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drivers/timers/mcp7941x.c: Add support for the MCP741x external RTC.

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This commit is contained in:
Ouss4 2019-01-06 17:32:02 -06:00 committed by Gregory Nutt
parent a0ba6a12a4
commit e998acee67
5 changed files with 736 additions and 1 deletions
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20
drivers/timers/Kconfig
View File

@ -211,7 +211,7 @@ config RTC_PCF85263
select RTC_DATETIME
depends on RTC_EXTERNAL
---help---
Enables support for the Maxim Integrated DS3231 I2C RTC timer.
Enables support for the NXP PCF85263 I2C RTC timer.
if RTC_PCF85263
@ -221,6 +221,24 @@ config PCF85263_I2C_FREQUENCY
range 1 400000
endif # RTC_PCF85263
config RTC_MCP7941X
bool "MCP7941X RTC Driver"
default n
select I2C
select RTC_DATETIME
depends on RTC_EXTERNAL
---help---
Enables support for the Microchip MCP7941X I2C RTC timer.
if RTC_MCP7941X
config MCP7941X_I2C_FREQUENCY
int "MCP7941X I2C frequency"
default 400000
range 1 400000
endif # RTC_MCP7941X
endif # RTC
menuconfig WATCHDOG

6
drivers/timers/Make.defs
View File

@ -81,6 +81,12 @@ ifeq ($(CONFIG_RTC_PCF85263),y)
TMRVPATH = :timers
endif
ifeq ($(CONFIG_RTC_MCP7941X),y)
CSRCS += mcp7941x.c
TMRDEPPATH = --dep-path timers
TMRVPATH = :timers
endif
ifeq ($(CONFIG_RTC_ARCH),y)
CSRCS += arch_rtc.c
TMRDEPPATH = --dep-path timers

520
drivers/timers/mcp7941x.c Normal file
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@ -0,0 +1,520 @@
/****************************************************************************
* drivers/timers/mcp7941x.c
*
* Copyright (C) 2019 Abdelatif Guettouche. All rights reserved.
* Author: 2019 Abdelatif Guettouche <abdelatif.guettouche@gmail.com>
*
* This file is a part of NuttX:
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/timers/mcp7941x.h>
#include "mcp7941x.h"
#ifdef CONFIG_RTC_MCP7941X
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* This RTC implementation supports only date/time RTC hardware */
#ifndef CONFIG_RTC_DATETIME
# error CONFIG_RTC_DATETIME must be set to use this driver
#endif
#ifdef CONFIG_RTC_HIRES
# error CONFIG_RTC_HIRES must NOT be set with this driver
#endif
#ifndef CONFIG_MCP7941X_I2C_FREQUENCY
# error CONFIG_MCP7941X_I2C_FREQUENCY is not configured
# define CONFIG_MCP7941X_I2C_FREQUENCY 400000
#endif
#if CONFIG_MCP7941X_I2C_FREQUENCY > 400000
# error CONFIG_MCP7941X_I2C_FREQUENCY is out of range
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure describes the state of the MCP7941x chip.
* Only a single RTC is supported.
*/
struct mcp7941x_dev_s
{
FAR struct i2c_master_s *i2c; /* Contained reference to the I2C bus driver. */
uint8_t addr; /* The I2C device address. */
};
/****************************************************************************
* Public Data
****************************************************************************/
/* g_rtc_enabled is set true after the RTC has successfully initialized */
volatile bool g_rtc_enabled = false;
/****************************************************************************
* Private Data
****************************************************************************/
/* The state of the MCP7941x chip. Only a single RTC is supported */
static struct mcp7941x_dev_s g_mcp7941x;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: rtc_dumptime
*
* Description:
* Show the broken out time.
