(void)
 }
 
 /* Returns ERR_PTR(), NULL or refcounted hwrng */
+static struct hwrng *get_current_rng_nolock(void)
+{
+	if (current_rng)
+		kref_get(&current_rng->ref);
+
+	return current_rng;
+}
+
 static struct hwrng *get_current_rng(void)
 {
 	struct hwrng *rng;
@@ -118,9 +126,7 @@ static struct hwrng *get_current_rng(void)
 	if (mutex_lock_interruptible(&rng_mutex))
 		return ERR_PTR(-ERESTARTSYS);
 
-	rng = current_rng;
-	if (rng)
-		kref_get(&rng->ref);
+	rng = get_current_rng_nolock();
 
 	mutex_unlock(&rng_mutex);
 	return rng;
@@ -155,8 +161,6 @@ static int hwrng_init(struct hwrng *rng)
 	reinit_completion(&rng->cleanup_done);
 
 skip_init:
-	add_early_randomness(rng);
-
 	current_quality = rng->quality ? : default_quality;
 	if (current_quality > 1024)
 		current_quality = 1024;
@@ -320,12 +324,13 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
 					const char *buf, size_t len)
 {
 	int err = -ENODEV;
-	struct hwrng *rng;
+	struct hwrng *rng, *old_rng, *new_rng;
 
 	err = mutex_lock_interruptible(&rng_mutex);
 	if (err)
 		return -ERESTARTSYS;
 
+	old_rng = current_rng;
 	if (sysfs_streq(buf, "")) {
 		err = enable_best_rng();
 	} else {
@@ -337,9 +342,15 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
 			}
 		}
 	}
-
+	new_rng = get_current_rng_nolock();
 	mutex_unlock(&rng_mutex);
 
+	if (new_rng) {
+		if (new_rng != old_rng)
+			add_early_randomness(new_rng);
+		put_rng(new_rng);
+	}
+
 	return err ? : len;
 }
 
@@ -457,13 +468,15 @@ static void start_khwrngd(void)
 int hwrng_register(struct hwrng *rng)
 {
 	int err = -EINVAL;
-	struct hwrng *old_rng, *tmp;
+	struct hwrng *tmp;
 	struct list_head *rng_list_ptr;
+	bool is_new_current = false;
 
 	if (!rng->name || (!rng->data_read && !rng->read))
 		goto out;
 
 	mutex_lock(&rng_mutex);
+
 	/* Must not register two RNGs with the same name. */
 	err = -EEXIST;
 	list_for_each_entry(tmp, &rng_list, list) {
@@ -482,10 +495,8 @@ int hwrng_register(struct hwrng *rng)
 	}
 	list_add_tail(&rng->list, rng_list_ptr);
 
-	old_rng = current_rng;
-	err = 0;
-	if (!old_rng ||
-	    (!cur_rng_set_by_user && rng->quality > old_rng->quality)) {
+	if (!current_rng ||
+	    (!cur_rng_set_by_user && rng->quality > current_rng->quality)) {
 		/*
 		 * Set new rng as current as the new rng source
 		 * provides better entropy quality and was not
@@ -494,19 +505,26 @@ int hwrng_register(struct hwrng *rng)
 		err = set_current_rng(rng);
 		if (err)
 			goto out_unlock;
+		/* to use current_rng in add_early_randomness() we need
+		 * to take a ref
+		 */
+		is_new_current = true;
+		kref_get(&rng->ref);
 	}
-
-	if (old_rng && !rng->init) {
+	mutex_unlock(&rng_mutex);
+	if (is_new_current || !rng->init) {
 		/*
 		 * Use a new device's input to add some randomness to
 		 * the system.  If this rng device isn't going to be
 		 * used right away, its init function hasn't been
-		 * called yet; so only use the randomness from devices
-		 * that don't need an init callback.
+		 * called yet by set_current_rng(); so only use the
+		 * randomness from devices that don't need an init callback
 		 */
 		add_early_randomness(rng);
 	}
-
+	if (is_new_current)
+		put_rng(rng);
+	return 0;
 out_unlock:
 	mutex_unlock(&rng_mutex);
 out:
@@ -516,10 +534,12 @@ EXPORT_SYMBOL_GPL(hwrng_register);
 
 void hwrng_unregister(struct hwrng *rng)
 {
+	struct hwrng *old_rng, *new_rng;
 	int err;
 
 	mutex_lock(&rng_mutex);
 
