[PATCH v3 3/3] RTC: nuvoton: Add NCT3018Y real time clock driver

medadyoung
2022-05-27T08:47:24Z

From: Medad CChien <ctcchien@nuvoton.com>

Add real time clock support for NCT3018Y.

Signed-off-by: Medad CChien <ctcchien@nuvoton.com>
---
MAINTAINERS | 1 +
drivers/rtc/Kconfig | 10 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-nct3018y.c | 559 +++++++++++++++++++++++++++++++++++++
4 files changed, 571 insertions(+)
create mode 100644 drivers/rtc/rtc-nct3018y.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 5a4302e9aad2..7a8f3b04ca61 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2372,6 +2372,7 @@ F: arch/arm/boot/dts/nuvoton-npcm*
F: arch/arm/mach-npcm/
F: drivers/*/*npcm*
F: drivers/*/*/*npcm*
+F: drivers/rtc/rtc-nct3018y.c
F: include/dt-bindings/clock/nuvoton,npcm7xx-clock.h

ARM/NUVOTON WPCM450 ARCHITECTURE
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d85a3c31347c..a61f9fd0b8fc 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -383,6 +383,16 @@ config RTC_DRV_MAX77686
This driver can also be built as a module. If so, the module
will be called rtc-max77686.

+config RTC_DRV_NCT3018Y
+ tristate "Nuvoton NCT3018Y"
+ depends on OF
+ help
+ If you say yes here you get support for the Nuvoton NCT3018Y I2C RTC
+ chip.
+
+ This driver can also be built as a module, if so, the module will be
+ called "rtc-nct3018y".
+
config RTC_DRV_RK808
tristate "Rockchip RK805/RK808/RK809/RK817/RK818 RTC"
depends on MFD_RK808
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index e92f3e943245..d3c100e43d1f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -112,6 +112,7 @@ obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
obj-$(CONFIG_RTC_DRV_MXC_V2) += rtc-mxc_v2.o
obj-$(CONFIG_RTC_DRV_GAMECUBE) += rtc-gamecube.o
+obj-$(CONFIG_RTC_DRV_NCT3018Y) += rtc-nct3018y.o
obj-$(CONFIG_RTC_DRV_NTXEC) += rtc-ntxec.o
obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o
obj-$(CONFIG_RTC_DRV_OPAL) += rtc-opal.o
diff --git a/drivers/rtc/rtc-nct3018y.c b/drivers/rtc/rtc-nct3018y.c
new file mode 100644
index 000000000000..1a175e8dda9d
--- /dev/null
+++ b/drivers/rtc/rtc-nct3018y.c
@@ -0,0 +1,559 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Nuvoton Technology Corporation
+
+#include <linux/bcd.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+#define NCT3018Y_REG_SC 0x00 /* seconds */
+#define NCT3018Y_REG_SCA 0x01 /* alarm */
+#define NCT3018Y_REG_MN 0x02
+#define NCT3018Y_REG_MNA 0x03 /* alarm */
+#define NCT3018Y_REG_HR 0x04
+#define NCT3018Y_REG_HRA 0x05 /* alarm */
+#define NCT3018Y_REG_DW 0x06
+#define NCT3018Y_REG_DM 0x07
+#define NCT3018Y_REG_MO 0x08
+#define NCT3018Y_REG_YR 0x09
+#define NCT3018Y_REG_CTRL 0x0A /* timer control */
+#define NCT3018Y_REG_ST 0x0B /* status */
+#define NCT3018Y_REG_CLKO 0x0C /* clock out */
+
+#define NCT3018Y_BIT_AF BIT(7)
+#define NCT3018Y_BIT_ST BIT(7)
+#define NCT3018Y_BIT_DM BIT(6)
+#define NCT3018Y_BIT_HF BIT(5)
+#define NCT3018Y_BIT_DSM BIT(4)
+#define NCT3018Y_BIT_AIE BIT(3)
+#define NCT3018Y_BIT_OFIE BIT(2)
+#define NCT3018Y_BIT_CIE BIT(1)
+#define NCT3018Y_BIT_TWO BIT(0)
+
+#define NCT3018Y_REG_BAT_MASK 0x07
+#define NCT3018Y_REG_CLKO_F_MASK 0x03 /* frequenc mask */
+#define NCT3018Y_REG_CLKO_CKE 0x80 /* clock out enabled */
+
+struct nct3018y {
+ struct rtc_device *rtc;
+ struct i2c_client *client;
+#ifdef CONFIG_COMMON_CLK
+ struct clk_hw clkout_hw;
+#endif
+};
+
+static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
+{
+ int err, flags;
+
+ dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
+ if (flags < 0) {
+ dev_err(&client->dev,
+ "Failed to read NCT3018Y_REG_CTRL\n");
+ return flags;
+ }
+
+ if (on)
+ flags |= NCT3018Y_BIT_AIE;
+ else
+ flags &= ~NCT3018Y_BIT_AIE;
+
+ flags |= NCT3018Y_BIT_CIE;
