drivers/rtc/rtc-pcf85063.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * An I2C driver for the PCF85063 RTC
  * Copyright 2014 Rose Technology
  *
  * Author: Søren Andersen <san@rosetechnology.dk>
  * Maintainers: http://www.nslu2-linux.org/
  *
  * Copyright (C) 2019 Micro Crystal AG
  * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
  */
 #include <linux/clk-provider.h>
 #include <linux/i2c.h>
 #include <linux/bcd.h>
 #include <linux/rtc.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/regmap.h>

 /*
  * Information for this driver was pulled from the following datasheets.
  *
  *  https://www.nxp.com/documents/data_sheet/PCF85063A.pdf
  *  https://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
  *
  *  PCF85063A -- Rev. 6 — 18 November 2015
  *  PCF85063TP -- Rev. 4 — 6 May 2015
  *
  *  https://www.microcrystal.com/fileadmin/Media/Products/RTC/App.Manual/RV-8263-C7_App-Manual.pdf
  *  RV8263 -- Rev. 1.0 — January 2019
  */

 #define PCF85063_REG_CTRL1		0x00 /* status */
 #define PCF85063_REG_CTRL1_CAP_SEL	BIT(0)
 #define PCF85063_REG_CTRL1_STOP		BIT(5)

 #define PCF85063_REG_CTRL2		0x01
 #define PCF85063_CTRL2_AF		BIT(6)
 #define PCF85063_CTRL2_AIE		BIT(7)

 #define PCF85063_REG_OFFSET		0x02
 #define PCF85063_OFFSET_SIGN_BIT	6	/* 2's complement sign bit */
 #define PCF85063_OFFSET_MODE		BIT(7)
 #define PCF85063_OFFSET_STEP0		4340
 #define PCF85063_OFFSET_STEP1		4069

 #define PCF85063_REG_CLKO_F_MASK	0x07 /* frequency mask */
 #define PCF85063_REG_CLKO_F_32768HZ	0x00
 #define PCF85063_REG_CLKO_F_OFF		0x07

 #define PCF85063_REG_RAM		0x03

 #define PCF85063_REG_SC			0x04 /* datetime */
 #define PCF85063_REG_SC_OS		0x80

 #define PCF85063_REG_ALM_S		0x0b
 #define PCF85063_AEN			BIT(7)

 struct pcf85063_config {
 	struct regmap_config regmap;
 	unsigned has_alarms:1;
 	unsigned force_cap_7000:1;
 };

 struct pcf85063 {
 	struct rtc_device	*rtc;
 	struct regmap		*regmap;
 #ifdef CONFIG_COMMON_CLK
 	struct clk_hw		clkout_hw;
 #endif
 };

 static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	int rc;
 	u8 regs[7];

 	/*
 	 * while reading, the time/date registers are blocked and not updated
 	 * anymore until the access is finished. To not lose a second
 	 * event, the access must be finished within one second. So, read all
 	 * time/date registers in one turn.
 	 */
 	rc = regmap_bulk_read(pcf85063->regmap, PCF85063_REG_SC, regs,
 			      sizeof(regs));
 	if (rc)
 		return rc;

 	/* if the clock has lost its power it makes no sense to use its time */
 	if (regs[0] & PCF85063_REG_SC_OS) {
 		dev_warn(&pcf85063->rtc->dev, "Power loss detected, invalid time\n");
 		return -EINVAL;
 	}

 	tm->tm_sec = bcd2bin(regs[0] & 0x7F);
 	tm->tm_min = bcd2bin(regs[1] & 0x7F);
 	tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
 	tm->tm_mday = bcd2bin(regs[3] & 0x3F);
 	tm->tm_wday = regs[4] & 0x07;
 	tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
 	tm->tm_year = bcd2bin(regs[6]);
 	tm->tm_year += 100;

 	return 0;
 }

 static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	int rc;
 	u8 regs[7];

 	/*
 	 * to accurately set the time, reset the divider chain and keep it in
 	 * reset state until all time/date registers are written
 	 */
 	rc = regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
 				PCF85063_REG_CTRL1_STOP,
 				PCF85063_REG_CTRL1_STOP);
 	if (rc)
 		return rc;

 	/* hours, minutes and seconds */
 	regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */

 	regs[1] = bin2bcd(tm->tm_min);
 	regs[2] = bin2bcd(tm->tm_hour);

 	/* Day of month, 1 - 31 */
 	regs[3] = bin2bcd(tm->tm_mday);

 	/* Day, 0 - 6 */
 	regs[4] = tm->tm_wday & 0x07;

 	/* month, 1 - 12 */
 	regs[5] = bin2bcd(tm->tm_mon + 1);

 	/* year and century */
 	regs[6] = bin2bcd(tm->tm_year - 100);

 	/* write all registers at once */
 	rc = regmap_bulk_write(pcf85063->regmap, PCF85063_REG_SC,
 			       regs, sizeof(regs));
 	if (rc)
 		return rc;