+	old_rng = current_rng;
 	list_del(&rng->list);
 	if (current_rng == rng) {
 		err = enable_best_rng();
@@ -529,6 +549,7 @@ void hwrng_unregister(struct hwrng *rng)
 		}
 	}
 
+	new_rng = get_current_rng_nolock();
 	if (list_empty(&rng_list)) {
 		mutex_unlock(&rng_mutex);
 		if (hwrng_fill)
@@ -536,6 +557,12 @@ void hwrng_unregister(struct hwrng *rng)
 	} else
 		mutex_unlock(&rng_mutex);
 
+	if (new_rng) {
+		if (old_rng != new_rng)
+			add_early_randomness(new_rng);
+		put_rng(new_rng);
+	}
+
 	wait_for_completion(&rng->cleanup_done);
 }
 EXPORT_SYMBOL_GPL(hwrng_unregister);
diff --git a/drivers/char/hw_random/exynos-trng.c b/drivers/char/hw_random/exynos-trng.c
index b4b52ab23b6b..8e1fe3f8dd2d 100644
--- a/drivers/char/hw_random/exynos-trng.c
+++ b/drivers/char/hw_random/exynos-trng.c
@@ -109,7 +109,6 @@ static int exynos_trng_init(struct hwrng *rng)
 static int exynos_trng_probe(struct platform_device *pdev)
 {
 	struct exynos_trng_dev *trng;
-	struct resource *res;
 	int ret = -ENOMEM;
 
 	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
@@ -128,8 +127,7 @@ static int exynos_trng_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, trng);
 	trng->dev = &pdev->dev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	trng->mem = devm_ioremap_resource(&pdev->dev, res);
+	trng->mem = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(trng->mem))
 		return PTR_ERR(trng->mem);
 
diff --git a/drivers/char/hw_random/hisi-rng.c b/drivers/char/hw_random/hisi-rng.c
index c663d5dd85bb..6815e17a9834 100644
--- a/drivers/char/hw_random/hisi-rng.c
+++ b/drivers/char/hw_random/hisi-rng.c
@@ -73,7 +73,6 @@ static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 static int hisi_rng_probe(struct platform_device *pdev)
 {
 	struct hisi_rng *rng;
-	struct resource *res;
 	int ret;
 
 	rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
@@ -82,8 +81,7 @@ static int hisi_rng_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, rng);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	rng->base = devm_ioremap_resource(&pdev->dev, res);
+	rng->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rng->base))
 		return PTR_ERR(rng->base);
 
