drivers/rtc/rtc-ds1343.c - kernel/common - Git at Google

 /* rtc-ds1343.c
  *
  * Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
  * Real Time Clock
  *
  * Author : Raghavendra Chandra Ganiga <[email protected]>
  *	    Ankur Srivastava <[email protected]> : DS1343 Nvram Support
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */

 #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/slab.h>

 #define DS1343_DRV_VERSION	"01.00"
 #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 spi_device *spi;
 	struct rtc_device *rtc;
 	struct regmap *map;
 	struct mutex mutex;
 	unsigned int irqen;
 	int irq;
 	int alarm_sec;
 	int alarm_min;
 	int alarm_hour;
 	int alarm_mday;
 };

 static int ds1343_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
 #ifdef RTC_SET_CHARGE
 	case RTC_SET_CHARGE:
 	{
 		int val;

 		if (copy_from_user(&val, (int __user *)arg, sizeof(int)))
 			return -EFAULT;

 		return regmap_write(priv->map, DS1343_TRICKLE_REG, val);
 	}
 	break;
 #endif
 	}

 	return -ENOIOCTLCMD;
 }

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

 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

 	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);
 	int data;

 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

 	if (strncmp(buf, "enabled", 7) == 0)
 		data |= DS1343_EGFIL;

 	else if (strncmp(buf, "disabled", 8) == 0)
 		data &= ~(DS1343_EGFIL);

 	else
 		return -EINVAL;

 	regmap_write(priv->map, DS1343_CONTROL_REG, data);

 	return count;
 }

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

 static ssize_t ds1343_nvram_write(struct file *filp, struct kobject *kobj,
 			struct bin_attribute *attr,
 			char *buf, loff_t off, size_t count)
 {
 	int ret;
 	unsigned char address;
 	struct device *dev = kobj_to_dev(kobj);
 	struct ds1343_priv *priv = dev_get_drvdata(dev);

 	if (unlikely(!count))
 		return count;

 	if ((count + off) > DS1343_NVRAM_LEN)
 		count = DS1343_NVRAM_LEN - off;

 	address = DS1343_NVRAM + off;

 	ret = regmap_bulk_write(priv->map, address, buf, count);
 	if (ret < 0)
 		dev_err(&priv->spi->dev, "Error in nvram write %d", ret);

 	return (ret < 0) ? ret : count;
 }


 static ssize_t ds1343_nvram_read(struct file *filp, struct kobject *kobj,
 				struct bin_attribute *attr,
 				char *buf, loff_t off, size_t count)
 {
 	int ret;
 	unsigned char address;
 	struct device *dev = kobj_to_dev(kobj);
 	struct ds1343_priv *priv = dev_get_drvdata(dev);

 	if (unlikely(!count))
 		return count;

 	if ((count + off) > DS1343_NVRAM_LEN)
 		count = DS1343_NVRAM_LEN - off;

 	address = DS1343_NVRAM + off;

 	ret = regmap_bulk_read(priv->map, address, buf, count);
 	if (ret < 0)
 		dev_err(&priv->spi->dev, "Error in nvram read %d\n", ret);

 	return (ret < 0) ? ret : count;
 }


 static struct bin_attribute nvram_attr = {
 	.attr.name	= "nvram",
 	.attr.mode	= S_IRUGO | S_IWUSR,
 	.read		= ds1343_nvram_read,
 	.write		= ds1343_nvram_write,
 	.size		= DS1343_NVRAM_LEN,
 };

 static ssize_t ds1343_show_alarmstatus(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int alarmstatus, data;

 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

 	alarmstatus = !!(data & DS1343_A0IE);