 	/*
 	 * Write the control register as a separate action since the size of
 	 * the register space is different between the PCF85063TP and
 	 * PCF85063A devices.  The rollover point can not be used.
 	 */
 	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
 				  PCF85063_REG_CTRL1_STOP, 0);
 }

 static int pcf85063_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	u8 buf[4];
 	unsigned int val;
 	int ret;

 	ret = regmap_bulk_read(pcf85063->regmap, PCF85063_REG_ALM_S,
 			       buf, sizeof(buf));
 	if (ret)
 		return ret;

 	alrm->time.tm_sec = bcd2bin(buf[0]);
 	alrm->time.tm_min = bcd2bin(buf[1]);
 	alrm->time.tm_hour = bcd2bin(buf[2]);
 	alrm->time.tm_mday = bcd2bin(buf[3]);

 	ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &val);
 	if (ret)
 		return ret;

 	alrm->enabled =  !!(val & PCF85063_CTRL2_AIE);

 	return 0;
 }

 static int pcf85063_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	u8 buf[5];
 	int ret;

 	buf[0] = bin2bcd(alrm->time.tm_sec);
 	buf[1] = bin2bcd(alrm->time.tm_min);
 	buf[2] = bin2bcd(alrm->time.tm_hour);
 	buf[3] = bin2bcd(alrm->time.tm_mday);
 	buf[4] = PCF85063_AEN; /* Do not match on week day */

 	ret = regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
 				 PCF85063_CTRL2_AIE | PCF85063_CTRL2_AF, 0);
 	if (ret)
 		return ret;

 	ret = regmap_bulk_write(pcf85063->regmap, PCF85063_REG_ALM_S,
 				buf, sizeof(buf));
 	if (ret)
 		return ret;

 	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
 				  PCF85063_CTRL2_AIE | PCF85063_CTRL2_AF,
 				  alrm->enabled ? PCF85063_CTRL2_AIE | PCF85063_CTRL2_AF : PCF85063_CTRL2_AF);
 }

 static int pcf85063_rtc_alarm_irq_enable(struct device *dev,
 					 unsigned int enabled)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);

 	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
 				  PCF85063_CTRL2_AIE,
 				  enabled ? PCF85063_CTRL2_AIE : 0);
 }

 static irqreturn_t pcf85063_rtc_handle_irq(int irq, void *dev_id)
 {
 	struct pcf85063 *pcf85063 = dev_id;
 	unsigned int val;
 	int err;

 	err = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &val);
 	if (err)
 		return IRQ_NONE;

 	if (val & PCF85063_CTRL2_AF) {
 		rtc_update_irq(pcf85063->rtc, 1, RTC_IRQF | RTC_AF);
 		regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
 				   PCF85063_CTRL2_AIE | PCF85063_CTRL2_AF,
 				   0);
 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 static int pcf85063_read_offset(struct device *dev, long *offset)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	long val;
 	u32 reg;
 	int ret;

 	ret = regmap_read(pcf85063->regmap, PCF85063_REG_OFFSET, &reg);
 	if (ret < 0)
 		return ret;

 	val = sign_extend32(reg & ~PCF85063_OFFSET_MODE,
 			    PCF85063_OFFSET_SIGN_BIT);

 	if (reg & PCF85063_OFFSET_MODE)
 		*offset = val * PCF85063_OFFSET_STEP1;
 	else
 		*offset = val * PCF85063_OFFSET_STEP0;

 	return 0;
 }

 static int pcf85063_set_offset(struct device *dev, long offset)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	s8 mode0, mode1, reg;
 	unsigned int error0, error1;

 	if (offset > PCF85063_OFFSET_STEP0 * 63)
 		return -ERANGE;
 	if (offset < PCF85063_OFFSET_STEP0 * -64)
 		return -ERANGE;

 	mode0 = DIV_ROUND_CLOSEST(offset, PCF85063_OFFSET_STEP0);
 	mode1 = DIV_ROUND_CLOSEST(offset, PCF85063_OFFSET_STEP1);

 	error0 = abs(offset - (mode0 * PCF85063_OFFSET_STEP0));
 	error1 = abs(offset - (mode1 * PCF85063_OFFSET_STEP1));
 	if (mode1 > 63 || mode1 < -64 || error0 < error1)
 		reg = mode0 & ~PCF85063_OFFSET_MODE;
 	else
 		reg = mode1 | PCF85063_OFFSET_MODE;

 	return regmap_write(pcf85063->regmap, PCF85063_REG_OFFSET, reg);
 }

 static int pcf85063_ioctl(struct device *dev, unsigned int cmd,
 			  unsigned long arg)
 {
 	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
 	int status, ret = 0;

 	switch (cmd) {
 	case RTC_VL_READ:
 		ret = regmap_read(pcf85063->regmap, PCF85063_REG_SC, &status);
 		if (ret < 0)
 			return ret;

 		status = status & PCF85063_REG_SC_OS ? RTC_VL_DATA_INVALID : 0;

 		return put_user(status, (unsigned int __user *)arg);