diff --git a/drivers/char/hw_random/hisi-trng-v2.c b/drivers/char/hw_random/hisi-trng-v2.c
new file mode 100644
index 000000000000..6a65b8232ce0
--- /dev/null
+++ b/drivers/char/hw_random/hisi-trng-v2.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 HiSilicon Limited. */
+
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+
+#define HISI_TRNG_REG		0x00F0
+#define HISI_TRNG_BYTES		4
+#define HISI_TRNG_QUALITY	512
+#define SLEEP_US		10
+#define TIMEOUT_US		10000
+
+struct hisi_trng {
+	void __iomem *base;
+	struct hwrng rng;
+};
+
+static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct hisi_trng *trng;
+	int currsize = 0;
+	u32 val = 0;
+	u32 ret;
+
+	trng = container_of(rng, struct hisi_trng, rng);
+
+	do {
+		ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
+					 val, SLEEP_US, TIMEOUT_US);
+		if (ret)
+			return currsize;
+
+		if (max - currsize >= HISI_TRNG_BYTES) {
+			memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
+			currsize += HISI_TRNG_BYTES;
+			if (currsize == max)
+				return currsize;
+			continue;
+		}
+
+		/* copy remaining bytes */
+		memcpy(buf + currsize, &val, max - currsize);
+		currsize = max;
+	} while (currsize < max);
+
+	return currsize;
+}
+
+static int hisi_trng_probe(struct platform_device *pdev)
+{
+	struct hisi_trng *trng;
+	int ret;
+
+	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
+	if (!trng)
+		return -ENOMEM;
+
+	trng->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(trng->base))
+		return PTR_ERR(trng->base);
+
+	trng->rng.name = pdev->name;
+	trng->rng.read = hisi_trng_read;
+	trng->rng.quality = HISI_TRNG_QUALITY;
+
+	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
+	if (ret)
+		dev_err(&pdev->dev, "failed to register hwrng!\n");
+
+	return ret;
+}
+
+static const struct acpi_device_id hisi_trng_acpi_match[] = {
+	{ "HISI02B3", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);
+
+static struct platform_driver hisi_trng_driver = {
+	.probe		= hisi_trng_probe,
+	.driver		= {
+		.name	= "hisi-trng-v2",
+		.acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
+	},
+};
+
+module_platform_driver(hisi_trng_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
+MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
+MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");
diff --git a/drivers/char/hw_random/iproc-rng200.c b/drivers/char/hw_random/iproc-rng200.c
index 92be1c0ab99f..899ff25f4f28 100644
--- a/drivers/char/hw_random/iproc-rng200.c
+++ b/drivers/char/hw_random/iproc-rng200.c
@@ -181,7 +181,6 @@ static void iproc_rng200_cleanup(struct hwrng *rng)
 static int iproc_rng200_probe(struct platform_device *pdev)
 {
 	struct iproc_rng200_dev *priv;
-	struct resource *res;
 	struct device *dev = &pdev->dev;
 	int ret;
 
@@ -190,13 +189,7 @@ static int iproc_rng200_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	/* Map peripheral */
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(dev, "failed to get rng resources\n");
-		return -EINVAL;
-	}
-
-	priv->base = devm_ioremap_resource(dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base)) {
 		dev_err(dev, "failed to remap rng regs\n");
 		return PTR_ERR(priv->base);
diff --git a/drivers/char/hw_random/ks-sa-rng.c b/drivers/char/hw_random/ks-sa-rng.c
index a67430010aa6..e2330e757f1f 100644
--- a/drivers/char/hw_random/ks-sa-rng.c
+++ b/drivers/char/hw_random/ks-sa-rng.c
@@ -21,6 +21,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/delay.h>
+#include <linux/timekeeping.h>
 
 #define SA_CMD_STATUS_OFS			0x8
 
@@ -84,14 +85,37 @@ struct ks_sa_rng {
 	struct hwrng	rng;
 	struct clk	*clk;
 	struct regmap	*regmap_cfg;
-	struct trng_regs *reg_rng;
+	struct trng_regs __iomem *reg_rng;
+	u64 ready_ts;
+	unsigned int refill_delay_ns;
 };
 
+static unsigned int cycles_to_ns(unsigned long clk_rate, unsigned int cycles)
+{
+	return DIV_ROUND_UP_ULL((TRNG_DEF_CLK_DIV_CYCLES + 1) * 1000000000ull *
+				cycles, clk_rate);
+}
+
+static unsigned int startup_delay_ns(unsigned long clk_rate)
+{
+	if (!TRNG_DEF_STARTUP_CYCLES)
+		return cycles_to_ns(clk_rate, BIT(24));
+	return cycles_to_ns(clk_rate, 256 * TRNG_DEF_STARTUP_CYCLES);
+}
+
+static unsigned int refill_delay_ns(unsigned long clk_rate)
+{
+	if (!TRNG_DEF_MAX_REFILL_CYCLES)
+		return cycles_to_ns(clk_rate, BIT(24));
+	return cycles_to_ns(clk_rate, 256 * TRNG_DEF_MAX_REFILL_CYCLES);
+}
+
 static int ks_sa_rng_init(struct hwrng *rng)
 {
 	u32 value;
 	struct device *dev = (struct device *)rng->priv;
 	struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
+	unsigned long clk_rate = clk_get_rate(ks_sa_rng->clk);
 
