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Openwrt adds RTC (mcp7940 I2C bus) drive details
2022-07-27 16:01:00 【xhoufei2010】
One 、 Hardware platform
1.1 controller ：MT7620（A9 kernel ）1.2 RTC chip ：MCP7940（I2C Bus ）
Two 、 software platform
2.1、 development environment ：Ubuntu12.04
2.2、 Software version ：openwrt official 15.05 edition SDK Development kit （CHAOS CALMER 15.05 edition ）
3、 ... and 、 Functional specifications
The target chip selected in this article is MT7620,profile The choice is “Xiaomi MiWiFi Mini ”.
3.1、 stay openwrt On the system , transplant mcp7940 Of rtc Chip driver .
3.2、 stay openwrt On the system , Add to i2c Bus support .
matters needing attention ：openwrt The system is strange , stay menuconfig Configuration in progress , Configured with i2c, Still can't support . Additional modifications are required “*.dts” file , Ability to support i2c Bus .
Four 、 Operation steps
4.1 Add system for i2c Bus support
For the system, add i2c Bus support , Need modification 2 A place to
1、openwrt Add to i2c Support .
2、 modify dts file , Add to i2c Support .
[ 18.100000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.110000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.120000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.130000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.140000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.150000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.160000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)
[ 18.170000] i2c_core: exports duplicate symbol __i2c_transfer (owned by kernel)4.1.1 To configure openwrt Of I2C
stay openwrt Under the table of contents , perform “make menuconfig” command .
Enter menu Kernel modules --->I2C support --->, In the menu options , Configuration is shown in figure 4-1 Shown .
chart 4-1 I2C support
4.1.2 Configure the target chip I2C
stay openwrt Under the table of contents , perform "make kernel_menuconfig" command , Configure the target chip kernel .
Enter menu , Device Drivers ---> I2C support --->, Pictured 4-2 Shown .
chart 4-2 Target chip I2C Bus configuration
In the figure 4-2 in , choice “I2C Hardware Bus support ---> ”, To configure I2C Hardware bus support , choice “Ralink I2C Controller”, Pictured 4-3 Shown .
chart 4-3 I2C Hardware Bus support
4.1.3 modify DTS The configuration file
default openwrt System , No, right I2C Bus support , I need to modify myself DTS The configuration file . Because the chip selected in this article is MT7620A, The goal is profile The choice is “Xiaomi MiWiFi Mini”, Therefore, the document to be modified is “XIAOMI-MIWIFI-MINI.dts”
The path of the file is “openwrt/target/linux/ramips/dts/XIAOMI-MIWIFI-MINI.dts”
Before modification DTS file ：
[email protected] {
gpio0: [email protected] {
status = "okay";
};
gpio1: [email protected] {
status = "okay";
};
gpio2: [email protected] {
status = "okay";
};
[email protected] {
status = "okay";
[email protected] {
stay palmbus In nodes , increase MT7620A Yes I2C Bus and RTC Chip support , Modified DTS file ：
[email protected] {
gpio0: [email protected] {
status = "okay";
};
gpio1: [email protected] {
status = "okay";
};
gpio2: [email protected] {
status = "okay";
};
[email protected] {
compatible ="ralink,mt7620a-i2c", "ralink,rt2880-i2c";
reg= <0x900 0x100>;
resets = <&rstctrl 16>;
reset-names= "i2c";
#address-cells = <1>;
#size-cells= <0>;
status= "okay";
[email protected] {
compatible = "mcp,mcp7940";
reg = <0x6f>;
};
};
[email protected] {
status = "okay";
[email protected] {
1、[email protected] by MT7620A Of I2C node ;
2、 about MCP7940 chip , By looking up the chip manual , Know that its mailing address is 0x6f. If you need to change to another chip , Then the corresponding address 0x6f Change it to its corresponding address .
