[PATCH v5 1/2] drivers: rtc: add max313xx series rtc driver

From: Ibrahim Tilki
Date: Mon Apr 03 2023 - 11:45:22 EST

Adding support for Analog Devices MAX313XX series RTCs.

Signed-off-by: Ibrahim Tilki <Ibrahim.Tilki@xxxxxxxxxx>
Signed-off-by: Zeynep Arslanbenzer <Zeynep.Arslanbenzer@xxxxxxxxxx>
---
drivers/rtc/Kconfig | 11 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-max313xx.c | 1053 ++++++++++++++++++++++++++++++++++++
3 files changed, 1065 insertions(+)
create mode 100644 drivers/rtc/rtc-max313xx.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 753872408..2160619ed 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -323,6 +323,17 @@ config RTC_DRV_LP8788
help
Say Y to enable support for the LP8788 RTC/ALARM driver.

+config RTC_DRV_MAX313XX
+ tristate "Analog Devices MAX313XX RTC driver"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ If you say yes here you will get support for the
+ Analog Devices MAX313XX series RTC family.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-max313xx.
+
config RTC_DRV_MAX6900
tristate "Maxim MAX6900"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index ea445d1eb..880db99be 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
+obj-$(CONFIG_RTC_DRV_MAX313XX) += rtc-max313xx.o
obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o
obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
obj-$(CONFIG_RTC_DRV_MAX6916) += rtc-max6916.o
diff --git a/drivers/rtc/rtc-max313xx.c b/drivers/rtc/rtc-max313xx.c
new file mode 100644
index 000000000..043528d7d
--- /dev/null
+++ b/drivers/rtc/rtc-max313xx.c
@@ -0,0 +1,1053 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices MAX313XX series I2C RTC driver
+ *
+ * Copyright 2023 Analog Devices Inc.
+ */
+#include <asm-generic/unaligned.h>
+#include <linux/bcd.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/util_macros.h>
+
+/* common registers */
+#define MAX313XX_INT_ALARM1 BIT(0)
+#define MAX313XX_HRS_F_AM_PM BIT(5)
+#define MAX313XX_HRS_F_12_24 BIT(6)
+#define MAX313XX_MONTH_CENTURY BIT(7)
+
+#define MAX313XX_TIME_SIZE 0x07
+
+/* device specific registers */
+#define MAX3134X_CFG2_REG 0x01
+#define MAX3134X_CFG2_SET_RTC BIT(1)
+
+#define MAX31341_TRICKLE_RES_MASK GENMASK(1, 0)
+#define MAX31341_TRICKLE_DIODE_EN BIT(2)
+#define MAX31341_TRICKLE_ENABLE_BIT BIT(3)
+#define MAX31341_POWER_MGMT_REG 0x56
+#define MAX31341_POWER_MGMT_TRICKLE_BIT BIT(0)
+
+#define MAX3133X_TRICKLE_RES_MASK GENMASK(2, 1)
+#define MAX3133X_TRICKLE_DIODE_EN BIT(3)
+#define MAX3133X_TRICKLE_ENABLE_BIT BIT(0)
+
+#define MAX31329_TRICKLE_ENABLE_BIT BIT(7)
+#define MAX31343_TRICKLE_ENABLE_MASK GENMASK(7, 4)
+#define MAX31343_TRICKLE_ENABLE_CODE 5
+#define MAX31329_43_TRICKLE_RES_MASK GENMASK(1, 0)
+#define MAX31329_43_TRICKLE_DIODE_EN BIT(2)
+
+#define MAX31329_CONFIG2_REG 0x04
+#define MAX31329_CONFIG2_CLKIN_EN BIT(2)
+#define MAX31329_CONFIG2_CLKIN_FREQ GENMASK(1, 0)
+
+#define MAX31341_42_CONFIG1_REG 0x00
+#define MAX31341_42_CONFIG1_CLKIN_EN BIT(7)
+#define MAX31341_42_CONFIG1_CLKIN_FREQ GENMASK(5, 4)
+#define MAX31341_42_CONFIG1_OSC_DISABLE BIT(3)
+#define MAX31341_42_CONFIG1_SWRST BIT(0)
+
+enum max313xx_ids {
+ ID_MAX31328,
+ ID_MAX31329,
+ ID_MAX31331,
+ ID_MAX31334,
+ ID_MAX31341,
+ ID_MAX31342,
+ ID_MAX31343,
+ MAX313XX_ID_NR
+};
+
+struct clkout_cfg {
+ const int *freq_avail;
+ u8 freq_size;
+ u8 freq_pos;
+ u8 reg;
+ u8 en_bit;