 	/* Enable RNG module */
 	regmap_write_bits(ks_sa_rng->regmap_cfg, SA_CMD_STATUS_OFS,
@@ -120,6 +144,10 @@ static int ks_sa_rng_init(struct hwrng *rng)
 	value |= TRNG_CNTL_REG_TRNG_ENABLE;
 	writel(value, &ks_sa_rng->reg_rng->control);
 
+	ks_sa_rng->refill_delay_ns = refill_delay_ns(clk_rate);
+	ks_sa_rng->ready_ts = ktime_get_ns() +
+			      startup_delay_ns(clk_rate);
+
 	return 0;
 }
 
@@ -144,6 +172,7 @@ static int ks_sa_rng_data_read(struct hwrng *rng, u32 *data)
 	data[1] = readl(&ks_sa_rng->reg_rng->output_h);
 
 	writel(TRNG_INTACK_REG_READY, &ks_sa_rng->reg_rng->intack);
+	ks_sa_rng->ready_ts = ktime_get_ns() + ks_sa_rng->refill_delay_ns;
 
 	return sizeof(u32) * 2;
 }
@@ -152,10 +181,19 @@ static int ks_sa_rng_data_present(struct hwrng *rng, int wait)
 {
 	struct device *dev = (struct device *)rng->priv;
 	struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
+	u64 now = ktime_get_ns();
 
 	u32	ready;
 	int	j;
 
+	if (wait && now < ks_sa_rng->ready_ts) {
+		/* Max delay expected here is 81920000 ns */
+		unsigned long min_delay =
+			DIV_ROUND_UP((u32)(ks_sa_rng->ready_ts - now), 1000);
+
+		usleep_range(min_delay, min_delay + SA_RNG_DATA_RETRY_DELAY);
+	}
+
 	for (j = 0; j < SA_MAX_RNG_DATA_RETRIES; j++) {
 		ready = readl(&ks_sa_rng->reg_rng->status);
 		ready &= TRNG_STATUS_REG_READY;
@@ -174,7 +212,6 @@ static int ks_sa_rng_probe(struct platform_device *pdev)
 	struct ks_sa_rng	*ks_sa_rng;
 	struct device		*dev = &pdev->dev;
 	int			ret;
-	struct resource		*mem;
 
 	ks_sa_rng = devm_kzalloc(dev, sizeof(*ks_sa_rng), GFP_KERNEL);
 	if (!ks_sa_rng)
@@ -190,8 +227,7 @@ static int ks_sa_rng_probe(struct platform_device *pdev)
 	};
 	ks_sa_rng->rng.priv = (unsigned long)dev;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	ks_sa_rng->reg_rng = devm_ioremap_resource(dev, mem);
+	ks_sa_rng->reg_rng = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(ks_sa_rng->reg_rng))
 		return PTR_ERR(ks_sa_rng->reg_rng);
 
diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index 76e693da5dde..e446236e81f2 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c
@@ -42,7 +42,6 @@ static int meson_rng_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct meson_rng_data *data;
-	struct resource *res;
 	int ret;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
@@ -51,8 +50,7 @@ static int meson_rng_probe(struct platform_device *pdev)
 
 	data->pdev = pdev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	data->base = devm_ioremap_resource(dev, res);
+	data->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
 
