This is a patch to add support for
maxim dallas rtc max6917.
Signed-off-by: Venkat Prashanth B U <venkat.prashanth2...@gmail.com>
---
---
drivers/rtc/Kconfig | 9 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-max6917.c | 406 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 416 insertions(+)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e215f50..2163606 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -277,6 +277,15 @@ config RTC_DRV_MAX6900
This driver can also be built as a module. If so, the module
will be called rtc-max6900.
+config RTC_DRV_MAX6917
+ tristate "Maxim MAX6917"
+ help
+ If you say yes here you will get support for the
+ Maxim MAX6917 I2C RTC chip.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-max6917.
+
config RTC_DRV_MAX8907
tristate "Maxim MAX8907"
depends on MFD_MAX8907
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 7cf7ad5..29332fb 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o
obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
obj-$(CONFIG_RTC_DRV_MAX6916) += rtc-max6916.o
+obj-$(CONFIG_RTC_DRV_MAX6917) += rtc-max6917.o
obj-$(CONFIG_RTC_DRV_MAX77686) += rtc-max77686.o
obj-$(CONFIG_RTC_DRV_MAX8907) += rtc-max8907.o
obj-$(CONFIG_RTC_DRV_MAX8925) += rtc-max8925.o
diff --git a/drivers/rtc/rtc-max6917.c b/drivers/rtc/rtc-max6917.c
index e69de29..1176384 100644
--- a/drivers/rtc/rtc-max6917.c
+++ b/drivers/rtc/rtc-max6917.c
@@ -0,0 +1,406 @@
+ /* rtc-max6917.c
+ *
+ * Driver for MAXIM max6917 I2C-Compatible Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <venkat.prashanth2...@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/bcd.h>
+ #include <linux/i2c.h>
+ #include <linux/init.h>
+ #include <linux/module.h>
+ #include <linux/rtc.h>
+ #include <linux/string.h>
+ #include <linux/delay.h>
+ #include <linux/clk-provider.h>
+ #include <linux/slab.h>
+
+ #define MAX6917_REG_SECS 0x01 /* 00-59 */
+ #define MAX6917_REG_MIN 0x02 /* 00-59 */
+ #define MAX6917_REG_HOUR 0x03 /* 00-23, or
1-12{am,pm} */
+ #define MAX6917_REG_WDAY 0x04 /* 01-07 */
+ #define MAX6917_REG_MDAY 0x05 /* 01-31 */
+ #define MAX6917_REG_MONTH 0x06 /* 01-12 */
+ #define MAX6917_REG_YEAR 0x07 /* 00-99 */
+ #define MAX6917_REG_CONTROL 0x08
+ #define MAX6917_REG_STATUS 0x0c
+ #define MAX6917_REG_ALARM 0x0a
+ #define MAX6917_BURST_LEN 8 /* can burst r/w first
8 regs */
+ #define MAX6917_REG_CENTURY 9 /* century */
+ #define MAX6917_REG_LEN 10
+ #define MAX6917_REG_CT_WP (1 << 7) /* Write
Protect */
+ /*
+ * register read/write commands
+ */
+ #define MAX6917_REG_CONTROL_WRITE 0x8e
+ #define MAX6917_REG_CENTURY_WRITE 0x92
+ #define MAX6917_REG_CENTURY_READ 0x93
+ #define MAX6917_REG_RESERVED_READ 0x96
+ #define MAX6917_REG_BURST_WRITE 0xbe
+ #define MAX6917_REG_BURST_READ 0xbf
+
+ #define MAX6917_IDLE_TIME_AFTER_WRITE 3 /* specification says
2.5 mS */
+
+ static struct i2c_driver max6917_driver;
+
+ struct max6917
+ {
+ u8 offset; /* register's offset */
+ u8 regs[11];
+ u16 nvram_offset;
+ struct bin_attribute *nvram;
+ unsigned long flags;
