Message-Id: <20201013144110.1942218-3-alexandre.belloni@bootlin.com>
Date:   Tue, 13 Oct 2020 16:41:10 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-rtc@...r.kernel.org
Subject: [PATCH v3 3/3] rtc: rv3032: Add a driver for Microcrystal RV-3032

New driver for the Microcrystal RV-3032, including support for:
 - Date/time
 - Alarms
 - Low voltage detection
 - Trickle charge
 - Trimming
 - Clkout
 - RAM
 - EEPROM
 - Temperature sensor

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---

changes in v3:
 - properly handle EEPROM configuration register update

 drivers/rtc/Kconfig      |  10 +
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-rv3032.c | 925 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 936 insertions(+)
 create mode 100644 drivers/rtc/rtc-rv3032.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b54d87d45c89..91faf74e188c 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -668,6 +668,16 @@ config RTC_DRV_RV3028
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-rv3028.
 
+config RTC_DRV_RV3032
+	tristate "Micro Crystal RV3032"
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for the Micro Crystal
+	  RV3032.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-rv3032.
+
 config RTC_DRV_RV8803
 	tristate "Micro Crystal RV8803, Epson RX8900"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0721752c6ed4..7bb8367538db 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -142,6 +142,7 @@ obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o
 obj-$(CONFIG_RTC_DRV_RTD119X)	+= rtc-rtd119x.o
 obj-$(CONFIG_RTC_DRV_RV3028)	+= rtc-rv3028.o
 obj-$(CONFIG_RTC_DRV_RV3029C2)	+= rtc-rv3029c2.o
+obj-$(CONFIG_RTC_DRV_RV3032)	+= rtc-rv3032.o
 obj-$(CONFIG_RTC_DRV_RV8803)	+= rtc-rv8803.o
 obj-$(CONFIG_RTC_DRV_RX4581)	+= rtc-rx4581.o
 obj-$(CONFIG_RTC_DRV_RX6110)	+= rtc-rx6110.o
diff --git a/drivers/rtc/rtc-rv3032.c b/drivers/rtc/rtc-rv3032.c
new file mode 100644
index 000000000000..3e67f71f4261
--- /dev/null
+++ b/drivers/rtc/rtc-rv3032.c
@@ -0,0 +1,925 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for the Micro Crystal RV3032
+ *
+ * Copyright (C) 2020 Micro Crystal SA
+ *
+ * Alexandre Belloni <alexandre.belloni@...tlin.com>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/bcd.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+
+#define RV3032_SEC			0x01
+#define RV3032_MIN			0x02
+#define RV3032_HOUR			0x03
+#define RV3032_WDAY			0x04
+#define RV3032_DAY			0x05
+#define RV3032_MONTH			0x06
+#define RV3032_YEAR			0x07
+#define RV3032_ALARM_MIN		0x08
+#define RV3032_ALARM_HOUR		0x09
+#define RV3032_ALARM_DAY		0x0A
+#define RV3032_STATUS			0x0D
+#define RV3032_TLSB			0x0E
+#define RV3032_TMSB			0x0F
+#define RV3032_CTRL1			0x10
+#define RV3032_CTRL2			0x11
+#define RV3032_CTRL3			0x12
+#define RV3032_TS_CTRL			0x13
+#define RV3032_CLK_IRQ			0x14
+#define RV3032_EEPROM_ADDR		0x3D
+#define RV3032_EEPROM_DATA		0x3E
+#define RV3032_EEPROM_CMD		0x3F
+#define RV3032_RAM1			0x40
+#define RV3032_PMU			0xC0
+#define RV3032_OFFSET			0xC1
+#define RV3032_CLKOUT1			0xC2
+#define RV3032_CLKOUT2			0xC3
