drivers/rtc/rtc-ds1343.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* rtc-ds1343.c
  *
  * Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
  * Real Time Clock
  *
  * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
  *	    Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/spi/spi.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/pm.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/slab.h>

 #define DALLAS_MAXIM_DS1343	0
 #define DALLAS_MAXIM_DS1344	1

 /* RTC DS1343 Registers */
 #define DS1343_SECONDS_REG	0x00
 #define DS1343_MINUTES_REG	0x01
 #define DS1343_HOURS_REG	0x02
 #define DS1343_DAY_REG		0x03
 #define DS1343_DATE_REG		0x04
 #define DS1343_MONTH_REG	0x05
 #define DS1343_YEAR_REG		0x06
 #define DS1343_ALM0_SEC_REG	0x07
 #define DS1343_ALM0_MIN_REG	0x08
 #define DS1343_ALM0_HOUR_REG	0x09
 #define DS1343_ALM0_DAY_REG	0x0A
 #define DS1343_ALM1_SEC_REG	0x0B
 #define DS1343_ALM1_MIN_REG	0x0C
 #define DS1343_ALM1_HOUR_REG	0x0D
 #define DS1343_ALM1_DAY_REG	0x0E
 #define DS1343_CONTROL_REG	0x0F
 #define DS1343_STATUS_REG	0x10
 #define DS1343_TRICKLE_REG	0x11
 #define DS1343_NVRAM		0x20

 #define DS1343_NVRAM_LEN	96

 /* DS1343 Control Registers bits */
 #define DS1343_EOSC		0x80
 #define DS1343_DOSF		0x20
 #define DS1343_EGFIL		0x10
 #define DS1343_SQW		0x08
 #define DS1343_INTCN		0x04
 #define DS1343_A1IE		0x02
 #define DS1343_A0IE		0x01

 /* DS1343 Status Registers bits */
 #define DS1343_OSF		0x80
 #define DS1343_IRQF1		0x02
 #define DS1343_IRQF0		0x01

 /* DS1343 Trickle Charger Registers bits */
 #define DS1343_TRICKLE_MAGIC	0xa0
 #define DS1343_TRICKLE_DS1	0x08
 #define DS1343_TRICKLE_1K	0x01
 #define DS1343_TRICKLE_2K	0x02
 #define DS1343_TRICKLE_4K	0x03

 static const struct spi_device_id ds1343_id[] = {
 	{ "ds1343", DALLAS_MAXIM_DS1343 },
 	{ "ds1344", DALLAS_MAXIM_DS1344 },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ds1343_id);

 struct ds1343_priv {
 	struct rtc_device *rtc;
 	struct regmap *map;
 	int irq;
 };

 static ssize_t ds1343_show_glitchfilter(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 	int glitch_filt_status, data;
 	int res;

 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
 	if (res)
 		return res;

 	glitch_filt_status = !!(data & DS1343_EGFIL);

 	if (glitch_filt_status)
 		return sprintf(buf, "enabled\n");
 	else
 		return sprintf(buf, "disabled\n");
 }

 static ssize_t ds1343_store_glitchfilter(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 	int data = 0;
 	int res;

 	if (strncmp(buf, "enabled", 7) == 0)
 		data = DS1343_EGFIL;
 	else if (strncmp(buf, "disabled", 8))
 		return -EINVAL;

 	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 				 DS1343_EGFIL, data);
 	if (res)
 		return res;

 	return count;
 }

 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
 			ds1343_store_glitchfilter);

