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.bell...@bootlin.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.bell...@bootlin.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.bell...@bootlin.com>");
+MODULE_DESCRIPTION("Micro Crystal RV3032 RTC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2

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