+#define RV3032_TREF0			0xC4
+#define RV3032_TREF1			0xC5
+
+#define RV3032_STATUS_VLF		BIT(0)
+#define RV3032_STATUS_PORF		BIT(1)
+#define RV3032_STATUS_EVF		BIT(2)
+#define RV3032_STATUS_AF		BIT(3)
+#define RV3032_STATUS_TF		BIT(4)
+#define RV3032_STATUS_UF		BIT(5)
+#define RV3032_STATUS_TLF		BIT(6)
+#define RV3032_STATUS_THF		BIT(7)
+
+#define RV3032_TLSB_CLKF		BIT(1)
+#define RV3032_TLSB_EEBUSY		BIT(2)
+#define RV3032_TLSB_TEMP		GENMASK(7, 4)
+
+#define RV3032_CLKOUT2_HFD_MSK		GENMASK(4, 0)
+#define RV3032_CLKOUT2_FD_MSK		GENMASK(6, 5)
+#define RV3032_CLKOUT2_OS		BIT(7)
+
+#define RV3032_CTRL1_EERD		BIT(3)
+#define RV3032_CTRL1_WADA		BIT(5)
+
+#define RV3032_CTRL2_STOP		BIT(0)
+#define RV3032_CTRL2_EIE		BIT(2)
+#define RV3032_CTRL2_AIE		BIT(3)
+#define RV3032_CTRL2_TIE		BIT(4)
+#define RV3032_CTRL2_UIE		BIT(5)
+#define RV3032_CTRL2_CLKIE		BIT(6)
+#define RV3032_CTRL2_TSE		BIT(7)
+
+#define RV3032_PMU_TCM			GENMASK(1, 0)
+#define RV3032_PMU_TCR			GENMASK(3, 2)
+#define RV3032_PMU_BSM			GENMASK(5, 4)
+#define RV3032_PMU_NCLKE		BIT(6)
+
+#define RV3032_PMU_BSM_DSM		1
+#define RV3032_PMU_BSM_LSM		2
+
+#define RV3032_OFFSET_MSK		GENMASK(5, 0)
+
+#define RV3032_EVT_CTRL_TSR		BIT(2)
+
+#define RV3032_EEPROM_CMD_UPDATE	0x11
+#define RV3032_EEPROM_CMD_WRITE		0x21
+#define RV3032_EEPROM_CMD_READ		0x22
+
+#define RV3032_EEPROM_USER		0xCB
+
+#define RV3032_EEBUSY_POLL		10000
+#define RV3032_EEBUSY_TIMEOUT		100000
+
+#define OFFSET_STEP_PPT			238419
+
+struct rv3032_data {
+	struct regmap *regmap;
+	struct rtc_device *rtc;
+#ifdef CONFIG_COMMON_CLK
+	struct clk_hw clkout_hw;
+#endif
+};
+
+static u16 rv3032_trickle_resistors[] = {1000, 2000, 7000, 11000};
+static u16 rv3032_trickle_voltages[] = {0, 1750, 3000, 4400};
+
+static int rv3032_exit_eerd(struct rv3032_data *rv3032, u32 eerd)
+{
+	if (eerd)
+		return 0;
+
+	return regmap_update_bits(rv3032->regmap, RV3032_CTRL1, RV3032_CTRL1_EERD, 0);
+}
+
+static int rv3032_enter_eerd(struct rv3032_data *rv3032, u32 *eerd)
+{
+	u32 ctrl1, status;
+	int ret;
+
+	ret = regmap_read(rv3032->regmap, RV3032_CTRL1, &ctrl1);
+	if (ret)
+		return ret;
+
+	*eerd = ctrl1 & RV3032_CTRL1_EERD;
+	if (*eerd)
+		return 0;
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL1,
+				 RV3032_CTRL1_EERD, RV3032_CTRL1_EERD);
+	if (ret)
+		return ret;
+
+	ret = regmap_read_poll_timeout(rv3032->regmap, RV3032_TLSB, status,
+				       !(status & RV3032_TLSB_EEBUSY),
+				       RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+	if (ret) {
+		rv3032_exit_eerd(rv3032, *eerd);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rv3032_update_cfg(struct rv3032_data *rv3032, unsigned int reg,
+			     unsigned int mask, unsigned int val)
+{
+	u32 status, eerd;
+	int ret;
+
+	ret = rv3032_enter_eerd(rv3032, &eerd);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(rv3032->regmap, reg, mask, val);
+	if (ret)
+		goto exit_eerd;
+
+	ret = regmap_write(rv3032->regmap, RV3032_EEPROM_CMD, RV3032_EEPROM_CMD_UPDATE);
+	if (ret)
+		goto exit_eerd;
+
+	usleep_range(46000, RV3032_EEBUSY_TIMEOUT);
+
