This patch adds the driver for RTC chip DS3232 via I2C bus
Signed-off-by: Mingkai Hu <Mingkai.hu@xxxxxxxxxxxxx>
Signed-off-by: Jingchang Lu <b22599@xxxxxxxxxxxxx>
Signed-off-by: Srikanth Srinivasan <srikanth.srinivasan@xxxxxxxxxxxxx>
Signed-off-by: Roy Zang <tie-fei.zang@xxxxxxxxxxxxx>
---
Tested on MPC8536DS and P4080DS board
drivers/rtc/Kconfig | 11 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-ds3232.c | 466 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 478 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-ds3232.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 6a13037..13c2fdb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -166,6 +166,17 @@ config RTC_DRV_DS1672
This driver can also be built as a module. If so, the module
will be called rtc-ds1672.
+config RTC_DRV_DS3232
+ tristate "Dallas/Maxim DS3232"
+ depends on RTC_CLASS && I2C
+ help
+ If you say yes here you get support for Dallas Semiconductor
+ DS3232 real-time clock chips. If an interrupt is associated
+ with the device, the alarm functionality is supported.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-ds3232.
+
config RTC_DRV_MAX6900
tristate "Maxim MAX6900"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 44ef194..0af190c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o
obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o
obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
+obj-$(CONFIG_RTC_DRV_DS3232) += rtc-ds3232.o
obj-$(CONFIG_RTC_DRV_DS3234) += rtc-ds3234.o
obj-$(CONFIG_RTC_DRV_EFI) += rtc-efi.o
obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
new file mode 100644
index 0000000..21e1599
--- /dev/null
+++ b/drivers/rtc/rtc-ds3232.c
@@ -0,0 +1,466 @@
+/*
+ * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
+ *
+ * Copyright (C) 2009-2010 Freescale Semiconductor.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+/*
+ * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
+ * recommened in .../Documentation/i2c/writing-clients section
+ * "Sending and receiving", using SMBus level communication is preferred.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+
+#define DS3232_REG_SECONDS 0x00
+#define DS3232_REG_MINUTES 0x01
+#define DS3232_REG_HOURS 0x02
+#define DS3232_REG_AMPM 0x02
+#define DS3232_REG_DAY 0x03
+#define DS3232_REG_DATE 0x04
+#define DS3232_REG_MONTH 0x05
+#define DS3232_REG_CENTURY 0x05
+#define DS3232_REG_YEAR 0x06
+#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
+#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
+#define DS3232_REG_CR 0x0E /* Control register */
+# define DS3232_REG_CR_nEOSC 0x80
+# define DS3232_REG_CR_INTCN 0x04
+# define DS3232_REG_CR_A2IE 0x02
+# define DS3232_REG_CR_A1IE 0x01
+
+#define DS3232_REG_SR 0x0F /* control/status register */
+# define DS3232_REG_SR_OSF 0x80
+# define DS3232_REG_SR_BSY 0x04
+# define DS3232_REG_SR_A2F 0x02
+# define DS3232_REG_SR_A1F 0x01
+
+struct ds3232 {
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+ struct work_struct work;
+
+ /* The mutex protects alarm operations, and prevents a race
+ * between the enable_irq() in the workqueue and the free_irq()
+ * in the remove function.
+ */
+ struct mutex mutex;
+ int exiting;
+};
+
+static struct i2c_driver ds3232_driver;
+
+static int ds3232_check_rtc_status(struct i2c_client *client)
+{
+ int ret = 0;
+ int control, stat;
+
+ stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
+ if (stat < 0)
+ return stat;
+
+ if (stat & DS3232_REG_SR_OSF)
+ dev_warn(&client->dev,
+ "oscillator discontinuity flagged, "
+ "time unreliable\n");
+
+ stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
+
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
+ if (ret < 0)
+ return ret;
+
+ /* If the alarm is pending, clear it before requesting
+ * the interrupt, so an interrupt event isn't reported
+ * before everything is initialized.