3、 about RTC The name description of also needs attention ,compatible = "mcp,mcp7940", among mcp7940 Corresponding to this article 5.1 chapter , The driver rtc_mcp7940.c pass the civil examinations 93 That's ok ,“struct i2c_device_id” in The name of . If the names don't match , Will cause the driver to execute to probe Function failed , Lead to rtc Drive load loss Defeat .
static const struct i2c_device_id mcp7940_id[] = {
{ "mcp7940", mcp7940 },
{ }
};4、 If I2C The pin of , No settings , By default, it may work in GPIO Pattern , Particular attention ！ In this paper RTC The driver , take I2C The pin of is set to I2C Pattern , So in DTS In file , No more settings I2C The working mode of the pin . If your own RTC In driver , No settings I2C Pin , Please be there. DTS Set its working as I2C Pattern , Lest it work by default GPIO In the pattern ！
[email protected] {
compatible ="ralink,mt7620a-i2c", "ralink,rt2880-i2c";
reg= <0x900 0x100>;
resets = <&rstctrl 16>;
reset-names= "i2c";
#address-cells = <1>;
#size-cells= <0>;
status= "okay";
[email protected] {
compatible = "mcp,mcp7940";
reg = <0x6f>;
};
};
If necessary, change to ds1307 chip , You just need to put rtc Address and comatible You can modify it. .ds1307 The mailing address of is 0x68, Then modify as follows ：
[email protected] {
compatible = "dallas,ds1307";
reg = <0x68>;
};4.2 Add to RTC Support for
4.2.1 modify target file
The system is in ./scripts/medatata.pl Judge and deal with RTC_SUPPORT switch , After analysis , It turned out to be target/linux/ramips/mt7620/target.mk in , Put the original content :
FEATURES+=usbIt is amended as follows :
FEATURES+=usb rtcYou can open mt7620 Yes rtc Support for . After the modification ,target.mk The contents are as follows ：
#
# Copyright (C) 2009 OpenWrt.org
#
SUBTARGET:=mt7620
BOARDNAME:=MT7620 based boards
ARCH_PACKAGES:=ramips_24kec
FEATURES+=usb rtc
CPU_TYPE:=24kec
CPU_SUBTYPE:=dsp
DEFAULT_PACKAGES += kmod-rt2800-pci kmod-rt2800-soc
define Target/Description
Build firmware images for Ralink MT7620 based boards.
endef
4.2.2 Configure the kernel RTC
1、 stay openwrt Of SDK In the development package , perform “make kernel_menuconfig” command .
In the pop-up menu “Linux/mips 3.18.29 Kernel Configuration” in , choice “Device Drivers ---> Real Time Clock --->”, Turn on RTC Function options , Pictured 4-4 Shown .
chart 4-4 Turn on RTC function
2、 Get into “ Real Time Clock--->”, Yes RTC To configure
Configuration is shown in figure 4-5 Shown , among ：
（1） Remove options “Set system time from RTC on startup and resume”, Don't start it when you start it RTC drive . Because in this article , Plan to start after , Then mount by yourself RTC drive . If it is not mounted at the beginning RTC drive , Turn on this option , An error message will appear “drivers/rtc/hctosys.c: unable to open rtc device (rtc0)”.
（2） about “RTC debug support”, It depends on personal preference , After opening , You can see RTC Debugging information for .
chart 4-5 RTC To configure
5、 ... and 、RTC Program
5.1 RTC The driver
The file name corresponding to the driver is ：rtc_mcp7940.c, The procedure is as follows ：
/*
* rtc-mcp7940.c - RTC driver for some mostly-compatible I2C chips.
*
* Copyright (C) 2005 James Chapman (ds1337 core)
* Copyright (C) 2006 David Brownell
* Copyright (C) 2009 Matthias Fuchs (rx8025 support)
*
* 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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#define RALINK_SYSCTL_BASE 0xB0000000
#define RALINK_TIMER_BASE 0xB0000100
#define RALINK_INTCL_BASE 0xB0000200
#define RALINK_SYSCTL_ADDR RALINK_SYSCTL_BASE // system control
#define RALINK_REG_GPIOMODE (RALINK_SYSCTL_ADDR + 0x60) // GPIO MODE
#define __devexit
#define __devinitdata
#define __devinit
#define __devexit_p
/* We can't determine type by probing, but if we expect pre-Linux code
* to have set the chip up as a clock (turning on the oscillator and
* setting the date and time), Linux can ignore the non-clock features.
* That's a natural job for a factory or repair bench.