+	ret = regmap_read_poll_timeout(rv3032->regmap, RV3032_TLSB, status,
+				       !(status & RV3032_TLSB_EEBUSY),
+				       RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+
+exit_eerd:
+	rv3032_exit_eerd(rv3032, eerd);
+
+	return ret;
+}
+
+static irqreturn_t rv3032_handle_irq(int irq, void *dev_id)
+{
+	struct rv3032_data *rv3032 = dev_id;
+	unsigned long events = 0;
+	u32 status = 0, ctrl = 0;
+
+	if (regmap_read(rv3032->regmap, RV3032_STATUS, &status) < 0 ||
+	    status == 0) {
+		return IRQ_NONE;
+	}
+
+	if (status & RV3032_STATUS_TF) {
+		status |= RV3032_STATUS_TF;
+		ctrl |= RV3032_CTRL2_TIE;
+		events |= RTC_PF;
+	}
+
+	if (status & RV3032_STATUS_AF) {
+		status |= RV3032_STATUS_AF;
+		ctrl |= RV3032_CTRL2_AIE;
+		events |= RTC_AF;
+	}
+
+	if (status & RV3032_STATUS_UF) {
+		status |= RV3032_STATUS_UF;
+		ctrl |= RV3032_CTRL2_UIE;
+		events |= RTC_UF;
+	}
+
+	if (events) {
+		rtc_update_irq(rv3032->rtc, 1, events);
+		regmap_update_bits(rv3032->regmap, RV3032_STATUS, status, 0);
+		regmap_update_bits(rv3032->regmap, RV3032_CTRL2, ctrl, 0);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int rv3032_get_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	u8 date[7];
+	int ret, status;
+
+	ret = regmap_read(rv3032->regmap, RV3032_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	if (status & (RV3032_STATUS_PORF | RV3032_STATUS_VLF))
+		return -EINVAL;
+
+	ret = regmap_bulk_read(rv3032->regmap, RV3032_SEC, date, sizeof(date));
+	if (ret)
+		return ret;
+
+	tm->tm_sec  = bcd2bin(date[0] & 0x7f);
+	tm->tm_min  = bcd2bin(date[1] & 0x7f);
+	tm->tm_hour = bcd2bin(date[2] & 0x3f);
+	tm->tm_wday = date[3] & 0x7;
+	tm->tm_mday = bcd2bin(date[4] & 0x3f);
+	tm->tm_mon  = bcd2bin(date[5] & 0x1f) - 1;
+	tm->tm_year = bcd2bin(date[6]) + 100;
+
+	return 0;
+}
+
+static int rv3032_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	u8 date[7];
+	int ret;
+
+	date[0] = bin2bcd(tm->tm_sec);
+	date[1] = bin2bcd(tm->tm_min);
+	date[2] = bin2bcd(tm->tm_hour);
+	date[3] = tm->tm_wday;
+	date[4] = bin2bcd(tm->tm_mday);
+	date[5] = bin2bcd(tm->tm_mon + 1);
+	date[6] = bin2bcd(tm->tm_year - 100);
+
+	ret = regmap_bulk_write(rv3032->regmap, RV3032_SEC, date,
+				sizeof(date));
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_STATUS,
+				 RV3032_STATUS_PORF | RV3032_STATUS_VLF, 0);
+
+	return ret;
+}
+
+static int rv3032_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	u8 alarmvals[3];
+	int status, ctrl, ret;
+
+	ret = regmap_bulk_read(rv3032->regmap, RV3032_ALARM_MIN, alarmvals,
+			       sizeof(alarmvals));
+	if (ret)
+		return ret;
+
+	ret = regmap_read(rv3032->regmap, RV3032_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(rv3032->regmap, RV3032_CTRL2, &ctrl);
+	if (ret < 0)
+		return ret;
+
+	alrm->time.tm_sec  = 0;
+	alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);
+	alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
+	alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
+
+	alrm->enabled = !!(ctrl & RV3032_CTRL2_AIE);
+	alrm->pending = (status & RV3032_STATUS_AF) && alrm->enabled;
+
+	return 0;
+}
+