+ */
+
+ control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (control < 0)
+ return control;
+
+ control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
+ control |= DS3232_REG_CR_INTCN;
+
+ return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
+}
+
+static int ds3232_read_time(struct device *dev, struct rtc_time *time)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int ret;
+ u8 buf[7];
+ unsigned int year, month, day, hour, minute, second;
+ unsigned int week, twelve_hr, am_pm;
+ unsigned int century, add_century = 0;
+
+ ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
+
+ if (ret < 0)
+ return ret;
+ if (ret < 7)
+ return -EIO;
+
+ second = buf[0];
+ minute = buf[1];
+ hour = buf[2];
+ week = buf[3];
+ day = buf[4];
+ month = buf[5];
+ year = buf[6];
+
+ /* Extract additional information for AM/PM and century */
+
+ twelve_hr = hour & 0x40;
+ am_pm = hour & 0x20;
+ century = month & 0x80;
+
+ /* Write to rtc_time structure */
+
+ time->tm_sec = bcd2bin(second);
+ time->tm_min = bcd2bin(minute);
+ if (twelve_hr) {
+ /* Convert to 24 hr */
+ if (am_pm)
+ time->tm_hour = bcd2bin(hour & 0x1F) + 12;
+ else
+ time->tm_hour = bcd2bin(hour & 0x1F);
+ } else {
+ time->tm_hour = bcd2bin(hour);
+ }
+
+ time->tm_wday = bcd2bin(week);
+ time->tm_mday = bcd2bin(day);
+ time->tm_mon = bcd2bin(month & 0x7F);
+ if (century)
+ add_century = 100;
+
+ time->tm_year = bcd2bin(year) + add_century;
+
+ return 0;
+}
+
+static int ds3232_set_time(struct device *dev, struct rtc_time *time)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ u8 buf[7];
+
+ /* Extract time from rtc_time and load into ds3232*/
+
+ buf[0] = bin2bcd(time->tm_sec);
+ buf[1] = bin2bcd(time->tm_min);
+ buf[2] = bin2bcd(time->tm_hour);
+ buf[3] = bin2bcd(time->tm_wday); /* Day of the week */
+ buf[4] = bin2bcd(time->tm_mday); /* Date */
+ buf[5] = bin2bcd(time->tm_mon);
+ if (time->tm_year >= 100) {
+ buf[5] |= 0x80;
+ buf[6] = bin2bcd(time->tm_year - 100);
+ } else {
+ buf[6] = bin2bcd(time->tm_year);
+ }
+
+ return i2c_smbus_write_i2c_block_data(client,
+ DS3232_REG_SECONDS, 7, buf);
+}
+
+/*
+ * DS3232 has two alarm, we only use alarm1
+ * According to linux specification, only support one-shot alarm
+ * no periodic alarm mode
+ */
+static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ds3232 *ds3232 = i2c_get_clientdata(client);
+ int control, stat;
+ int ret = 0;
+ u8 buf[4];
+
+ mutex_lock(&ds3232->mutex);
+ stat = ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
+ if (stat < 0)
+ goto out;
+
+ control = ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (control < 0)
+ goto out;
+
+ ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
+ if (ret < 0)
+ goto out;
+
+ alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
+ alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
+ alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
+ alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
+
+ 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;
+
+ alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
+ alarm->pending = !!(stat & DS3232_REG_SR_A1F);
+out:
+ mutex_unlock(&ds3232->mutex);
+
+ return ret;
+}
+
+/*
+ * linux rtc-module does not support wday alarm
+ * and only 24h time mode supported indeed
+ */
+static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ds3232 *ds3232 = i2c_get_clientdata(client);
+ int control, stat;
+ int ret = 0;
+ u8 buf[4];
+
+ if (client->irq <= 0)
+ return -EINVAL;
+
+ mutex_lock(&ds3232->mutex);
+
+ 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);
+
+ /* clear alarm interrupt enable bit */
+ ret = control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (ret < 0)
+ goto out;
+ control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
+ if (ret < 0)
+ goto out;
+
+ /* clear any pending alarm flag */
+ stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
+ if (stat < 0)
+ return stat;
+
+ stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
+
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_write_i2c_block_data(client,
+ DS3232_REG_ALARM1, 4, buf);
+
+ if (alarm->enabled) {
+ control |= DS3232_REG_CR_A1IE;