+ bool en_invert;
+};
+
+struct chip_desc {
+ struct clkout_cfg *clkout;
+ const char *clkout_name;
+ u8 sec_reg;
+ u8 alarm1_sec_reg;
+
+ u8 int_en_reg;
+ u8 int_status_reg;
+
+ u8 ram_reg;
+ u8 ram_size;
+
+ u8 temp_reg;
+
+ u8 trickle_reg;
+};
+
+#define clk_hw_to_max313xx(_hw) container_of(_hw, struct max313xx, clkout)
+
+struct max313xx {
+ enum max313xx_ids id;
+ struct regmap *regmap;
+ struct rtc_device *rtc;
+ struct clk_hw clkout;
+ struct clk *clkin;
+ const struct chip_desc *chip;
+ int irq;
+};
+
+static const int max313xx_clkin_freq[] = { 1, 50, 60, 32768 };
+
+static const int max31328_clkout_freq[] = { 1, 1024, 4096, 8192 };
+static const int max31329_clkout_freq[] = { 1, 4096, 8192, 32768 };
+static const int max3133x_clkout_freq[] = { 1, 64, 1024, 32768 };
+static const int max31341_42_clkout_freq[] = { 1, 50, 60, 32768 };
+static const int max31343_clkout_freq[] = { 1, 2, 4, 8, 16, 32, 64, 128, 32875 };
+
+static struct clkout_cfg max31328_clkout = {
+ .freq_avail = max31328_clkout_freq,
+ .freq_size = ARRAY_SIZE(max31328_clkout_freq),
+ .freq_pos = 3,
+ .reg = 0x0E,
+ .en_bit = BIT(3),
+ .en_invert = true,
+};
+
+static struct clkout_cfg max31329_clkout = {
+ .freq_avail = max31329_clkout_freq,
+ .freq_size = ARRAY_SIZE(max31329_clkout_freq),
+ .freq_pos = 5,
+ .reg = 0x04,
+ .en_bit = BIT(7),
+};
+
+static struct clkout_cfg max3133x_clkout = {
+ .freq_avail = max3133x_clkout_freq,
+ .freq_size = ARRAY_SIZE(max3133x_clkout_freq),
+ .freq_pos = 0,
+ .reg = 0x04,
+ .en_bit = BIT(2),
+};
+
+static struct clkout_cfg max31341_42_clkout = {
+ .freq_avail = max31341_42_clkout_freq,
+ .freq_size = ARRAY_SIZE(max31341_42_clkout_freq),
+ .freq_pos = 1,
+ .reg = 0x00,
+ .en_bit = BIT(6),
+ .en_invert = true,
+};
+
+static struct clkout_cfg max31343_clkout = {
+ .freq_avail = max31343_clkout_freq,
+ .freq_size = ARRAY_SIZE(max31343_clkout_freq),
+ .freq_pos = 3,
+ .reg = 0x04,
+ .en_bit = BIT(7),
+};
+
+static const struct chip_desc chip[MAX313XX_ID_NR] = {
+ [ID_MAX31328] = {
+ .int_en_reg = 0x0E,
+ .int_status_reg = 0x0F,
+ .sec_reg = 0x00,
+ .alarm1_sec_reg = 0x07,
+ .temp_reg = 0x11,
+ .clkout = &max31328_clkout,
+ .clkout_name = "max31328-sqw",
+ },
+ [ID_MAX31329] = {
+ .int_en_reg = 0x01,
+ .int_status_reg = 0x00,
+ .sec_reg = 0x06,
+ .alarm1_sec_reg = 0x0D,
+ .ram_reg = 0x22,
+ .ram_size = 64,
+ .trickle_reg = 0x19,
+ .clkout = &max31329_clkout,
+ .clkout_name = "max31329-clkout",
+ },
+ [ID_MAX31331] = {
+ .int_en_reg = 0x01,
+ .int_status_reg = 0x00,
+ .sec_reg = 0x08,
+ .alarm1_sec_reg = 0x0F,
+ .ram_reg = 0x20,
+ .ram_size = 32,
+ .trickle_reg = 0x1B,
+ .clkout = &max3133x_clkout,
+ .clkout_name = "max31331-clkout",
+ },
+ [ID_MAX31334] = {
+ .int_en_reg = 0x01,
+ .int_status_reg = 0x00,
+ .sec_reg = 0x09,
+ .alarm1_sec_reg = 0x10,
+ .ram_reg = 0x30,
+ .ram_size = 32,
+ .trickle_reg = 0x1E,
+ .clkout = &max3133x_clkout,
+ .clkout_name = "max31334-clkout",
+ },
+ [ID_MAX31341] = {
+ .int_en_reg = 0x04,
+ .int_status_reg = 0x05,
+ .sec_reg = 0x06,
+ .alarm1_sec_reg = 0x0D,
+ .ram_reg = 0x16,
+ .ram_size = 64,
+ .trickle_reg = 0x57,
+ .clkout = &max31341_42_clkout,
+ .clkout_name = "max31341-clkout",
+ },
+ [ID_MAX31342] = {
+ .int_en_reg = 0x04,
+ .int_status_reg = 0x05,
+ .sec_reg = 0x06,
+ .alarm1_sec_reg = 0x0D,
+ .clkout = &max31341_42_clkout,
+ .clkout_name = "max31342-clkout",
+ },
+ [ID_MAX31343] = {
+ .int_en_reg = 0x01,