+static int rv3032_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	u8 alarmvals[3];
+	u8 ctrl = 0;
+	int ret;
+
+	/* The alarm has no seconds, round up to nearest minute */
+	if (alrm->time.tm_sec) {
+		time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
+
+		alarm_time += 60 - alrm->time.tm_sec;
+		rtc_time64_to_tm(alarm_time, &alrm->time);
+	}
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL2,
+				 RV3032_CTRL2_AIE | RV3032_CTRL2_UIE, 0);
+	if (ret)
+		return ret;
+
+	alarmvals[0] = bin2bcd(alrm->time.tm_min);
+	alarmvals[1] = bin2bcd(alrm->time.tm_hour);
+	alarmvals[2] = bin2bcd(alrm->time.tm_mday);
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_STATUS,
+				 RV3032_STATUS_AF, 0);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_write(rv3032->regmap, RV3032_ALARM_MIN, alarmvals,
+				sizeof(alarmvals));
+	if (ret)
+		return ret;
+
+	if (alrm->enabled) {
+		if (rv3032->rtc->uie_rtctimer.enabled)
+			ctrl |= RV3032_CTRL2_UIE;
+		if (rv3032->rtc->aie_timer.enabled)
+			ctrl |= RV3032_CTRL2_AIE;
+	}
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL2,
+				 RV3032_CTRL2_UIE | RV3032_CTRL2_AIE, ctrl);
+
+	return ret;
+}
+
+static int rv3032_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	int ctrl = 0, ret;
+
+	if (enabled) {
+		if (rv3032->rtc->uie_rtctimer.enabled)
+			ctrl |= RV3032_CTRL2_UIE;
+		if (rv3032->rtc->aie_timer.enabled)
+			ctrl |= RV3032_CTRL2_AIE;
+	}
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_STATUS,
+				 RV3032_STATUS_AF | RV3032_STATUS_UF, 0);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL2,
+				 RV3032_CTRL2_UIE | RV3032_CTRL2_AIE, ctrl);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int rv3032_read_offset(struct device *dev, long *offset)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	int ret, value, steps;
+
+	ret = regmap_read(rv3032->regmap, RV3032_OFFSET, &value);
+	if (ret < 0)
+		return ret;
+
+	steps = sign_extend32(FIELD_GET(RV3032_OFFSET_MSK, value), 5);
+
+	*offset = DIV_ROUND_CLOSEST(steps * OFFSET_STEP_PPT, 1000);
+
+	return 0;
+}
+
+static int rv3032_set_offset(struct device *dev, long offset)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+
+	offset = clamp(offset, -7629L, 7391L) * 1000;
+	offset = DIV_ROUND_CLOSEST(offset, OFFSET_STEP_PPT);
+
+	return rv3032_update_cfg(rv3032, RV3032_OFFSET, RV3032_OFFSET_MSK,
+				 FIELD_PREP(RV3032_OFFSET_MSK, offset));
+}
+
+static int rv3032_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	int status, val = 0, ret = 0;
+
+	switch (cmd) {
+	case RTC_VL_READ:
+		ret = regmap_read(rv3032->regmap, RV3032_STATUS, &status);
+		if (ret < 0)
+			return ret;
+
+		if (status & (RV3032_STATUS_PORF | RV3032_STATUS_VLF))
+			val = RTC_VL_DATA_INVALID;
+		return put_user(val, (unsigned int __user *)arg);
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static int rv3032_nvram_write(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	return regmap_bulk_write(priv, RV3032_RAM1 + offset, val, bytes);
+}
+
+static int rv3032_nvram_read(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	return regmap_bulk_read(priv, RV3032_RAM1 + offset, val, bytes);