 	default:
 		return -ENOIOCTLCMD;
 	}
 }

 static const struct rtc_class_ops pcf85063_rtc_ops = {
 	.read_time	= pcf85063_rtc_read_time,
 	.set_time	= pcf85063_rtc_set_time,
 	.read_offset	= pcf85063_read_offset,
 	.set_offset	= pcf85063_set_offset,
 	.ioctl		= pcf85063_ioctl,
 };

 static const struct rtc_class_ops pcf85063_rtc_ops_alarm = {
 	.read_time	= pcf85063_rtc_read_time,
 	.set_time	= pcf85063_rtc_set_time,
 	.read_offset	= pcf85063_read_offset,
 	.set_offset	= pcf85063_set_offset,
 	.read_alarm	= pcf85063_rtc_read_alarm,
 	.set_alarm	= pcf85063_rtc_set_alarm,
 	.alarm_irq_enable = pcf85063_rtc_alarm_irq_enable,
 	.ioctl		= pcf85063_ioctl,
 };

 static int pcf85063_nvmem_read(void *priv, unsigned int offset,
 			       void *val, size_t bytes)
 {
 	return regmap_read(priv, PCF85063_REG_RAM, val);
 }

 static int pcf85063_nvmem_write(void *priv, unsigned int offset,
 				void *val, size_t bytes)
 {
 	return regmap_write(priv, PCF85063_REG_RAM, *(u8 *)val);
 }

 static int pcf85063_load_capacitance(struct pcf85063 *pcf85063,
 				     const struct device_node *np,
 				     unsigned int force_cap)
 {
 	u32 load = 7000;
 	u8 reg = 0;

 	if (force_cap)
 		load = force_cap;
 	else
 		of_property_read_u32(np, "quartz-load-femtofarads", &load);

 	switch (load) {
 	default:
 		dev_warn(&pcf85063->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 7000",
 			 load);
 		fallthrough;
 	case 7000:
 		break;
 	case 12500:
 		reg = PCF85063_REG_CTRL1_CAP_SEL;
 		break;
 	}

 	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
 				  PCF85063_REG_CTRL1_CAP_SEL, reg);
 }

 #ifdef CONFIG_COMMON_CLK
 /*
  * Handling of the clkout
  */

 #define clkout_hw_to_pcf85063(_hw) container_of(_hw, struct pcf85063, clkout_hw)

 static int clkout_rates[] = {
 	32768,
 	16384,
 	8192,
 	4096,
 	2048,
 	1024,
 	1,
 	0
 };

 static unsigned long pcf85063_clkout_recalc_rate(struct clk_hw *hw,
 						 unsigned long parent_rate)
 {
 	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
 	unsigned int buf;
 	int ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &buf);

 	if (ret < 0)
 		return 0;

 	buf &= PCF85063_REG_CLKO_F_MASK;
 	return clkout_rates[buf];
 }

 static long pcf85063_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
 				       unsigned long *prate)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 		if (clkout_rates[i] <= rate)
 			return clkout_rates[i];

 	return 0;
 }

 static int pcf85063_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
 				    unsigned long parent_rate)
 {
 	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
 	int i;

 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 		if (clkout_rates[i] == rate)
 			return regmap_update_bits(pcf85063->regmap,
 				PCF85063_REG_CTRL2,
 				PCF85063_REG_CLKO_F_MASK, i);

 	return -EINVAL;
 }

 static int pcf85063_clkout_control(struct clk_hw *hw, bool enable)
 {
 	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
 	unsigned int buf;
 	int ret;

 	ret = regmap_read(pcf85063->regmap, PCF85063_REG_OFFSET, &buf);
 	if (ret < 0)
 		return ret;
 	buf &= PCF85063_REG_CLKO_F_MASK;

 	if (enable) {
 		if (buf == PCF85063_REG_CLKO_F_OFF)
 			buf = PCF85063_REG_CLKO_F_32768HZ;
 		else
 			return 0;
 	} else {
 		if (buf != PCF85063_REG_CLKO_F_OFF)
 			buf = PCF85063_REG_CLKO_F_OFF;
 		else
 			return 0;
 	}

 	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
 					PCF85063_REG_CLKO_F_MASK, buf);
 }

 static int pcf85063_clkout_prepare(struct clk_hw *hw)
 {
 	return pcf85063_clkout_control(hw, 1);
 }

 static void pcf85063_clkout_unprepare(struct clk_hw *hw)
 {
 	pcf85063_clkout_control(hw, 0);
 }

 static int pcf85063_clkout_is_prepared(struct clk_hw *hw)
 {
 	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
 	unsigned int buf;
 	int ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &buf);

 	if (ret < 0)
 		return 0;

 	return (buf & PCF85063_REG_CLKO_F_MASK) != PCF85063_REG_CLKO_F_OFF;
 }

 static const struct clk_ops pcf85063_clkout_ops = {
 	.prepare = pcf85063_clkout_prepare,
 	.unprepare = pcf85063_clkout_unprepare,
 	.is_prepared = pcf85063_clkout_is_prepared,
 	.recalc_rate = pcf85063_clkout_recalc_rate,
 	.round_rate = pcf85063_clkout_round_rate,
 	.set_rate = pcf85063_clkout_set_rate,
 };

 static struct clk *pcf85063_clkout_register_clk(struct pcf85063 *pcf85063)
 {
 	struct clk *clk;
 	struct clk_init_data init;
 	struct device_node *node = pcf85063->rtc->dev.parent->of_node;

 	init.name = "pcf85063-clkout";
 	init.ops = &pcf85063_clkout_ops;
 	init.flags = 0;
 	init.parent_names = NULL;
 	init.num_parents = 0;
 	pcf85063->clkout_hw.init = &init;