 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
 			      size_t bytes)
 {
 	struct ds1343_priv *ds1343 = priv;

 	return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
 }

 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
 			     size_t bytes)
 {
 	struct ds1343_priv *ds1343 = priv;

 	return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
 }

 static ssize_t ds1343_show_tricklecharger(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 	int res, data;
 	char *diodes = "disabled", *resistors = " ";

 	res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
 	if (res)
 		return res;

 	if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
 		switch (data & 0x0c) {
 		case DS1343_TRICKLE_DS1:
 			diodes = "one diode,";
 			break;

 		default:
 			diodes = "no diode,";
 			break;
 		}

 		switch (data & 0x03) {
 		case DS1343_TRICKLE_1K:
 			resistors = "1k Ohm";
 			break;

 		case DS1343_TRICKLE_2K:
 			resistors = "2k Ohm";
 			break;

 		case DS1343_TRICKLE_4K:
 			resistors = "4k Ohm";
 			break;

 		default:
 			diodes = "disabled";
 			break;
 		}
 	}

 	return sprintf(buf, "%s %s\n", diodes, resistors);
 }

 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);

 static struct attribute *ds1343_attrs[] = {
 	&dev_attr_glitch_filter.attr,
 	&dev_attr_trickle_charger.attr,
 	NULL
 };

 static const struct attribute_group ds1343_attr_group = {
 	.attrs  = ds1343_attrs,
 };

 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	unsigned char buf[7];
 	int res;

 	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
 	if (res)
 		return res;

 	dt->tm_sec	= bcd2bin(buf[0]);
 	dt->tm_min	= bcd2bin(buf[1]);
 	dt->tm_hour	= bcd2bin(buf[2] & 0x3F);
 	dt->tm_wday	= bcd2bin(buf[3]) - 1;
 	dt->tm_mday	= bcd2bin(buf[4]);
 	dt->tm_mon	= bcd2bin(buf[5] & 0x1F) - 1;
 	dt->tm_year	= bcd2bin(buf[6]) + 100; /* year offset from 1900 */

 	return 0;
 }

 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	u8 buf[7];

 	buf[0] = bin2bcd(dt->tm_sec);
 	buf[1] = bin2bcd(dt->tm_min);
 	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
 	buf[3] = bin2bcd(dt->tm_wday + 1);
 	buf[4] = bin2bcd(dt->tm_mday);
 	buf[5] = bin2bcd(dt->tm_mon + 1);
 	buf[6] = bin2bcd(dt->tm_year - 100);

 	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
 				 buf, sizeof(buf));
 }

 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	unsigned char buf[4];
 	unsigned int val;
 	int res;

 	if (priv->irq <= 0)
 		return -EINVAL;

 	res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
 	if (res)
 		return res;

 	alarm->pending = !!(val & DS1343_IRQF0);

 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
 	if (res)
 		return res;
 	alarm->enabled = !!(val & DS1343_A0IE);

 	res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 	if (res)
 		return res;

 	alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
 	alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
 	alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
 	alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;

 	return 0;
 }

 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	unsigned char buf[4];
 	int res = 0;

 	if (priv->irq <= 0)
 		return -EINVAL;

 	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
 	if (res)
 		return res;

 	buf[0] = bin2bcd(alarm->time.tm_sec);
 	buf[1] = bin2bcd(alarm->time.tm_min);
 	buf[2] = bin2bcd(alarm->time.tm_hour);
 	buf[3] = bin2bcd(alarm->time.tm_mday);

 	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 	if (res)
 		return res;

 	if (alarm->enabled)
 		res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 					 DS1343_A0IE, DS1343_A0IE);

 	return res;
 }

 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);

 	if (priv->irq <= 0)
 		return -EINVAL;

 	return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 				  DS1343_A0IE, enabled ? DS1343_A0IE : 0);
 }

 static irqreturn_t ds1343_thread(int irq, void *dev_id)
 {
 	struct ds1343_priv *priv = dev_id;
 	unsigned int stat;
 	int res = 0;

 	rtc_lock(priv->rtc);

 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
 	if (res)
 		goto out;

 	if (stat & DS1343_IRQF0) {
 		stat &= ~DS1343_IRQF0;
 		regmap_write(priv->map, DS1343_STATUS_REG, stat);