+}
+
+static int rv3032_eeprom_write(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	struct rv3032_data *rv3032 = priv;
+	u32 status, eerd;
+	int i, ret;
+	u8 *buf = val;
+
+	ret = rv3032_enter_eerd(rv3032, &eerd);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < bytes; i++) {
+		ret = regmap_write(rv3032->regmap, RV3032_EEPROM_ADDR,
+				   RV3032_EEPROM_USER + offset + i);
+		if (ret)
+			goto exit_eerd;
+
+		ret = regmap_write(rv3032->regmap, RV3032_EEPROM_DATA, buf[i]);
+		if (ret)
+			goto exit_eerd;
+
+		ret = regmap_write(rv3032->regmap, RV3032_EEPROM_CMD,
+				   RV3032_EEPROM_CMD_WRITE);
+		if (ret)
+			goto exit_eerd;
+
+		usleep_range(RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+
+		ret = regmap_read_poll_timeout(rv3032->regmap, RV3032_TLSB, status,
+					       !(status & RV3032_TLSB_EEBUSY),
+					       RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+		if (ret)
+			goto exit_eerd;
+	}
+
+exit_eerd:
+	rv3032_exit_eerd(rv3032, eerd);
+
+	return ret;
+}
+
+static int rv3032_eeprom_read(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	struct rv3032_data *rv3032 = priv;
+	u32 status, eerd, data;
+	int i, ret;
+	u8 *buf = val;
+
+	ret = rv3032_enter_eerd(rv3032, &eerd);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < bytes; i++) {
+		ret = regmap_write(rv3032->regmap, RV3032_EEPROM_ADDR,
+				   RV3032_EEPROM_USER + offset + i);
+		if (ret)
+			goto exit_eerd;
+
+		ret = regmap_write(rv3032->regmap, RV3032_EEPROM_CMD,
+				   RV3032_EEPROM_CMD_READ);
+		if (ret)
+			goto exit_eerd;
+
+		ret = regmap_read_poll_timeout(rv3032->regmap, RV3032_TLSB, status,
+					       !(status & RV3032_TLSB_EEBUSY),
+					       RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+		if (ret)
+			goto exit_eerd;
+
+		ret = regmap_read(rv3032->regmap, RV3032_EEPROM_DATA, &data);
+		if (ret)
+			goto exit_eerd;
+		buf[i] = data;
+	}
+
+exit_eerd:
+	rv3032_exit_eerd(rv3032, eerd);
+
+	return ret;
+}
+
+static int rv3032_trickle_charger_setup(struct device *dev, struct rv3032_data *rv3032)
+{
+	u32 val, ohms, voltage;
+	int i;
+
+	val = FIELD_PREP(RV3032_PMU_TCM, 1) | FIELD_PREP(RV3032_PMU_BSM, RV3032_PMU_BSM_DSM);
+	if (!device_property_read_u32(dev, "trickle-voltage-millivolt", &voltage)) {
+		for (i = 0; i < ARRAY_SIZE(rv3032_trickle_voltages); i++)
+			if (voltage == rv3032_trickle_voltages[i])
+				break;
+		if (i < ARRAY_SIZE(rv3032_trickle_voltages))
+			val = FIELD_PREP(RV3032_PMU_TCM, i) |
+			      FIELD_PREP(RV3032_PMU_BSM, RV3032_PMU_BSM_LSM);
+	}
+
+	if (device_property_read_u32(dev, "trickle-resistor-ohms", &ohms))
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(rv3032_trickle_resistors); i++)
+		if (ohms == rv3032_trickle_resistors[i])
+			break;
+
+	if (i >= ARRAY_SIZE(rv3032_trickle_resistors)) {
+		dev_warn(dev, "invalid trickle resistor value\n");
+
+		return 0;
+	}
+
+	return rv3032_update_cfg(rv3032, RV3032_PMU,
+				 RV3032_PMU_TCR | RV3032_PMU_TCM | RV3032_PMU_BSM,
+				 val | FIELD_PREP(RV3032_PMU_TCR, i));
+}
+
+#ifdef CONFIG_COMMON_CLK