 	/* optional override of the clockname */
 	of_property_read_string(node, "clock-output-names", &init.name);

 	/* register the clock */
 	clk = devm_clk_register(&pcf85063->rtc->dev, &pcf85063->clkout_hw);

 	if (!IS_ERR(clk))
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);

 	return clk;
 }
 #endif

 static const struct pcf85063_config pcf85063a_config = {
 	.regmap = {
 		.reg_bits = 8,
 		.val_bits = 8,
 		.max_register = 0x11,
 	},
 	.has_alarms = 1,
 };

 static const struct pcf85063_config pcf85063tp_config = {
 	.regmap = {
 		.reg_bits = 8,
 		.val_bits = 8,
 		.max_register = 0x0a,
 	},
 };

 static const struct pcf85063_config rv8263_config = {
 	.regmap = {
 		.reg_bits = 8,
 		.val_bits = 8,
 		.max_register = 0x11,
 	},
 	.has_alarms = 1,
 	.force_cap_7000 = 1,
 };

 static int pcf85063_probe(struct i2c_client *client)
 {
 	struct pcf85063 *pcf85063;
 	unsigned int tmp;
 	int err;
 	const struct pcf85063_config *config = &pcf85063tp_config;
 	const void *data = of_device_get_match_data(&client->dev);
 	struct nvmem_config nvmem_cfg = {
 		.name = "pcf85063_nvram",
 		.reg_read = pcf85063_nvmem_read,
 		.reg_write = pcf85063_nvmem_write,
 		.type = NVMEM_TYPE_BATTERY_BACKED,
 		.size = 1,
 	};

 	dev_dbg(&client->dev, "%s\n", __func__);

 	pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063),
 				GFP_KERNEL);
 	if (!pcf85063)
 		return -ENOMEM;

 	if (data)
 		config = data;

 	pcf85063->regmap = devm_regmap_init_i2c(client, &config->regmap);
 	if (IS_ERR(pcf85063->regmap))
 		return PTR_ERR(pcf85063->regmap);

 	i2c_set_clientdata(client, pcf85063);

 	err = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL1, &tmp);
 	if (err) {
 		dev_err(&client->dev, "RTC chip is not present\n");
 		return err;
 	}

 	pcf85063->rtc = devm_rtc_allocate_device(&client->dev);
 	if (IS_ERR(pcf85063->rtc))
 		return PTR_ERR(pcf85063->rtc);

 	err = pcf85063_load_capacitance(pcf85063, client->dev.of_node,
 					config->force_cap_7000 ? 7000 : 0);
 	if (err < 0)
 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 			 err);

 	pcf85063->rtc->ops = &pcf85063_rtc_ops;
 	pcf85063->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	pcf85063->rtc->range_max = RTC_TIMESTAMP_END_2099;
 	pcf85063->rtc->uie_unsupported = 1;

 	if (config->has_alarms && client->irq > 0) {
 		err = devm_request_threaded_irq(&client->dev, client->irq,
 						NULL, pcf85063_rtc_handle_irq,
 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 						"pcf85063", pcf85063);
 		if (err) {
 			dev_warn(&pcf85063->rtc->dev,
 				 "unable to request IRQ, alarms disabled\n");
 		} else {
 			pcf85063->rtc->ops = &pcf85063_rtc_ops_alarm;
 			device_init_wakeup(&client->dev, true);
 			err = dev_pm_set_wake_irq(&client->dev, client->irq);
 			if (err)
 				dev_err(&pcf85063->rtc->dev,
 					"failed to enable irq wake\n");
 		}
 	}

 	nvmem_cfg.priv = pcf85063->regmap;
 	rtc_nvmem_register(pcf85063->rtc, &nvmem_cfg);

 #ifdef CONFIG_COMMON_CLK
 	/* register clk in common clk framework */
 	pcf85063_clkout_register_clk(pcf85063);
 #endif

 	return rtc_register_device(pcf85063->rtc);
 }

 #ifdef CONFIG_OF
 static const struct of_device_id pcf85063_of_match[] = {
 	{ .compatible = "nxp,pcf85063", .data = &pcf85063tp_config },
 	{ .compatible = "nxp,pcf85063tp", .data = &pcf85063tp_config },
 	{ .compatible = "nxp,pcf85063a", .data = &pcf85063a_config },
 	{ .compatible = "microcrystal,rv8263", .data = &rv8263_config },
 	{}
 };
 MODULE_DEVICE_TABLE(of, pcf85063_of_match);
 #endif

 static struct i2c_driver pcf85063_driver = {
 	.driver		= {
 		.name	= "rtc-pcf85063",
 		.of_match_table = of_match_ptr(pcf85063_of_match),
 	},
 	.probe_new	= pcf85063_probe,
 };

 module_i2c_driver(pcf85063_driver);

 MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
 MODULE_DESCRIPTION("PCF85063 RTC driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* An I2C driver for the PCF85063 RTC
	* Copyright 2014 Rose Technology
	*
	* Author: Søren Andersen <san@rosetechnology.dk>
	* Maintainers: http://www.nslu2-linux.org/
	*
	* Copyright (C) 2019 Micro Crystal AG
	* Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
	*/
	#include <linux/clk-provider.h>
	#include <linux/i2c.h>
	#include <linux/bcd.h>
	#include <linux/rtc.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/pm_wakeirq.h>
	#include <linux/regmap.h>

	/*
	* Information for this driver was pulled from the following datasheets.
	*
	* https://www.nxp.com/documents/data_sheet/PCF85063A.pdf
	* https://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
	*
	* PCF85063A -- Rev. 6 — 18 November 2015
	* PCF85063TP -- Rev. 4 — 6 May 2015
	*
	* https://www.microcrystal.com/fileadmin/Media/Products/RTC/App.Manual/RV-8263-C7_App-Manual.pdf
	* RV8263 -- Rev. 1.0 — January 2019
	*/

	#define PCF85063_REG_CTRL1 0x00 /* status */
	#define PCF85063_REG_CTRL1_CAP_SEL BIT(0)
	#define PCF85063_REG_CTRL1_STOP BIT(5)

	#define PCF85063_REG_CTRL2 0x01
	#define PCF85063_CTRL2_AF BIT(6)
	#define PCF85063_CTRL2_AIE BIT(7)

	#define PCF85063_REG_OFFSET 0x02
	#define PCF85063_OFFSET_SIGN_BIT 6 /* 2's complement sign bit */
	#define PCF85063_OFFSET_MODE BIT(7)
	#define PCF85063_OFFSET_STEP0 4340
	#define PCF85063_OFFSET_STEP1 4069

	#define PCF85063_REG_CLKO_F_MASK 0x07 /* frequency mask */
	#define PCF85063_REG_CLKO_F_32768HZ 0x00
	#define PCF85063_REG_CLKO_F_OFF 0x07

	#define PCF85063_REG_RAM 0x03

	#define PCF85063_REG_SC 0x04 /* datetime */
	#define PCF85063_REG_SC_OS 0x80

	#define PCF85063_REG_ALM_S 0x0b
	#define PCF85063_AEN BIT(7)

	struct pcf85063_config {
	struct regmap_config regmap;
	unsigned has_alarms:1;
	unsigned force_cap_7000:1;
	};

	struct pcf85063 {
	struct rtc_device *rtc;
	struct regmap *regmap;
	#ifdef CONFIG_COMMON_CLK
	struct clk_hw clkout_hw;
	#endif
	};

	static int pcf85063_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	int rc;
	u8 regs[7];

	/*
	* while reading, the time/date registers are blocked and not updated
	* anymore until the access is finished. To not lose a second
	* event, the access must be finished within one second. So, read all
	* time/date registers in one turn.
	*/
	rc = regmap_bulk_read(pcf85063->regmap, PCF85063_REG_SC, regs,
	sizeof(regs));
	if (rc)
	return rc;

	/* if the clock has lost its power it makes no sense to use its time */
	if (regs[0] & PCF85063_REG_SC_OS) {
	dev_warn(&pcf85063->rtc->dev, "Power loss detected, invalid time\n");
	return -EINVAL;
	}

	tm->tm_sec = bcd2bin(regs[0] & 0x7F);
	tm->tm_min = bcd2bin(regs[1] & 0x7F);
	tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
	tm->tm_mday = bcd2bin(regs[3] & 0x3F);
	tm->tm_wday = regs[4] & 0x07;
	tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
	tm->tm_year = bcd2bin(regs[6]);
	tm->tm_year += 100;

	return 0;
	}

	static int pcf85063_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	int rc;
	u8 regs[7];

	/*
	* to accurately set the time, reset the divider chain and keep it in
	* reset state until all time/date registers are written
	*/
	rc = regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
	PCF85063_REG_CTRL1_STOP,
	PCF85063_REG_CTRL1_STOP);
	if (rc)
	return rc;

	/* hours, minutes and seconds */
	regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */

	regs[1] = bin2bcd(tm->tm_min);
	regs[2] = bin2bcd(tm->tm_hour);

	/* Day of month, 1 - 31 */
	regs[3] = bin2bcd(tm->tm_mday);

	/* Day, 0 - 6 */
	regs[4] = tm->tm_wday & 0x07;

	/* month, 1 - 12 */
	regs[5] = bin2bcd(tm->tm_mon + 1);