*/
enum ds_type
{
mcp7940,
};
/* RTC registers don't differ much, except for the century flag */
#define MCP7940_REG_SECS 0x00 /* 00-59 */
#define MCP7940_BIT_CH 0x80
#define MCP7940_BIT_ST 0x80
#define MCP7940_REG_MIN 0x01 /* 00-59 */
#define MCP7940_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
#define MCP7940_BIT_12HR 0x40 /* in REG_HOUR */
#define MCP7940_BIT_PM 0x20 /* in REG_HOUR */
#define MCP7940_REG_WDAY 0x03 /* 01-07 */
#define MCP7940_REG_MDAY 0x04 /* 01-31 */
#define MCP7940_REG_MONTH 0x05 /* 01-12 */
#define MCP7940_REG_YEAR 0x06 /* 00-99 */
#define MCP7940_BIT_VBATEN 0x08
/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
* start at 7, and they differ a LOT. Only control and status matter for
* basic RTC date and time functionality; be careful using them.
*/
#define MCP7940_REG_CONTROL 0x07
#define MCP7940_BIT_OUT 0x80
#define MCP7940_BIT_SQWE 0x10
#define MCP7940_BIT_RS1 0x02
#define MCP7940_BIT_RS0 0x01
struct mcp7940 {
u8 offset; /* register's offset */
u8 regs[11];
enum ds_type type;
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;
struct work_struct work;
s32 (*read_block_data)(struct i2c_client *client, u8 command,
u8 length, u8 *values);
s32 (*write_block_data)(struct i2c_client *client, u8 command,
u8 length, const u8 *values);
};
struct chip_desc {
unsigned nvram56:1;
unsigned alarm:1;
};
static const struct i2c_device_id mcp7940_id[] = {
{ "mcp7940", mcp7940 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mcp7940_id);
/*----------------------------------------------------------------------*/
#define BLOCK_DATA_MAX_TRIES 10
static s32 mcp7940_read_block_data_once(struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
s32 i, data;
for (i = 0; i < length; i++) {
data = i2c_smbus_read_byte_data(client, command + i);
if (data < 0)
return data;
values[i] = data;
}
return i;
}
static s32 mcp7940_read_block_data(struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
s32 ret;
int tries = 0;
dev_dbg(&client->dev, "mcp7940_read_block_data (length=%d)\n", length);
ret = mcp7940_read_block_data_once(client, command, length, values);
if (ret < 0)
return ret;
do {
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"mcp7940_read_block_data failed\n");
return -EIO;
}
memcpy(oldvalues, values, length);
ret = mcp7940_read_block_data_once(client, command, length,
values);
if (ret < 0)
return ret;
} while (memcmp(oldvalues, values, length));
return length;
}
static s32 mcp7940_write_block_data(struct i2c_client *client, u8 command,
u8 length, const u8 *values)
{
u8 currvalues[I2C_SMBUS_BLOCK_MAX];
int tries = 0;
dev_dbg(&client->dev, "mcp7940_write_block_data (length=%d)\n", length);
do
{
s32 i, ret;
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"mcp7940_write_block_data failed\n");
return -EIO;
}
for (i = 0; i < length; i++) {
ret = i2c_smbus_write_byte_data(client, command + i,
values[i]);
if (ret < 0)
return ret;
}
ret = mcp7940_read_block_data_once(client, command, length,
currvalues);
if (ret < 0)
return ret;
} while (memcmp(currvalues, values, length));
return length;
}
static int mcp7940_get_time(struct device *dev, struct rtc_time *t)
{
struct mcp7940 *mcp7940 = dev_get_drvdata(dev);
int tmp;
/* read the RTC date and time registers all at once */
tmp = mcp7940->read_block_data(mcp7940->client,
mcp7940->offset, 7, mcp7940->regs);
if (tmp != 7) {
dev_err(dev, "%s error %d\n", "read", tmp);
return -EIO;
}
dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
"read",
mcp7940->regs[0], mcp7940->regs[1],
mcp7940->regs[2], mcp7940->regs[3],
mcp7940->regs[4], mcp7940->regs[5],
mcp7940->regs[6]);
t->tm_sec = bcd2bin(mcp7940->regs[MCP7940_REG_SECS] & 0x7f);
t->tm_min = bcd2bin(mcp7940->regs[MCP7940_REG_MIN] & 0x7f);
tmp = mcp7940->regs[MCP7940_REG_HOUR] & 0x3f;
t->tm_hour = bcd2bin(tmp);
t->tm_wday = bcd2bin(mcp7940->regs[MCP7940_REG_WDAY] & 0x07) - 1;
t->tm_mday = bcd2bin(mcp7940->regs[MCP7940_REG_MDAY] & 0x3f);