+ #define HAS_NVRAM 0 /* bit 0 == sysfs file
active */
+ #define HAS_ALARM 1 /* bit 1 == irq claimed
*/
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+ s32 (*read_block_data) (const struct i2c_client * client, u8
command,
+ u8 length, u8 * values);
+ s32 (*write_block_data) (const struct i2c_client * client, u8
command,
+ u8 length, const u8 * values);
+ };
+
+ struct chip_desc
+ {
+ unsigned alarm:1;
+ u16 nvram_offset;
+ u16 nvram_size;
+ };
+
+ static int
+ max6917_i2c_read_regs (struct i2c_client *client, u8 * buf)
+ {
+ u8 reg_burst_read[1] = { MAX6917_REG_BURST_READ };
+ u8 reg_century_read[1] = { MAX6917_REG_CENTURY_READ };
+ struct i2c_msg msgs[4] = {
+ {
+ .addr = client->addr,
+ .flags = 0, /* write */
+ .len = sizeof (reg_burst_read),
+ .buf = reg_burst_read}
+ ,
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = MAX6917_BURST_LEN,
+ .buf = buf}
+ ,
+ {
+ .addr = client->addr,
+ .flags = 0, /* write */
+ .len = sizeof (reg_century_read),
+ .buf = reg_century_read}
+ ,
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = sizeof (buf[MAX6917_REG_CENTURY]),
+ .buf = &buf[MAX6917_REG_CENTURY]}
+ };
+ int rc;
+
+ rc = i2c_transfer (client->adapter, msgs, ARRAY_SIZE (msgs));
+ if (rc != ARRAY_SIZE (msgs))
+ {
+ dev_err (&client->dev, "%s: register read failed\n",
__func__);
+ return -EIO;
+ }
+ return 0;
+ }
+
+ static int
+ max6917_i2c_write_regs (struct i2c_client *client, u8 const *buf)
+ {
+ u8 i2c_century_buf[1 + 1] = { MAX6917_REG_CENTURY_WRITE };
+ struct i2c_msg century_msgs[1] = {
+ {
+ .addr = client->addr,
+ .flags = 0, /* write */
+ .len = sizeof (i2c_century_buf),
+ .buf = i2c_century_buf}
+ };
+ u8 i2c_burst_buf[MAX6917_BURST_LEN + 1] = { MAX6917_REG_BURST_WRITE };
+ struct i2c_msg burst_msgs[1] = {
+ {
+ .addr = client->addr,
+ .flags = 0, /* write */
+ .len = sizeof (i2c_burst_buf),
+ .buf = i2c_burst_buf}
+ };
+ int rc;
+
+ /*
+ * We have to make separate calls to i2c_transfer because of
+ * the need to delay after each write to the chip. Also,
+ * we write the century byte first, since we set the
write-protect
+ * bit as part of the burst write.
+ */
+ i2c_century_buf[1] = buf[MAX6917_REG_CENTURY];
+
+ rc = i2c_transfer (client->adapter, century_msgs,
+ ARRAY_SIZE (century_msgs));
+ if (rc != ARRAY_SIZE (century_msgs))
+ goto write_failed;
+
+ msleep (MAX6917_IDLE_TIME_AFTER_WRITE);
+
+ memcpy (&i2c_burst_buf[1], buf, MAX6917_BURST_LEN);
+
+ rc = i2c_transfer (client->adapter, burst_msgs, ARRAY_SIZE
(burst_msgs));
+ if (rc != ARRAY_SIZE (burst_msgs))
+ goto write_failed;
+ msleep (MAX6917_IDLE_TIME_AFTER_WRITE);
+
+ return 0;
+
+ write_failed:
+ dev_err (&client->dev, "%s: register write failed\n", __func__);
+ return -EIO;
+ }
+
+ static int
+ max6917_i2c_read_time (struct i2c_client *client, struct rtc_time *tm)
+ {
+ int rc;
+ u8 regs[MAX6917_REG_LEN];
+
+ rc = max6917_i2c_read_regs (client, regs);
+ if (rc < 0)
+ return rc;
+
+ tm->tm_sec = bcd2bin (regs[MAX6917_REG_SECS]);
+ tm->tm_min = bcd2bin (regs[MAX6917_REG_MIN]);