diff --git a/drivers/char/hw_random/mtk-rng.c b/drivers/char/hw_random/mtk-rng.c
index e649be5a5f13..8ad7b515a51b 100644
--- a/drivers/char/hw_random/mtk-rng.c
+++ b/drivers/char/hw_random/mtk-rng.c
@@ -105,16 +105,9 @@ static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 
 static int mtk_rng_probe(struct platform_device *pdev)
 {
-	struct resource *res;
 	int ret;
 	struct mtk_rng *priv;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "no iomem resource\n");
-		return -ENXIO;
-	}
-
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -135,7 +128,7 @@ static int mtk_rng_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
diff --git a/drivers/char/hw_random/npcm-rng.c b/drivers/char/hw_random/npcm-rng.c
new file mode 100644
index 000000000000..01d04404d8c0
--- /dev/null
+++ b/drivers/char/hw_random/npcm-rng.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/pm_runtime.h>
+
+#define NPCM_RNGCS_REG		0x00	/* Control and status register */
+#define NPCM_RNGD_REG		0x04	/* Data register */
+#define NPCM_RNGMODE_REG	0x08	/* Mode register */
+
+#define NPCM_RNG_CLK_SET_25MHZ	GENMASK(4, 3) /* 20-25 MHz */
+#define NPCM_RNG_DATA_VALID	BIT(1)
+#define NPCM_RNG_ENABLE		BIT(0)
+#define NPCM_RNG_M1ROSEL	BIT(1)
+
+#define NPCM_RNG_TIMEOUT_USEC	20000
+#define NPCM_RNG_POLL_USEC	1000
+
+#define to_npcm_rng(p)	container_of(p, struct npcm_rng, rng)
+
+struct npcm_rng {
+	void __iomem *base;
+	struct hwrng rng;
+};
+
+static int npcm_rng_init(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+	       priv->base + NPCM_RNGCS_REG);
+
+	return 0;
+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+}
+
+static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+	int retval = 0;
+	int ready;
+
+	pm_runtime_get_sync((struct device *)priv->rng.priv);
+
+	while (max >= sizeof(u32)) {
+		if (wait) {
+			if (readl_poll_timeout(priv->base + NPCM_RNGCS_REG,
+					       ready,
+					       ready & NPCM_RNG_DATA_VALID,
+					       NPCM_RNG_POLL_USEC,
+					       NPCM_RNG_TIMEOUT_USEC))
+				break;
+		} else {
+			if ((readl(priv->base + NPCM_RNGCS_REG) &
+			    NPCM_RNG_DATA_VALID) == 0)
+				break;
+		}
+
+		*(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
+		retval += sizeof(u32);
+		buf += sizeof(u32);
+		max -= sizeof(u32);
+	}
+
+	pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+	pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
+	return retval || !wait ? retval : -EIO;
+}
+
+static int npcm_rng_probe(struct platform_device *pdev)
+{
+	struct npcm_rng *priv;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	dev_set_drvdata(&pdev->dev, priv);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+#ifndef CONFIG_PM
+	priv->rng.init = npcm_rng_init;
+	priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+	priv->rng.name = pdev->name;
+	priv->rng.read = npcm_rng_read;
+	priv->rng.priv = (unsigned long)&pdev->dev;
+	priv->rng.quality = 1000;
+
+	writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+
+	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+			ret);
+		pm_runtime_disable(&pdev->dev);
+		pm_runtime_set_suspended(&pdev->dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+	struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+	devm_hwrng_unregister(&pdev->dev, &priv->rng);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int npcm_rng_runtime_suspend(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	npcm_rng_cleanup(&priv->rng);
+
+	return 0;
+}
+
+static int npcm_rng_runtime_resume(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	return npcm_rng_init(&priv->rng);
+}
+#endif
+
+static const struct dev_pm_ops npcm_rng_pm_ops = {
+	SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,
+			   npcm_rng_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
+static const struct of_device_id rng_dt_id[] = {
+	{ .compatible = "nuvoton,npcm750-rng",  },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rng_dt_id);
+
+static struct platform_driver npcm_rng_driver = {
+	.driver = {
+		.name		= "npcm-rng",
+		.pm		= &npcm_rng_pm_ops,
+		.of_match_table = of_match_ptr(rng_dt_id),
+	},
+	.probe		= npcm_rng_probe,
+	.remove		= npcm_rng_remove,
+};
+
+module_platform_driver(npcm_rng_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
index b27f39688b5e..0ed07d16ec8e 100644
--- a/drivers/char/hw_random/omap-rng.c
+++ b/drivers/char/hw_random/omap-rng.c
@@ -66,6 +66,13 @@
 #define OMAP4_RNG_OUTPUT_SIZE			0x8
 #define EIP76_RNG_OUTPUT_SIZE			0x10
 
