/* rtc-da9063.c - Real time clock device driver for DA9063
 * Copyright (C) 2013-2015  Dialog Semiconductor Ltd.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/slab.h>

#include <linux/mfd/da9062/registers.h>
#include <linux/mfd/da9063/registers.h>
#include <linux/mfd/da9063/core.h>

#define YEARS_TO_DA9063(year)		((year) - 100)
#define MONTHS_TO_DA9063(month)		((month) + 1)
#define YEARS_FROM_DA9063(year)		((year) + 100)
#define MONTHS_FROM_DA9063(month)	((month) - 1)

enum {
	RTC_SEC	= 0,
	RTC_MIN	= 1,
	RTC_HOUR = 2,
	RTC_DAY	= 3,
	RTC_MONTH = 4,
	RTC_YEAR = 5,
	RTC_DATA_LEN
};

struct da9063_compatible_rtc_regmap {
	/* REGS */
	int rtc_enable_reg;
	int rtc_enable_32k_crystal_reg;
	int rtc_alarm_secs_reg;
	int rtc_alarm_year_reg;
	int rtc_count_secs_reg;
	int rtc_count_year_reg;
	int rtc_event_reg;
	/* MASKS */
	int rtc_enable_mask;
	int rtc_crystal_mask;
	int rtc_event_alarm_mask;
	int rtc_alarm_on_mask;
	int rtc_alarm_status_mask;
	int rtc_tick_on_mask;
	int rtc_ready_to_read_mask;
	int rtc_count_sec_mask;
	int rtc_count_min_mask;
	int rtc_count_hour_mask;
	int rtc_count_day_mask;
	int rtc_count_month_mask;
	int rtc_count_year_mask;
	/* ALARM CONFIG */
	int rtc_data_start;
	int rtc_alarm_len;
};

struct da9063_compatible_rtc {
	struct rtc_device *rtc_dev;
	struct rtc_time alarm_time;
	struct regmap *regmap;
	const struct da9063_compatible_rtc_regmap *config;
	bool rtc_sync;
};

static const struct da9063_compatible_rtc_regmap da9063_ad_regs = {
	/* REGS */
	.rtc_enable_reg             = DA9063_REG_CONTROL_E,
	.rtc_alarm_secs_reg         = DA9063_AD_REG_ALARM_MI,
	.rtc_alarm_year_reg         = DA9063_AD_REG_ALARM_Y,
	.rtc_count_secs_reg         = DA9063_REG_COUNT_S,
	.rtc_count_year_reg         = DA9063_REG_COUNT_Y,
	.rtc_event_reg              = DA9063_REG_EVENT_A,
	/* MASKS */
	.rtc_enable_mask            = DA9063_RTC_EN,
	.rtc_crystal_mask           = DA9063_CRYSTAL,
	.rtc_enable_32k_crystal_reg = DA9063_REG_EN_32K,
	.rtc_event_alarm_mask       = DA9063_E_ALARM,
	.rtc_alarm_on_mask          = DA9063_ALARM_ON,
	.rtc_alarm_status_mask      = DA9063_ALARM_STATUS_ALARM |
				      DA9063_ALARM_STATUS_TICK,
	.rtc_tick_on_mask           = DA9063_TICK_ON,
	.rtc_ready_to_read_mask     = DA9063_RTC_READ,
	.rtc_count_sec_mask         = DA9063_COUNT_SEC_MASK,
	.rtc_count_min_mask         = DA9063_COUNT_MIN_MASK,
	.rtc_count_hour_mask        = DA9063_COUNT_HOUR_MASK,
	.rtc_count_day_mask         = DA9063_COUNT_DAY_MASK,
	.rtc_count_month_mask       = DA9063_COUNT_MONTH_MASK,
	.rtc_count_year_mask        = DA9063_COUNT_YEAR_MASK,
	/* ALARM CONFIG */
	.rtc_data_start             = RTC_MIN,
	.rtc_alarm_len              = RTC_DATA_LEN - 1,
};