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

 static DEVICE_ATTR(alarm_status, S_IRUGO, ds1343_show_alarmstatus, NULL);

 static ssize_t ds1343_show_alarmmode(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int alarm_mode, data;
 	char *alarm_str;

 	regmap_read(priv->map, DS1343_ALM0_SEC_REG, &data);
 	alarm_mode = (data & 0x80) >> 4;

 	regmap_read(priv->map, DS1343_ALM0_MIN_REG, &data);
 	alarm_mode |= (data & 0x80) >> 5;

 	regmap_read(priv->map, DS1343_ALM0_HOUR_REG, &data);
 	alarm_mode |= (data & 0x80) >> 6;

 	regmap_read(priv->map, DS1343_ALM0_DAY_REG, &data);
 	alarm_mode |= (data & 0x80) >> 7;

 	switch (alarm_mode) {
 	case 15:
 		alarm_str = "each second";
 		break;

 	case 7:
 		alarm_str = "seconds match";
 		break;

 	case 3:
 		alarm_str = "minutes and seconds match";
 		break;

 	case 1:
 		alarm_str = "hours, minutes and seconds match";
 		break;

 	case 0:
 		alarm_str = "day, hours, minutes and seconds match";
 		break;

 	default:
 		alarm_str = "invalid";
 		break;
 	}

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

 static DEVICE_ATTR(alarm_mode, S_IRUGO, ds1343_show_alarmmode, NULL);

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

 	regmap_read(priv->map, DS1343_TRICKLE_REG, &data);

 	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 int ds1343_sysfs_register(struct device *dev)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int err;

 	err = device_create_file(dev, &dev_attr_glitch_filter);
 	if (err)
 		return err;

 	err = device_create_file(dev, &dev_attr_trickle_charger);
 	if (err)
 		goto error1;

 	err = device_create_bin_file(dev, &nvram_attr);
 	if (err)
 		goto error2;

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

 	err = device_create_file(dev, &dev_attr_alarm_mode);
 	if (err)
 		goto error3;

 	err = device_create_file(dev, &dev_attr_alarm_status);
 	if (!err)
 		return err;

 	device_remove_file(dev, &dev_attr_alarm_mode);

 error3:
 	device_remove_bin_file(dev, &nvram_attr);

 error2:
 	device_remove_file(dev, &dev_attr_trickle_charger);

 error1:
 	device_remove_file(dev, &dev_attr_glitch_filter);

 	return err;
 }

 static void ds1343_sysfs_unregister(struct device *dev)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);

 	device_remove_file(dev, &dev_attr_glitch_filter);
 	device_remove_file(dev, &dev_attr_trickle_charger);
 	device_remove_bin_file(dev, &nvram_attr);

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

 	device_remove_file(dev, &dev_attr_alarm_status);
 	device_remove_file(dev, &dev_attr_alarm_mode);
 }

 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 rtc_valid_tm(dt);
 }

 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int res;

 	res = regmap_write(priv->map, DS1343_SECONDS_REG,
 				bin2bcd(dt->tm_sec));
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_MINUTES_REG,
 				bin2bcd(dt->tm_min));
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_HOURS_REG,
 				bin2bcd(dt->tm_hour) & 0x3F);
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_DAY_REG,
 				bin2bcd(dt->tm_wday + 1));
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_DATE_REG,
 				bin2bcd(dt->tm_mday));
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_MONTH_REG,
 				bin2bcd(dt->tm_mon + 1));
 	if (res)
 		return res;

 	dt->tm_year %= 100;

 	res = regmap_write(priv->map, DS1343_YEAR_REG,
 				bin2bcd(dt->tm_year));
 	if (res)
 		return res;

 	return 0;
 }

 static int ds1343_update_alarm(struct device *dev)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	unsigned int control, stat;
 	unsigned char buf[4];
 	int res = 0;

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

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

 	control &= ~(DS1343_A0IE);
 	stat &= ~(DS1343_IRQF0);

