Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 354 insertions, 40 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d7502433c7..3814e0845e 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1351,7 +1351,7 @@ config RTC_DRV_DIGICOLOR
 
 config RTC_DRV_IMXDI
 	tristate "Freescale IMX DryIce Real Time Clock"
-	depends on ARCH_MXC
+	depends on ARCH_MXC || COMPILE_TEST
 	depends on OF
 	help
 	   Support for Freescale IMX DryIce RTC
@@ -1984,4 +1984,15 @@ config RTC_DRV_POLARFIRE_SOC
 	  This driver can also be built as a module, if so, the module
 	  will be called "rtc-mpfs".
 
+config RTC_DRV_SSD202D
+	tristate "SigmaStar SSD202D RTC"
+	depends on ARCH_MSTARV7 || COMPILE_TEST
+	default ARCH_MSTARV7
+	help
+	  If you say yes here you get support for the SigmaStar SSD202D On-Chip
+	  Real Time Clock.
+
+	  This driver can also be built as a module, if so, the module
+	  will be called "rtc-ssd20xd".
+
 endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index fd209883ee..7b03c3abfd 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_RTC_DRV_MESON)	+= rtc-meson.o
 obj-$(CONFIG_RTC_DRV_MOXART)	+= rtc-moxart.o
 obj-$(CONFIG_RTC_DRV_MPC5121)	+= rtc-mpc5121.o
 obj-$(CONFIG_RTC_DRV_MSC313)	+= rtc-msc313.o
+obj-$(CONFIG_RTC_DRV_SSD202D)	+= rtc-ssd202d.o
 obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o
 obj-$(CONFIG_RTC_DRV_MT2712)	+= rtc-mt2712.o
 obj-$(CONFIG_RTC_DRV_MT6397)	+= rtc-mt6397.o
diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
index 07ede21cee..37df7e8052 100644
--- a/drivers/rtc/nvmem.c
+++ b/drivers/rtc/nvmem.c
@@ -21,6 +21,7 @@ int devm_rtc_nvmem_register(struct rtc_device *rtc,
 
 	nvmem_config->dev = dev;
 	nvmem_config->owner = rtc->owner;
+	nvmem_config->add_legacy_fixed_of_cells = true;
 	nvmem = devm_nvmem_register(dev, nvmem_config);
 	if (IS_ERR(nvmem))
 		dev_err(dev, "failed to register nvmem device for RTC\n");
diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index add4f71d7b..c16fe711a0 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -558,7 +558,7 @@ err_clk:
 /*
  * Disable and remove the RTC driver
  */
-static int __exit at91_rtc_remove(struct platform_device *pdev)
+static void __exit at91_rtc_remove(struct platform_device *pdev)
 {
 	/* Disable all interrupts */
 	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
@@ -566,8 +566,6 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
 					AT91_RTC_CALEV);
 
 	clk_disable_unprepare(sclk);
-
-	return 0;
 }
 
 static void at91_rtc_shutdown(struct platform_device *pdev)
@@ -635,8 +633,14 @@ static int at91_rtc_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 
-static struct platform_driver at91_rtc_driver = {
-	.remove		= __exit_p(at91_rtc_remove),
+/*
+ * at91_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver at91_rtc_driver __refdata = {
+	.remove_new	= __exit_p(at91_rtc_remove),
 	.shutdown	= at91_rtc_shutdown,
 	.driver		= {
 		.name	= "at91_rtc",
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index dc6b0f4a54..fa8bf82df9 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -227,7 +227,7 @@ static int efi_procfs(struct device *dev, struct seq_file *seq)
 			   enabled == 1 ? "yes" : "no",
 			   pending == 1 ? "yes" : "no");
 