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
+ }
+out:
+ mutex_unlock(&ds3232->mutex);
+ return ret;
+}
+
+static irqreturn_t ds3232_irq(int irq, void *dev_id)
+{
+ struct i2c_client *client = dev_id;
+ struct ds3232 *ds3232 = i2c_get_clientdata(client);
+
+ disable_irq_nosync(irq);
+ schedule_work(&ds3232->work);
+ return IRQ_HANDLED;
+}
+
+static void ds3232_work(struct work_struct *work)
+{
+ struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
+ struct i2c_client *client = ds3232->client;
+ int stat, control;
+
+ mutex_lock(&ds3232->mutex);
+
+ stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
+ if (stat < 0)
+ goto unlock;
+
+ if (stat & DS3232_REG_SR_A1F) {
+ control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (control < 0)
+ goto out;
+ /* disable alarm1 interrupt */
+ control &= ~(DS3232_REG_CR_A1IE);
+ i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
+
+ /* clear the alarm pend flag */
+ stat &= ~DS3232_REG_SR_A1F;
+ i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
+
+ rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
+ }
+
+out:
+ if (!ds3232->exiting)
+ enable_irq(client->irq);
+unlock:
+ mutex_unlock(&ds3232->mutex);
+}
+
+static int ds3232_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ds3232 *ds3232 = i2c_get_clientdata(client);
+ int ret = -ENOIOCTLCMD;
+
+ mutex_lock(&ds3232->mutex);
+ switch (cmd) {
+ case RTC_AIE_OFF:
+ ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (ret < 0)
+ goto out;
+
+ ret &= ~DS3232_REG_CR_A1IE;
+
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, ret);
+ if (ret < 0)
+ goto out;
+
+ break;
+
+ case RTC_AIE_ON:
+ ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
+ if (ret < 0)
+ goto out;
+
+ ret |= DS3232_REG_CR_A1IE;
+
+ ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, ret);
+ if (ret < 0)
+ goto out;
+
+ break;
+ }
+out:
+ mutex_unlock(&ds3232->mutex);
+
+ return ret;
+}
+
+static const struct rtc_class_ops ds3232_rtc_ops = {
+ .read_time = ds3232_read_time,
+ .set_time = ds3232_set_time,
+ .read_alarm = ds3232_read_alarm,
+ .set_alarm = ds3232_set_alarm,
+ .ioctl = ds3232_ioctl,
+};
+
+static int ds3232_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ds3232 *ds3232;
+ int ret;
+
+ ds3232 = kzalloc(sizeof(struct ds3232), GFP_KERNEL);
+ if (!ds3232)
+ return -ENOMEM;
+
+ ds3232->client = client;
+ i2c_set_clientdata(client, ds3232);
+
+ INIT_WORK(&ds3232->work, ds3232_work);
+ mutex_init(&ds3232->mutex);
+
+ ret = ds3232_check_rtc_status(client);
+ if (ret)
+ goto out_free;
+
+ if (client->irq >= 0) {
+ ret = request_irq(client->irq, ds3232_irq, 0,
+ "ds3232", client);
+ if (ret)
+ goto out_free;
+ }
+
+ ds3232->rtc = rtc_device_register(client->name, &client->dev,
+ &ds3232_rtc_ops, THIS_MODULE);
+ if (IS_ERR(ds3232->rtc)) {
+ ret = PTR_ERR(ds3232->rtc);
+ dev_err(&client->dev, "unable to register the class device\n");
+ goto out_irq;
+ }
+
+ return 0;
+
+out_irq:
+ if (client->irq >= 0)
+ free_irq(client->irq, client);
+
+out_free:
+ i2c_set_clientdata(client, NULL);
+ kfree(ds3232);
+ return ret;
+}
+
+static int __devexit ds3232_remove(struct i2c_client *client)
+{
+ struct ds3232 *ds3232 = i2c_get_clientdata(client);
+
+ if (client->irq >= 0) {
+ mutex_lock(&ds3232->mutex);
+ ds3232->exiting = 1;
+ mutex_unlock(&ds3232->mutex);
+
+ free_irq(client->irq, client);
+ flush_scheduled_work();
+ }
+
+ rtc_device_unregister(ds3232->rtc);
+ i2c_set_clientdata(client, NULL);
+ kfree(ds3232);
+ return 0;
+}
+
+static const struct i2c_device_id ds3232_id[] = {
+ { "ds3232", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ds3232_id);
+
+static struct i2c_driver ds3232_driver = {
+ .driver = {
+ .name = "rtc-ds3232",
+ .owner = THIS_MODULE,
+ },
+ .probe = ds3232_probe,
+ .remove = __devexit_p(ds3232_remove),
+ .id_table = ds3232_id,
+};
+
+static int __init ds3232_init(void)
+{
+ return i2c_add_driver(&ds3232_driver);
+}
+
+static void __exit ds3232_exit(void)
+{
+ i2c_del_driver(&ds3232_driver);
+}
+
+module_init(ds3232_init);
+module_exit(ds3232_exit);
+
+MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
+MODULE_LICENSE("GPL");
--
1.5.6.5
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