 	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
 	if (res)
 		return res;

 	res = regmap_write(priv->map, DS1343_STATUS_REG, stat);
 	if (res)
 		return res;

 	buf[0] = priv->alarm_sec < 0 || (priv->irqen & RTC_UF) ?
 		0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
 	buf[1] = priv->alarm_min < 0 || (priv->irqen & RTC_UF) ?
 		0x80 : bin2bcd(priv->alarm_min) & 0x7F;
 	buf[2] = priv->alarm_hour < 0 || (priv->irqen & RTC_UF) ?
 		0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
 	buf[3] = priv->alarm_mday < 0 || (priv->irqen & RTC_UF) ?
 		0x80 : bin2bcd(priv->alarm_mday) & 0x7F;

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

 	if (priv->irqen) {
 		control |= DS1343_A0IE;
 		res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
 	}

 	return res;
 }

 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int res = 0;
 	unsigned int stat;

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

 	mutex_lock(&priv->mutex);

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

 	alarm->enabled = !!(priv->irqen & RTC_AF);
 	alarm->pending = !!(stat & DS1343_IRQF0);

 	alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
 	alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
 	alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
 	alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;

 	alarm->time.tm_mon = -1;
 	alarm->time.tm_year = -1;
 	alarm->time.tm_wday = -1;
 	alarm->time.tm_yday = -1;
 	alarm->time.tm_isdst = -1;

 out:
 	mutex_unlock(&priv->mutex);
 	return res;
 }

 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int res = 0;

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

 	mutex_lock(&priv->mutex);

 	priv->alarm_sec = alarm->time.tm_sec;
 	priv->alarm_min = alarm->time.tm_min;
 	priv->alarm_hour = alarm->time.tm_hour;
 	priv->alarm_mday = alarm->time.tm_mday;

 	if (alarm->enabled)
 		priv->irqen |= RTC_AF;

 	res = ds1343_update_alarm(dev);

 	mutex_unlock(&priv->mutex);

 	return res;
 }

 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
 	int res = 0;

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

 	mutex_lock(&priv->mutex);

 	if (enabled)
 		priv->irqen |= RTC_AF;
 	else
 		priv->irqen &= ~RTC_AF;

 	res = ds1343_update_alarm(dev);

 	mutex_unlock(&priv->mutex);

 	return res;
 }

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

 	mutex_lock(&priv->mutex);

 	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);

 		res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
 		if (res)
 			goto out;

 		control &= ~DS1343_A0IE;
 		regmap_write(priv->map, DS1343_CONTROL_REG, control);

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

 out:
 	mutex_unlock(&priv->mutex);
 	return IRQ_HANDLED;
 }

 static const struct rtc_class_ops ds1343_rtc_ops = {
 	.ioctl		= ds1343_ioctl,
 	.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;
 	unsigned int data;
 	int res;

 	memset(&config, 0, sizeof(config));
 	config.reg_bits = 8;
 	config.val_bits = 8;
 	config.write_flag_mask = 0x80;

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

 	priv->spi = spi;
 	mutex_init(&priv->mutex);

 	/* RTC DS1347 works in spi mode 3 and
 	 * its chip select is active high
 	 */
 	spi->mode = SPI_MODE_3 | 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_device_register(&spi->dev, "ds1343",
 					&ds1343_rtc_ops, THIS_MODULE);
 	if (IS_ERR(priv->rtc)) {
 		dev_err(&spi->dev, "unable to register rtc ds1343\n");
 		return PTR_ERR(priv->rtc);
 	}

 	priv->irq = spi->irq;

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

 	res = ds1343_sysfs_register(&spi->dev);
 	if (res)
 		dev_err(&spi->dev,
 			"unable to create sysfs entries for rtc ds1343\n");

 	return 0;
 }

 static int ds1343_remove(struct spi_device *spi)
 {
 	struct ds1343_priv *priv = spi_get_drvdata(spi);

 	if (spi->irq) {
 		mutex_lock(&priv->mutex);
 		priv->irqen &= ~RTC_AF;
 		mutex_unlock(&priv->mutex);

 		devm_free_irq(&spi->dev, spi->irq, priv);
 	}

 	spi_set_drvdata(spi, NULL);

 	ds1343_sysfs_unregister(&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",
 		.owner = THIS_MODULE,
 		.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 <[email protected]>,"
 		"Ankur Srivastava <[email protected]>");
 MODULE_LICENSE("GPL v2");
 MODULE_VERSION(DS1343_DRV_VERSION);
	/* rtc-ds1343.c
	*
	* Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
	* Real Time Clock
	*
	* Author : Raghavendra Chandra Ganiga <[email protected]>
	* Ankur Srivastava <[email protected]> : DS1343 Nvram Support
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	*/