+ .int_status_reg = 0x00,
+ .sec_reg = 0x06,
+ .alarm1_sec_reg = 0x0D,
+ .ram_reg = 0x22,
+ .ram_size = 64,
+ .temp_reg = 0x1A,
+ .trickle_reg = 0x19,
+ .clkout = &max31343_clkout,
+ .clkout_name = "max31343-clko",
+ },
+};
+
+static const u32 max313xx_trickle_ohms[] = { 3000, 6000, 11000 };
+
+static bool max313xx_volatile_reg(struct device *dev, unsigned int reg)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ const struct chip_desc *chip = rtc->chip;
+
+ /* time keeping registers */
+ if (reg >= chip->sec_reg && reg < chip->sec_reg + MAX313XX_TIME_SIZE)
+ return true;
+
+ /* interrupt status register */
+ if (reg == chip->int_status_reg)
+ return true;
+
+ /* temperature registers */
+ return chip->temp_reg &&
+ (reg == chip->temp_reg || reg == chip->temp_reg + 1);
+}
+
+static const struct regmap_config regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .cache_type = REGCACHE_RBTREE,
+ .volatile_reg = max313xx_volatile_reg,
+};
+
+static int max313xx_get_hour(u8 hour_reg)
+{
+ int hour;
+
+ /* 24Hr mode */
+ if (!FIELD_GET(MAX313XX_HRS_F_12_24, hour_reg))
+ return bcd2bin(hour_reg & 0x3f);
+
+ /* 12Hr mode */
+ hour = bcd2bin(hour_reg & 0x1f);
+ if (hour == 12)
+ hour = 0;
+
+ if (FIELD_GET(MAX313XX_HRS_F_AM_PM, hour_reg))
+ hour += 12;
+
+ return hour;
+}
+
+static int max313xx_read_time(struct device *dev, struct rtc_time *t)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ u8 regs[7];
+ int ret;
+
+ ret = regmap_bulk_read(rtc->regmap, rtc->chip->sec_reg, regs, 7);
+ if (ret)
+ return ret;
+
+ t->tm_sec = bcd2bin(regs[0] & 0x7f);
+ t->tm_min = bcd2bin(regs[1] & 0x7f);
+ t->tm_hour = max313xx_get_hour(regs[2]);
+ t->tm_wday = bcd2bin(regs[3] & 0x07) - 1;
+ t->tm_mday = bcd2bin(regs[4] & 0x3f);
+ t->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
+ t->tm_year = bcd2bin(regs[6]) + 100;
+
+ if (FIELD_GET(MAX313XX_MONTH_CENTURY, regs[5]))
+ t->tm_year += 100;
+
+ return 0;
+}
+
+static int max313xx_pre_set_time(struct max313xx *rtc)
+{
+ if (!rtc->clkin)
+ return 0;
+
+ /* Clkin needs to be disabled before setting time. */
+ switch (rtc->id) {
+ case ID_MAX31341:
+ case ID_MAX31342:
+ return regmap_clear_bits(rtc->regmap,
+ MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_CLKIN_EN);
+ default:
+ return 0;
+ }
+}
+
+static int max313xx_post_set_time(struct max313xx *rtc)
+{
+ int ret;
+
+ switch (rtc->id) {
+ case ID_MAX31341:
+ case ID_MAX31342:
+ ret = regmap_set_bits(rtc->regmap, MAX3134X_CFG2_REG,
+ MAX3134X_CFG2_SET_RTC);
+ if (ret)
+ return ret;
+
+ fsleep(10000);
+
+ ret = regmap_clear_bits(rtc->regmap, MAX3134X_CFG2_REG,
+ MAX3134X_CFG2_SET_RTC);
+ if (ret)
+ return ret;
+
+ if (rtc->clkin)
+ ret = regmap_set_bits(rtc->regmap,
+ MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_CLKIN_EN);
+
+ break;
+ default:
+ return 0;
+ }
+
+ return ret;
+}
+
+static int max313xx_set_time(struct device *dev, struct rtc_time *t)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ u8 regs[7];
+ int ret;
+
+ regs[0] = bin2bcd(t->tm_sec);
+ regs[1] = bin2bcd(t->tm_min);
+ regs[2] = bin2bcd(t->tm_hour);
+ regs[3] = bin2bcd(t->tm_wday + 1);
+ regs[4] = bin2bcd(t->tm_mday);
+ regs[5] = bin2bcd(t->tm_mon + 1);
+ regs[6] = bin2bcd(t->tm_year % 100);
+
+ if (t->tm_year >= 200)
+ regs[5] |= FIELD_PREP(MAX313XX_MONTH_CENTURY, 1);
+
+ ret = max313xx_pre_set_time(rtc);
+ if (ret)
+ return ret;
+