-		if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
+		if (alm.timezone == EFI_UNSPECIFIED_TIMEZONE)
 			seq_puts(seq, "Timezone\t: unspecified\n");
 		else
 			/* XXX fixme: convert to string? */
diff --git a/drivers/rtc/rtc-ep93xx.c b/drivers/rtc/rtc-ep93xx.c
index acae7f1680..1fdd20d015 100644
--- a/drivers/rtc/rtc-ep93xx.c
+++ b/drivers/rtc/rtc-ep93xx.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 #include <linux/rtc.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
@@ -148,9 +149,16 @@ static int ep93xx_rtc_probe(struct platform_device *pdev)
 	return devm_rtc_register_device(ep93xx_rtc->rtc);
 }
 
+static const struct of_device_id ep93xx_rtc_of_ids[] = {
+	{ .compatible = "cirrus,ep9301-rtc" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ep93xx_rtc_of_ids);
+
 static struct platform_driver ep93xx_rtc_driver = {
 	.driver		= {
 		.name	= "ep93xx-rtc",
+		.of_match_table = ep93xx_rtc_of_ids,
 	},
 	.probe		= ep93xx_rtc_probe,
 };
diff --git a/drivers/rtc/rtc-imxdi.c b/drivers/rtc/rtc-imxdi.c
index 4b712e5ab0..284011c419 100644
--- a/drivers/rtc/rtc-imxdi.c
+++ b/drivers/rtc/rtc-imxdi.c
@@ -830,7 +830,7 @@ err:
 	return rc;
 }
 
-static int __exit dryice_rtc_remove(struct platform_device *pdev)
+static void __exit dryice_rtc_remove(struct platform_device *pdev)
 {
 	struct imxdi_dev *imxdi = platform_get_drvdata(pdev);
 
@@ -840,8 +840,6 @@ static int __exit dryice_rtc_remove(struct platform_device *pdev)
 	writel(0, imxdi->ioaddr + DIER);
 
 	clk_disable_unprepare(imxdi->clk);
-
-	return 0;
 }
 
 static const struct of_device_id dryice_dt_ids[] = {
@@ -851,12 +849,18 @@ static const struct of_device_id dryice_dt_ids[] = {
 
 MODULE_DEVICE_TABLE(of, dryice_dt_ids);
 
-static struct platform_driver dryice_rtc_driver = {
+/*
+ * dryice_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver dryice_rtc_driver __refdata = {
 	.driver = {
 		   .name = "imxdi_rtc",
 		   .of_match_table = dryice_dt_ids,
 		   },
-	.remove = __exit_p(dryice_rtc_remove),
+	.remove_new = __exit_p(dryice_rtc_remove),
 };
 
 module_platform_driver_probe(dryice_rtc_driver, dryice_rtc_probe);
diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
index 6c526e2ec5..db31da56bf 100644
--- a/drivers/rtc/rtc-mv.c
+++ b/drivers/rtc/rtc-mv.c
@@ -282,7 +282,7 @@ out:
 	return ret;
 }
 
-static int __exit mv_rtc_remove(struct platform_device *pdev)
+static void __exit mv_rtc_remove(struct platform_device *pdev)
 {
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 
@@ -291,8 +291,6 @@ static int __exit mv_rtc_remove(struct platform_device *pdev)
 
 	if (!IS_ERR(pdata->clk))
 		clk_disable_unprepare(pdata->clk);
-
-	return 0;
 }
 
 #ifdef CONFIG_OF
@@ -303,8 +301,14 @@ static const struct of_device_id rtc_mv_of_match_table[] = {
 MODULE_DEVICE_TABLE(of, rtc_mv_of_match_table);
 #endif
 
-static struct platform_driver mv_rtc_driver = {
-	.remove		= __exit_p(mv_rtc_remove),
+/*
+ * mv_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver mv_rtc_driver __refdata = {
+	.remove_new	= __exit_p(mv_rtc_remove),
 	.driver		= {
 		.name	= "rtc-mv",
 		.of_match_table = of_match_ptr(rtc_mv_of_match_table),
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 5b10ab06cd..c6155c48a4 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -18,12 +18,12 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/of_device.h>
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinconf-generic.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 #include <linux/rtc.h>
 #include <linux/rtc/rtc-omap.h>
 
