1 files changed, 574 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-rx8025.c b/drivers/rtc/rtc-rx8025.c
new file mode 100644
index 000000000..a24f85893
--- /dev/null
+++ b/drivers/rtc/rtc-rx8025.c
@@ -0,0 +1,574 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Epson's RTC module RX-8025 SA/NB
+ *
+ * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * Copyright (C) 2005 by Digi International Inc.
+ * All rights reserved.
+ *
+ * Modified by fengjh at rising.com.cn
+ * <lm-sensors@lm-sensors.org>
+ * 2006.11
+ *
+ * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
+ * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
+ * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
+ */
+#include <linux/bcd.h>
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+
+/* Register definitions */
+#define RX8025_REG_SEC		0x00
+#define RX8025_REG_MIN		0x01
+#define RX8025_REG_HOUR		0x02
+#define RX8025_REG_WDAY		0x03
+#define RX8025_REG_MDAY		0x04
+#define RX8025_REG_MONTH	0x05
+#define RX8025_REG_YEAR		0x06
+#define RX8025_REG_DIGOFF	0x07
+#define RX8025_REG_ALWMIN	0x08
+#define RX8025_REG_ALWHOUR	0x09
+#define RX8025_REG_ALWWDAY	0x0a
+#define RX8025_REG_ALDMIN	0x0b
+#define RX8025_REG_ALDHOUR	0x0c
+/* 0x0d is reserved */
+#define RX8025_REG_CTRL1	0x0e
+#define RX8025_REG_CTRL2	0x0f
+
+#define RX8025_BIT_CTRL1_CT	(7 << 0)
+/* 1 Hz periodic level irq */
+#define RX8025_BIT_CTRL1_CT_1HZ	4
+#define RX8025_BIT_CTRL1_TEST	BIT(3)
+#define RX8025_BIT_CTRL1_1224	BIT(5)
+#define RX8025_BIT_CTRL1_DALE	BIT(6)
+#define RX8025_BIT_CTRL1_WALE	BIT(7)
+
+#define RX8025_BIT_CTRL2_DAFG	BIT(0)
+#define RX8025_BIT_CTRL2_WAFG	BIT(1)
+#define RX8025_BIT_CTRL2_CTFG	BIT(2)
+#define RX8025_BIT_CTRL2_PON	BIT(4)
+#define RX8025_BIT_CTRL2_XST	BIT(5)
+#define RX8025_BIT_CTRL2_VDET	BIT(6)
+
+/* Clock precision adjustment */
+#define RX8025_ADJ_RESOLUTION	3050 /* in ppb */
+#define RX8025_ADJ_DATA_MAX	62
+#define RX8025_ADJ_DATA_MIN	-62
+
+static const struct i2c_device_id rx8025_id[] = {
+	{ "rx8025", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rx8025_id);
+
+struct rx8025_data {
+	struct rtc_device *rtc;
+	u8 ctrl1;
+};
+
+static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
+{
+	return i2c_smbus_read_byte_data(client, number << 4);
+}
+
+static int rx8025_read_regs(const struct i2c_client *client,
+			    u8 number, u8 length, u8 *values)
+{
+	int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
+						values);
+	if (ret != length)
+		return ret < 0 ? ret : -EIO;
+
+	return 0;
+}
+
+static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
+			    u8 value)
+{
+	return i2c_smbus_write_byte_data(client, number << 4, value);
+}
+
+static s32 rx8025_write_regs(const struct i2c_client *client,
+			     u8 number, u8 length, const u8 *values)
+{
+	return i2c_smbus_write_i2c_block_data(client, number << 4,
+					      length, values);
+}
+
+static int rx8025_check_validity(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int ctrl2;
+
+	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	if (ctrl2 & RX8025_BIT_CTRL2_VDET)
+		dev_warn(dev, "power voltage drop detected\n");
+
+	if (ctrl2 & RX8025_BIT_CTRL2_PON) {
+		dev_warn(dev, "power-on reset detected, date is invalid\n");
+		return -EINVAL;
+	}
+
+	if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
+		dev_warn(dev, "crystal stopped, date is invalid\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rx8025_reset_validity(struct i2c_client *client)
+{
+	int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
+
+	return rx8025_write_reg(client, RX8025_REG_CTRL2,
+				ctrl2 | RX8025_BIT_CTRL2_XST);
+}
+
+static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
+{
+	struct i2c_client *client = dev_id;
+	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
+	struct mutex *lock = &rx8025->rtc->ops_lock;
+	int status;
+
+	mutex_lock(lock);
+	status = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (status < 0)
+		goto out;
+
+	if (!(status & RX8025_BIT_CTRL2_XST))
+		dev_warn(&client->dev, "Oscillation stop was detected,"
+			 "you may have to readjust the clock\n");
+
+	if (status & RX8025_BIT_CTRL2_CTFG) {
+		/* periodic */
+		status &= ~RX8025_BIT_CTRL2_CTFG;
+		rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
+	}
+
+	if (status & RX8025_BIT_CTRL2_DAFG) {
+		/* alarm */
+		status &= RX8025_BIT_CTRL2_DAFG;
+		if (rx8025_write_reg(client, RX8025_REG_CTRL1,
+				     rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
+			goto out;
+		rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
+	}
+
+out:
+	mutex_unlock(lock);
+
+	return IRQ_HANDLED;
+}
+
+static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 date[7];
+	int err;
+
+	err = rx8025_check_validity(dev);
+	if (err)
+		return err;
+
+	err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
+	if (err)
+		return err;
+
+	dev_dbg(dev, "%s: read %7ph\n", __func__, date);
+
+	dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
+	dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