static const struct da9063_compatible_rtc_regmap da9063_bb_regs = {
	/* REGS */
	.rtc_enable_reg             = DA9063_REG_CONTROL_E,
	.rtc_alarm_secs_reg         = DA9063_BB_REG_ALARM_S,
	.rtc_alarm_year_reg         = DA9063_BB_REG_ALARM_Y,
	.rtc_count_secs_reg         = DA9063_REG_COUNT_S,
	.rtc_count_year_reg         = DA9063_REG_COUNT_Y,
	.rtc_event_reg              = DA9063_REG_EVENT_A,
	/* MASKS */
	.rtc_enable_mask            = DA9063_RTC_EN,
	.rtc_crystal_mask           = DA9063_CRYSTAL,
	.rtc_enable_32k_crystal_reg = DA9063_REG_EN_32K,
	.rtc_event_alarm_mask       = DA9063_E_ALARM,
	.rtc_alarm_on_mask          = DA9063_ALARM_ON,
	.rtc_alarm_status_mask      = DA9063_ALARM_STATUS_ALARM |
				      DA9063_ALARM_STATUS_TICK,
	.rtc_tick_on_mask           = DA9063_TICK_ON,
	.rtc_ready_to_read_mask     = DA9063_RTC_READ,
	.rtc_count_sec_mask         = DA9063_COUNT_SEC_MASK,
	.rtc_count_min_mask         = DA9063_COUNT_MIN_MASK,
	.rtc_count_hour_mask        = DA9063_COUNT_HOUR_MASK,
	.rtc_count_day_mask         = DA9063_COUNT_DAY_MASK,
	.rtc_count_month_mask       = DA9063_COUNT_MONTH_MASK,
	.rtc_count_year_mask        = DA9063_COUNT_YEAR_MASK,
	/* ALARM CONFIG */
	.rtc_data_start             = RTC_SEC,
	.rtc_alarm_len              = RTC_DATA_LEN,
};

static const struct da9063_compatible_rtc_regmap da9062_aa_regs = {
	/* REGS */
	.rtc_enable_reg             = DA9062AA_CONTROL_E,
	.rtc_alarm_secs_reg         = DA9062AA_ALARM_S,
	.rtc_alarm_year_reg         = DA9062AA_ALARM_Y,
	.rtc_count_secs_reg         = DA9062AA_COUNT_S,
	.rtc_count_year_reg         = DA9062AA_COUNT_Y,
	.rtc_event_reg              = DA9062AA_EVENT_A,
	/* MASKS */
	.rtc_enable_mask            = DA9062AA_RTC_EN_MASK,
	.rtc_crystal_mask           = DA9062AA_CRYSTAL_MASK,
	.rtc_enable_32k_crystal_reg = DA9062AA_EN_32K,
	.rtc_event_alarm_mask       = DA9062AA_M_ALARM_MASK,
	.rtc_alarm_on_mask          = DA9062AA_ALARM_ON_MASK,
	.rtc_alarm_status_mask      = (0x02 << 6),
	.rtc_tick_on_mask           = DA9062AA_TICK_ON_MASK,
	.rtc_ready_to_read_mask     = DA9062AA_RTC_READ_MASK,
	.rtc_count_sec_mask         = DA9062AA_COUNT_SEC_MASK,
	.rtc_count_min_mask         = DA9062AA_COUNT_MIN_MASK,
	.rtc_count_hour_mask        = DA9062AA_COUNT_HOUR_MASK,
	.rtc_count_day_mask         = DA9062AA_COUNT_DAY_MASK,
	.rtc_count_month_mask       = DA9062AA_COUNT_MONTH_MASK,
	.rtc_count_year_mask        = DA9062AA_COUNT_YEAR_MASK,
	/* ALARM CONFIG */
	.rtc_data_start             = RTC_SEC,
	.rtc_alarm_len              = RTC_DATA_LEN,
};

static const struct of_device_id da9063_compatible_reg_id_table[] = {
	{ .compatible = "dlg,da9063-rtc", .data = &da9063_bb_regs },
	{ .compatible = "dlg,da9062-rtc", .data = &da9062_aa_regs },
	{ },
};
MODULE_DEVICE_TABLE(of, da9063_compatible_reg_id_table);

static void da9063_data_to_tm(u8 *data, struct rtc_time *tm,
			      struct da9063_compatible_rtc *rtc)
{
	const struct da9063_compatible_rtc_regmap *config = rtc->config;

	tm->tm_sec  = data[RTC_SEC]  & config->rtc_count_sec_mask;
	tm->tm_min  = data[RTC_MIN]  & config->rtc_count_min_mask;
	tm->tm_hour = data[RTC_HOUR] & config->rtc_count_hour_mask;
	tm->tm_mday = data[RTC_DAY]  & config->rtc_count_day_mask;
	tm->tm_mon  = MONTHS_FROM_DA9063(data[RTC_MONTH] &
					 config->rtc_count_month_mask);
	tm->tm_year = YEARS_FROM_DA9063(data[RTC_YEAR] &
					config->rtc_count_year_mask);
}

static void da9063_tm_to_data(struct rtc_time *tm, u8 *data,
			      struct da9063_compatible_rtc *rtc)
{
	const struct da9063_compatible_rtc_regmap *config = rtc->config;