tmp = mcp7940->regs[MCP7940_REG_MONTH] & 0x1f;
t->tm_mon = bcd2bin(tmp) - 1;
/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
t->tm_year = bcd2bin(mcp7940->regs[MCP7940_REG_YEAR]) + 100;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"read", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
/* initial clock setting can be undefined */
return rtc_valid_tm(t);
}
static int mcp7940_set_time(struct device *dev, struct rtc_time *t)
{
struct mcp7940 *mcp7940 = dev_get_drvdata(dev);
int result;
int tmp;
u8 *buf = mcp7940->regs;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"write", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
buf[MCP7940_REG_SECS] = bin2bcd(t->tm_sec);
buf[MCP7940_REG_MIN] = bin2bcd(t->tm_min);
buf[MCP7940_REG_HOUR] = bin2bcd(t->tm_hour);
buf[MCP7940_REG_WDAY] = bin2bcd(t->tm_wday + 1);
buf[MCP7940_REG_MDAY] = bin2bcd(t->tm_mday);
buf[MCP7940_REG_MONTH] = bin2bcd(t->tm_mon + 1);
/* assume 20YY not 19YY */
tmp = t->tm_year - 100;
buf[MCP7940_REG_YEAR] = bin2bcd(tmp);
buf[MCP7940_REG_SECS] |= MCP7940_BIT_ST;
buf[MCP7940_REG_WDAY] |= MCP7940_BIT_VBATEN;
dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
"write", buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);
result = mcp7940->write_block_data(mcp7940->client,
mcp7940->offset, 7, buf);
if (result < 0)
{
dev_err(dev, "%s error %d\n", "write", result);
return result;
}
return 0;
}
static int mcp7940_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct rtc_time time;
void __user *uarg = (void __user *) arg;
switch (cmd)
{
case RTC_RD_TIME:
mcp7940_get_time(dev, &time);
if (copy_to_user(uarg, &time, sizeof(time)))
{
printk("RTC_RD_TIME error, can not copy to user\n");
return -EFAULT;
}
break;
case RTC_SET_TIME:
if (copy_from_user(&time, uarg, sizeof(time)))
{
printk("RTC_SET_TIME error, can not copy from user\n");
return -EFAULT;
}
mcp7940_set_time(dev, &time);
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static const struct rtc_class_ops mcp7940_rtc_ops =
{
.read_time = mcp7940_get_time,
.set_time = mcp7940_set_time,
.ioctl = mcp7940_ioctl,
};
/*----------------------------------------------------------------------*/
static struct i2c_driver mcp7940_driver;
static int __devinit mcp7940_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mcp7940 *mcp7940;
int err = -ENODEV;
int tmp;
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
unsigned char *buf;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
return -EIO;
if (!(mcp7940 = kzalloc(sizeof(struct mcp7940), GFP_KERNEL)))
return -ENOMEM;
i2c_set_clientdata(client, mcp7940);
mcp7940->client = client;
mcp7940->type = id->driver_data;
mcp7940->offset = 0;
buf = mcp7940->regs;
if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
mcp7940->read_block_data = i2c_smbus_read_i2c_block_data;
mcp7940->write_block_data = i2c_smbus_write_i2c_block_data;
} else {
mcp7940->read_block_data = mcp7940_read_block_data;
mcp7940->write_block_data = mcp7940_write_block_data;
}
read_rtc:
/* read RTC registers */
tmp = mcp7940->read_block_data(mcp7940->client, 0, 8, buf);
if (tmp != 8)
{
pr_debug("read error %d\n", tmp);
err = -EIO;
goto exit_free;
}
/* minimal sanity checking; some chips (like DS1340) don't
* specify the extra bits as must-be-zero, but there are
* still a few values that are clearly out-of-range.
*/
tmp = mcp7940->regs[MCP7940_REG_SECS];
/* make sure that the backup battery is enabled */
if (!(mcp7940->regs[MCP7940_REG_WDAY] & MCP7940_BIT_VBATEN)) {
i2c_smbus_write_byte_data(client, MCP7940_REG_WDAY,
mcp7940->regs[MCP7940_REG_WDAY]
| MCP7940_BIT_VBATEN);
}
/* clock halted? turn it on, so clock can tick. */
if (!(tmp & MCP7940_BIT_ST)) {
i2c_smbus_write_byte_data(client, MCP7940_REG_SECS,
MCP7940_BIT_ST);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
tmp = mcp7940->regs[MCP7940_REG_HOUR];
switch (mcp7940->type) {
default:
if (!(tmp & MCP7940_BIT_12HR))
break;
/* Be sure we're in 24 hour mode. Multi-master systems
* take note...