@@ -729,16 +729,14 @@ static int omap_rtc_probe(struct platform_device *pdev)
 	struct omap_rtc	*rtc;
 	u8 reg, mask, new_ctrl;
 	const struct platform_device_id *id_entry;
-	const struct of_device_id *of_id;
 	int ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;
 
-	of_id = of_match_device(omap_rtc_of_match, &pdev->dev);
-	if (of_id) {
-		rtc->type = of_id->data;
+	rtc->type = device_get_match_data(&pdev->dev);
+	if (rtc->type) {
 		rtc->is_pmic_controller = rtc->type->has_pmic_mode &&
 			of_device_is_system_power_controller(pdev->dev.of_node);
 	} else {
diff --git a/drivers/rtc/rtc-pcap.c b/drivers/rtc/rtc-pcap.c
index 8c7a98a545..d6651611a0 100644
--- a/drivers/rtc/rtc-pcap.c
+++ b/drivers/rtc/rtc-pcap.c
@@ -166,13 +166,7 @@ static int __init pcap_rtc_probe(struct platform_device *pdev)
 	return devm_rtc_register_device(pcap_rtc->rtc);
 }
 
-static int __exit pcap_rtc_remove(struct platform_device *pdev)
-{
-	return 0;
-}
-
 static struct platform_driver pcap_rtc_driver = {
-	.remove = __exit_p(pcap_rtc_remove),
 	.driver = {
 		.name  = "pcap-rtc",
 	},
diff --git a/drivers/rtc/rtc-pxa.c b/drivers/rtc/rtc-pxa.c
index e400c78252..cdb39fc4ca 100644
--- a/drivers/rtc/rtc-pxa.c
+++ b/drivers/rtc/rtc-pxa.c
@@ -365,12 +365,11 @@ static int __init pxa_rtc_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int __exit pxa_rtc_remove(struct platform_device *pdev)
+static void __exit pxa_rtc_remove(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 
 	pxa_rtc_release(dev);
-	return 0;
 }
 
 #ifdef CONFIG_OF
@@ -403,8 +402,14 @@ static int pxa_rtc_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(pxa_rtc_pm_ops, pxa_rtc_suspend, pxa_rtc_resume);
 
-static struct platform_driver pxa_rtc_driver = {
-	.remove		= __exit_p(pxa_rtc_remove),
+/*
+ * pxa_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver pxa_rtc_driver __refdata = {
+	.remove_new	= __exit_p(pxa_rtc_remove),
 	.driver		= {
 		.name	= "pxa-rtc",
 		.of_match_table = of_match_ptr(pxa_rtc_dt_ids),
diff --git a/drivers/rtc/rtc-r7301.c b/drivers/rtc/rtc-r7301.c
index 5dbaeb7af6..ef913cf859 100644
--- a/drivers/rtc/rtc-r7301.c
+++ b/drivers/rtc/rtc-r7301.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/delay.h>
+#include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
@@ -55,12 +56,23 @@ struct rtc7301_priv {
 	u8 bank;
 };
 
-static const struct regmap_config rtc7301_regmap_config = {
+/*
+ * When the device is memory-mapped, some platforms pack the registers into
+ * 32-bit access using the lower 8 bits at each 4-byte stride, while others
+ * expose them as simply consecutive bytes.
+ */
+static const struct regmap_config rtc7301_regmap_32_config = {
 	.reg_bits = 32,
 	.val_bits = 8,
 	.reg_stride = 4,
 };
 
+static const struct regmap_config rtc7301_regmap_8_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.reg_stride = 1,
+};
+
 static u8 rtc7301_read(struct rtc7301_priv *priv, unsigned int reg)
 {
 	int reg_stride = regmap_get_reg_stride(priv->regmap);
@@ -356,7 +368,9 @@ static int __init rtc7301_rtc_probe(struct platform_device *dev)
 	void __iomem *regs;
 	struct rtc7301_priv *priv;
 	struct rtc_device *rtc;
+	static const struct regmap_config *mapconf;
 	int ret;
+	u32 val;
 
 	priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -366,8 +380,25 @@ static int __init rtc7301_rtc_probe(struct platform_device *dev)
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);
 