 		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);

 		regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 				   DS1343_A0IE, 0);
 	}

 out:
 	rtc_unlock(priv->rtc);
 	return IRQ_HANDLED;
 }

 static const struct rtc_class_ops ds1343_rtc_ops = {
 	.read_time	= ds1343_read_time,
 	.set_time	= ds1343_set_time,
 	.read_alarm	= ds1343_read_alarm,
 	.set_alarm	= ds1343_set_alarm,
 	.alarm_irq_enable = ds1343_alarm_irq_enable,
 };

 static int ds1343_probe(struct spi_device *spi)
 {
 	struct ds1343_priv *priv;
 	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
 					.write_flag_mask = 0x80, };
 	unsigned int data;
 	int res;
 	struct nvmem_config nvmem_cfg = {
 		.name = "ds1343-",
 		.word_size = 1,
 		.stride = 1,
 		.size = DS1343_NVRAM_LEN,
 		.reg_read = ds1343_nvram_read,
 		.reg_write = ds1343_nvram_write,
 	};

 	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	/* RTC DS1347 works in spi mode 3 and
 	 * its chip select is active high. Active high should be defined as
 	 * "inverse polarity" as GPIO-based chip selects can be logically
 	 * active high but inverted by the GPIO library.
 	 */
 	spi->mode |= SPI_MODE_3;
 	spi->mode ^= SPI_CS_HIGH;
 	spi->bits_per_word = 8;
 	res = spi_setup(spi);
 	if (res)
 		return res;

 	spi_set_drvdata(spi, priv);

 	priv->map = devm_regmap_init_spi(spi, &config);

 	if (IS_ERR(priv->map)) {
 		dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
 		return PTR_ERR(priv->map);
 	}

 	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
 	if (res)
 		return res;

 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
 	data |= DS1343_INTCN;
 	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
 	regmap_write(priv->map, DS1343_CONTROL_REG, data);

 	regmap_read(priv->map, DS1343_STATUS_REG, &data);
 	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
 	regmap_write(priv->map, DS1343_STATUS_REG, data);

 	priv->rtc = devm_rtc_allocate_device(&spi->dev);
 	if (IS_ERR(priv->rtc))
 		return PTR_ERR(priv->rtc);

 	priv->rtc->nvram_old_abi = true;
 	priv->rtc->ops = &ds1343_rtc_ops;
 	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;

 	res = rtc_add_group(priv->rtc, &ds1343_attr_group);
 	if (res)
 		dev_err(&spi->dev,
 			"unable to create sysfs entries for rtc ds1343\n");

 	res = rtc_register_device(priv->rtc);
 	if (res)
 		return res;

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

 	priv->irq = spi->irq;

 	if (priv->irq >= 0) {
 		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
 						ds1343_thread, IRQF_ONESHOT,
 						"ds1343", priv);
 		if (res) {
 			priv->irq = -1;
 			dev_err(&spi->dev,
 				"unable to request irq for rtc ds1343\n");
 		} else {
 			device_init_wakeup(&spi->dev, true);
 			dev_pm_set_wake_irq(&spi->dev, spi->irq);
 		}
 	}

 	return 0;
 }

 static int ds1343_remove(struct spi_device *spi)
 {
 	dev_pm_clear_wake_irq(&spi->dev);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP

 static int ds1343_suspend(struct device *dev)
 {
 	struct spi_device *spi = to_spi_device(dev);

 	if (spi->irq >= 0 && device_may_wakeup(dev))
 		enable_irq_wake(spi->irq);

 	return 0;
 }

 static int ds1343_resume(struct device *dev)
 {
 	struct spi_device *spi = to_spi_device(dev);

 	if (spi->irq >= 0 && device_may_wakeup(dev))
 		disable_irq_wake(spi->irq);

 	return 0;
 }

 #endif

 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);

 static struct spi_driver ds1343_driver = {
 	.driver = {
 		.name = "ds1343",
 		.pm = &ds1343_pm,
 	},
 	.probe = ds1343_probe,
 	.remove = ds1343_remove,
 	.id_table = ds1343_id,
 };

 module_spi_driver(ds1343_driver);

 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
 MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
 		"Ankur Srivastava <sankurece@gmail.com>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/* rtc-ds1343.c
	*
	* Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
	* Real Time Clock
	*
	* Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
	* Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/device.h>
	#include <linux/spi/spi.h>
	#include <linux/regmap.h>
	#include <linux/rtc.h>
	#include <linux/bcd.h>
	#include <linux/pm.h>
	#include <linux/pm_wakeirq.h>
	#include <linux/slab.h>

