[PATCH] rtc: add support for maxim dallas rtc ds1343 and ds1344

[RAGHAVENDRA GANIGA <ravi23ganiga@gmail.com>]

>From 54dad3ebbce5aba4d749a14d8173e94297e14b1a Mon Sep 17 00:00:00 2001
From: Raghavendra Ganiga <ravi23ganiga@gmail.com>
Date: Sun, 13 Apr 2014 20:02:59 +0530
Subject: [PATCH] rtc: add support for maxim dallas rtc ds1343 and ds1344

This is patch to add support for
maxim dallas rtc ds1343 and ds1344

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
---
 drivers/rtc/Kconfig      |   10 +
 drivers/rtc/Makefile     |    1 +
 drivers/rtc/rtc-ds1343.c |  619 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 630 insertions(+)
 create mode 100644 drivers/rtc/rtc-ds1343.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2e565f8..eb5cdcb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -573,6 +573,16 @@ config RTC_DRV_DS1305
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-ds1305.
 
+config RTC_DRV_DS1343
+	tristate "Dallas/Maxim DS1343/DS1344"
+	help
+	  If you say yes here you get support for the
+	  Dallas/Maxim DS1343 and DS1344 real time clock chips.
+	  Support for trickle charger, alarm is provided.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-ds1343.
+
 config RTC_DRV_DS1347
 	tristate "Dallas/Maxim DS1347"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 40a0991..a8daf6c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_RTC_DRV_DS1286)	+= rtc-ds1286.o
 obj-$(CONFIG_RTC_DRV_DS1302)	+= rtc-ds1302.o
 obj-$(CONFIG_RTC_DRV_DS1305)	+= rtc-ds1305.o
 obj-$(CONFIG_RTC_DRV_DS1307)	+= rtc-ds1307.o
+obj-$(CONFIG_RTC_DRV_DS1343)	+= rtc-ds1343.o
 obj-$(CONFIG_RTC_DRV_DS1347)	+= rtc-ds1347.o
 obj-$(CONFIG_RTC_DRV_DS1374)	+= rtc-ds1374.o
 obj-$(CONFIG_RTC_DRV_DS1390)	+= rtc-ds1390.o
diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
new file mode 100644
index 0000000..9bd9313
--- /dev/null
+++ b/drivers/rtc/rtc-ds1343.c
@@ -0,0 +1,619 @@
+/* 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/rtc.h>
+#include <linux/bcd.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#define DS1343_DRV_VERSION	"01.00"
+
+/* 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", 0 },
+	{ "ds1344", 1 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ds1343_id);
+
+struct ds1343_priv {
+	struct spi_device *spi;
+	struct rtc_device *rtc;
+	struct mutex mutex;
+	struct work_struct work;
+	unsigned int irqen;
+	int alarm_sec;
+	int alarm_min;
+	int alarm_hour;
+	int alarm_mday;
+};
+
+static int ds1343_get_reg(struct device *dev, unsigned char address,
+				unsigned char *buf)
+{
+	struct spi_device *spi = to_spi_device(dev);
+
+	/* MSB of the spi address                        _
+	   in this rtc should be zero for read operation R/W */
+	*buf = address;
+
+	return spi_write_then_read(spi, buf, 1, buf, 1);
+}
+
+static int ds1343_set_reg(struct device *dev, unsigned char address,
+				unsigned char data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned char buf[2];
+
+	/* MSB of the spi address                        _
+	   in this rtc should be one for write operation R/W */
+	buf[0] = address | 0x80;
+	buf[1] = data;
+
+	return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+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 ds1343_set_reg(dev, DS1343_TRICKLE_REG, val);
+	}
+	break;
+#endif
+	}
+
+	return -ENOIOCTLCMD;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static int ds1343_proc(struct device *dev, struct seq_file *seq)
+{
+	struct ds1343_priv *priv = dev_get_drvdata(dev);
+	struct  spi_device *spi = priv->spi;
+	unsigned char data, alarm_mode = 0;
+	const char *alarm_str, *diodes = "disabled", *resistors = " ";
+
+	ds1343_get_reg(&spi->dev, DS1343_CONTROL_REG, &data);
+
+	seq_printf(seq,
+			"oscillator\t: %s\n"
+			"disable_oscillator_stop_flag\t: %s\n"
+			"glitch_filter\t: %s\n"
+			"square_wave\t: %s\n"
+			"alarm_enable\t: %s\n",
+			(data & DS1343_EOSC) ? "disabled" : "enabled",
+			(data & DS1343_DOSF) ? "disabled" : "enabled",
+			(data & DS1343_EGFIL) ? "enabled" : "disabled",
+			(data & DS1343_SQW) ? "enabled" : "disabled",
+			(data & DS1343_A0IE) ? "enabled" : "disabled");
+
+	ds1343_get_reg(&spi->dev, DS1343_ALM0_SEC_REG, &data);
+	alarm_mode = (data & 0x80) >> 4;
+
+	ds1343_get_reg(&spi->dev, DS1343_ALM0_MIN_REG, &data);
+	alarm_mode |= (data & 0x80) >> 5;
+
+	ds1343_get_reg(&spi->dev, DS1343_ALM0_HOUR_REG, &data);
+	alarm_mode |= (data & 0x80) >> 6;
+
+	ds1343_get_reg(&spi->dev, 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;
+	}
+
+	seq_printf(seq, "alarm_mode\t: %s\n", alarm_str);
+
+	ds1343_get_reg(dev, DS1343_STATUS_REG, &data);
+	seq_printf(seq,
+			"alarm_pending\t: %s\n"
+			"oscillator_stop_flag\t: %s\n",