	/* year and century */
	regs[6] = bin2bcd(tm->tm_year - 100);

	/* write all registers at once */
	rc = regmap_bulk_write(pcf85063->regmap, PCF85063_REG_SC,
	regs, sizeof(regs));
	if (rc)
	return rc;

	/*
	* Write the control register as a separate action since the size of
	* the register space is different between the PCF85063TP and
	* PCF85063A devices. The rollover point can not be used.
	*/
	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
	PCF85063_REG_CTRL1_STOP, 0);
	}

	static int pcf85063_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	u8 buf[4];
	unsigned int val;
	int ret;

	ret = regmap_bulk_read(pcf85063->regmap, PCF85063_REG_ALM_S,
	buf, sizeof(buf));
	if (ret)
	return ret;

	alrm->time.tm_sec = bcd2bin(buf[0]);
	alrm->time.tm_min = bcd2bin(buf[1]);
	alrm->time.tm_hour = bcd2bin(buf[2]);
	alrm->time.tm_mday = bcd2bin(buf[3]);

	ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &val);
	if (ret)
	return ret;

	alrm->enabled = !!(val & PCF85063_CTRL2_AIE);

	return 0;
	}

	static int pcf85063_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	u8 buf[5];
	int ret;

	buf[0] = bin2bcd(alrm->time.tm_sec);
	buf[1] = bin2bcd(alrm->time.tm_min);
	buf[2] = bin2bcd(alrm->time.tm_hour);
	buf[3] = bin2bcd(alrm->time.tm_mday);
	buf[4] = PCF85063_AEN; /* Do not match on week day */

	ret = regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
	PCF85063_CTRL2_AIE \| PCF85063_CTRL2_AF, 0);
	if (ret)
	return ret;

	ret = regmap_bulk_write(pcf85063->regmap, PCF85063_REG_ALM_S,
	buf, sizeof(buf));
	if (ret)
	return ret;

	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
	PCF85063_CTRL2_AIE \| PCF85063_CTRL2_AF,
	alrm->enabled ? PCF85063_CTRL2_AIE \| PCF85063_CTRL2_AF : PCF85063_CTRL2_AF);
	}

	static int pcf85063_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);

	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
	PCF85063_CTRL2_AIE,
	enabled ? PCF85063_CTRL2_AIE : 0);
	}

	static irqreturn_t pcf85063_rtc_handle_irq(int irq, void *dev_id)
	{
	struct pcf85063 *pcf85063 = dev_id;
	unsigned int val;
	int err;

	err = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &val);
	if (err)
	return IRQ_NONE;

	if (val & PCF85063_CTRL2_AF) {
	rtc_update_irq(pcf85063->rtc, 1, RTC_IRQF \| RTC_AF);
	regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
	PCF85063_CTRL2_AIE \| PCF85063_CTRL2_AF,
	0);
	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	static int pcf85063_read_offset(struct device dev, long offset)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	long val;
	u32 reg;
	int ret;

	ret = regmap_read(pcf85063->regmap, PCF85063_REG_OFFSET, &reg);
	if (ret < 0)
	return ret;

	val = sign_extend32(reg & ~PCF85063_OFFSET_MODE,
	PCF85063_OFFSET_SIGN_BIT);

	if (reg & PCF85063_OFFSET_MODE)
	offset = val PCF85063_OFFSET_STEP1;
	else
	offset = val PCF85063_OFFSET_STEP0;

	return 0;
	}

	static int pcf85063_set_offset(struct device *dev, long offset)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	s8 mode0, mode1, reg;
	unsigned int error0, error1;

	if (offset > PCF85063_OFFSET_STEP0 * 63)
	return -ERANGE;
	if (offset < PCF85063_OFFSET_STEP0 * -64)
	return -ERANGE;

	mode0 = DIV_ROUND_CLOSEST(offset, PCF85063_OFFSET_STEP0);
	mode1 = DIV_ROUND_CLOSEST(offset, PCF85063_OFFSET_STEP1);

	error0 = abs(offset - (mode0 * PCF85063_OFFSET_STEP0));
	error1 = abs(offset - (mode1 * PCF85063_OFFSET_STEP1));
	if (mode1 > 63 \|\| mode1 < -64 \|\| error0 < error1)
	reg = mode0 & ~PCF85063_OFFSET_MODE;
	else
	reg = mode1 \| PCF85063_OFFSET_MODE;

	return regmap_write(pcf85063->regmap, PCF85063_REG_OFFSET, reg);
	}

	static int pcf85063_ioctl(struct device *dev, unsigned int cmd,
	unsigned long arg)
	{
	struct pcf85063 *pcf85063 = dev_get_drvdata(dev);
	int status, ret = 0;

	switch (cmd) {
	case RTC_VL_READ:
	ret = regmap_read(pcf85063->regmap, PCF85063_REG_SC, &status);
	if (ret < 0)
	return ret;

	status = status & PCF85063_REG_SC_OS ? RTC_VL_DATA_INVALID : 0;