+ ret = regmap_bulk_write(rtc->regmap, rtc->chip->sec_reg, regs, 7);
+ if (ret)
+ return ret;
+
+ return max313xx_post_set_time(rtc);
+}
+
+static int max313xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ unsigned int status, int_en;
+ struct rtc_time time;
+ u8 regs[6];
+ int ret;
+
+ ret = regmap_bulk_read(rtc->regmap, rtc->chip->alarm1_sec_reg, regs,
+ sizeof(regs));
+ if (ret)
+ return ret;
+
+ t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
+ t->time.tm_min = bcd2bin(regs[1] & 0x7f);
+ t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
+ t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
+ t->time.tm_mon = bcd2bin(regs[4] & 0x1f) - 1;
+ t->time.tm_year = bcd2bin(regs[5]) + 100;
+
+ ret = max313xx_read_time(dev, &time);
+ if (ret)
+ return ret;
+
+ if (time.tm_year >= 200)
+ t->time.tm_year += 100;
+
+ ret = regmap_read(rtc->regmap, rtc->chip->int_status_reg, &status);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(rtc->regmap, rtc->chip->int_en_reg, &int_en);
+ if (ret)
+ return ret;
+
+ t->enabled = FIELD_GET(MAX313XX_INT_ALARM1, int_en);
+ t->pending = FIELD_GET(MAX313XX_INT_ALARM1, status);
+
+ return 0;
+}
+
+static int max313xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ unsigned int reg;
+ u8 regs[6];
+ int ret;
+
+ regs[0] = bin2bcd(t->time.tm_sec);
+ regs[1] = bin2bcd(t->time.tm_min);
+ regs[2] = bin2bcd(t->time.tm_hour);
+ regs[3] = bin2bcd(t->time.tm_mday);
+ regs[4] = bin2bcd(t->time.tm_mon + 1);
+ regs[5] = bin2bcd(t->time.tm_year % 100);
+
+ ret = regmap_bulk_write(rtc->regmap, rtc->chip->alarm1_sec_reg, regs,
+ sizeof(regs));
+ if (ret)
+ return ret;
+
+ reg = FIELD_PREP(MAX313XX_INT_ALARM1, t->enabled);
+ ret = regmap_update_bits(rtc->regmap, rtc->chip->int_en_reg,
+ MAX313XX_INT_ALARM1, reg);
+ if (ret)
+ return ret;
+
+ /* Clear status register */
+ return regmap_read(rtc->regmap, rtc->chip->int_status_reg, &reg);
+}
+
+static int max313xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+
+ return regmap_update_bits(rtc->regmap, rtc->chip->int_en_reg,
+ MAX313XX_INT_ALARM1,
+ FIELD_PREP(MAX313XX_INT_ALARM1, enabled));
+}
+
+static const struct rtc_class_ops max3133x_rtc_ops = {
+ .read_time = max313xx_read_time,
+ .set_time = max313xx_set_time,
+ .read_alarm = max313xx_read_alarm,
+ .set_alarm = max313xx_set_alarm,
+ .alarm_irq_enable = max313xx_alarm_irq_enable,
+};
+
+static irqreturn_t max313xx_irq(int irq, void *dev_id)
+{
+ struct max313xx *rtc = dev_id;
+ struct mutex *lock = &rtc->rtc->ops_lock;
+ int stat, ret;
+
+ mutex_lock(lock);
+ ret = regmap_read(rtc->regmap, rtc->chip->int_status_reg, &stat);
+ if (ret)
+ goto out;
+
+ if (FIELD_GET(MAX313XX_INT_ALARM1, stat)) {
+ ret = regmap_update_bits(rtc->regmap, rtc->chip->int_en_reg,
+ MAX313XX_INT_ALARM1, 0);
+ if (ret)
+ goto out;
+
+ rtc_update_irq(rtc->rtc, 1, RTC_AF | RTC_IRQF);
+ }
+
+out:
+ mutex_unlock(lock);
+
+ return IRQ_HANDLED;
+}
+
+static int max313xx_nvmem_reg_read(void *priv, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct max313xx *rtc = priv;
+ unsigned int reg = rtc->chip->ram_reg + offset;
+
+ return regmap_bulk_read(rtc->regmap, reg, val, bytes);
+}
+
+static int max313xx_nvmem_reg_write(void *priv, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct max313xx *rtc = priv;
+ unsigned int reg = rtc->chip->ram_reg + offset;
+
+ return regmap_bulk_write(rtc->regmap, reg, val, bytes);
+}
+
