path: root/drivers/rtc/rtc-rv3028.c

// SPDX-License-Identifier: GPL-2.0
/*
 * RTC driver for the Micro Crystal RV3028
 *
 * Copyright (C) 2019 Micro Crystal SA
 *
 * Alexandre Belloni <alexandre.belloni@bootlin.com>
 *
 */

#include <linux/clk-provider.h>
#include <linux/bcd.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/rtc.h>

#define RV3028_SEC			0x00
#define RV3028_MIN			0x01
#define RV3028_HOUR			0x02
#define RV3028_WDAY			0x03
#define RV3028_DAY			0x04
#define RV3028_MONTH			0x05
#define RV3028_YEAR			0x06
#define RV3028_ALARM_MIN		0x07
#define RV3028_ALARM_HOUR		0x08
#define RV3028_ALARM_DAY		0x09
#define RV3028_STATUS			0x0E
#define RV3028_CTRL1			0x0F
#define RV3028_CTRL2			0x10
#define RV3028_EVT_CTRL			0x13
#define RV3028_TS_COUNT			0x14
#define RV3028_TS_SEC			0x15
#define RV3028_RAM1			0x1F
#define RV3028_EEPROM_ADDR		0x25
#define RV3028_EEPROM_DATA		0x26
#define RV3028_EEPROM_CMD		0x27
#define RV3028_CLKOUT			0x35
#define RV3028_OFFSET			0x36
#define RV3028_BACKUP			0x37

#define RV3028_STATUS_PORF		BIT(0)
#define RV3028_STATUS_EVF		BIT(1)
#define RV3028_STATUS_AF		BIT(2)
#define RV3028_STATUS_TF		BIT(3)
#define RV3028_STATUS_UF		BIT(4)
#define RV3028_STATUS_BSF		BIT(5)
#define RV3028_STATUS_CLKF		BIT(6)
#define RV3028_STATUS_EEBUSY		BIT(7)

#define RV3028_CLKOUT_FD_MASK		GENMASK(2, 0)
#define RV3028_CLKOUT_PORIE		BIT(3)
#define RV3028_CLKOUT_CLKSY		BIT(6)
#define RV3028_CLKOUT_CLKOE		BIT(7)

#define RV3028_CTRL1_EERD		BIT(3)
#define RV3028_CTRL1_WADA		BIT(5)

#define RV3028_CTRL2_RESET		BIT(0)
#define RV3028_CTRL2_12_24		BIT(1)
#define RV3028_CTRL2_EIE		BIT(2)
#define RV3028_CTRL2_AIE		BIT(3)
#define RV3028_CTRL2_TIE		BIT(4)
#define RV3028_CTRL2_UIE		BIT(5)
#define RV3028_CTRL2_TSE		BIT(7)

#define RV3028_EVT_CTRL_TSR		BIT(2)

#define RV3028_EEPROM_CMD_UPDATE	0x11
#define RV3028_EEPROM_CMD_WRITE		0x21
#define RV3028_EEPROM_CMD_READ		0x22

#define RV3028_EEBUSY_POLL		10000
#define RV3028_EEBUSY_TIMEOUT		100000

#define RV3028_BACKUP_TCE		BIT(5)
#define RV3028_BACKUP_TCR_MASK		GENMASK(1,0)
#define RV3028_BACKUP_BSM		GENMASK(3,2)

#define RV3028_BACKUP_BSM_DSM		0x1
#define RV3028_BACKUP_BSM_LSM		0x3

#define OFFSET_STEP_PPT			953674

enum rv3028_type {
	rv_3028,
};

struct rv3028_data {
	struct regmap *regmap;
	struct rtc_device *rtc;
	enum rv3028_type type;
#ifdef CONFIG_COMMON_CLK
	struct clk_hw clkout_hw;
#endif
};

static u16 rv3028_trickle_resistors[] = {3000, 5000, 9000, 15000};

static ssize_t timestamp0_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);

	regmap_update_bits(rv3028->regmap, RV3028_EVT_CTRL, RV3028_EVT_CTRL_TSR,
			   RV3028_EVT_CTRL_TSR);

	return count;
};

static ssize_t timestamp0_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
	struct rtc_time tm;
	int ret, count;
	u8 date[6];

	ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
	if (ret)
		return ret;

	if (!count)
		return 0;

	ret = regmap_bulk_read(rv3028->regmap, RV3028_TS_SEC, date,
			       sizeof(date));
	if (ret)
		return ret;

	tm.tm_sec = bcd2bin(date[0]);
	tm.tm_min = bcd2bin(date[1]);
	tm.tm_hour = bcd2bin(date[2]);
	tm.tm_mday = bcd2bin(date[3]);
	tm.tm_mon = bcd2bin(date[4]) - 1;
	tm.tm_year = bcd2bin(date[5]) + 100;

	ret = rtc_valid_tm(&tm);
	if (ret)
		return ret;

	return sprintf(buf, "%llu\n",
		       (unsigned long long)rtc_tm_to_time64(&tm));
};

static DEVICE_ATTR_RW(timestamp0);

static ssize_t timestamp0_count_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
	int ret, count;

	ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
	if (ret)
		return ret;

	return sprintf(buf, "%u\n", count);
};

static DEVICE_ATTR_RO(timestamp0_count);

static struct attribute *rv3028_attrs[] = {
	&dev_attr_timestamp0.attr,
	&dev_attr_timestamp0_count.attr,
	NULL
};

static const struct attribute_group rv3028_attr_group = {
	.attrs	= rv3028_attrs,
};

static int rv3028_exit_eerd(struct rv3028_data *rv3028, u32 eerd)
{
	if (eerd)
		return 0;

	return regmap_update_bits(rv3028->regmap, RV3028_CTRL1, RV3028_CTRL1_EERD, 0);
}

static int rv3028_enter_eerd(struct rv3028_data *rv3028, u32 *eerd)
{
	u32 ctrl1, status;
	int ret;

	ret = regmap_read(rv3028->regmap, RV3028_CTRL1, &ctrl1);
	if (ret)
		return ret;

	*eerd = ctrl1 & RV3028_CTRL1_EERD;
	if (*eerd)
		return 0;

	ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL1,
				 RV3028_CTRL1_EERD, RV3028_CTRL1_EERD);
	if (ret)
		return ret;

	ret = regmap_read_poll_timeout(rv3028->regmap, RV3028_STATUS, status,
				       !(status & RV3028_STATUS_EEBUSY),
				       RV3028_EEBUSY_POLL, RV3028_EEBUSY_TIMEOUT);
	if (ret) {
		rv3028_exit_eerd(rv3028, *eerd);

		return ret;
	}

	return 0;
}

static int rv3028_update_eeprom(struct rv3028_data *rv3028, u32 eerd)
{
	u32 status;<