[RFC PATCH v2 2/2] rtc: add driver for Marvell 88PM886 PMIC RTC
From: Karel Balej
Date: Sat Oct 12 2024 - 15:34:49 EST
RTC lives on the chip's base register page. Add the relevant register
definitions and implement a basic set/read time functionality. Tested
with the samsung,coreprimevelte smartphone which contains this PMIC and
whose vendor kernel tree has also served as the sole reference for this.
Signed-off-by: Karel Balej <balejk@xxxxxxxxx>
---
Notes:
RFC v2:
- Move in the register definitions from the preceding patch and reword
the commit message accordingly.
- Rebase to v6.12-rc2.
MAINTAINERS | 1 +
drivers/rtc/Kconfig | 10 ++++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-88pm886.c | 97 +++++++++++++++++++++++++++++++++++++
include/linux/mfd/88pm886.h | 9 ++++
5 files changed, 118 insertions(+)
create mode 100644 drivers/rtc/rtc-88pm886.c
diff --git a/MAINTAINERS b/MAINTAINERS
index a097afd76ded..3a15b8711041 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13710,6 +13710,7 @@ F: Documentation/devicetree/bindings/mfd/marvell,88pm886-a1.yaml
F: drivers/input/misc/88pm886-onkey.c
F: drivers/mfd/88pm886.c
F: drivers/regulator/88pm886-regulator.c
+F: drivers/rtc/rtc-88pm886.c
F: include/linux/mfd/88pm886.h
MARVELL ARMADA 3700 PHY DRIVERS
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 66eb1122248b..2718ea194dd4 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -182,6 +182,16 @@ config RTC_DRV_88PM80X
This driver can also be built as a module. If so, the module
will be called rtc-88pm80x.
+config RTC_DRV_88PM886
+ tristate "Marvell 88PM886 RTC driver"
+ depends on MFD_88PM886_PMIC
+ help
+ If you say yes here you will get support for the RTC function in the
+ Marvell 88PM886 chip.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-88pm886.
+
config RTC_DRV_ABB5ZES3
select REGMAP_I2C
tristate "Abracon AB-RTCMC-32.768kHz-B5ZE-S3"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index f62340ecc534..70bbce968a43 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_RTC_LIB_KUNIT_TEST) += lib_test.o
obj-$(CONFIG_RTC_DRV_88PM80X) += rtc-88pm80x.o
obj-$(CONFIG_RTC_DRV_88PM860X) += rtc-88pm860x.o
+obj-$(CONFIG_RTC_DRV_88PM886) += rtc-88pm886.o
obj-$(CONFIG_RTC_DRV_AB8500) += rtc-ab8500.o
obj-$(CONFIG_RTC_DRV_ABB5ZES3) += rtc-ab-b5ze-s3.o
obj-$(CONFIG_RTC_DRV_ABEOZ9) += rtc-ab-eoz9.o
diff --git a/drivers/rtc/rtc-88pm886.c b/drivers/rtc/rtc-88pm886.c
new file mode 100644
index 000000000000..57e9b0a66eed
--- /dev/null
+++ b/drivers/rtc/rtc-88pm886.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/limits.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#include <linux/mfd/88pm886.h>
+
+/*
+ * Time is calculated as the sum of a 32-bit read-only advancing counter and a
+ * writeable constant offset stored in the chip's spare registers.
+ */
+
+static int pm886_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+ u32 time;
+ u32 buf;
+ int ret;
+
+ ret = regmap_bulk_read(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
+ if (ret)
+ return ret;
+ time = buf;
+
+ ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
+ if (ret)
+ return ret;
+ time += buf;
+
+ rtc_time64_to_tm(time, tm);
+
+ return 0;
+}
+
+static int pm886_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+ u32 buf;
+ int ret;
+
+ ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
+ if (ret)
+ return ret;
+
+ buf = rtc_tm_to_time64(tm) - buf;
+
+ return regmap_bulk_write(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
+}
+
+static const struct rtc_class_ops pm886_rtc_ops = {
+ .read_time = pm886_rtc_read_time,
+ .set_time = pm886_rtc_set_time,
+};
+
+static int pm886_rtc_probe(struct platform_device *pdev)
+{
+ struct pm886_chip *chip = dev_get_drvdata(pdev->dev.parent);
+ struct device *dev = &pdev->dev;
+ struct rtc_device *rtc;
+ int ret;
+
+ platform_set_drvdata(pdev, chip->regmap);
+
+ rtc = devm_rtc_allocate_device(dev);
+ if (IS_ERR(rtc))
+ return dev_err_probe(dev, PTR_ERR(rtc),
+ "Failed to allocate RTC device\n");
+
+ rtc->ops = &pm886_rtc_ops;
+ rtc->range_max = U32_MAX;
+
+ ret = devm_rtc_register_device(rtc);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to register RTC device\n");
+
+ return 0;
+}
+
+static const struct platform_device_id pm886_rtc_id_table[] = {
+ { "88pm886-rtc", },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, pm886_rtc_id_table);
+
+static struct platform_driver pm886_rtc_driver = {
+ .driver = {
+ .name = "88pm886-rtc",
+ },
+ .probe = pm886_rtc_probe,
+ .id_table = pm886_rtc_id_table,
+};
+module_platform_driver(pm886_rtc_driver);
+
+MODULE_DESCRIPTION("Marvell 88PM886 RTC driver");
+MODULE_AUTHOR("Karel Balej <balejk@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/88pm886.h b/include/linux/mfd/88pm886.h
index 133aa302e492..85eca44f39ab 100644
--- a/include/linux/mfd/88pm886.h
+++ b/include/linux/mfd/88pm886.h
@@ -31,6 +31,15 @@
#define PM886_INT_WC BIT(1)
#define PM886_INT_MASK_MODE BIT(2)
+#define PM886_REG_RTC_CNT1 0xd1
+#define PM886_REG_RTC_CNT2 0xd2
+#define PM886_REG_RTC_CNT3 0xd3
+#define PM886_REG_RTC_CNT4 0xd4
+#define PM886_REG_RTC_SPARE1 0xea
+#define PM886_REG_RTC_SPARE2 0xeb
+#define PM886_REG_RTC_SPARE3 0xec
+#define PM886_REG_RTC_SPARE4 0xed
+#define PM886_REG_RTC_SPARE5 0xee
#define PM886_REG_RTC_SPARE6 0xef
#define PM886_REG_BUCK_EN 0x08
--
2.47.0