+struct nvmem_config max313xx_nvmem_cfg = {
+ .reg_read = max313xx_nvmem_reg_read,
+ .reg_write = max313xx_nvmem_reg_write,
+ .word_size = 8,
+};
+
+static unsigned long max313xx_clkout_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ const struct clkout_cfg *clkout = rtc->chip->clkout;
+ unsigned int freq_mask;
+ unsigned int reg;
+ int ret;
+
+ ret = regmap_read(rtc->regmap, clkout->reg, &reg);
+ if (ret)
+ return 0;
+
+ freq_mask = __roundup_pow_of_two(clkout->freq_size) - 1;
+
+ return clkout->freq_avail[(reg >> clkout->freq_pos) & freq_mask];
+}
+
+static long max313xx_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ struct clkout_cfg *clkout = rtc->chip->clkout;
+ int index;
+
+ index = find_closest(rate, clkout->freq_avail, clkout->freq_size);
+ return clkout->freq_avail[index];
+}
+
+static int max313xx_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ struct clkout_cfg *clkout = rtc->chip->clkout;
+ unsigned int freq_mask;
+ int index;
+
+ index = find_closest(rate, clkout->freq_avail, clkout->freq_size);
+ freq_mask = __roundup_pow_of_two(clkout->freq_size) - 1;
+
+ return regmap_update_bits(rtc->regmap, clkout->reg,
+ freq_mask << clkout->freq_pos,
+ index << clkout->freq_pos);
+}
+
+static int max313xx_clkout_enable(struct clk_hw *hw)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ struct clkout_cfg *clkout = rtc->chip->clkout;
+
+ if (clkout->en_invert)
+ return regmap_clear_bits(rtc->regmap, clkout->reg,
+ clkout->en_bit);
+
+ return regmap_set_bits(rtc->regmap, clkout->reg, clkout->en_bit);
+}
+
+static void max313xx_clkout_disable(struct clk_hw *hw)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ struct clkout_cfg *clkout = rtc->chip->clkout;
+
+ switch (rtc->id) {
+ case ID_MAX31331:
+ case ID_MAX31334:
+ if (rtc->irq > 0) {
+ dev_err(rtc->rtc->dev.parent,
+ "clkout cannot be disabled when IRQ is requested");
+ return;
+ }
+ break;
+ default:
+ break;
+ }
+
+ if (clkout->en_invert)
+ regmap_set_bits(rtc->regmap, clkout->reg, clkout->en_bit);
+ else
+ regmap_clear_bits(rtc->regmap, clkout->reg, clkout->en_bit);
+}
+
+static int max313xx_clkout_is_enabled(struct clk_hw *hw)
+{
+ struct max313xx *rtc = clk_hw_to_max313xx(hw);
+ struct clkout_cfg *clkout = rtc->chip->clkout;
+ unsigned int reg;
+ int ret;
+
+ ret = regmap_read(rtc->regmap, clkout->reg, &reg);
+ if (ret)
+ return ret;
+
+ return !!(reg & clkout->en_bit) ^ clkout->en_invert;
+}
+
+static const struct clk_ops max313xx_clkout_ops = {
+ .recalc_rate = max313xx_clkout_recalc_rate,
+ .round_rate = max313xx_clkout_round_rate,
+ .set_rate = max313xx_clkout_set_rate,
+ .enable = max313xx_clkout_enable,
+ .disable = max313xx_clkout_disable,
+ .is_enabled = max313xx_clkout_is_enabled,
+};
+
+struct clk_init_data max313xx_clk_init = {
+ .name = "max313xx-clkout",
+ .ops = &max313xx_clkout_ops,
+};
+
+static int max313xx_read_temp(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ u8 reg[2];
+ s16 temp;
+ int ret;
+
+ if (type != hwmon_temp || attr != hwmon_temp_input)
+ return -EOPNOTSUPP;
+
+ ret = regmap_bulk_read(rtc->regmap, rtc->chip->temp_reg, reg, 2);
+ if (ret)
+ return ret;
+
+ temp = get_unaligned_be16(reg);
+
+ *val = (temp / 64) * 250;
+
+ return 0;
+}
+
+static umode_t max313xx_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type == hwmon_temp && attr == hwmon_temp_input)
+ return 0444;
+
+ return 0;
+}
+