*/
tmp = bcd2bin(tmp & 0x1f);
if (tmp == 12)
tmp = 0;
if (mcp7940->regs[MCP7940_REG_HOUR] & MCP7940_BIT_PM)
tmp += 12;
i2c_smbus_write_byte_data(client,
MCP7940_REG_HOUR,
bin2bcd(tmp));
}
mcp7940->rtc = rtc_device_register(client->name, &client->dev,
&mcp7940_rtc_ops, THIS_MODULE);
if (IS_ERR(mcp7940->rtc)) {
err = PTR_ERR(mcp7940->rtc);
dev_err(&client->dev,
"unable to register the class device\n");
goto exit_free;
}
return 0;
exit_free:
kfree(mcp7940);
return err;
}
static int __devexit mcp7940_remove(struct i2c_client *client)
{
struct mcp7940 *mcp7940 = i2c_get_clientdata(client);
rtc_device_unregister(mcp7940->rtc);
kfree(mcp7940);
return 0;
}
static struct i2c_driver mcp7940_driver =
{
.driver =
{
.name = "rtc-mcp7940",
.owner = THIS_MODULE,
},
.probe = mcp7940_probe,
.remove = __devexit_p(mcp7940_remove),
.id_table = mcp7940_id,
};
static void rtc_pin_mux_init(void)
{
u32 mode = 0;
mode = le32_to_cpu(*(volatile u32 *)(RALINK_REG_GPIOMODE));
mode &= ~(0x1 << 0); // I2C_GPIO_MODE Pin , Set to I2C Pattern , namely I2C_SD(GPIO#1)I2C_SCLK(GPIO#2) Set to I2C Pattern
*(volatile u32 *)(RALINK_REG_GPIOMODE) = cpu_to_le32(mode);
}
static int __init mcp7940_init(void)
{
rtc_pin_mux_init();
return i2c_add_driver(&mcp7940_driver);
}
module_init(mcp7940_init);
static void __exit mcp7940_exit(void)
{
i2c_del_driver(&mcp7940_driver);
}
module_exit(mcp7940_exit);
MODULE_AUTHOR("sky.houfei");
MODULE_DESCRIPTION("RTC driver for MCP7940");
MODULE_LICENSE("GPL");
5.2 RTC Driven makefile
makefile The name is makefile
############################## mcp7940 rtc driver makefile #########################
obj-m = rtc_mcp7940.o
TARGET_NAME=rtc_mcp7940.ko
PWD=$(shell pwd)
KERNEL_DIR?=/home/sky/develop/openWrt/openwrt/build_dir/target-mipsel_24kec+dsp_glibc-2.21/linux-ramips_mt7620/linux-3.18.29/
TOOL_CAHIN="/home/sky/develop/openWrt/openwrt/staging_dir/toolchain-mipsel_24kec+dsp_gcc-4.8-linaro_glibc-2.21/bin/mipsel-openwrt-linux-gnu-"
OUTPUT_DIR=$(PWD)/../../build_openwrt/mnt/sau2ag1/
###############################################################################
all:
make -C $(KERNEL_DIR) \
ARCH=mips \
CROSS_COMPILE=$(TOOL_CAHIN) \
M=$(PWD) \
modules
clean:
rm -f $(obj-m)
rm -f *.mod.c
rm -f *.mod.o
rm -f *.order
rm -f *.sysvers
#make command:
#make
#make clean
5.3 RTC Applications
mcp7940 The application is rtc_app.c, Application , The storage time is UTC Format time .
about UTC Time ,year = year -1900, month = month -1, The application is as follows .
/*
* Real Time Clock Driver Test/Example Program
*
* Compile with:
* gcc -s -Wall -Wstrict-prototypes rtctest.c -o rtctest
*
* Copyright (C) 1996, Paul Gortmaker.
*
* Released under the GNU General Public License, version 2,
* included herein by reference.
*
*/
#include <stdio.h>
#include <linux/rtc.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
/*
* This expects the new RTC class driver framework, working with
* clocks that will often not be clones of what the PC-AT had.
* Use the command line to specify another RTC if you need one.