	#define DALLAS_MAXIM_DS1343 0
	#define DALLAS_MAXIM_DS1344 1

	/* RTC DS1343 Registers */
	#define DS1343_SECONDS_REG 0x00
	#define DS1343_MINUTES_REG 0x01
	#define DS1343_HOURS_REG 0x02
	#define DS1343_DAY_REG 0x03
	#define DS1343_DATE_REG 0x04
	#define DS1343_MONTH_REG 0x05
	#define DS1343_YEAR_REG 0x06
	#define DS1343_ALM0_SEC_REG 0x07
	#define DS1343_ALM0_MIN_REG 0x08
	#define DS1343_ALM0_HOUR_REG 0x09
	#define DS1343_ALM0_DAY_REG 0x0A
	#define DS1343_ALM1_SEC_REG 0x0B
	#define DS1343_ALM1_MIN_REG 0x0C
	#define DS1343_ALM1_HOUR_REG 0x0D
	#define DS1343_ALM1_DAY_REG 0x0E
	#define DS1343_CONTROL_REG 0x0F
	#define DS1343_STATUS_REG 0x10
	#define DS1343_TRICKLE_REG 0x11
	#define DS1343_NVRAM 0x20

	#define DS1343_NVRAM_LEN 96

	/* DS1343 Control Registers bits */
	#define DS1343_EOSC 0x80
	#define DS1343_DOSF 0x20
	#define DS1343_EGFIL 0x10
	#define DS1343_SQW 0x08
	#define DS1343_INTCN 0x04
	#define DS1343_A1IE 0x02
	#define DS1343_A0IE 0x01

	/* DS1343 Status Registers bits */
	#define DS1343_OSF 0x80
	#define DS1343_IRQF1 0x02
	#define DS1343_IRQF0 0x01

	/* DS1343 Trickle Charger Registers bits */
	#define DS1343_TRICKLE_MAGIC 0xa0
	#define DS1343_TRICKLE_DS1 0x08
	#define DS1343_TRICKLE_1K 0x01
	#define DS1343_TRICKLE_2K 0x02
	#define DS1343_TRICKLE_4K 0x03

	static const struct spi_device_id ds1343_id[] = {
	{ "ds1343", DALLAS_MAXIM_DS1343 },
	{ "ds1344", DALLAS_MAXIM_DS1344 },
	{ }
	};
	MODULE_DEVICE_TABLE(spi, ds1343_id);

	struct ds1343_priv {
	struct rtc_device *rtc;
	struct regmap *map;
	int irq;
	};

	static ssize_t ds1343_show_glitchfilter(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
	int glitch_filt_status, data;
	int res;

	res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
	if (res)
	return res;

	glitch_filt_status = !!(data & DS1343_EGFIL);

	if (glitch_filt_status)
	return sprintf(buf, "enabled\n");
	else
	return sprintf(buf, "disabled\n");
	}

	static ssize_t ds1343_store_glitchfilter(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
	int data = 0;
	int res;

	if (strncmp(buf, "enabled", 7) == 0)
	data = DS1343_EGFIL;
	else if (strncmp(buf, "disabled", 8))
	return -EINVAL;

	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
	DS1343_EGFIL, data);
	if (res)
	return res;

	return count;
	}

	static DEVICE_ATTR(glitch_filter, S_IRUGO \| S_IWUSR, ds1343_show_glitchfilter,
	ds1343_store_glitchfilter);

	static int ds1343_nvram_write(void priv, unsigned int off, void val,
	size_t bytes)
	{
	struct ds1343_priv *ds1343 = priv;

	return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
	}

	static int ds1343_nvram_read(void priv, unsigned int off, void val,
	size_t bytes)
	{
	struct ds1343_priv *ds1343 = priv;

	return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
	}

	static ssize_t ds1343_show_tricklecharger(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
	int res, data;
	char diodes = "disabled", resistors = " ";

	res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
	if (res)
	return res;