+			(data & DS1343_IRQF0) ? "yes" : "no",
+			(data & DS1343_OSF) ? "1" : "0");
+
+	ds1343_get_reg(dev, 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;
+		}
+	}
+
+	seq_printf(seq,
+			"trickle_charger\t: %s %s\n",
+			diodes, resistors);
+
+	return 0;
+}
+
+#else
+
+#define ds1343_proc NULL
+
+#endif
+
+static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned char buf[7];
+	int res;
+
+	buf[0] = DS1343_SECONDS_REG;
+
+	res = spi_write_then_read(spi, buf, 1, 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)
+{
+	int res;
+	res = ds1343_set_reg(dev, DS1343_SECONDS_REG,
+				bin2bcd(dt->tm_sec));
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_MINUTES_REG,
+				bin2bcd(dt->tm_min));
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_HOURS_REG,
+				bin2bcd(dt->tm_hour) & 0x3F);
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_DAY_REG,
+				bin2bcd(dt->tm_wday + 1));
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_DATE_REG,
+				bin2bcd(dt->tm_mday));
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_MONTH_REG,
+				bin2bcd(dt->tm_mon + 1));
+	if (res)
+		return res;
+
+	dt->tm_year %= 100;
+
+	res = ds1343_set_reg(dev, 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);
+	struct spi_device *spi = priv->spi;
+	unsigned char control, stat;
+	unsigned char buf[5];
+	int res = 0;
+
+	res = ds1343_get_reg(dev, DS1343_CONTROL_REG, &control);
+	if (res)
+		return res;
+
+	res = ds1343_get_reg(dev, DS1343_STATUS_REG, &stat);
+	if (res)
+		return res;
+
+	control &= ~(DS1343_A0IE);
+	stat &= ~(DS1343_IRQF0);
+
+	res = ds1343_set_reg(dev, DS1343_CONTROL_REG, control);
+	if (res)
+		return res;
+
+	res = ds1343_set_reg(dev, DS1343_STATUS_REG, stat);
+	if (res)
+		return res;
+
+	buf[0] = DS1343_ALM0_SEC_REG | 0x80;
+	buf[1] = priv->alarm_sec < 0 || (priv->irqen & RTC_UF) ?
+		0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
+	buf[2] = priv->alarm_min < 0 || (priv->irqen & RTC_UF) ?
+		0x80 : bin2bcd(priv->alarm_min) & 0x7F;
+	buf[3] = priv->alarm_hour < 0 || (priv->irqen & RTC_UF) ?
+		0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
+	buf[4] = priv->alarm_mday < 0 || (priv->irqen & RTC_UF) ?
+		0x80 : bin2bcd(priv->alarm_mday) & 0x7F;
+
+	res = spi_write_then_read(spi, buf, 5, NULL, 0);
+	if (res)
+		return res;
+
+	if (priv->irqen) {
+		control |= DS1343_A0IE;
+		res = ds1343_set_reg(dev, 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 char stat;
+
+	if (spi->irq <= 0)
+		return -EINVAL;
+
+	mutex_lock(&priv->mutex);
+
+	res = ds1343_get_reg(dev, 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_irq(int irq, void *dev_id)
+{
+	struct ds1343_priv *priv = dev_id;
+
+	disable_irq_nosync(irq);
+	schedule_work(&priv->work);
+	return IRQ_HANDLED;
+}
+
+static void ds1343_work(struct work_struct *work)
+{
+	struct ds1343_priv *priv = container_of(work, struct ds1343_priv, work);
+	struct spi_device *spi = priv->spi;
+	unsigned char stat, control;
+	int res = 0;
+
+	mutex_lock(&priv->mutex);
+
+	res = ds1343_get_reg(&spi->dev, DS1343_STATUS_REG, &stat);
+	if (res)
+		goto out;
+
+	if (stat & DS1343_IRQF0) {
+		stat &= ~DS1343_IRQF0;
+		ds1343_set_reg(&spi->dev, DS1343_STATUS_REG, stat);
+
+		res = ds1343_get_reg(&spi->dev, DS1343_CONTROL_REG, &control);
+		if (res)
+			goto out;
+
+		control &= ~DS1343_A0IE;
+		ds1343_set_reg(&spi->dev, DS1343_CONTROL_REG, control);
+
+		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
+	}
+
+out:
+	if (priv->irqen)
+		enable_irq(spi->irq);
+
+	mutex_unlock(&priv->mutex);
+}
+
+static const struct rtc_class_ops ds1343_rtc_ops = {
+	.ioctl		= ds1343_ioctl,
+	.proc		= ds1343_proc,
+	.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;
+	unsigned char data;
+	int res;
+
+	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi = spi;
+	mutex_init(&priv->mutex);
+	INIT_WORK(&priv->work, ds1343_work);
+
+	/* 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);
+
+	res = ds1343_get_reg(&spi->dev, DS1343_SECONDS_REG, &data);
+	if (res)
+		return res;
+
+	ds1343_get_reg(&spi->dev, DS1343_CONTROL_REG, &data);
+	data |= DS1343_INTCN;
+	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
+	ds1343_set_reg(&spi->dev, DS1343_CONTROL_REG, data);
+
+	ds1343_get_reg(&spi->dev, DS1343_STATUS_REG, &data);
+	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
+	ds1343_set_reg(&spi->dev, 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_irq(&spi->dev, spi->irq, ds1343_irq, 0,
+				"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);
+	}
+
+	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);
+		cancel_work_sync(&priv->work);
+	}
+
+	spi_set_drvdata(spi, NULL);
+
+	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);
-- 
1.7.10.4