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
+ return err;
+ }
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
+ if (flags < 0) {
+ dev_err(&client->dev,
+ "Failed to read NCT3018Y_REG_ST\n");
+ return flags;
+ }
+
+ flags &= ~(NCT3018Y_BIT_AF);
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_ST\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *alarm_enable,
+ unsigned char *alarm_flag)
+{
+ int err, flags;
+
+ if (alarm_enable) {
+ dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
+ if (flags < 0)
+ return flags;
+ *alarm_enable = flags & NCT3018Y_BIT_AIE;
+ }
+
+ if (alarm_flag) {
+ dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
+ if (flags < 0)
+ return flags;
+ *alarm_flag = flags & NCT3018Y_BIT_AF;
+ }
+
+ dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
+ __func__, *alarm_enable, *alarm_flag);
+
+ return 0;
+}
+
+static irqreturn_t nct3018y_irq(int irq, void *dev_id)
+{
+ struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
+ struct i2c_client *client = nct3018y->client;
+ int err;
+ unsigned char alarm_flag;
+ unsigned char alarm_enable;
+
+ dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
+ err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
+ if (err)
+ return IRQ_NONE;
+
+ if (alarm_flag) {
+ dev_dbg(&client->dev, "%s:alarm flag:%x\n",
+ __func__, alarm_flag);
+ rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF | RTC_AF);
+ nct3018y_set_alarm_mode(nct3018y->client, 0);
+ dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+/*
+ * In the routines that deal directly with the nct3018y hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
+ */
+static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[10];
+ int err;
+
+ err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SC, sizeof(buf), buf);
+ if (err < 0)
+ return err;
+
+ tm->tm_sec = bcd2bin(buf[0] & 0x7F);
+ tm->tm_min = bcd2bin(buf[2] & 0x7F);
+ tm->tm_hour = bcd2bin(buf[4] & 0x3F);
+ tm->tm_wday = buf[6] & 0x07;
+ tm->tm_mday = bcd2bin(buf[7] & 0x3F);
+ tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1;
+ tm->tm_year = bcd2bin(buf[9]) + 100;
+
+ return 0;
+}
+
+static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[4] = {0};
+ int err;
+
+ buf[0] = bin2bcd(tm->tm_sec);
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_SC\n");
+ return err;
+ }
+
+ buf[0] = bin2bcd(tm->tm_min);
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MN, buf[0]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_MN\n");
+ return err;
+ }
+
+ buf[0] = bin2bcd(tm->tm_hour);
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HR, buf[0]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_HR\n");
+ return err;
+ }
+
+ buf[0] = tm->tm_wday & 0x07;
+ buf[1] = bin2bcd(tm->tm_mday);
+ buf[2] = bin2bcd(tm->tm_mon+1);
+ buf[3] = bin2bcd(tm->tm_year - 100);
+ err = i2c_smbus_write_i2c_block_data(client, NCT3018Y_REG_DW,
+ sizeof(buf), buf);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write for day and mon and year\n");
+ return -EIO;
+ }
+
+ return err;
+}
+
+static int nct3018y_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[5];
+ int err;
+
+ err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SCA,
+ sizeof(buf), buf);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to read date\n");
+ return -EIO;
+ }
+
+ dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
+ __func__, buf[0], buf[2], buf[4]);
+
+ tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
+ tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
+ tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);
+
+ err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
+ if (err < 0)
+ return err;
+
+ dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