*/
static const char default_rtc[] = "/dev/rtc0";
int main(int argc, char **argv)
{
int i, fd, retval, irqcount = 0;
unsigned int cmd = 0;
unsigned long tmp, data;
struct rtc_time rtc_tm;
const char *rtc = default_rtc;
fd = open(default_rtc, O_RDONLY);
if (fd == -1)
{
printf("Can not open %s, exit the app\n", default_rtc);
}
rtc_tm.tm_year = 2015 - 1900;
rtc_tm.tm_mon = 10;
rtc_tm.tm_mday = 28;
rtc_tm.tm_wday = 3;
rtc_tm.tm_hour = 15;
rtc_tm.tm_min = 22;
rtc_tm.tm_sec = 10;
i = atoi(argv[1]);
switch(i)
{
case 1:
cmd = RTC_RD_TIME;
break;
case 2:
cmd = RTC_SET_TIME;
printf( "app set time %d-%d-%d week%d, %02d:%02d:%02d.\n",
rtc_tm.tm_year + 1900, rtc_tm.tm_mon, rtc_tm.tm_mday, rtc_tm.tm_wday,
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);
break;
default:
cmd = RTC_RD_TIME;
break;
}
retval = ioctl(fd, cmd, &rtc_tm);
if (retval == -1)
{
printf("ioctl cmd = %d, error, exit the rtc app\n");
exit(errno);
}
printf( "rtc app date/time is %d-%d-%d week%d, %02d:%02d:%02d.\n",
rtc_tm.tm_year + 1900, rtc_tm.tm_mon, rtc_tm.tm_mday, rtc_tm.tm_wday,
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);
close(fd);
printf("rtc test end\n");
return 0;
}
6、 ... and 、RTC FAQ analysis
6.1 View yes i2c Whether the bus is on
stay MT7620 Development board , Enter the command "ls /dev/i2c*", Pictured 6-1 Shown . You can see that in the diagram i2c-0, explain I2C The bus has been turned on .
6.2 see I2C Bus supported slaves device
stay MT7620 Development board , Enter the command “ls /sys/bus/i2c/devices/”, Pictured 6-2 Shown .
In the figure 6-2 in , You can see the support 0x006f The slave device （mcp7940 The address of the chip is just 0x6f）.
chart 6-2 see I2C Bus supported slaves device
explain ： If you don't see d0x006f Or other than i2c-0 Other equipment , shows i2c Bus does not support device Slave , At this point any i2c chip ( Slave device) Mount to MT7620 On , It is impossible to communicate , Because the mainframe （MT620 chip ） The address of the slave is not supported . You need to check 4.1.3 chapter ,dts Whether the document is modified correctly .
6.3 see i2c Bus mounted driver
stay MT7620 Development board , Enter the command “ls /sys/bus/i2c/drivers/”, Pictured 6-3 Shown . It can be seen from the picture that , The device has successfully rtc-mcp7940 The driver is mounted to i2c Bus .
chart 6-3 see i2c Bus mounted driver
explain ： If you don't see rtc-mcp7940, shows rtc There is a problem with the driver of , Need to check 5.1 Chapter driver .
6.4 see rtc equipment
stay MT7620 Development board , Enter the command “ls /dev/rtc*”, Pictured 6-4 Shown . It can be seen from the picture that ,rtc The drive has been successful , You can see rtc equipment .
chart 6-4 see rtc equipment
explain ： If you don't see rtc0 Or something rtc equipment , shows rtc There is a problem with the configuration of , The system does not support rtc, Need to check 4.2 Chapter rtc To configure .
7、 test
1、 mount rtc drive
rtc The compiled driver name is rtc_mcp7940, Execution mount , The message is as follows , explain rtc Successfully mounted in 0-006f Under the node , And registered as /dev/rtc0：
[email protected]:/tmp# insmod ./rtc_mcp7940.ko
[ 203.740000] rtc-mcp7940 0-006f: rtc core: registered mcp7940 as rtc0
[email protected]:/tmp# 2、 function rtc The test program
Set the time first , After setting up , Read again rtc Time , It is found that the normal reading and writing time , And right . And restart the device , After reboot ,rtc The time is also timed normally , During restart , Time is not lost or stopped .
[email protected]:/tmp# ./rtc_app_openwrt 2
app set time 2015-10-28 week3, 15:22:10.
rtc app date/time is 2015-10-28 week3, 15:22:10.
rtc test end
[email protected]:/tmp# ./rtc_app_openwrt 1
rtc app date/time is 2015-10-28 week3, 15:22:26.
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