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_DEBUG_RTC_INFO
static void rtc_dumptime(FAR struct tm *tp, FAR const char *msg)
{
rtcinfo("%s:\n", msg);
rtcinfo(" tm_sec: %08x\n", tp->tm_sec);
rtcinfo(" tm_min: %08x\n", tp->tm_min);
rtcinfo(" tm_hour: %08x\n", tp->tm_hour);
rtcinfo(" tm_mday: %08x\n", tp->tm_mday);
rtcinfo(" tm_mon: %08x\n", tp->tm_mon);
rtcinfo(" tm_year: %08x\n", tp->tm_year);
#if defined(CONFIG_LIBC_LOCALTIME) || defined(CONFIG_TIME_EXTENDED)
rtcinfo(" tm_wday: %08x\n", tp->tm_wday);
rtcinfo(" tm_yday: %08x\n", tp->tm_yday);
rtcinfo(" tm_isdst: %08x\n", tp->tm_isdst);
#endif
}
#else
# define rtc_dumptime(tp, msg)
#endif
/****************************************************************************
* Name: rtc_bin2bcd
*
* Description:
* Converts a 2 digit binary to BCD format
*
* Input Parameters:
* value - The byte to be converted.
*
* Returned Value:
* The value in BCD representation
*
****************************************************************************/
static uint8_t rtc_bin2bcd(int value)
{
uint8_t msbcd = 0;
while (value >= 10)
{
msbcd++;
value -= 10;
}
return (msbcd << 4) | value;
}
/****************************************************************************
* Name: rtc_bcd2bin
*
* Description:
* Convert from 2 digit BCD to binary.
*
* Input Parameters:
* value - The BCD value to be converted.
*
* Returned Value:
* The value in binary representation
*
****************************************************************************/
static int rtc_bcd2bin(uint8_t value)
{
int tens = ((int)value >> 4) * 10;
return tens + (value & 0x0f);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mcp7941x_rtc_initialize
*
* Description:
* Initialize the hardware RTC per the selected configuration. This
* function is called once during the OS initialization sequence by board-
* specific logic.
*
* After mcp7941x_rtc_initialize() is called, the OS function
* clock_synchronize() should also be called to synchronize the system
* timer to a hardware RTC. That operation is normally performed
* automatically by the system during clock initialization. However, when
* an external RTC is used, the board logic will need to explicitly re-
* synchronize the system timer to the RTC when the RTC becomes available.
*
* Input Parameters:
* i2c - An instance of the I2C interface used to access the MCP7941x
* device
* addr - The (7-bit) I2C address of the MCP7941x device
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
****************************************************************************/
int mcp7941x_rtc_initialize(FAR struct i2c_master_s *i2c, uint8_t addr)
{
/* Remember the i2c device and claim that the RTC is enabled */
g_mcp7941x.i2c = i2c;
g_mcp7941x.addr = addr;
g_rtc_enabled = true;
return OK;
}
/****************************************************************************
* Name: up_rtc_getdatetime
*
* Description:
* Get the current date and time from the date/time RTC. This interface
* is only supported by the date/time RTC hardware implementation.
* It is used to replace the system timer. It is only used by the RTOS
* during initialization to set up the system time when CONFIG_RTC and
* CONFIG_RTC_DATETIME are selected (and CONFIG_RTC_HIRES is not).
*
* NOTE: Some date/time RTC hardware is capability of sub-second accuracy.
* That sub-second accuracy is lost in this interface. However, since the
* system time is reinitialized on each power-up/reset, there will be no
* timing inaccuracy in the long run.
*
* Input Parameters:
* tp - The location to return the high resolution time value.
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
****************************************************************************/
int up_rtc_getdatetime(FAR struct tm *tp)
{
struct i2c_msg_s msg[4];
uint8_t secaddr;
uint8_t buffer[7];
uint8_t seconds;
int ret;
/* If this function is called before the RTC has been initialized (and it
* will be), then just return the data/time of the epoch, 12:00 am, Jan 1,
* 1970.
*/
if (!g_rtc_enabled)
{
tp->tm_sec = 0;
tp->tm_min = 0;
tp->tm_hour = 0;
#if defined(CONFIG_LIBC_LOCALTIME) || defined(CONFIG_TIME_EXTENDED)
/* Jan 1, 1970 was a Thursday */
tp->tm_wday = 4;
#endif
tp->tm_mday = 1;
tp->tm_mon = 0;
tp->tm_year = 70;
return -EAGAIN;
}
/* The start address of the read is the seconds address (0x00)
* The chip increments the address to read from after each read.