+#define clkout_hw_to_rv3032(hw) container_of(hw, struct rv3032_data, clkout_hw)
+
+static int clkout_xtal_rates[] = {
+	32768,
+	1024,
+	64,
+	1,
+};
+
+#define RV3032_HFD_STEP 8192
+
+static unsigned long rv3032_clkout_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	int clkout, ret;
+	struct rv3032_data *rv3032 = clkout_hw_to_rv3032(hw);
+
+	ret = regmap_read(rv3032->regmap, RV3032_CLKOUT2, &clkout);
+	if (ret < 0)
+		return 0;
+
+	if (clkout & RV3032_CLKOUT2_OS) {
+		unsigned long rate = FIELD_GET(RV3032_CLKOUT2_HFD_MSK, clkout) << 8;
+
+		ret = regmap_read(rv3032->regmap, RV3032_CLKOUT1, &clkout);
+		if (ret < 0)
+			return 0;
+
+		rate += clkout + 1;
+
+		return rate * RV3032_HFD_STEP;
+	}
+
+	return clkout_xtal_rates[FIELD_GET(RV3032_CLKOUT2_FD_MSK, clkout)];
+}
+
+static long rv3032_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *prate)
+{
+	int i, hfd;
+
+	if (rate < RV3032_HFD_STEP)
+		for (i = 0; i < ARRAY_SIZE(clkout_xtal_rates); i++)
+			if (clkout_xtal_rates[i] <= rate)
+				return clkout_xtal_rates[i];
+
+	hfd = DIV_ROUND_CLOSEST(rate, RV3032_HFD_STEP);
+
+	return RV3032_HFD_STEP * clamp(hfd, 0, 8192);
+}
+
+static int rv3032_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct rv3032_data *rv3032 = clkout_hw_to_rv3032(hw);
+	u32 status, eerd;
+	int i, hfd, ret;
+
+	for (i = 0; i < ARRAY_SIZE(clkout_xtal_rates); i++) {
+		if (clkout_xtal_rates[i] == rate) {
+			return rv3032_update_cfg(rv3032, RV3032_CLKOUT2, 0xff,
+						 FIELD_PREP(RV3032_CLKOUT2_FD_MSK, i));
+		}
+	}
+
+	hfd = DIV_ROUND_CLOSEST(rate, RV3032_HFD_STEP);
+	hfd = clamp(hfd, 1, 8192) - 1;
+
+	ret = rv3032_enter_eerd(rv3032, &eerd);
+	if (ret)
+		goto exit_eerd;
+
+	ret = regmap_write(rv3032->regmap, RV3032_CLKOUT1, hfd & 0xff);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(rv3032->regmap, RV3032_CLKOUT2, RV3032_CLKOUT2_OS |
+			    FIELD_PREP(RV3032_CLKOUT2_HFD_MSK, hfd >> 8));
+	if (ret)
+		goto exit_eerd;
+
+	ret = regmap_write(rv3032->regmap, RV3032_EEPROM_CMD, RV3032_EEPROM_CMD_UPDATE);
+	if (ret)
+		goto exit_eerd;
+
+	usleep_range(46000, RV3032_EEBUSY_TIMEOUT);
+
+	ret = regmap_read_poll_timeout(rv3032->regmap, RV3032_TLSB, status,
+				       !(status & RV3032_TLSB_EEBUSY),
+				       RV3032_EEBUSY_POLL, RV3032_EEBUSY_TIMEOUT);
+
+exit_eerd:
+	rv3032_exit_eerd(rv3032, eerd);
+
+	return ret;
+}
+
+static int rv3032_clkout_prepare(struct clk_hw *hw)
+{
+	struct rv3032_data *rv3032 = clkout_hw_to_rv3032(hw);
+
+	return rv3032_update_cfg(rv3032, RV3032_PMU, RV3032_PMU_NCLKE, 0);
+}
+
+static void rv3032_clkout_unprepare(struct clk_hw *hw)
+{
+	struct rv3032_data *rv3032 = clkout_hw_to_rv3032(hw);
+
+	rv3032_update_cfg(rv3032, RV3032_PMU, RV3032_PMU_NCLKE, RV3032_PMU_NCLKE);
+}
+
+static int rv3032_clkout_is_prepared(struct clk_hw *hw)
+{
+	int val, ret;
+	struct rv3032_data *rv3032 = clkout_hw_to_rv3032(hw);
+
+	ret = regmap_read(rv3032->regmap, RV3032_PMU, &val);
+	if (ret < 0)
+		return ret;
+
+	return !(val & RV3032_PMU_NCLKE);
+}
+
+static const struct clk_ops rv3032_clkout_ops = {
+	.prepare = rv3032_clkout_prepare,
