drivers/rtc: add support for maxim dallas rtc ds1343 and ds1344

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 679 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
new file mode 100644
index 0000000..8ccc750
--- /dev/null
+++ b/drivers/rtc/rtc-ds1343.c
@@ -0,0 +1,679 @@
+/* rtc-ds1343.c
+ *
+ * Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
+ *
+ * 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
+
+/* 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 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_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)
+{
+	int err;
+
+	err = device_create_file(dev, &dev_attr_glitch_filter);
+	if (err)
+		return err;
+
+	err = device_create_file(dev, &dev_attr_alarm_status);
+	if (err)
+		goto error1;
+
+	err = device_create_file(dev, &dev_attr_alarm_mode);
+	if (err)
+		goto error2;
+
+	err = device_create_file(dev, &dev_attr_trickle_charger);
+	if (!err)
+		return err;
+
+	device_remove_file(dev, &dev_attr_alarm_mode);
+
+error2:
+	device_remove_file(dev, &dev_attr_alarm_status);
+
+error1:
+	device_remove_file(dev, &dev_attr_glitch_filter);
+
+	return err;
+}
+
+static void ds1343_sysfs_unregister(struct device *dev)
+{
+	device_remove_file(dev, &dev_attr_glitch_filter);
+	device_remove_file(dev, &dev_attr_alarm_status);
+	device_remove_file(dev, &dev_attr_alarm_mode);
+	device_remove_file(dev, &dev_attr_trickle_charger);
+}
+
+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);
+	struct spi_device *spi = priv->spi;
+	int res = 0;
+	unsigned int stat;
+
+	if (spi->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);
+	struct spi_device *spi = priv->spi;
+	int res = 0;
+
+	if (spi->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);
+	struct spi_device *spi = priv->spi;
+	int res = 0;
+
+	if (spi->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);
+	}
+
+	if (spi->irq >= 0) {
+		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+						ds1343_thread,
+						IRQF_NO_SUSPEND | IRQF_ONESHOT,
+						"ds1343", priv);
+		if (res) {
+			dev_err(&spi->dev,
+				"unable to request irq for rtc ds1343\n");
+			return res;
+		}
+
+		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 <ravi23ganiga@gmail.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION(DS1343_DRV_VERSION);