	#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/slab.h>

	#define DS1343_DRV_VERSION "01.00"
	#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 spi_device *spi;
	struct rtc_device *rtc;
	struct regmap *map;
	struct mutex mutex;
	unsigned int irqen;
	int irq;
	int alarm_sec;
	int alarm_min;
	int alarm_hour;
	int alarm_mday;
	};

	static int ds1343_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	{
	switch (cmd) {
	#ifdef RTC_SET_CHARGE
	case RTC_SET_CHARGE:
	{
	int val;

	if (copy_from_user(&val, (int __user *)arg, sizeof(int)))
	return -EFAULT;

	return regmap_write(priv->map, DS1343_TRICKLE_REG, val);
	}
	break;
	#endif
	}

	return -ENOIOCTLCMD;
	}

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

	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

	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);
	int data;

	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

	if (strncmp(buf, "enabled", 7) == 0)
	data \|= DS1343_EGFIL;

	else if (strncmp(buf, "disabled", 8) == 0)
	data &= ~(DS1343_EGFIL);

	else
	return -EINVAL;

	regmap_write(priv->map, DS1343_CONTROL_REG, data);

	return count;
	}

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

	static ssize_t ds1343_nvram_write(struct file filp, struct kobject kobj,
	struct bin_attribute *attr,
	char *buf, loff_t off, size_t count)
	{
	int ret;
	unsigned char address;
	struct device *dev = kobj_to_dev(kobj);
	struct ds1343_priv *priv = dev_get_drvdata(dev);

	if (unlikely(!count))
	return count;

	if ((count + off) > DS1343_NVRAM_LEN)
	count = DS1343_NVRAM_LEN - off;

	address = DS1343_NVRAM + off;

	ret = regmap_bulk_write(priv->map, address, buf, count);
	if (ret < 0)
	dev_err(&priv->spi->dev, "Error in nvram write %d", ret);

	return (ret < 0) ? ret : count;
	}


	static ssize_t ds1343_nvram_read(struct file filp, struct kobject kobj,
	struct bin_attribute *attr,
	char *buf, loff_t off, size_t count)
	{
	int ret;
	unsigned char address;
	struct device *dev = kobj_to_dev(kobj);
	struct ds1343_priv *priv = dev_get_drvdata(dev);

	if (unlikely(!count))
	return count;

	if ((count + off) > DS1343_NVRAM_LEN)
	count = DS1343_NVRAM_LEN - off;

	address = DS1343_NVRAM + off;

	ret = regmap_bulk_read(priv->map, address, buf, count);
	if (ret < 0)
	dev_err(&priv->spi->dev, "Error in nvram read %d\n", ret);

	return (ret < 0) ? ret : count;
	}


	static struct bin_attribute nvram_attr = {
	.attr.name = "nvram",
	.attr.mode = S_IRUGO \| S_IWUSR,
	.read = ds1343_nvram_read,
	.write = ds1343_nvram_write,
	.size = DS1343_NVRAM_LEN,
	};

	static ssize_t ds1343_show_alarmstatus(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int alarmstatus, data;

	regmap_read(priv->map, DS1343_CONTROL_REG, &data);

	alarmstatus = !!(data & DS1343_A0IE);