+/*
+ * EIP76 RNG takes approx. 700us to produce 16 bytes of output data
+ * as per testing results. And to account for the lack of udelay()'s
+ * reliability, we keep the timeout as 1000us.
+ */
+#define RNG_DATA_FILL_TIMEOUT			100
+
 enum {
 	RNG_OUTPUT_0_REG = 0,
 	RNG_OUTPUT_1_REG,
@@ -176,7 +183,7 @@ static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max,
 	if (max < priv->pdata->data_size)
 		return 0;
 
-	for (i = 0; i < 20; i++) {
+	for (i = 0; i < RNG_DATA_FILL_TIMEOUT; i++) {
 		present = priv->pdata->data_present(priv);
 		if (present || !wait)
 			break;
@@ -432,7 +439,6 @@ static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng)
 static int omap_rng_probe(struct platform_device *pdev)
 {
 	struct omap_rng_dev *priv;
-	struct resource *res;
 	struct device *dev = &pdev->dev;
 	int ret;
 
@@ -449,8 +455,7 @@ static int omap_rng_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, priv);
 	priv->dev = dev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base)) {
 		ret = PTR_ERR(priv->base);
 		goto err_ioremap;
diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c
index 38b719017186..e08a8887e718 100644
--- a/drivers/char/hw_random/omap3-rom-rng.c
+++ b/drivers/char/hw_random/omap3-rom-rng.c
@@ -11,8 +11,6 @@
  * warranty of any kind, whether express or implied.
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/random.h>
@@ -20,117 +18,159 @@
 #include <linux/workqueue.h>
 #include <linux/clk.h>
 #include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #define RNG_RESET			0x01
 #define RNG_GEN_PRNG_HW_INIT		0x02
 #define RNG_GEN_HW			0x08
 
-/* param1: ptr, param2: count, param3: flag */
-static u32 (*omap3_rom_rng_call)(u32, u32, u32);
-
-static struct delayed_work idle_work;
-static int rng_idle;
-static struct clk *rng_clk;
+struct omap_rom_rng {
+	struct clk *clk;
+	struct device *dev;
+	struct hwrng ops;
+	u32 (*rom_rng_call)(u32 ptr, u32 count, u32 flag);
+};
 
-static void omap3_rom_rng_idle(struct work_struct *work)
+static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)
 {
+	struct omap_rom_rng *ddata;
+	u32 ptr;
 	int r;
 
-	r = omap3_rom_rng_call(0, 0, RNG_RESET);
-	if (r != 0) {
-		pr_err("reset failed: %d\n", r);
-		return;
+	ddata = (struct omap_rom_rng *)rng->priv;
+
+	r = pm_runtime_get_sync(ddata->dev);
+	if (r < 0) {
+		pm_runtime_put_noidle(ddata->dev);
+
+		return r;
 	}
-	clk_disable_unprepare(rng_clk);
-	rng_idle = 1;
+
+	ptr = virt_to_phys(data);
+	r = ddata->rom_rng_call(ptr, 4, RNG_GEN_HW);
+	if (r != 0)
+		r = -EINVAL;
+	else
+		r = 4;
+
+	pm_runtime_mark_last_busy(ddata->dev);
+	pm_runtime_put_autosuspend(ddata->dev);
+
+	return r;
 }
 
-static int omap3_rom_rng_get_random(void *buf, unsigned int count)
+static int __maybe_unused omap_rom_rng_runtime_suspend(struct device *dev)
 {
-	u32 r;
-	u32 ptr;
+	struct omap_rom_rng *ddata;
+	int r;
 
-	cancel_delayed_work_sync(&idle_work);
-	if (rng_idle) {
-		r = clk_prepare_enable(rng_clk);
-		if (r)
-			return r;
-
-		r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
-		if (r != 0) {
-			clk_disable_unprepare(rng_clk);
-			pr_err("HW init failed: %d\n", r);
-			return -EIO;
-		}
-		rng_idle = 0;
-	}
+	ddata = dev_get_drvdata(dev);
 
-	ptr = virt_to_phys(buf);
-	r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
-	schedule_delayed_work(&idle_work, msecs_to_jiffies(500));
+	r = ddata->rom_rng_call(0, 0, RNG_RESET);
 	if (r != 0)
-		return -EINVAL;
+		dev_err(dev, "reset failed: %d\n", r);
+
+	clk_disable_unprepare(ddata->clk);
+
 	return 0;
 }
 