*/
secaddr = MCP7941X_REG_TIME_SEC;
msg[0].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[0].addr = g_mcp7941x.addr;
msg[0].flags = I2C_M_NOSTOP;
msg[0].buffer = &secaddr;
msg[0].length = 1;
/* Setup the read. Seven (7) registers will be read.
* (Seconds, minutes, hours, wday, date, month and year)
*/
msg[1].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[1].addr = g_mcp7941x.addr;
msg[1].flags = I2C_M_READ;
msg[1].buffer = buffer;
msg[1].length = 7;
/* Read the seconds register again */
msg[2].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[2].addr = g_mcp7941x.addr;
msg[2].flags = I2C_M_NOSTOP;
msg[2].buffer = &secaddr;
msg[2].length = 1;
msg[3].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[3].addr = g_mcp7941x.addr;
msg[3].flags = I2C_M_READ;
msg[3].buffer = &seconds;
msg[3].length = 1;
/* Perform the transfer. The transfer may be performed repeatedly of the
* seconds values decreases, meaning that was a rollover in the seconds.
*/
do
{
ret = I2C_TRANSFER(g_mcp7941x.i2c, msg, 4);
if (ret < 0)
{
rtcerr("ERROR: I2C_TRANSFER failed: %d\n", ret);
return ret;
}
}
while ((buffer[0] & MCP7941X_TIME_SEC_BCDMASK) >
(seconds & MCP7941X_TIME_SEC_BCDMASK));
/* Format the return time */
/* Return seconds (0-59) */
tp->tm_sec = rtc_bcd2bin(buffer[0] & MCP7941X_TIME_SEC_BCDMASK);
/* Return minutes (0-59) */
tp->tm_min = rtc_bcd2bin(buffer[1] & MCP7941X_TIME_MIN_BCDMASK);
/* Return hour (0-23). This assumes 24-hour time was set. */
tp->tm_hour = rtc_bcd2bin(buffer[2] & MCP7941X_TIME_HOUR_BCDMASK);
#if defined(CONFIG_LIBC_LOCALTIME) || defined(CONFIG_TIME_EXTENDED)
/* Return the day of the week (0-6) */
tp->tm_wday = (rtc_bcd2bin(buffer[3]) & MCP7941X_TIME_DAY_BCDMASK) - 1;
#endif
/* Return the day of the month (1-31) */
tp->tm_mday = rtc_bcd2bin(buffer[4] & MCP7941X_TIME_DATE_BCDMASK);
/* Return the month (0-11) */
tp->tm_mon = rtc_bcd2bin(buffer[5] & MCP7941X_TIME_MONTH_BCDMASK) - 1;
/* Return the years since 1900 */
tp->tm_year = rtc_bcd2bin(buffer[6] & MCP7941X_TIME_YEAR_BCDMASK);
rtc_dumptime(tp, "Returning");
return OK;
}
/****************************************************************************
* Name: up_rtc_settime
*
* Description:
* Set the RTC to the provided time. All RTC implementations must be able
* to set their time based on a standard timespec.
*
* Input Parameters:
* tp - the time to use
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
****************************************************************************/
int up_rtc_settime(FAR const struct timespec *tp)
{
struct i2c_msg_s msg[3];
struct tm newtm;
time_t newtime;
uint8_t buffer[8];
uint8_t secaddr;
uint8_t seconds;
int ret;
/* If this function is called before the RTC has been initialized then
* just return an error.