	if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
	switch (data & 0x0c) {
	case DS1343_TRICKLE_DS1:
	diodes = "one diode,";
	break;

	default:
	diodes = "no diode,";
	break;
	}

	switch (data & 0x03) {
	case DS1343_TRICKLE_1K:
	resistors = "1k Ohm";
	break;

	case DS1343_TRICKLE_2K:
	resistors = "2k Ohm";
	break;

	case DS1343_TRICKLE_4K:
	resistors = "4k Ohm";
	break;

	default:
	diodes = "disabled";
	break;
	}
	}

	return sprintf(buf, "%s %s\n", diodes, resistors);
	}

	static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);

	static struct attribute *ds1343_attrs[] = {
	&dev_attr_glitch_filter.attr,
	&dev_attr_trickle_charger.attr,
	NULL
	};

	static const struct attribute_group ds1343_attr_group = {
	.attrs = ds1343_attrs,
	};

	static int ds1343_read_time(struct device dev, struct rtc_time dt)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	unsigned char buf[7];
	int res;

	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
	if (res)
	return res;

	dt->tm_sec = bcd2bin(buf[0]);
	dt->tm_min = bcd2bin(buf[1]);
	dt->tm_hour = bcd2bin(buf[2] & 0x3F);
	dt->tm_wday = bcd2bin(buf[3]) - 1;
	dt->tm_mday = bcd2bin(buf[4]);
	dt->tm_mon = bcd2bin(buf[5] & 0x1F) - 1;
	dt->tm_year = bcd2bin(buf[6]) + 100; /* year offset from 1900 */

	return 0;
	}

	static int ds1343_set_time(struct device dev, struct rtc_time dt)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	u8 buf[7];

	buf[0] = bin2bcd(dt->tm_sec);
	buf[1] = bin2bcd(dt->tm_min);
	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
	buf[3] = bin2bcd(dt->tm_wday + 1);
	buf[4] = bin2bcd(dt->tm_mday);
	buf[5] = bin2bcd(dt->tm_mon + 1);
	buf[6] = bin2bcd(dt->tm_year - 100);

	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
	buf, sizeof(buf));
	}

	static int ds1343_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	unsigned char buf[4];
	unsigned int val;
	int res;

	if (priv->irq <= 0)
	return -EINVAL;

	res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
	if (res)
	return res;

	alarm->pending = !!(val & DS1343_IRQF0);

	res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
	if (res)
	return res;
	alarm->enabled = !!(val & DS1343_A0IE);

	res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
	if (res)
	return res;

	alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
	alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
	alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
	alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;

	return 0;
	}

	static int ds1343_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	unsigned char buf[4];
	int res = 0;

	if (priv->irq <= 0)
	return -EINVAL;

	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
	if (res)
	return res;

	buf[0] = bin2bcd(alarm->time.tm_sec);
	buf[1] = bin2bcd(alarm->time.tm_min);
	buf[2] = bin2bcd(alarm->time.tm_hour);
	buf[3] = bin2bcd(alarm->time.tm_mday);

	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
	if (res)
	return res;

	if (alarm->enabled)
	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
	DS1343_A0IE, DS1343_A0IE);

	return res;
	}

	static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);

	if (priv->irq <= 0)
	return -EINVAL;

	return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
	DS1343_A0IE, enabled ? DS1343_A0IE : 0);
	}

	static irqreturn_t ds1343_thread(int irq, void *dev_id)
	{
	struct ds1343_priv *priv = dev_id;
	unsigned int stat;
	int res = 0;

	rtc_lock(priv->rtc);