	return put_user(status, (unsigned int __user *)arg);

	default:
	return -ENOIOCTLCMD;
	}
	}

	static const struct rtc_class_ops pcf85063_rtc_ops = {
	.read_time = pcf85063_rtc_read_time,
	.set_time = pcf85063_rtc_set_time,
	.read_offset = pcf85063_read_offset,
	.set_offset = pcf85063_set_offset,
	.ioctl = pcf85063_ioctl,
	};

	static const struct rtc_class_ops pcf85063_rtc_ops_alarm = {
	.read_time = pcf85063_rtc_read_time,
	.set_time = pcf85063_rtc_set_time,
	.read_offset = pcf85063_read_offset,
	.set_offset = pcf85063_set_offset,
	.read_alarm = pcf85063_rtc_read_alarm,
	.set_alarm = pcf85063_rtc_set_alarm,
	.alarm_irq_enable = pcf85063_rtc_alarm_irq_enable,
	.ioctl = pcf85063_ioctl,
	};

	static int pcf85063_nvmem_read(void *priv, unsigned int offset,
	void *val, size_t bytes)
	{
	return regmap_read(priv, PCF85063_REG_RAM, val);
	}

	static int pcf85063_nvmem_write(void *priv, unsigned int offset,
	void *val, size_t bytes)
	{
	return regmap_write(priv, PCF85063_REG_RAM, (u8 )val);
	}

	static int pcf85063_load_capacitance(struct pcf85063 *pcf85063,
	const struct device_node *np,
	unsigned int force_cap)
	{
	u32 load = 7000;
	u8 reg = 0;

	if (force_cap)
	load = force_cap;
	else
	of_property_read_u32(np, "quartz-load-femtofarads", &load);

	switch (load) {
	default:
	dev_warn(&pcf85063->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 7000",
	load);
	fallthrough;
	case 7000:
	break;
	case 12500:
	reg = PCF85063_REG_CTRL1_CAP_SEL;
	break;
	}

	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL1,
	PCF85063_REG_CTRL1_CAP_SEL, reg);
	}

	#ifdef CONFIG_COMMON_CLK
	/*
	* Handling of the clkout
	*/

	#define clkout_hw_to_pcf85063(_hw) container_of(_hw, struct pcf85063, clkout_hw)

	static int clkout_rates[] = {
	32768,
	16384,
	8192,
	4096,
	2048,
	1024,
	1,
	0
	};

	static unsigned long pcf85063_clkout_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
	unsigned int buf;
	int ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &buf);

	if (ret < 0)
	return 0;

	buf &= PCF85063_REG_CLKO_F_MASK;
	return clkout_rates[buf];
	}

	static long pcf85063_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *prate)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
	if (clkout_rates[i] <= rate)
	return clkout_rates[i];

	return 0;
	}

	static int pcf85063_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
	int i;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
	if (clkout_rates[i] == rate)
	return regmap_update_bits(pcf85063->regmap,
	PCF85063_REG_CTRL2,
	PCF85063_REG_CLKO_F_MASK, i);

	return -EINVAL;
	}

	static int pcf85063_clkout_control(struct clk_hw *hw, bool enable)
	{
	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
	unsigned int buf;
	int ret;

	ret = regmap_read(pcf85063->regmap, PCF85063_REG_OFFSET, &buf);
	if (ret < 0)
	return ret;
	buf &= PCF85063_REG_CLKO_F_MASK;

	if (enable) {
	if (buf == PCF85063_REG_CLKO_F_OFF)
	buf = PCF85063_REG_CLKO_F_32768HZ;
	else
	return 0;
	} else {
	if (buf != PCF85063_REG_CLKO_F_OFF)
	buf = PCF85063_REG_CLKO_F_OFF;
	else
	return 0;
	}

	return regmap_update_bits(pcf85063->regmap, PCF85063_REG_CTRL2,
	PCF85063_REG_CLKO_F_MASK, buf);
	}

	static int pcf85063_clkout_prepare(struct clk_hw *hw)
	{
	return pcf85063_clkout_control(hw, 1);
	}

	static void pcf85063_clkout_unprepare(struct clk_hw *hw)
	{
	pcf85063_clkout_control(hw, 0);
	}

	static int pcf85063_clkout_is_prepared(struct clk_hw *hw)
	{
	struct pcf85063 *pcf85063 = clkout_hw_to_pcf85063(hw);
	unsigned int buf;
	int ret = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL2, &buf);

	if (ret < 0)
	return 0;

	return (buf & PCF85063_REG_CLKO_F_MASK) != PCF85063_REG_CLKO_F_OFF;
	}

	static const struct clk_ops pcf85063_clkout_ops = {
	.prepare = pcf85063_clkout_prepare,
	.unprepare = pcf85063_clkout_unprepare,
	.is_prepared = pcf85063_clkout_is_prepared,
	.recalc_rate = pcf85063_clkout_recalc_rate,
	.round_rate = pcf85063_clkout_round_rate,
	.set_rate = pcf85063_clkout_set_rate,
	};

	static struct clk pcf85063_clkout_register_clk(struct pcf85063 pcf85063)
	{
	struct clk *clk;
	struct clk_init_data init;
	struct device_node *node = pcf85063->rtc->dev.parent->of_node;

	init.name = "pcf85063-clkout";
	init.ops = &pcf85063_clkout_ops;
	init.flags = 0;
	init.parent_names = NULL;
	init.num_parents = 0;
	pcf85063->clkout_hw.init = &init;