	data[RTC_SEC]   = tm->tm_sec & config->rtc_count_sec_mask;
	data[RTC_MIN]   = tm->tm_min & config->rtc_count_min_mask;
	data[RTC_HOUR]  = tm->tm_hour & config->rtc_count_hour_mask;
	data[RTC_DAY]   = tm->tm_mday & config->rtc_count_day_mask;
	data[RTC_MONTH] = MONTHS_TO_DA9063(tm->tm_mon) &
				config->rtc_count_month_mask;
	data[RTC_YEAR]  = YEARS_TO_DA9063(tm->tm_year) &
				config->rtc_count_year_mask;
}

static int da9063_rtc_stop_alarm(struct device *dev)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;

	return regmap_update_bits(rtc->regmap,
				  config->rtc_alarm_year_reg,
				  config->rtc_alarm_on_mask,
				  0);
}

static int da9063_rtc_start_alarm(struct device *dev)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;

	return regmap_update_bits(rtc->regmap,
				  config->rtc_alarm_year_reg,
				  config->rtc_alarm_on_mask,
				  config->rtc_alarm_on_mask);
}

static int da9063_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;
	unsigned long tm_secs;
	unsigned long al_secs;
	u8 data[RTC_DATA_LEN];
	int ret;

	ret = regmap_bulk_read(rtc->regmap,
			       config->rtc_count_secs_reg,
			       data, RTC_DATA_LEN);
	if (ret < 0) {
		dev_err(dev, "Failed to read RTC time data: %d\n", ret);
		return ret;
	}

	if (!(data[RTC_SEC] & config->rtc_ready_to_read_mask)) {
		dev_dbg(dev, "RTC not yet ready to be read by the host\n");
		return -EINVAL;
	}

	da9063_data_to_tm(data, tm, rtc);

	rtc_tm_to_time(tm, &tm_secs);
	rtc_tm_to_time(&rtc->alarm_time, &al_secs);

	/* handle the rtc synchronisation delay */
	if (rtc->rtc_sync == true && al_secs - tm_secs == 1)
		memcpy(tm, &rtc->alarm_time, sizeof(struct rtc_time));
	else
		rtc->rtc_sync = false;

	return 0;
}

static int da9063_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;
	u8 data[RTC_DATA_LEN];
	int ret;

	da9063_tm_to_data(tm, data, rtc);
	ret = regmap_bulk_write(rtc->regmap,
				config->rtc_count_secs_reg,
				data, RTC_DATA_LEN);
	if (ret < 0)
		dev_err(dev, "Failed to set RTC time data: %d\n", ret);

	return ret;
}

static int da9063_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;
	u8 data[RTC_DATA_LEN];
	int ret;
	unsigned int val;

	data[RTC_SEC] = 0;
	ret = regmap_bulk_read(rtc->regmap,
			       config->rtc_alarm_secs_reg,
			       &data[config->rtc_data_start],
			       config->rtc_alarm_len);
	if (ret < 0)
		return ret;

	da9063_data_to_tm(data, &alrm->time, rtc);

	alrm->enabled = !!(data[RTC_YEAR] & config->rtc_alarm_on_mask);

	ret = regmap_read(rtc->regmap,
			  config->rtc_event_reg,
			  &val);
	if (ret < 0)
		return ret;

	if (val & config->rtc_event_alarm_mask)
		alrm->pending = 1;
	else
		alrm->pending = 0;

	return 0;
}

static int da9063_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
	const struct da9063_compatible_rtc_regmap *config = rtc->config;
	u8 data[RTC_DATA_LEN];
	int ret;

	da9063_tm_to_data(&alrm->time, data, rtc);

	ret = da9063_rtc_stop_alarm(dev);
	if (ret < 0) {
		dev_err(dev, "Failed to stop alarm: %d\n", ret);
		return ret;
	}

	ret = regmap_bulk_write(rtc->regmap,
				config->rtc_alarm_secs_reg,
				&data[config->rtc_data_start],
				config->rtc_alarm_len);
	if (ret < 0) {
		dev_err(dev, "Failed to write alarm: %d\n", ret);
		return ret;
	}

	da9063_data_to_tm(data, &rtc->alarm_time, rtc);

	if (alrm->enabled) {
		ret = da9063_rtc_start_alarm(dev);
		if (ret < 0) {
			dev_err(dev, "Failed to start alarm: %d\n", ret);
			return ret;
		}
	}

	return ret;
}

static int da9063_rtc_alarm_irq_enable(struct device *dev,
				       unsigned int enabled)
{
	if (enabled)
		return da9063_rtc_start_alarm(dev);
	else
		return da9063_rtc_stop_alarm(dev);
}