+static const struct hwmon_channel_info *max313xx_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops max313xx_hwmon_ops = {
+ .is_visible = max313xx_is_visible,
+ .read = max313xx_read_temp,
+};
+
+static const struct hwmon_chip_info max313xx_chip_info = {
+ .ops = &max313xx_hwmon_ops,
+ .info = max313xx_info,
+};
+
+static int max313xx_init(struct max313xx *rtc)
+{
+ int ret;
+
+ switch (rtc->id) {
+ case ID_MAX31341:
+ case ID_MAX31342:
+ ret = regmap_clear_bits(rtc->regmap, MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_OSC_DISABLE);
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(rtc->regmap, MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_SWRST);
+ default:
+ return 0;
+ }
+}
+
+static int max313xx_clkout_register(struct device *dev)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ int ret;
+
+ if (!device_property_present(dev, "#clock-cells"))
+ return 0;
+
+ max313xx_clk_init.name = rtc->chip->clkout_name;
+ device_property_read_string(dev, "clock-output-names",
+ &max313xx_clk_init.name);
+ rtc->clkout.init = &max313xx_clk_init;
+
+ ret = devm_clk_hw_register(dev, &rtc->clkout);
+ if (ret)
+ return dev_err_probe(dev, ret, "cannot register clock\n");
+
+ return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+ &rtc->clkout);
+}
+
+static int max313xx_trickle_charger_setup(struct device *dev)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ bool trickle_diode_en;
+ u32 charger_en = 0;
+ int index, reg;
+ u32 ohms = 0;
+ int ret;
+
+ device_property_read_u32(dev, "aux-voltage-chargeable", &charger_en);
+ switch (charger_en) {
+ case 0:
+ return 0;
+ case 1:
+ trickle_diode_en = 0;
+ break;
+ case 2:
+ trickle_diode_en = 1;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ device_property_read_u32(dev, "trickle-resistor-ohms", &ohms);
+
+ if (!rtc->chip->trickle_reg)
+ return 0;
+
+ index = find_closest(ohms, max313xx_trickle_ohms,
+ ARRAY_SIZE(max313xx_trickle_ohms)) + 1;
+
+ switch (rtc->id) {
+ case ID_MAX31329:
+ reg = FIELD_PREP(MAX31329_TRICKLE_ENABLE_BIT, 1) |
+ FIELD_PREP(MAX31329_43_TRICKLE_RES_MASK, index) |
+ FIELD_PREP(MAX31329_43_TRICKLE_DIODE_EN, trickle_diode_en);
+ break;
+ case ID_MAX31331:
+ case ID_MAX31334:
+ reg = FIELD_PREP(MAX3133X_TRICKLE_ENABLE_BIT, 1) |
+ FIELD_PREP(MAX3133X_TRICKLE_RES_MASK, index) |
+ FIELD_PREP(MAX3133X_TRICKLE_DIODE_EN, trickle_diode_en);
+ break;
+ case ID_MAX31341:
+ if (index == 1)
+ index = 0;
+
+ reg = FIELD_PREP(MAX31341_TRICKLE_ENABLE_BIT, 1) |
+ FIELD_PREP(MAX31341_TRICKLE_RES_MASK, index) |
+ FIELD_PREP(MAX31341_TRICKLE_DIODE_EN, trickle_diode_en);
+
+ ret = regmap_set_bits(rtc->regmap, MAX31341_POWER_MGMT_REG,
+ MAX31341_POWER_MGMT_TRICKLE_BIT);
+ if (ret)
+ return ret;
+
+ break;
+ case ID_MAX31343:
+ reg = FIELD_PREP(MAX31329_43_TRICKLE_RES_MASK, index) |
+ FIELD_PREP(MAX31329_43_TRICKLE_DIODE_EN, trickle_diode_en) |
+ FIELD_PREP(MAX31343_TRICKLE_ENABLE_MASK,
+ MAX31343_TRICKLE_ENABLE_CODE);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return regmap_write(rtc->regmap, rtc->chip->trickle_reg, reg);
+}
+
+static int max313xx_find_clkin_freq_index(struct clk *clk)
+{
+ unsigned long rate = clk_get_rate(clk);
+ int freq;
+ int i;
+
+ i = find_closest(rate, max313xx_clkin_freq,
+ ARRAY_SIZE(max313xx_clkin_freq));
+ if (max313xx_clkin_freq[i] == rate)
+ return i;
+
+ for (i = ARRAY_SIZE(max313xx_clkin_freq) - 1; i >= 0; i--) {
+ freq = max313xx_clkin_freq[i];