-static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)
+static int __maybe_unused omap_rom_rng_runtime_resume(struct device *dev)
 {
+	struct omap_rom_rng *ddata;
 	int r;
 
-	r = omap3_rom_rng_get_random(data, 4);
+	ddata = dev_get_drvdata(dev);
+
+	r = clk_prepare_enable(ddata->clk);
 	if (r < 0)
 		return r;
-	return 4;
+
+	r = ddata->rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
+	if (r != 0) {
+		clk_disable(ddata->clk);
+		dev_err(dev, "HW init failed: %d\n", r);
+
+		return -EIO;
+	}
+
+	return 0;
 }
 
-static struct hwrng omap3_rom_rng_ops = {
-	.name		= "omap3-rom",
-	.read		= omap3_rom_rng_read,
-};
+static void omap_rom_rng_finish(void *data)
+{
+	struct omap_rom_rng *ddata = data;
+
+	pm_runtime_dont_use_autosuspend(ddata->dev);
+	pm_runtime_disable(ddata->dev);
+}
 
 static int omap3_rom_rng_probe(struct platform_device *pdev)
 {
+	struct omap_rom_rng *ddata;
 	int ret = 0;
 
-	pr_info("initializing\n");
+	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
 
-	omap3_rom_rng_call = pdev->dev.platform_data;
-	if (!omap3_rom_rng_call) {
-		pr_err("omap3_rom_rng_call is NULL\n");
+	ddata->dev = &pdev->dev;
+	ddata->ops.priv = (unsigned long)ddata;
+	ddata->ops.name = "omap3-rom";
+	ddata->ops.read = of_device_get_match_data(&pdev->dev);
+	ddata->ops.quality = 900;
+	if (!ddata->ops.read) {
+		dev_err(&pdev->dev, "missing rom code handler\n");
+
+		return -ENODEV;
+	}
+	dev_set_drvdata(ddata->dev, ddata);
+
+	ddata->rom_rng_call = pdev->dev.platform_data;
+	if (!ddata->rom_rng_call) {
+		dev_err(ddata->dev, "rom_rng_call is NULL\n");
 		return -EINVAL;
 	}
 
-	INIT_DELAYED_WORK(&idle_work, omap3_rom_rng_idle);
-	rng_clk = devm_clk_get(&pdev->dev, "ick");
-	if (IS_ERR(rng_clk)) {
-		pr_err("unable to get RNG clock\n");
-		return PTR_ERR(rng_clk);
+	ddata->clk = devm_clk_get(ddata->dev, "ick");
+	if (IS_ERR(ddata->clk)) {
+		dev_err(ddata->dev, "unable to get RNG clock\n");
+		return PTR_ERR(ddata->clk);
 	}
 
-	/* Leave the RNG in reset state. */
-	ret = clk_prepare_enable(rng_clk);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 500);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
+	ret = devm_add_action_or_reset(ddata->dev, omap_rom_rng_finish,
+				       ddata);
 	if (ret)
 		return ret;
-	omap3_rom_rng_idle(0);
 
-	return hwrng_register(&omap3_rom_rng_ops);
+	return devm_hwrng_register(ddata->dev, &ddata->ops);
 }
 
-static int omap3_rom_rng_remove(struct platform_device *pdev)
-{
-	cancel_delayed_work_sync(&idle_work);
-	hwrng_unregister(&omap3_rom_rng_ops);
-	clk_disable_unprepare(rng_clk);
-	return 0;
-}
+static const struct of_device_id omap_rom_rng_match[] = {
+	{ .compatible = "nokia,n900-rom-rng", .data = omap3_rom_rng_read, },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, omap_rom_rng_match);
+
+static const struct dev_pm_ops omap_rom_rng_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(omap_rom_rng_runtime_suspend,
+				omap_rom_rng_runtime_resume)
+};
 