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

	static DEVICE_ATTR(alarm_status, S_IRUGO, ds1343_show_alarmstatus, NULL);

	static ssize_t ds1343_show_alarmmode(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int alarm_mode, data;
	char *alarm_str;

	regmap_read(priv->map, DS1343_ALM0_SEC_REG, &data);
	alarm_mode = (data & 0x80) >> 4;

	regmap_read(priv->map, DS1343_ALM0_MIN_REG, &data);
	alarm_mode \|= (data & 0x80) >> 5;

	regmap_read(priv->map, DS1343_ALM0_HOUR_REG, &data);
	alarm_mode \|= (data & 0x80) >> 6;

	regmap_read(priv->map, DS1343_ALM0_DAY_REG, &data);
	alarm_mode \|= (data & 0x80) >> 7;

	switch (alarm_mode) {
	case 15:
	alarm_str = "each second";
	break;

	case 7:
	alarm_str = "seconds match";
	break;

	case 3:
	alarm_str = "minutes and seconds match";
	break;

	case 1:
	alarm_str = "hours, minutes and seconds match";
	break;

	case 0:
	alarm_str = "day, hours, minutes and seconds match";
	break;

	default:
	alarm_str = "invalid";
	break;
	}

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

	static DEVICE_ATTR(alarm_mode, S_IRUGO, ds1343_show_alarmmode, NULL);

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

	regmap_read(priv->map, DS1343_TRICKLE_REG, &data);

	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 int ds1343_sysfs_register(struct device *dev)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int err;

	err = device_create_file(dev, &dev_attr_glitch_filter);
	if (err)
	return err;

	err = device_create_file(dev, &dev_attr_trickle_charger);
	if (err)
	goto error1;

	err = device_create_bin_file(dev, &nvram_attr);
	if (err)
	goto error2;

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

	err = device_create_file(dev, &dev_attr_alarm_mode);
	if (err)
	goto error3;

	err = device_create_file(dev, &dev_attr_alarm_status);
	if (!err)
	return err;

	device_remove_file(dev, &dev_attr_alarm_mode);

	error3:
	device_remove_bin_file(dev, &nvram_attr);

	error2:
	device_remove_file(dev, &dev_attr_trickle_charger);

	error1:
	device_remove_file(dev, &dev_attr_glitch_filter);

	return err;
	}

	static void ds1343_sysfs_unregister(struct device *dev)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);

	device_remove_file(dev, &dev_attr_glitch_filter);
	device_remove_file(dev, &dev_attr_trickle_charger);
	device_remove_bin_file(dev, &nvram_attr);

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

	device_remove_file(dev, &dev_attr_alarm_status);
	device_remove_file(dev, &dev_attr_alarm_mode);
	}

	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 rtc_valid_tm(dt);
	}

	static int ds1343_set_time(struct device dev, struct rtc_time dt)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int res;

	res = regmap_write(priv->map, DS1343_SECONDS_REG,
	bin2bcd(dt->tm_sec));
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_MINUTES_REG,
	bin2bcd(dt->tm_min));
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_HOURS_REG,
	bin2bcd(dt->tm_hour) & 0x3F);
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_DAY_REG,
	bin2bcd(dt->tm_wday + 1));
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_DATE_REG,
	bin2bcd(dt->tm_mday));
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_MONTH_REG,
	bin2bcd(dt->tm_mon + 1));
	if (res)
	return res;

	dt->tm_year %= 100;

	res = regmap_write(priv->map, DS1343_YEAR_REG,
	bin2bcd(dt->tm_year));
	if (res)
	return res;

	return 0;
	}

	static int ds1343_update_alarm(struct device *dev)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	unsigned int control, stat;
	unsigned char buf[4];
	int res = 0;

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

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

	control &= ~(DS1343_A0IE);
	stat &= ~(DS1343_IRQF0);

	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
	if (res)
	return res;

	res = regmap_write(priv->map, DS1343_STATUS_REG, stat);
	if (res)
	return res;

	buf[0] = priv->alarm_sec < 0 \|\| (priv->irqen & RTC_UF) ?
	0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
	buf[1] = priv->alarm_min < 0 \|\| (priv->irqen & RTC_UF) ?
	0x80 : bin2bcd(priv->alarm_min) & 0x7F;
	buf[2] = priv->alarm_hour < 0 \|\| (priv->irqen & RTC_UF) ?
	0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
	buf[3] = priv->alarm_mday < 0 \|\| (priv->irqen & RTC_UF) ?
	0x80 : bin2bcd(priv->alarm_mday) & 0x7F;