+ __func__, tm->time.tm_sec, tm->time.tm_min,
+ tm->time.tm_hour, tm->enabled, tm->pending);
+
+ return 0;
+}
+
+static int nct3018y_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[3];
+ int err;
+
+ dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
+ __func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
+ tm->enabled);
+
+ buf[0] = bin2bcd(tm->time.tm_sec);
+ buf[1] = bin2bcd(tm->time.tm_min);
+ buf[2] = bin2bcd(tm->time.tm_hour);
+
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SCA, buf[0]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_SCA\n");
+ return err;
+ }
+
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MNA, buf[1]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_MNA\n");
+ return err;
+ }
+
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HRA, buf[2]);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_HRA\n");
+ return err;
+ }
+
+ return nct3018y_set_alarm_mode(client, tm->enabled);
+}
+
+static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
+{
+ dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);
+
+ return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
+}
+
+static int nct3018y_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int status, flags = 0;
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ status = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
+ if (status < 0)
+ return status;
+
+ if (!(status & NCT3018Y_REG_BAT_MASK))
+ flags |= RTC_VL_DATA_INVALID;
+
+ return put_user(flags, (unsigned int __user *)arg);
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+#ifdef CONFIG_COMMON_CLK
+/*
+ * Handling of the clkout
+ */
+
+#define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)
+
+static const int clkout_rates[] = {
+ 32768,
+ 1024,
+ 32,
+ 1,
+};
+
+static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
+ struct i2c_client *client = nct3018y->client;
+ int flags;
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
+ if (flags < 0)
+ return 0;
+
+ flags &= NCT3018Y_REG_CLKO_F_MASK;
+ return clkout_rates[flags];
+}
+
+static long nct3018y_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+ if (clkout_rates[i] <= rate)
+ return clkout_rates[i];
+
+ return 0;
+}
+
+static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
+ struct i2c_client *client = nct3018y->client;
+ int i, flags;
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
+ if (flags < 0)
+ return flags;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+ if (clkout_rates[i] == rate) {
+ flags &= ~NCT3018Y_REG_CLKO_F_MASK;
+ flags |= i;
+ return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
+ }
+
+ return -EINVAL;
+}
+
+static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
+{
+ struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
+ struct i2c_client *client = nct3018y->client;
+ int flags;
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
+ if (flags < 0)
+ return flags;
+
+
+ if (enable)
+ flags |= NCT3018Y_REG_CLKO_CKE;
+ else
+ flags &= ~NCT3018Y_REG_CLKO_CKE;
+
+ return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
+}
+
+static int nct3018y_clkout_prepare(struct clk_hw *hw)
+{
+ return nct3018y_clkout_control(hw, 1);
+}
+
+static void nct3018y_clkout_unprepare(struct clk_hw *hw)
+{
+ nct3018y_clkout_control(hw, 0);
+}
+
+static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
+{
+ struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
+ struct i2c_client *client = nct3018y->client;
+ int flags;
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
+ if (flags < 0)
+ return flags;
+
+ return flags & NCT3018Y_REG_CLKO_CKE;
+}
+
+static const struct clk_ops nct3018y_clkout_ops = {
+ .prepare = nct3018y_clkout_prepare,
+ .unprepare = nct3018y_clkout_unprepare,