	/* optional override of the clockname */
	of_property_read_string(node, "clock-output-names", &init.name);

	/* register the clock */
	clk = devm_clk_register(&pcf85063->rtc->dev, &pcf85063->clkout_hw);

	if (!IS_ERR(clk))
	of_clk_add_provider(node, of_clk_src_simple_get, clk);

	return clk;
	}
	#endif

	static const struct pcf85063_config pcf85063a_config = {
	.regmap = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x11,
	},
	.has_alarms = 1,
	};

	static const struct pcf85063_config pcf85063tp_config = {
	.regmap = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x0a,
	},
	};

	static const struct pcf85063_config rv8263_config = {
	.regmap = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x11,
	},
	.has_alarms = 1,
	.force_cap_7000 = 1,
	};

	static int pcf85063_probe(struct i2c_client *client)
	{
	struct pcf85063 *pcf85063;
	unsigned int tmp;
	int err;
	const struct pcf85063_config *config = &pcf85063tp_config;
	const void *data = of_device_get_match_data(&client->dev);
	struct nvmem_config nvmem_cfg = {
	.name = "pcf85063_nvram",
	.reg_read = pcf85063_nvmem_read,
	.reg_write = pcf85063_nvmem_write,
	.type = NVMEM_TYPE_BATTERY_BACKED,
	.size = 1,
	};

	dev_dbg(&client->dev, "%s\n", __func__);

	pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063),
	GFP_KERNEL);
	if (!pcf85063)
	return -ENOMEM;

	if (data)
	config = data;

	pcf85063->regmap = devm_regmap_init_i2c(client, &config->regmap);
	if (IS_ERR(pcf85063->regmap))
	return PTR_ERR(pcf85063->regmap);

	i2c_set_clientdata(client, pcf85063);

	err = regmap_read(pcf85063->regmap, PCF85063_REG_CTRL1, &tmp);
	if (err) {
	dev_err(&client->dev, "RTC chip is not present\n");
	return err;
	}

	pcf85063->rtc = devm_rtc_allocate_device(&client->dev);
	if (IS_ERR(pcf85063->rtc))
	return PTR_ERR(pcf85063->rtc);

	err = pcf85063_load_capacitance(pcf85063, client->dev.of_node,
	config->force_cap_7000 ? 7000 : 0);
	if (err < 0)
	dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
	err);

	pcf85063->rtc->ops = &pcf85063_rtc_ops;
	pcf85063->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	pcf85063->rtc->range_max = RTC_TIMESTAMP_END_2099;
	pcf85063->rtc->uie_unsupported = 1;

	if (config->has_alarms && client->irq > 0) {
	err = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, pcf85063_rtc_handle_irq,
	IRQF_TRIGGER_LOW \| IRQF_ONESHOT,
	"pcf85063", pcf85063);
	if (err) {
	dev_warn(&pcf85063->rtc->dev,
	"unable to request IRQ, alarms disabled\n");
	} else {
	pcf85063->rtc->ops = &pcf85063_rtc_ops_alarm;
	device_init_wakeup(&client->dev, true);
	err = dev_pm_set_wake_irq(&client->dev, client->irq);
	if (err)
	dev_err(&pcf85063->rtc->dev,
	"failed to enable irq wake\n");
	}
	}

	nvmem_cfg.priv = pcf85063->regmap;
	rtc_nvmem_register(pcf85063->rtc, &nvmem_cfg);

	#ifdef CONFIG_COMMON_CLK
	/* register clk in common clk framework */
	pcf85063_clkout_register_clk(pcf85063);
	#endif

	return rtc_register_device(pcf85063->rtc);
	}

	#ifdef CONFIG_OF
	static const struct of_device_id pcf85063_of_match[] = {
	{ .compatible = "nxp,pcf85063", .data = &pcf85063tp_config },
	{ .compatible = "nxp,pcf85063tp", .data = &pcf85063tp_config },
	{ .compatible = "nxp,pcf85063a", .data = &pcf85063a_config },
	{ .compatible = "microcrystal,rv8263", .data = &rv8263_config },
	{}
	};
	MODULE_DEVICE_TABLE(of, pcf85063_of_match);
	#endif

	static struct i2c_driver pcf85063_driver = {
	.driver = {
	.name = "rtc-pcf85063",
	.of_match_table = of_match_ptr(pcf85063_of_match),
	},
	.probe_new = pcf85063_probe,
	};

	module_i2c_driver(pcf85063_driver);

	MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
	MODULE_DESCRIPTION("PCF85063 RTC driver");
	MODULE_LICENSE("GPL");