+	ret = device_property_read_u32(&dev->dev, "reg-io-width", &val);
+	if (ret)
+		/* Default to 32bit accesses */
+		val = 4;
+
+	switch (val) {
+	case 1:
+		mapconf = &rtc7301_regmap_8_config;
+		break;
+	case 4:
+		mapconf = &rtc7301_regmap_32_config;
+		break;
+	default:
+		dev_err(&dev->dev, "invalid reg-io-width %d\n", val);
+		return -EINVAL;
+	}
+
 	priv->regmap = devm_regmap_init_mmio(&dev->dev, regs,
-					     &rtc7301_regmap_config);
+					     mapconf);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);
 
diff --git a/drivers/rtc/rtc-sh.c b/drivers/rtc/rtc-sh.c
index cd146b5741..27a191fa37 100644
--- a/drivers/rtc/rtc-sh.c
+++ b/drivers/rtc/rtc-sh.c
@@ -469,7 +469,7 @@ static int __init sh_rtc_probe(struct platform_device *pdev)
 {
 	struct sh_rtc *rtc;
 	struct resource *res;
-	char clk_name[6];
+	char clk_name[14];
 	int clk_id, ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
@@ -620,7 +620,7 @@ err_unmap:
 	return ret;
 }
 
-static int __exit sh_rtc_remove(struct platform_device *pdev)
+static void __exit sh_rtc_remove(struct platform_device *pdev)
 {
 	struct sh_rtc *rtc = platform_get_drvdata(pdev);
 
@@ -628,8 +628,6 @@ static int __exit sh_rtc_remove(struct platform_device *pdev)
 	sh_rtc_setcie(&pdev->dev, 0);
 
 	clk_disable(rtc->clk);
-
-	return 0;
 }
 
 static void sh_rtc_set_irq_wake(struct device *dev, int enabled)
@@ -668,13 +666,19 @@ static const struct of_device_id sh_rtc_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, sh_rtc_of_match);
 
-static struct platform_driver sh_rtc_platform_driver = {
+/*
+ * sh_rtc_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver sh_rtc_platform_driver __refdata = {
 	.driver		= {
 		.name	= DRV_NAME,
 		.pm	= &sh_rtc_pm_ops,
 		.of_match_table = sh_rtc_of_match,
 	},
-	.remove		= __exit_p(sh_rtc_remove),
+	.remove_new	= __exit_p(sh_rtc_remove),
 };
 
