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

[Chris Packham <Chris.Packham@alliedtelesis.co.nz>]

Hi Ibrahim,

On 4/04/23 03:43, Ibrahim Tilki wrote:
> Adding support for Analog Devices MAX313XX series RTCs.
>
> Signed-off-by: Ibrahim Tilki <Ibrahim.Tilki@analog.com>
> Signed-off-by: Zeynep Arslanbenzer <Zeynep.Arslanbenzer@analog.com>

Just taking this version for a spin on my board with the MAX31331. 
Compared to patchset 3 I'm finding that the RTC isn't actually running 
after it is set. I haven't begun to debug why this might be. I suspect 
it's not being enabled.

Here's the snippet of dts that I'm using (which worked with patchset 3).

         i2c@1 {
                         rtc@68 {
                                 compatible = "adi,max31331";
                                 reg = <0x68>;
                         };
         };

And here's an example of it not working

root@x240-26GHXm ~]# date
Mon Apr 24 10:49:54 UTC 2023
[root@x240-26GHXm ~]# hwclock -w
[root@x240-26GHXm ~]# hwclock -r
Sat Jan  1 00:00:00 2000  0.000000 seconds

And finally a register dump which I'll start looking at shortly

[root@x240-26GHXm ~]# i2cdump -f -y 2 0x68
No size specified (using byte-data access)
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f 0123456789abcdef
00: 40 00 01 43 03 04 04 00 00 00 00 01 01 01 00 00 @.?C???....???..
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 ...............?
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
40: 00 00 00 00 00 00 00 00 00 ff ff ff ff ff ff ff ................
50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
60: 00 00 00 ff ff ff ff ff ff ff ff ff ff ff ff ff ................
70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................

> ---
>   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@analog.com>");
> +MODULE_AUTHOR("Ibrahim Tilki <Ibrahim.Tilki@analog.com>");
> +MODULE_SOFTDEP("pre: regmap-i2c");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("1.0");