+	.unprepare = rv3032_clkout_unprepare,
+	.is_prepared = rv3032_clkout_is_prepared,
+	.recalc_rate = rv3032_clkout_recalc_rate,
+	.round_rate = rv3032_clkout_round_rate,
+	.set_rate = rv3032_clkout_set_rate,
+};
+
+static int rv3032_clkout_register_clk(struct rv3032_data *rv3032,
+				      struct i2c_client *client)
+{
+	int ret;
+	struct clk *clk;
+	struct clk_init_data init;
+	struct device_node *node = client->dev.of_node;
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_TLSB, RV3032_TLSB_CLKF, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL2, RV3032_CTRL2_CLKIE, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(rv3032->regmap, RV3032_CLK_IRQ, 0);
+	if (ret < 0)
+		return ret;
+
+	init.name = "rv3032-clkout";
+	init.ops = &rv3032_clkout_ops;
+	init.flags = 0;
+	init.parent_names = NULL;
+	init.num_parents = 0;
+	rv3032->clkout_hw.init = &init;
+
+	of_property_read_string(node, "clock-output-names", &init.name);
+
+	clk = devm_clk_register(&client->dev, &rv3032->clkout_hw);
+	if (!IS_ERR(clk))
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+	return 0;
+}
+#endif
+
+static int rv3032_hwmon_read_temp(struct device *dev, long *mC)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+	u8 buf[2];
+	int temp, prev = 0;
+	int ret;
+
+	ret = regmap_bulk_read(rv3032->regmap, RV3032_TLSB, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	temp = sign_extend32(buf[1], 7) << 4;
+	temp |= FIELD_GET(RV3032_TLSB_TEMP, buf[0]);
+
+	/* No blocking or shadowing on RV3032_TLSB and RV3032_TMSB */
+	do {
+		prev = temp;
+
+		ret = regmap_bulk_read(rv3032->regmap, RV3032_TLSB, buf, sizeof(buf));
+		if (ret)
+			return ret;
+
+		temp = sign_extend32(buf[1], 7) << 4;
+		temp |= FIELD_GET(RV3032_TLSB_TEMP, buf[0]);
+	} while (temp != prev);
+
+	*mC = (temp * 1000) / 16;
+
+	return 0;
+}
+
+static umode_t rv3032_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+				       u32 attr, int channel)
+{
+	if (type != hwmon_temp)
+		return 0;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		return 0444;
+	default:
+		return 0;
+	}
+}
+
+static int rv3032_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			     u32 attr, int channel, long *temp)
+{
+	int err;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		err = rv3032_hwmon_read_temp(dev, temp);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+	return err;
+}
+
+static const struct hwmon_channel_info *rv3032_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
+	NULL
+};
+
+static const struct hwmon_ops rv3032_hwmon_hwmon_ops = {
+	.is_visible = rv3032_hwmon_is_visible,
+	.read = rv3032_hwmon_read,
+};
+
+static const struct hwmon_chip_info rv3032_hwmon_chip_info = {
+	.ops = &rv3032_hwmon_hwmon_ops,
+	.info = rv3032_hwmon_info,
+};
+
+static void rv3032_hwmon_register(struct device *dev)
+{
+	struct rv3032_data *rv3032 = dev_get_drvdata(dev);
+
+	if (!IS_REACHABLE(CONFIG_HWMON))
+		return;
+
+	devm_hwmon_device_register_with_info(dev, "rv3032", rv3032, &rv3032_hwmon_chip_info, NULL);
+}
+
+static struct rtc_class_ops rv3032_rtc_ops = {
+	.read_time = rv3032_get_time,