*/
if (!g_rtc_enabled)
{
return -EAGAIN;
}
rtcinfo("Setting time tp=(%d,%d)\n", (int)tp->tv_sec, (int)tp->tv_nsec);
/* Get the broken out time */
newtime = (time_t)tp->tv_sec;
if (tp->tv_nsec >= 500000000)
{
/* Round up */
newtime++;
}
#ifdef CONFIG_LIBC_LOCALTIME
if (localtime_r(&newtime, &newtm) == NULL)
{
rtcerr("ERROR: localtime_r failed\n");
return -EINVAL;
}
#else
if (gmtime_r(&newtime, &newtm) == NULL)
{
rtcerr("ERROR: gmtime_r failed\n");
return -EINVAL;
}
#endif
rtc_dumptime(&newtm, "New time");
/* Construct the message */
/* Write starting with the seconds register */
buffer[0] = MCP7941X_REG_TIME_SEC;
/* Save seconds (0-59) converted to BCD. And set the ST. */
buffer[1] = rtc_bin2bcd(newtm.tm_sec) | MCP7941X_TIME_SEC_ST;
/* Save minutes (0-59) converted to BCD */
buffer[2] = rtc_bin2bcd(newtm.tm_min);
/* Save hour (0-23) with 24-hour time indication */
buffer[3] = rtc_bin2bcd(newtm.tm_hour);
/* Save the day of the week (1-7) and enable VBAT. */
#if defined(CONFIG_LIBC_LOCALTIME) || defined(CONFIG_TIME_EXTENDED)
buffer[4] = rtc_bin2bcd(newtm.tm_wday + 1) | MCP7941X_TIME_DAY_VBATEN;
#else
buffer[4] = 1 | MCP7941X_TIME_DAY_VBATEN;
#endif
/* Save the day of the month (1-31) */
buffer[5] = rtc_bin2bcd(newtm.tm_mday);
/* Save the month (1-12) */
buffer[6] = rtc_bin2bcd(newtm.tm_mon + 1);
/* Save the year (00-99) */
buffer[7] = rtc_bin2bcd(newtm.tm_year);
/* Setup the I2C message */
msg[0].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[0].addr = g_mcp7941x.addr;
msg[0].flags = 0;
msg[0].buffer = buffer;
msg[0].length = 8;
/* Read back the seconds register */
secaddr = MCP7941X_REG_TIME_SEC;
msg[1].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[1].addr = g_mcp7941x.addr;
msg[1].flags = I2C_M_NOSTOP;
msg[1].buffer = &secaddr;
msg[1].length = 1;
msg[2].frequency = CONFIG_MCP7941X_I2C_FREQUENCY;
msg[2].addr = g_mcp7941x.addr;
msg[2].flags = I2C_M_READ;
msg[2].buffer = &seconds;
msg[2].length = 1;
/* Perform the transfer. This transfer will be repeated if the seconds
* count rolls over to a smaller value while writing.
*/
do
{
ret = I2C_TRANSFER(g_mcp7941x.i2c, msg, 3);
if (ret < 0)
{
rtcerr("ERROR: I2C_TRANSFER failed: %d\n", ret);
return ret;
}
}
while ((buffer[1] & MCP7941X_TIME_SEC_BCDMASK) >
(seconds & MCP7941X_TIME_SEC_BCDMASK));
return OK;
}
#endif /* CONFIG_RTC_MCP7941X */

94
drivers/timers/mcp7941x.h Normal file
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@ -0,0 +1,94 @@
/****************************************************************************
* drivers/timers/mcp7941x.h
*
* Copyright (C) 2019 Abdelatif Guettouche. All rights reserved.