 static struct platform_driver omap3_rom_rng_driver = {
 	.driver = {
 		.name		= "omap3-rom-rng",
+		.of_match_table = omap_rom_rng_match,
+		.pm = &omap_rom_rng_pm_ops,
 	},
 	.probe		= omap3_rom_rng_probe,
-	.remove		= omap3_rom_rng_remove,
 };
 
 module_platform_driver(omap3_rom_rng_driver);
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c
index 24b1460b49d4..2498d4ef9fe2 100644
--- a/drivers/char/hw_random/pasemi-rng.c
+++ b/drivers/char/hw_random/pasemi-rng.c
@@ -86,10 +86,8 @@ static struct hwrng pasemi_rng = {
 static int rng_probe(struct platform_device *pdev)
 {
 	void __iomem *rng_regs;
-	struct resource *res;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	rng_regs = devm_ioremap_resource(&pdev->dev, res);
+	rng_regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rng_regs))
 		return PTR_ERR(rng_regs);
 
diff --git a/drivers/char/hw_random/pic32-rng.c b/drivers/char/hw_random/pic32-rng.c
index 90f498c98947..81080cb2294e 100644
--- a/drivers/char/hw_random/pic32-rng.c
+++ b/drivers/char/hw_random/pic32-rng.c
@@ -70,7 +70,6 @@ static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max,
 static int pic32_rng_probe(struct platform_device *pdev)
 {
 	struct pic32_rng *priv;
-	struct resource *res;
 	u32 v;
 	int ret;
 
@@ -78,8 +77,7 @@ static int pic32_rng_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
diff --git a/drivers/char/hw_random/st-rng.c b/drivers/char/hw_random/st-rng.c
index 863448360a7d..783c24e3f8b7 100644
--- a/drivers/char/hw_random/st-rng.c
+++ b/drivers/char/hw_random/st-rng.c
@@ -72,7 +72,6 @@ static int st_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 static int st_rng_probe(struct platform_device *pdev)
 {
 	struct st_rng_data *ddata;
-	struct resource *res;
 	struct clk *clk;
 	void __iomem *base;
 	int ret;
@@ -81,8 +80,7 @@ static int st_rng_probe(struct platform_device *pdev)
 	if (!ddata)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, res);
+	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
diff --git a/drivers/char/hw_random/tx4939-rng.c b/drivers/char/hw_random/tx4939-rng.c
index 1093583b579c..c8bd34e740fd 100644
--- a/drivers/char/hw_random/tx4939-rng.c
+++ b/drivers/char/hw_random/tx4939-rng.c
@@ -107,14 +107,12 @@ static int tx4939_rng_data_read(struct hwrng *rng, u32 *buffer)
 static int __init tx4939_rng_probe(struct platform_device *dev)
 {
 	struct tx4939_rng *rngdev;
-	struct resource *r;
 	int i;
 
 	rngdev = devm_kzalloc(&dev->dev, sizeof(*rngdev), GFP_KERNEL);
 	if (!rngdev)
 		return -ENOMEM;
-	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
-	rngdev->base = devm_ioremap_resource(&dev->dev, r);
+	rngdev->base = devm_platform_ioremap_resource(dev, 0);
 	if (IS_ERR(rngdev->base))
 		return PTR_ERR(rngdev->base);
 
diff --git a/drivers/char/hw_random/xgene-rng.c b/drivers/char/hw_random/xgene-rng.c
index 7e568db87ae2..d7516a446987 100644
--- a/drivers/char/hw_random/xgene-rng.c
+++ b/drivers/char/hw_random/xgene-rng.c
@@ -313,7 +313,6 @@ static struct hwrng xgene_rng_func = {
 
 static int xgene_rng_probe(struct platform_device *pdev)
 {
-	struct resource *res;
 	struct xgene_rng_dev *ctx;
 	int rc = 0;
 
@@ -324,8 +323,7 @@ static int xgene_rng_probe(struct platform_device *pdev)
 	ctx->dev = &pdev->dev;
 	platform_set_drvdata(pdev, ctx);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	ctx->csr_base = devm_ioremap_resource(&pdev->dev, res);
+	ctx->csr_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(ctx->csr_base))
 		return PTR_ERR(ctx->csr_base);