+	.set_time = rv3032_set_time,
+	.read_offset = rv3032_read_offset,
+	.set_offset = rv3032_set_offset,
+	.ioctl = rv3032_ioctl,
+};
+
+static const struct regmap_config regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xCA,
+};
+
+static int rv3032_probe(struct i2c_client *client)
+{
+	struct rv3032_data *rv3032;
+	int ret, status;
+	struct nvmem_config nvmem_cfg = {
+		.name = "rv3032_nvram",
+		.word_size = 1,
+		.stride = 1,
+		.size = 16,
+		.type = NVMEM_TYPE_BATTERY_BACKED,
+		.reg_read = rv3032_nvram_read,
+		.reg_write = rv3032_nvram_write,
+	};
+	struct nvmem_config eeprom_cfg = {
+		.name = "rv3032_eeprom",
+		.word_size = 1,
+		.stride = 1,
+		.size = 32,
+		.type = NVMEM_TYPE_EEPROM,
+		.reg_read = rv3032_eeprom_read,
+		.reg_write = rv3032_eeprom_write,
+	};
+
+	rv3032 = devm_kzalloc(&client->dev, sizeof(struct rv3032_data),
+			      GFP_KERNEL);
+	if (!rv3032)
+		return -ENOMEM;
+
+	rv3032->regmap = devm_regmap_init_i2c(client, &regmap_config);
+	if (IS_ERR(rv3032->regmap))
+		return PTR_ERR(rv3032->regmap);
+
+	i2c_set_clientdata(client, rv3032);
+
+	ret = regmap_read(rv3032->regmap, RV3032_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	rv3032->rtc = devm_rtc_allocate_device(&client->dev);
+	if (IS_ERR(rv3032->rtc))
+		return PTR_ERR(rv3032->rtc);
+
+	if (client->irq > 0) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, rv3032_handle_irq,
+						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						"rv3032", rv3032);
+		if (ret) {
+			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
+			client->irq = 0;
+		} else {
+			rv3032_rtc_ops.read_alarm = rv3032_get_alarm;
+			rv3032_rtc_ops.set_alarm = rv3032_set_alarm;
+			rv3032_rtc_ops.alarm_irq_enable = rv3032_alarm_irq_enable;
+		}
+	}
+
+	ret = regmap_update_bits(rv3032->regmap, RV3032_CTRL1,
+				 RV3032_CTRL1_WADA, RV3032_CTRL1_WADA);
+	if (ret)
+		return ret;
+
+	rv3032_trickle_charger_setup(&client->dev, rv3032);
+
+	rv3032->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+	rv3032->rtc->range_max = RTC_TIMESTAMP_END_2099;
+	rv3032->rtc->ops = &rv3032_rtc_ops;
+	ret = rtc_register_device(rv3032->rtc);
+	if (ret)
+		return ret;
+
+	nvmem_cfg.priv = rv3032;
+	rtc_nvmem_register(rv3032->rtc, &nvmem_cfg);
+	eeprom_cfg.priv = rv3032;
+	rtc_nvmem_register(rv3032->rtc, &eeprom_cfg);
+
+	rv3032->rtc->max_user_freq = 1;
+
+#ifdef CONFIG_COMMON_CLK
+	rv3032_clkout_register_clk(rv3032, client);
+#endif
+
+	rv3032_hwmon_register(&client->dev);
+
+	return 0;
+}
+
+static const struct of_device_id rv3032_of_match[] = {
+	{ .compatible = "microcrystal,rv3032", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rv3032_of_match);
+
+static struct i2c_driver rv3032_driver = {
+	.driver = {
+		.name = "rtc-rv3032",
+		.of_match_table = of_match_ptr(rv3032_of_match),
+	},
+	.probe_new	= rv3032_probe,
+};
+module_i2c_driver(rv3032_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@...tlin.com>");
+MODULE_DESCRIPTION("Micro Crystal RV3032 RTC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2

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