	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
	if (res)
	goto out;

	if (stat & DS1343_IRQF0) {
	stat &= ~DS1343_IRQF0;
	regmap_write(priv->map, DS1343_STATUS_REG, stat);

	rtc_update_irq(priv->rtc, 1, RTC_AF \| RTC_IRQF);

	regmap_update_bits(priv->map, DS1343_CONTROL_REG,
	DS1343_A0IE, 0);
	}

	out:
	rtc_unlock(priv->rtc);
	return IRQ_HANDLED;
	}

	static const struct rtc_class_ops ds1343_rtc_ops = {
	.read_time = ds1343_read_time,
	.set_time = ds1343_set_time,
	.read_alarm = ds1343_read_alarm,
	.set_alarm = ds1343_set_alarm,
	.alarm_irq_enable = ds1343_alarm_irq_enable,
	};

	static int ds1343_probe(struct spi_device *spi)
	{
	struct ds1343_priv *priv;
	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
	.write_flag_mask = 0x80, };
	unsigned int data;
	int res;
	struct nvmem_config nvmem_cfg = {
	.name = "ds1343-",
	.word_size = 1,
	.stride = 1,
	.size = DS1343_NVRAM_LEN,
	.reg_read = ds1343_nvram_read,
	.reg_write = ds1343_nvram_write,
	};

	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	/* RTC DS1347 works in spi mode 3 and
	* its chip select is active high. Active high should be defined as
	* "inverse polarity" as GPIO-based chip selects can be logically
	* active high but inverted by the GPIO library.
	*/
	spi->mode \|= SPI_MODE_3;
	spi->mode ^= SPI_CS_HIGH;
	spi->bits_per_word = 8;
	res = spi_setup(spi);
	if (res)
	return res;

	spi_set_drvdata(spi, priv);

	priv->map = devm_regmap_init_spi(spi, &config);

	if (IS_ERR(priv->map)) {
	dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
	return PTR_ERR(priv->map);
	}

	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
	if (res)
	return res;

	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
	data \|= DS1343_INTCN;
	data &= ~(DS1343_EOSC \| DS1343_A1IE \| DS1343_A0IE);
	regmap_write(priv->map, DS1343_CONTROL_REG, data);

	regmap_read(priv->map, DS1343_STATUS_REG, &data);
	data &= ~(DS1343_OSF \| DS1343_IRQF1 \| DS1343_IRQF0);
	regmap_write(priv->map, DS1343_STATUS_REG, data);

	priv->rtc = devm_rtc_allocate_device(&spi->dev);
	if (IS_ERR(priv->rtc))
	return PTR_ERR(priv->rtc);

	priv->rtc->nvram_old_abi = true;
	priv->rtc->ops = &ds1343_rtc_ops;
	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;

	res = rtc_add_group(priv->rtc, &ds1343_attr_group);
	if (res)
	dev_err(&spi->dev,
	"unable to create sysfs entries for rtc ds1343\n");

	res = rtc_register_device(priv->rtc);
	if (res)
	return res;

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

	priv->irq = spi->irq;

	if (priv->irq >= 0) {
	res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
	ds1343_thread, IRQF_ONESHOT,
	"ds1343", priv);
	if (res) {
	priv->irq = -1;
	dev_err(&spi->dev,
	"unable to request irq for rtc ds1343\n");
	} else {
	device_init_wakeup(&spi->dev, true);
	dev_pm_set_wake_irq(&spi->dev, spi->irq);
	}
	}

	return 0;
	}

	static int ds1343_remove(struct spi_device *spi)
	{
	dev_pm_clear_wake_irq(&spi->dev);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP

	static int ds1343_suspend(struct device *dev)
	{
	struct spi_device *spi = to_spi_device(dev);

	if (spi->irq >= 0 && device_may_wakeup(dev))
	enable_irq_wake(spi->irq);

	return 0;
	}

	static int ds1343_resume(struct device *dev)
	{
	struct spi_device *spi = to_spi_device(dev);

	if (spi->irq >= 0 && device_may_wakeup(dev))
	disable_irq_wake(spi->irq);

	return 0;
	}

	#endif

	static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);

	static struct spi_driver ds1343_driver = {
	.driver = {
	.name = "ds1343",
	.pm = &ds1343_pm,
	},
	.probe = ds1343_probe,
	.remove = ds1343_remove,
	.id_table = ds1343_id,
	};

	module_spi_driver(ds1343_driver);

	MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
	MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
	"Ankur Srivastava <sankurece@gmail.com>");
	MODULE_LICENSE("GPL v2");