+ tm->tm_hour = bcd2bin (regs[MAX6917_REG_HOUR] & 0x3f);
+ tm->tm_mday = bcd2bin (regs[MAX6917_REG_MDAY]);
+ tm->tm_mon = bcd2bin (regs[MAX6917_REG_MONTH]) - 1;
+ tm->tm_year = bcd2bin (regs[MAX6917_REG_YEAR]) +
+ bcd2bin (regs[MAX6917_REG_CENTURY]) * 100 - 1900;
+ tm->tm_wday = bcd2bin (regs[MAX6917_REG_WDAY]);
+
+ return rtc_valid_tm (tm);
+ }
+
+ static int
+ max6917_i2c_clear_write_protect (struct i2c_client *client)
+ {
+ return i2c_smbus_write_byte_data (client, MAX6917_REG_CONTROL_WRITE, 0);
+ }
+
+ static int
+ max6917_i2c_set_time (struct i2c_client *client, struct rtc_time const
*tm)
+ {
+ u8 regs[MAX6917_REG_LEN];
+ int rc;
+
+ rc = max6917_i2c_clear_write_protect (client);
+ if (rc < 0)
+ return rc;
+
+ regs[MAX6917_REG_SECS] = bin2bcd (tm->tm_sec);
+ regs[MAX6917_REG_MIN] = bin2bcd (tm->tm_min);
+ regs[MAX6917_REG_HOUR] = bin2bcd (tm->tm_hour);
+ regs[MAX6917_REG_MDAY] = bin2bcd (tm->tm_mday);
+ regs[MAX6917_REG_MONTH] = bin2bcd (tm->tm_mon + 1);
+ regs[MAX6917_REG_WDAY] = bin2bcd (tm->tm_wday);
+ regs[MAX6917_REG_YEAR] = bin2bcd (tm->tm_year % 100);
+ regs[MAX6917_REG_CENTURY] = bin2bcd ((tm->tm_year + 1900) / 100);
+ /* set write protect */
+ regs[MAX6917_REG_CONTROL] = MAX6917_REG_CT_WP;
+
+ rc = max6917_i2c_write_regs (client, regs);
+ if (rc < 0)
+ return rc;
+
+ return 0;
+ }
+
+ static int
+ max6917_rtc_read_time (struct device *dev, struct rtc_time *tm)
+ {
+ return max6917_i2c_read_time (to_i2c_client (dev), tm);
+ }
+
+ static int
+ max6917_rtc_set_time (struct device *dev, struct rtc_time *tm)
+ {
+ return max6917_i2c_set_time (to_i2c_client (dev), tm);
+ }
+
+ static int
+ max6917_read_alarm (struct device *dev, struct rtc_wkalrm *t)
+ {
+ struct i2c_client *client = to_i2c_client (dev);
+ struct max6917 *max6917 = i2c_get_clientdata (client);
+ int ret;
+
+ if (!test_bit (HAS_ALARM, &max6917->flags))
+ return -EINVAL;
+
+ /* read all ALARM1, ALARM2, and status registers at once */
+ ret = max6917->read_block_data (client,
+ MAX6917_REG_ALARM, 9, max6917->regs);
+ if (ret != 9)
+ {
+ dev_err (dev, " error %d\n", "alarm read", ret);
+ return -EIO;
+ }
+
+ dev_dbg (dev, "%4ph, %3ph, %2ph\n", "alarm read",
+ &max6917->regs[0], &max6917->regs[4],
&max6917->regs[7]);
+
+ /*
+ * report alarm time (ALARM1); assume 24 hour and day-of-month
modes,
+ * and that all four fields are checked matches
+ */
+ t->time.tm_sec = bcd2bin (max6917->regs[0] & 0x7f);
+ t->time.tm_min = bcd2bin (max6917->regs[1] & 0x7f);
+ t->time.tm_hour = bcd2bin (max6917->regs[2] & 0x3f);
+ t->time.tm_mday = bcd2bin (max6917->regs[3] & 0x3f);
+
+ dev_dbg (dev, " %s secs=%d, mins=%d, "
+ "hours=%d, mday=%d, enabled=%d, pending=%d\n",
+ "alarm read", t->time.tm_sec, t->time.tm_min,
+ t->time.tm_hour, t->time.tm_mday);
+
+ return 0;
+ }
+
+ static int
+ max6917_set_alarm (struct device *dev, struct rtc_wkalrm *t)
+ {
+ struct i2c_client *client = to_i2c_client (dev);
+ struct max6917 *max6917 = i2c_get_clientdata (client);
+ unsigned char *buf = max6917->regs;
+ u8 control, status;
+ int ret;
+
+ if (!test_bit (HAS_ALARM, &max6917->flags))