+ if (freq == clk_round_rate(clk, freq))
+ return i;
+ }
+
+ /* supplied clock cannot produce one of desired frequency rate */
+ return -ENODEV;
+}
+
+static int max313xx_clkin_init(struct device *dev)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ int rate;
+ int ret;
+
+ rtc->clkin = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(rtc->clkin)) {
+ if (PTR_ERR(rtc->clkin) == -ENOENT)
+ rtc->clkin = NULL;
+ else
+ return dev_err_probe(dev, PTR_ERR(rtc->clkin),
+ "error while clkin setup\n");
+ }
+
+ if (!rtc->clkin) {
+ switch (rtc->id) {
+ case ID_MAX31329:
+ return regmap_clear_bits(rtc->regmap,
+ MAX31329_CONFIG2_REG,
+ MAX31329_CONFIG2_CLKIN_EN);
+ case ID_MAX31341:
+ case ID_MAX31342:
+ return regmap_clear_bits(rtc->regmap,
+ MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_CLKIN_EN);
+ default:
+ return 0;
+ }
+ }
+
+ rate = max313xx_find_clkin_freq_index(rtc->clkin);
+ if (rate < 0)
+ return dev_err_probe(dev, rate,
+ "clkin cannot produce required frequency\n");
+
+ ret = clk_set_rate(rtc->clkin, max313xx_clkin_freq[rate]);
+ if (ret)
+ return ret;
+
+ switch (rtc->id) {
+ case ID_MAX31329:
+ ret = regmap_update_bits(rtc->regmap, MAX31329_CONFIG2_REG,
+ MAX31329_CONFIG2_CLKIN_FREQ, rate);
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(rtc->regmap, MAX31329_CONFIG2_REG,
+ MAX31329_CONFIG2_CLKIN_EN);
+ case ID_MAX31341:
+ case ID_MAX31342:
+ ret = regmap_update_bits(rtc->regmap, MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_CLKIN_FREQ,
+ FIELD_PREP(MAX31341_42_CONFIG1_CLKIN_FREQ, rate));
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(rtc->regmap, MAX31341_42_CONFIG1_REG,
+ MAX31341_42_CONFIG1_CLKIN_EN);
+ default:
+ rtc->clkin = NULL;
+ dev_warn(dev, "device does not have clock input\n");
+ return 0;
+ }
+}
+
+static int max313xx_irq_init(struct device *dev, const char *devname)
+{
+ struct max313xx *rtc = dev_get_drvdata(dev);
+ int ret;
+
+ switch (rtc->id) {
+ case ID_MAX31328:
+ break;
+ case ID_MAX31331:
+ case ID_MAX31334:
+ if (rtc->clkout.clk) {
+ /*
+ * interrupt muxing depends on clkout so enable clkout
+ * if configured before requesting interrupt
+ */
+ ret = clk_prepare_enable(rtc->clkout.clk);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "cannot enable clkout\n");
+ }
+ break;
+ default:
+ if (rtc->clkin) {
+ if (rtc->clkout.clk && rtc->irq > 0)
+ return dev_err_probe(dev, -EOPNOTSUPP,
+ "irq not possible when both clkin and clkout are configured\n");
+
+ if (rtc->irq <= 0)
+ break;
+
+ /* clkout needs to be disabled for interrupt */
+ if (rtc->chip->clkout->en_invert)
+ ret = regmap_set_bits(rtc->regmap,
+ rtc->chip->clkout->reg,
+ rtc->chip->clkout->en_bit);
+ else
+ ret = regmap_clear_bits(rtc->regmap,
+ rtc->chip->clkout->reg,
+ rtc->chip->clkout->en_bit);
+
+ if (ret)
+ return ret;
+ }
+ break;
+ }
+
+ if (rtc->irq > 0) {
+ return devm_request_threaded_irq(dev, rtc->irq, NULL,
+ &max313xx_irq, IRQF_ONESHOT,
+ devname, rtc);
+ } else if (device_property_read_bool(dev, "wakeup-source")) {
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtc->features);
+ return device_init_wakeup(dev, true);
+ }
+
+ clear_bit(RTC_FEATURE_ALARM, rtc->rtc->features);
+
+ return 0;
+}
+
+static int max313xx_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct max313xx *max313xx;
+ struct device *hwmon;
+ const void *match;
+ int ret;
+
+ max313xx = devm_kzalloc(&client->dev, sizeof(*max313xx), GFP_KERNEL);