+ .is_prepared = nct3018y_clkout_is_prepared,
+ .recalc_rate = nct3018y_clkout_recalc_rate,
+ .round_rate = nct3018y_clkout_round_rate,
+ .set_rate = nct3018y_clkout_set_rate,
+};
+
+static struct clk *nct3018y_clkout_register_clk(struct nct3018y *nct3018y)
+{
+ struct i2c_client *client = nct3018y->client;
+ struct device_node *node = client->dev.of_node;
+ struct clk *clk;
+ struct clk_init_data init;
+ int flags, err;
+
+ /* disable the clkout output */
+ flags = 0;
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write oscillator status register\n");
+ return ERR_PTR(err);
+ }
+
+ init.name = "nct3018y-clkout";
+ init.ops = &nct3018y_clkout_ops;
+ init.flags = 0;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+ nct3018y->clkout_hw.init = &init;
+
+ /* optional override of the clockname */
+ of_property_read_string(node, "clock-output-names", &init.name);
+
+ /* register the clock */
+ clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);
+
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+ return clk;
+}
+#endif
+
+static const struct rtc_class_ops nct3018y_rtc_ops = {
+ .read_time = nct3018y_rtc_read_time,
+ .set_time = nct3018y_rtc_set_time,
+ .read_alarm = nct3018y_rtc_read_alarm,
+ .set_alarm = nct3018y_rtc_set_alarm,
+ .alarm_irq_enable = nct3018y_irq_enable,
+ .ioctl = nct3018y_ioctl,
+};
+
+static int nct3018y_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct nct3018y *nct3018y;
+ int err, flags;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(&client->dev, "%s: ENODEV\n", __func__);
+ return -ENODEV;
+ }
+
+ nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
+ GFP_KERNEL);
+ if (!nct3018y)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, nct3018y);
+ nct3018y->client = client;
+ device_set_wakeup_capable(&client->dev, 1);
+
+ flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
+ if (flags < 0) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return flags;
+ } else if (flags & NCT3018Y_BIT_TWO)
+ dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
+
+
+ flags = NCT3018Y_BIT_TWO;
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
+ if (err < 0) {
+ dev_err(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
+ return err;
+ }
+
+ flags = 0;
+ err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
+ if (err < 0) {
+ dev_err(&client->dev, "%s: write error\n", __func__);
+ return err;
+ }
+
+
+ nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
+ if (IS_ERR(nct3018y->rtc))
+ return PTR_ERR(nct3018y->rtc);
+
+ nct3018y->rtc->ops = &nct3018y_rtc_ops;
+ nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;
+
+ if (client->irq > 0) {
+ err = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, nct3018y_irq,
+ IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
+ "nct3018y", client);
+ if (err) {
+ dev_err(&client->dev, "unable to request IRQ %d\n", client->irq);
+ return err;
+ }
+ }
+
+ return devm_rtc_register_device(nct3018y->rtc);
+
+#ifdef CONFIG_COMMON_CLK
+ /* register clk in common clk framework */
+ nct3018y_clkout_register_clk(nct3018y);
+#endif
+
+ return 0;
+}
+
+static const struct i2c_device_id nct3018y_id[] = {
+ { "nct3018y", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, nct3018y_id);
+
+
+static const struct of_device_id nct3018y_of_match[] = {
+ { .compatible = "nuvoton,nct3018y" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, nct3018y_of_match);
+
+static struct i2c_driver nct3018y_driver = {
+ .driver = {
+ .name = "rtc-nct3018y",
+ .of_match_table = of_match_ptr(nct3018y_of_match),
+ },
+ .probe = nct3018y_probe,
+ .id_table = nct3018y_id,
+};
+
+module_i2c_driver(nct3018y_driver);
+
+MODULE_AUTHOR("Medad CChien <ctcchien@nuvoton.com>");
+MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1