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

	if (priv->irqen) {
	control \|= DS1343_A0IE;
	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
	}

	return res;
	}

	static int ds1343_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int res = 0;
	unsigned int stat;

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

	mutex_lock(&priv->mutex);

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

	alarm->enabled = !!(priv->irqen & RTC_AF);
	alarm->pending = !!(stat & DS1343_IRQF0);

	alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
	alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
	alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
	alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;

	alarm->time.tm_mon = -1;
	alarm->time.tm_year = -1;
	alarm->time.tm_wday = -1;
	alarm->time.tm_yday = -1;
	alarm->time.tm_isdst = -1;

	out:
	mutex_unlock(&priv->mutex);
	return res;
	}

	static int ds1343_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int res = 0;

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

	mutex_lock(&priv->mutex);

	priv->alarm_sec = alarm->time.tm_sec;
	priv->alarm_min = alarm->time.tm_min;
	priv->alarm_hour = alarm->time.tm_hour;
	priv->alarm_mday = alarm->time.tm_mday;

	if (alarm->enabled)
	priv->irqen \|= RTC_AF;

	res = ds1343_update_alarm(dev);

	mutex_unlock(&priv->mutex);

	return res;
	}

	static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct ds1343_priv *priv = dev_get_drvdata(dev);
	int res = 0;

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

	mutex_lock(&priv->mutex);

	if (enabled)
	priv->irqen \|= RTC_AF;
	else
	priv->irqen &= ~RTC_AF;

	res = ds1343_update_alarm(dev);

	mutex_unlock(&priv->mutex);

	return res;
	}

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

	mutex_lock(&priv->mutex);

	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);

	res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
	if (res)
	goto out;

	control &= ~DS1343_A0IE;
	regmap_write(priv->map, DS1343_CONTROL_REG, control);

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

	out:
	mutex_unlock(&priv->mutex);
	return IRQ_HANDLED;
	}

	static const struct rtc_class_ops ds1343_rtc_ops = {
	.ioctl = ds1343_ioctl,
	.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;
	unsigned int data;
	int res;

	memset(&config, 0, sizeof(config));
	config.reg_bits = 8;
	config.val_bits = 8;
	config.write_flag_mask = 0x80;

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

	priv->spi = spi;
	mutex_init(&priv->mutex);

	/* RTC DS1347 works in spi mode 3 and
	* its chip select is active high
	*/
	spi->mode = SPI_MODE_3 \| 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_device_register(&spi->dev, "ds1343",
	&ds1343_rtc_ops, THIS_MODULE);
	if (IS_ERR(priv->rtc)) {
	dev_err(&spi->dev, "unable to register rtc ds1343\n");
	return PTR_ERR(priv->rtc);
	}

	priv->irq = spi->irq;

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

	res = ds1343_sysfs_register(&spi->dev);
	if (res)
	dev_err(&spi->dev,
	"unable to create sysfs entries for rtc ds1343\n");

	return 0;
	}

	static int ds1343_remove(struct spi_device *spi)
	{
	struct ds1343_priv *priv = spi_get_drvdata(spi);

	if (spi->irq) {
	mutex_lock(&priv->mutex);
	priv->irqen &= ~RTC_AF;
	mutex_unlock(&priv->mutex);

	devm_free_irq(&spi->dev, spi->irq, priv);
	}

	spi_set_drvdata(spi, NULL);

	ds1343_sysfs_unregister(&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",
	.owner = THIS_MODULE,
	.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 <[email protected]>,"
	"Ankur Srivastava <[email protected]>");
	MODULE_LICENSE("GPL v2");
	MODULE_VERSION(DS1343_DRV_VERSION);