* Author: 2019 Abdelatif Guettouche <abdelatif.guettouche@gmail.com>
*
* This file is a part of NuttX:
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __DRIVERS_TIMERS_MCP7941X_H
#define __DRIVERS_TIMERS_MCP7941X_H
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define MCP7941X_REG_TIME_SEC 0x00 /* Seconds register. */
# define MCP7941X_TIME_SEC_10SEC (7 << 4)
# define MCP7941X_TIME_SEC_ST (1 << 7)
# define MCP7941X_TIME_SEC_BCDMASK 0x7F
#define MCP7941X_REG_TIME_MIN 0x01 /* Minutes register. */
# define MCP7941X_TIME_MIN_10MIN (7 << 4)
# define MCP7941X_TIME_MIN_BCDMASK 0x7F
#define MCP7941X_REG_TIME_HOUR 0x02 /* Hours register. */
# define MCP7941X_TIME_HOUR_10HOUR (3 << 4)
# define MCP7941X_TIME_HOUR_AMPM (1 << 5)
# define MCP7941X_TIME_HOUR_1224 (1 << 6)
# define MCP7941X_TIME_HOUR_BCDMASK 0x3F
#define MCP7941X_REG_TIME_DAY 0x03 /* Day register. */
# define MCP7941X_TIME_DAY_VBATEN (1 << 3)
# define MCP7941X_TIME_DAY_VBAT (1 << 4)
# define MCP7941X_TIME_DAY_OSCON (1 << 5)
# define MCP7941X_TIME_DAY_BCDMASK 0x07
#define MCP7941X_REG_TIME_DATE 0x04 /* Date register. */
# define MCP7941X_TIME_DATE_10DATE (3 << 4)
# define MCP7941X_TIME_DATE_BCDMASK 0x3F
#define MCP7941X_REG_TIME_MONTH 0x05 /* Month register. */
# define MCP7941X_TIME_MONTH_10MONTH (1 << 4)
# define MCP7941X_TIME_MONTH_LP (1 << 5)
# define MCP7941X_TIME_MONTH_BCDMASK 0x1F
#define MCP7941X_REG_TIME_YEAR 0x06 /* Year register. */
# define MCP7941X_TIME_YEAR_10YEAR (15 << 4)
# define MCP7941X_TIME_YEAR_BCDMASK 0xFF
#define MCP7941X_REG_CTRL 0x07 /* Control register. */
# define MCP7941X_CTRL_RS0 (1 << 0)
# define MCP7941X_CTRL_RS1 (1 << 1)
# define MCP7941X_CTRL_RS2 (1 << 2)
# define MCP7941X_CTRL_EXTOSC (1 << 3)
# define MCP7941X_CTRL_ALM0 (1 << 4)
# define MCP7941X_CTRL_ALM1 (1 << 5)
# define MCP7941X_CTRL_SQWE (1 << 6)
# define MCP7941X_CTRL_OUT (1 << 7)
#define MCP7941X_REG_CALIB 0x08 /* Calibration register. */
#define MCP7941X_REG_ID 0x09 /* ID register. */
#endif /* __DRIVERS_TIMERS_MCP7941X_H */

97
include/nuttx/timers/mcp7941x.h Normal file
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@ -0,0 +1,97 @@
/****************************************************************************
* include/nuttx/timers/mcp7941x.h
*
* Copyright (C) 2019 Abdelatif Guettouche. All rights reserved.
* Author: 2019 Abdelatif Guettouche <abdelatif.guettouche@gmail.com>
*
* This file is a part of NuttX:
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_TIMERS_MCP7941X_H
#define __INCLUDE_NUTTX_TIMERS_MCP7941X_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_RTC_MCP7941X
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Name: mcp7941x_rtc_initialize
*
* Description:
* Initialize the hardware RTC per the selected configuration. This
* function is called once during the OS initialization sequence by board-
* specific logic.
*
* After mcp7941x_rtc_initialize() is called, the OS function
* clock_synchronize() should also be called to synchronize the system
* timer to a hardware RTC. That operation is normally performed
* automatically by the system during clock initialization. However, when
* an external RTC is used, the board logic will need to explicitly re-
* synchronize the system timer to the RTC when the RTC becomes available.
*
* Input Parameters:
* i2c - An instance of the I2C interface used to access the MCP7941x
* device
* addr - The (7-bit) I2C address of the MCP7941x device
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
****************************************************************************/
struct i2c_master_s; /* Forward reference */
int mcp7941x_rtc_initialize(FAR struct i2c_master_s *i2c, uint8_t addr);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_RTC_MCP7941X */
#endif /* __INCLUDE_NUTTX_TIMERS_MCP7941X_H */