 module_platform_driver_probe(sh_rtc_platform_driver, sh_rtc_probe);
diff --git a/drivers/rtc/rtc-ssd202d.c b/drivers/rtc/rtc-ssd202d.c
new file mode 100644
index 0000000000..ed64932600
--- /dev/null
+++ b/drivers/rtc/rtc-ssd202d.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Real time clocks driver for MStar/SigmaStar SSD202D SoCs.
+ *
+ * (C) 2021 Daniel Palmer
+ * (C) 2023 Romain Perier
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/regmap.h>
+#include <linux/pm.h>
+
+#define REG_CTRL	0x0
+#define REG_CTRL1	0x4
+#define REG_ISO_CTRL	0xc
+#define REG_WRDATA_L	0x10
+#define REG_WRDATA_H	0x14
+#define REG_ISOACK	0x20
+#define REG_RDDATA_L	0x24
+#define REG_RDDATA_H	0x28
+#define REG_RDCNT_L	0x30
+#define REG_RDCNT_H	0x34
+#define REG_CNT_TRIG	0x38
+#define REG_PWRCTRL	0x3c
+#define REG_RTC_TEST	0x54
+
+#define CNT_RD_TRIG_BIT BIT(0)
+#define CNT_RD_BIT BIT(0)
+#define BASE_WR_BIT BIT(1)
+#define BASE_RD_BIT BIT(2)
+#define CNT_RST_BIT BIT(3)
+#define ISO_CTRL_ACK_MASK BIT(3)
+#define ISO_CTRL_ACK_SHIFT 3
+#define SW0_WR_BIT BIT(5)
+#define SW1_WR_BIT BIT(6)
+#define SW0_RD_BIT BIT(7)
+#define SW1_RD_BIT BIT(8)
+
+#define ISO_CTRL_MASK GENMASK(2, 0)
+
+struct ssd202d_rtc {
+	struct rtc_device *rtc_dev;
+	void __iomem *base;
+};
+
+static u8 read_iso_en(void __iomem *base)
+{
+	return readb(base + REG_RTC_TEST) & 0x1;
+}
+
+static u8 read_iso_ctrl_ack(void __iomem *base)
+{
+	return (readb(base + REG_ISOACK) & ISO_CTRL_ACK_MASK) >> ISO_CTRL_ACK_SHIFT;
+}
+
+static int ssd202d_rtc_isoctrl(struct ssd202d_rtc *priv)
+{
+	static const unsigned int sequence[] = { 0x0, 0x1, 0x3, 0x7, 0x5, 0x1, 0x0 };
+	unsigned int val;
+	struct device *dev = &priv->rtc_dev->dev;
+	int i, ret;
+
+	/*
+	 * This gates iso_en by writing a special sequence of bytes to iso_ctrl
+	 * and ensuring that it has been correctly applied by reading iso_ctrl_ack
+	 */
+	for (i = 0; i < ARRAY_SIZE(sequence); i++) {
+		writeb(sequence[i] & ISO_CTRL_MASK, priv->base +  REG_ISO_CTRL);
+
+		ret = read_poll_timeout(read_iso_ctrl_ack, val, val == (i % 2), 100,
+					20 * 100, true, priv->base);
+		if (ret) {
+			dev_dbg(dev, "Timeout waiting for ack byte %i (%x) of sequence\n", i,
+				sequence[i]);
+			return ret;
+		}
+	}
+
+	/*
+	 * At this point iso_en should be raised for 1ms
+	 */
+	ret = read_poll_timeout(read_iso_en, val, val, 100, 22 * 100, true, priv->base);
+	if (ret)
+		dev_dbg(dev, "Timeout waiting for iso_en\n");
+	mdelay(2);
+	return 0;
+}
+
+static void ssd202d_rtc_read_reg(struct ssd202d_rtc *priv, unsigned int reg,
+				 unsigned int field, unsigned int *base)
+{
+	unsigned int l, h;
+	u16 val;
+
+	/* Ask for the content of an RTC value into RDDATA by gating iso_en,
+	 * then iso_en is gated and the content of RDDATA can be read
+	 */
+	val = readw(priv->base + reg);
+	writew(val | field, priv->base + reg);
+	ssd202d_rtc_isoctrl(priv);
+	writew(val & ~field, priv->base + reg);
+
+	l = readw(priv->base + REG_RDDATA_L);
+	h = readw(priv->base + REG_RDDATA_H);
+
+	*base = (h << 16) | l;
+}
+
+static void ssd202d_rtc_write_reg(struct ssd202d_rtc *priv, unsigned int reg,
+				  unsigned int field, u32 base)
+{
+	u16 val;
+
+	/* Set the content of an RTC value from WRDATA by gating iso_en */
+	val = readw(priv->base + reg);