static irqreturn_t da9063_alarm_event(int irq, void *data)
{
	struct da9063_compatible_rtc *rtc = data;
	const struct da9063_compatible_rtc_regmap *config = rtc->config;

	regmap_update_bits(rtc->regmap,
			   config->rtc_alarm_year_reg,
			   config->rtc_alarm_on_mask,
			   0);

	rtc->rtc_sync = true;
	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);

	return IRQ_HANDLED;
}

static const struct rtc_class_ops da9063_rtc_ops = {
	.read_time = da9063_rtc_read_time,
	.set_time = da9063_rtc_set_time,
	.read_alarm = da9063_rtc_read_alarm,
	.set_alarm = da9063_rtc_set_alarm,
	.alarm_irq_enable = da9063_rtc_alarm_irq_enable,
};

static int da9063_rtc_probe(struct platform_device *pdev)
{
	struct da9063_compatible_rtc *rtc;
	const struct da9063_compatible_rtc_regmap *config;
	const struct of_device_id *match;
	int irq_alarm;
	u8 data[RTC_DATA_LEN];
	int ret;

	if (!pdev->dev.of_node)
		return -ENXIO;

	match = of_match_node(da9063_compatible_reg_id_table,
			      pdev->dev.of_node);

	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
	if (!rtc)
		return -ENOMEM;

	rtc->config = match->data;
	if (of_device_is_compatible(pdev->dev.of_node, "dlg,da9063-rtc")) {
		struct da9063 *chip = dev_get_drvdata(pdev->dev.parent);

		if (chip->variant_code == PMIC_DA9063_AD)
			rtc->config = &da9063_ad_regs;
	}

	rtc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!rtc->regmap) {
		dev_warn(&pdev->dev, "Parent regmap unavailable.\n");
		return -ENXIO;
	}

	config = rtc->config;
	ret = regmap_update_bits(rtc->regmap,
				 config->rtc_enable_reg,
				 config->rtc_enable_mask,
				 config->rtc_enable_mask);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to enable RTC\n");
		return ret;
	}

	ret = regmap_update_bits(rtc->regmap,
				 config->rtc_enable_32k_crystal_reg,
				 config->rtc_crystal_mask,
				 config->rtc_crystal_mask);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to run 32kHz oscillator\n");
		return ret;
	}

	ret = regmap_update_bits(rtc->regmap,
				 config->rtc_alarm_secs_reg,
				 config->rtc_alarm_status_mask,
				 0);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
		return ret;
	}

	ret = regmap_update_bits(rtc->regmap,
				 config->rtc_alarm_secs_reg,
				 DA9063_ALARM_STATUS_ALARM,
				 DA9063_ALARM_STATUS_ALARM);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
		return ret;
	}

	ret = regmap_update_bits(rtc->regmap,
				 config->rtc_alarm_year_reg,
				 config->rtc_tick_on_mask,
				 0);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to disable TICKs\n");
		return ret;
	}

	data[RTC_SEC] = 0;
	ret = regmap_bulk_read(rtc->regmap,
			       config->rtc_alarm_secs_reg,
			       &data[config->rtc_data_start],
			       config->rtc_alarm_len);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to read initial alarm data: %d\n",
			ret);
		return ret;
	}

	platform_set_drvdata(pdev, rtc);

	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, DA9063_DRVNAME_RTC,
					   &da9063_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc->rtc_dev))
		return PTR_ERR(rtc->rtc_dev);

	da9063_data_to_tm(data, &rtc->alarm_time, rtc);
	rtc->rtc_sync = false;

	/*
	 * TODO: some models have alarms on a minute boundary but still support
	 * real hardware interrupts. Add this once the core supports it.
	 */
	if (config->rtc_data_start != RTC_SEC)
		rtc->rtc_dev->uie_unsupported = 1;

	irq_alarm = platform_get_irq_byname(pdev, "ALARM");
	ret = devm_request_threaded_irq(&pdev->dev, irq_alarm, NULL,
					da9063_alarm_event,
					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					"ALARM", rtc);
	if (ret)
		dev_err(&pdev->dev, "Failed to request ALARM IRQ %d: %d\n",
			irq_alarm, ret);

	return ret;
}

static struct platform_driver da9063_rtc_driver = {
	.probe		= da9063_rtc_probe,
	.driver		= {
		.name	= DA9063_DRVNAME_RTC,
		.of_match_table = da9063_compatible_reg_id_table,
	},
};

module_platform_driver(da9063_rtc_driver);

MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
MODULE_DESCRIPTION("Real time clock device driver for Dialog DA9063");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DA9063_DRVNAME_RTC);