+ if (!max313xx)
+ return -ENOMEM;
+
+ dev_set_drvdata(&client->dev, max313xx);
+
+ max313xx->regmap = devm_regmap_init_i2c(client, &regmap_config);
+ if (IS_ERR(max313xx->regmap)) {
+ return dev_err_probe(dev, PTR_ERR(max313xx->regmap),
+ "regmap init failed\n");
+ }
+
+ i2c_set_clientdata(client, max313xx);
+
+ match = device_get_match_data(dev);
+ if (match)
+ max313xx->chip = match;
+ else if (id)
+ max313xx->chip = (struct chip_desc *)id->driver_data;
+ else
+ return -ENODEV;
+
+ max313xx->id = max313xx->chip - chip;
+
+ ret = max313xx_init(max313xx);
+ if (ret)
+ return ret;
+
+ max313xx->rtc = devm_rtc_allocate_device(dev);
+ if (IS_ERR(max313xx->rtc))
+ return PTR_ERR(max313xx->rtc);
+
+ max313xx->rtc->ops = &max3133x_rtc_ops;
+ max313xx->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ max313xx->rtc->range_max = RTC_TIMESTAMP_END_2199;
+
+ ret = devm_rtc_register_device(max313xx->rtc);
+ if (ret)
+ return ret;
+
+ max313xx->irq = client->irq;
+
+ ret = max313xx_clkout_register(dev);
+ if (ret)
+ return ret;
+
+ ret = max313xx_clkin_init(dev);
+ if (ret)
+ return ret;
+
+ /* IRQ wiring depends on the clock configuration so parse them first */
+ ret = max313xx_irq_init(dev, client->name);
+ if (ret)
+ return ret;
+
+ if (max313xx->chip->ram_size) {
+ max313xx_nvmem_cfg.size = max313xx->chip->ram_size;
+ max313xx_nvmem_cfg.priv = max313xx;
+
+ ret = devm_rtc_nvmem_register(max313xx->rtc, &max313xx_nvmem_cfg);
+ if (ret)
+ dev_warn(dev, "cannot register rtc nvmem\n");
+ }
+
+ if (max313xx->chip->temp_reg) {
+ hwmon = devm_hwmon_device_register_with_info(dev, client->name,
+ max313xx,
+ &max313xx_chip_info,
+ NULL);
+ if (IS_ERR(hwmon))
+ dev_warn(dev, "cannot register hwmon device: %li\n",
+ PTR_ERR(hwmon));
+ }
+
+ return max313xx_trickle_charger_setup(dev);
+}
+
+static const struct of_device_id max313xx_of_id[] = {
+ { .compatible = "adi,max31328", .data = &chip[ID_MAX31328] },
+ { .compatible = "adi,max31329", .data = &chip[ID_MAX31329] },
+ { .compatible = "adi,max31331", .data = &chip[ID_MAX31331] },
+ { .compatible = "adi,max31334", .data = &chip[ID_MAX31334] },
+ { .compatible = "adi,max31341", .data = &chip[ID_MAX31341] },
+ { .compatible = "adi,max31342", .data = &chip[ID_MAX31342] },
+ { .compatible = "adi,max31343", .data = &chip[ID_MAX31343] },
+ { }
+};
+MODULE_DEVICE_TABLE(of, max313xx_of_id);
+
+static const struct i2c_device_id max313xx_id[] = {
+ { "max31328", (kernel_ulong_t)&chip[ID_MAX31328] },
+ { "max31329", (kernel_ulong_t)&chip[ID_MAX31329] },
+ { "max31331", (kernel_ulong_t)&chip[ID_MAX31331] },
+ { "max31334", (kernel_ulong_t)&chip[ID_MAX31334] },
+ { "max31341", (kernel_ulong_t)&chip[ID_MAX31341] },
+ { "max31342", (kernel_ulong_t)&chip[ID_MAX31342] },
+ { "max31343", (kernel_ulong_t)&chip[ID_MAX31343] },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max313xx_id);
+
+static struct i2c_driver max313xx_driver = {
+ .driver = {
+ .name = "rtc-max313xx",
+ .of_match_table = max313xx_of_id,
+ },
+ .probe = max313xx_probe,
+ .id_table = max313xx_id,
+};
+module_i2c_driver(max313xx_driver);
+
+MODULE_DESCRIPTION("Analog Devices MAX313XX RTCs");
+MODULE_AUTHOR("Zeynep Arslanbenzer <Zeynep.Arslanbenzer@xxxxxxxxxx>");
+MODULE_AUTHOR("Ibrahim Tilki <Ibrahim.Tilki@xxxxxxxxxx>");
+MODULE_SOFTDEP("pre: regmap-i2c");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
--
2.25.1