+		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
+	else
+		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
+			+ (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
+
+	dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
+	dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
+	dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
+
+	dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
+
+	return 0;
+}
+
+static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 date[7];
+	int ret;
+
+	if ((dt->tm_year < 100) || (dt->tm_year > 199))
+		return -EINVAL;
+
+	/*
+	 * Here the read-only bits are written as "0".  I'm not sure if that
+	 * is sound.
+	 */
+	date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
+	date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
+		date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
+	else
+		date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
+			| bin2bcd((dt->tm_hour + 11) % 12 + 1);
+
+	date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
+	date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
+	date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
+	date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
+
+	dev_dbg(dev, "%s: write %7ph\n", __func__, date);
+
+	ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
+	if (ret < 0)
+		return ret;
+
+	return rx8025_reset_validity(client);
+}
+
+static int rx8025_init_client(struct i2c_client *client)
+{
+	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
+	u8 ctrl[2], ctrl2;
+	int need_clear = 0;
+	int err;
+
+	err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
+	if (err)
+		goto out;
+
+	/* Keep test bit zero ! */
+	rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
+
+	if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
+		dev_warn(&client->dev, "Alarm was detected\n");
+		need_clear = 1;
+	}
+
+	if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
+		need_clear = 1;
+
+	if (need_clear) {
+		ctrl2 = ctrl[1];
+		ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
+			   RX8025_BIT_CTRL2_DAFG);
+
+		err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
+	}
+out:
+	return err;
+}
+
+/* Alarm support */
+static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ald[2];
+	int ctrl2, err;
+
+	if (client->irq <= 0)
+		return -EINVAL;
+
+	err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
+	if (err)
+		return err;
+
+	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
+		__func__, ald[0], ald[1], ctrl2);
+
+	/* Hardware alarms precision is 1 minute! */
+	t->time.tm_sec = 0;
+	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
+		t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
+	else
+		t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
+			+ (ald[1] & 0x20 ? 12 : 0);
+
+	dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
+	t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
+	t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
+
+	return err;
+}
+
+static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ald[2];
+	int err;
+
+	if (client->irq <= 0)
+		return -EINVAL;
+
+	/*
+	 * Hardware alarm precision is 1 minute!
+	 * round up to nearest minute
+	 */
+	if (t->time.tm_sec) {
+		time64_t alarm_time = rtc_tm_to_time64(&t->time);
+
+		alarm_time += 60 - t->time.tm_sec;
+		rtc_time64_to_tm(alarm_time, &t->time);
+	}
+
+	ald[0] = bin2bcd(t->time.tm_min);
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
+		ald[1] = bin2bcd(t->time.tm_hour);
+	else
+		ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
+			| bin2bcd((t->time.tm_hour + 11) % 12 + 1);
+
+	dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
+
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
+		rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+	err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
+	if (err)
+		return err;
+
+	if (t->enabled) {
+		rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ctrl1;
+	int err;
+
+	ctrl1 = rx8025->ctrl1;
+	if (enabled)
+		ctrl1 |= RX8025_BIT_CTRL1_DALE;
+	else
+		ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
+
+	if (ctrl1 != rx8025->ctrl1) {
+		rx8025->ctrl1 = ctrl1;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops rx8025_rtc_ops = {
+	.read_time = rx8025_get_time,
+	.set_time = rx8025_set_time,
+	.read_alarm = rx8025_read_alarm,
+	.set_alarm = rx8025_set_alarm,
+	.alarm_irq_enable = rx8025_alarm_irq_enable,
+};
+
+/*
+ * Clock precision adjustment support
+ *
+ * According to the RX8025 SA/NB application manual the frequency and
+ * temperature characteristics can be approximated using the following
+ * equation:
+ *
+ *   df = a * (ut - t)**2
+ *
+ *   df: Frequency deviation in any temperature
+ *   a : Coefficient = (-35 +-5) * 10**-9
+ *   ut: Ultimate temperature in degree = +25 +-5 degree
+ *   t : Any temperature in degree
+ *
+ * Note that the clock adjustment in ppb must be entered (which is
+ * the negative value of the deviation).