+ return -EINVAL;
+
+ dev_dbg (dev, " %s secs=%d, mins=%d, "
+ "hours=%d, mday=%d, enabled=%d, pending=%d\n",
+ "alarm set", t->time.tm_sec, t->time.tm_min,
+ t->time.tm_hour, t->time.tm_mday);
+
+ /* read current status of both alarms and the chip */
+ ret = max6917->read_block_data (client, MAX6917_REG_ALARM, 9, buf);
+ if (ret != 9)
+ {
+ dev_err (dev, "%s error %d\n", "alarm write", ret);
+ return -EIO;
+ }
+ control = max6917->regs[7];
+ status = max6917->regs[8];
+
+ dev_dbg (dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
+ &max6917->regs[0], &max6917->regs[4], control, status);
+
+ /* set ALARM1, using 24 hour and day-of-month modes */
+ buf[0] = bin2bcd (t->time.tm_sec);
+ buf[1] = bin2bcd (t->time.tm_min);
+ buf[2] = bin2bcd (t->time.tm_hour);
+ buf[3] = bin2bcd (t->time.tm_mday);
+ buf[4] = 0;
+ buf[5] = 0;
+ buf[6] = 0;
+
+ ret = max6917->write_block_data (client, MAX6917_REG_ALARM, 9, buf);
+ if (ret < 0)
+ {
+ dev_err (dev, "can't set alarm time\n");
+ return ret;
+ }
+ return 0;
+ }
+
+ static ssize_t
+ max6917_nvram_read (struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+ {
+ struct i2c_client *client;
+ struct max6917 *max6917;
+ int result;
+
+ client = kobj_to_i2c_client (kobj);
+ max6917 = i2c_get_clientdata (client);
+
+ result = max6917->read_block_data (client, max6917->nvram_offset + off,
+ count, buf);
+ if (result < 0)
+ dev_err (&client->dev, "%s error %d\n", "nvram read", result);
+ return result;
+ }
+
+ static ssize_t
+ max6917_nvram_write (struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+ {
+ struct i2c_client *client;
+ struct max6917 *max6917;
+ int result;
+
+ client = kobj_to_i2c_client (kobj);
+ max6917 = i2c_get_clientdata (client);
+
+ result = max6917->write_block_data (client, max6917->nvram_offset + off,
+ count, buf);
+ if (result < 0)
+ {
+ dev_err (&client->dev, "%s error %d\n", "nvram write",
result);
+ return result;
+ }
+ return count;
+ }
+
+ static const struct rtc_class_ops max6917_rtc_ops = {
+ .read_time = max6917_rtc_read_time,
+ .set_time = max6917_rtc_set_time,
+ .read_alarm = max6917_read_alarm,
+ .set_alarm = max6917_set_alarm,
+ };
+
+ static int
+ max6917_probe (struct i2c_client *client, const struct i2c_device_id
*id)
+ {
+ struct rtc_device *rtc;
+
+ if (!i2c_check_functionality (client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ rtc = devm_rtc_device_register (&client->dev,
max6917_driver.driver.name,
+ &max6917_rtc_ops, THIS_MODULE);
+ if (IS_ERR (rtc))
+ return PTR_ERR (rtc);
+
+ i2c_set_clientdata (client, rtc);
+
+ return 0;
+ }
+
+ static struct i2c_device_id max6917_id[] = {
+ {"max6917", 0},
+ {}
+ };
+
+ MODULE_DEVICE_TABLE (i2c, max6917_id);
+
+ static struct i2c_driver max6917_driver = {
+ .driver = {
+ .name = "rtc-max6917",
+ },
+ .probe = max6917_probe,
+ .id_table = max6917_id,
+ };
+
+ module_i2c_driver (max6917_driver);
+
+ MODULE_DESCRIPTION ("Maxim MAX6917 RTC driver");
+ MODULE_AUTHOR ("Venkat Prashanth B U");
+ MODULE_LICENSE ("GPL");
--
1.9.2