+	writew(val | field, priv->base + reg);
+	writew(base, priv->base + REG_WRDATA_L);
+	writew(base >> 16, priv->base + REG_WRDATA_H);
+	ssd202d_rtc_isoctrl(priv);
+	writew(val & ~field, priv->base + reg);
+}
+
+static int ssd202d_rtc_read_counter(struct ssd202d_rtc *priv, unsigned int *counter)
+{
+	unsigned int l, h;
+	u16 val;
+
+	val = readw(priv->base + REG_CTRL1);
+	writew(val | CNT_RD_BIT, priv->base + REG_CTRL1);
+	ssd202d_rtc_isoctrl(priv);
+	writew(val & ~CNT_RD_BIT, priv->base + REG_CTRL1);
+
+	val = readw(priv->base + REG_CTRL1);
+	writew(val | CNT_RD_TRIG_BIT, priv->base + REG_CNT_TRIG);
+	writew(val & ~CNT_RD_TRIG_BIT, priv->base + REG_CNT_TRIG);
+
+	l = readw(priv->base + REG_RDCNT_L);
+	h = readw(priv->base + REG_RDCNT_H);
+
+	*counter = (h << 16) | l;
+
+	return 0;
+}
+
+static int ssd202d_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ssd202d_rtc *priv = dev_get_drvdata(dev);
+	unsigned int sw0, base, counter;
+	u32 seconds;
+	int ret;
+
+	/* Check that RTC is enabled by SW */
+	ssd202d_rtc_read_reg(priv, REG_CTRL, SW0_RD_BIT, &sw0);
+	if (sw0 != 1)
+		return -EINVAL;
+
+	/* Get RTC base value from RDDATA */
+	ssd202d_rtc_read_reg(priv, REG_CTRL, BASE_RD_BIT, &base);
+	/* Get RTC counter value from RDDATA */
+	ret = ssd202d_rtc_read_counter(priv, &counter);
+	if (ret)
+		return ret;
+
+	seconds = base + counter;
+
+	rtc_time64_to_tm(seconds, tm);
+
+	return 0;
+}
+
+static int ssd202d_rtc_reset_counter(struct ssd202d_rtc *priv)
+{
+	u16 val;
+
+	val = readw(priv->base + REG_CTRL);
+	writew(val | CNT_RST_BIT, priv->base + REG_CTRL);
+	ssd202d_rtc_isoctrl(priv);
+	writew(val & ~CNT_RST_BIT, priv->base + REG_CTRL);
+	ssd202d_rtc_isoctrl(priv);
+
+	return 0;
+}
+
+static int ssd202d_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ssd202d_rtc *priv = dev_get_drvdata(dev);
+	unsigned long seconds = rtc_tm_to_time64(tm);
+
+	ssd202d_rtc_write_reg(priv, REG_CTRL, BASE_WR_BIT, seconds);
+	ssd202d_rtc_reset_counter(priv);
+	ssd202d_rtc_write_reg(priv, REG_CTRL, SW0_WR_BIT, 1);
+
+	return 0;
+}
+
+static const struct rtc_class_ops ssd202d_rtc_ops = {
+	.read_time = ssd202d_rtc_read_time,
+	.set_time = ssd202d_rtc_set_time,
+};
+
+static int ssd202d_rtc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ssd202d_rtc *priv;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(struct ssd202d_rtc), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->rtc_dev = devm_rtc_allocate_device(dev);
+	if (IS_ERR(priv->rtc_dev))
+		return PTR_ERR(priv->rtc_dev);
+
+	priv->rtc_dev->ops = &ssd202d_rtc_ops;
+	priv->rtc_dev->range_max = U32_MAX;
+
+	platform_set_drvdata(pdev, priv);
+
+	return devm_rtc_register_device(priv->rtc_dev);
+}
+
+static const struct of_device_id ssd202d_rtc_of_match_table[] = {
+	{ .compatible = "mstar,ssd202d-rtc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ssd202d_rtc_of_match_table);
+
+static struct platform_driver ssd202d_rtc_driver = {
+	.probe = ssd202d_rtc_probe,
+	.driver = {
+		.name = "ssd202d-rtc",
+		.of_match_table = ssd202d_rtc_of_match_table,
+	},
+};
+module_platform_driver(ssd202d_rtc_driver);
+
+MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
+MODULE_AUTHOR("Romain Perier <romain.perier@gmail.com>");
+MODULE_DESCRIPTION("MStar SSD202D RTC Driver");
+MODULE_LICENSE("GPL");