+ */
+static int rx8025_get_clock_adjust(struct device *dev, int *adj)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int digoff;
+
+	digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
+	if (digoff < 0)
+		return digoff;
+
+	*adj = digoff >= 64 ? digoff - 128 : digoff;
+	if (*adj > 0)
+		(*adj)--;
+	*adj *= -RX8025_ADJ_RESOLUTION;
+
+	return 0;
+}
+
+static int rx8025_set_clock_adjust(struct device *dev, int adj)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	u8 digoff;
+	int err;
+
+	adj /= -RX8025_ADJ_RESOLUTION;
+	if (adj > RX8025_ADJ_DATA_MAX)
+		adj = RX8025_ADJ_DATA_MAX;
+	else if (adj < RX8025_ADJ_DATA_MIN)
+		adj = RX8025_ADJ_DATA_MIN;
+	else if (adj > 0)
+		adj++;
+	else if (adj < 0)
+		adj += 128;
+	digoff = adj;
+
+	err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
+	if (err)
+		return err;
+
+	dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
+
+	return 0;
+}
+
+static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
+					      struct device_attribute *attr,
+					      char *buf)
+{
+	int err, adj;
+
+	err = rx8025_get_clock_adjust(dev, &adj);
+	if (err)
+		return err;
+
+	return sprintf(buf, "%d\n", adj);
+}
+
+static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
+					       struct device_attribute *attr,
+					       const char *buf, size_t count)
+{
+	int adj, err;
+
+	if (sscanf(buf, "%i", &adj) != 1)
+		return -EINVAL;
+
+	err = rx8025_set_clock_adjust(dev, adj);
+
+	return err ? err : count;
+}
+
+static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
+		   rx8025_sysfs_show_clock_adjust,
+		   rx8025_sysfs_store_clock_adjust);
+
+static int rx8025_sysfs_register(struct device *dev)
+{
+	return device_create_file(dev, &dev_attr_clock_adjust_ppb);
+}
+
+static void rx8025_sysfs_unregister(struct device *dev)
+{
+	device_remove_file(dev, &dev_attr_clock_adjust_ppb);
+}
+
+static int rx8025_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct rx8025_data *rx8025;
+	int err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
+				     | I2C_FUNC_SMBUS_I2C_BLOCK)) {
+		dev_err(&adapter->dev,
+			"doesn't support required functionality\n");
+		return -EIO;
+	}
+
+	rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
+	if (!rx8025)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, rx8025);
+
+	err = rx8025_init_client(client);
+	if (err)
+		return err;
+
+	rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
+					  &rx8025_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rx8025->rtc)) {
+		dev_err(&client->dev, "unable to register the class device\n");
+		return PTR_ERR(rx8025->rtc);
+	}
+
+	if (client->irq > 0) {
+		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
+		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+						rx8025_handle_irq,
+						IRQF_ONESHOT,
+						"rx8025", client);
+		if (err) {
+			dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
+			client->irq = 0;
+		}
+	}
+
+	rx8025->rtc->max_user_freq = 1;
+
+	/* the rx8025 alarm only supports a minute accuracy */
+	rx8025->rtc->uie_unsupported = 1;
+
+	err = rx8025_sysfs_register(&client->dev);
+	return err;
+}
+
+static int rx8025_remove(struct i2c_client *client)
+{
+	rx8025_sysfs_unregister(&client->dev);
+	return 0;
+}
+
+static struct i2c_driver rx8025_driver = {
+	.driver = {
+		.name = "rtc-rx8025",
+	},
+	.probe		= rx8025_probe,
+	.remove		= rx8025_remove,
+	.id_table	= rx8025_id,
+};
+
+module_i2c_driver(rx8025_driver);
+
+MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
+MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
+MODULE_LICENSE("GPL");