drivers/rtc/rtc-max8998.c

Source file repositories/reference/linux-study-clean/drivers/rtc/rtc-max8998.c

File Facts

System
Linux kernel
Corpus path
drivers/rtc/rtc-max8998.c
Extension
.c
Size
7756 bytes
Lines
322
Domain
Driver Families
Bucket
drivers/rtc
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct max8998_rtc_info {
	struct device		*dev;
	struct max8998_dev	*max8998;
	struct i2c_client	*rtc;
	struct rtc_device	*rtc_dev;
	int irq;
	bool lp3974_bug_workaround;
};

static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
{
	tm->tm_sec = bcd2bin(data[RTC_SEC]);
	tm->tm_min = bcd2bin(data[RTC_MIN]);
	if (data[RTC_HOUR] & HOUR_12) {
		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
		if (data[RTC_HOUR] & HOUR_PM)
			tm->tm_hour += 12;
	} else
		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);

	tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
	tm->tm_mday = bcd2bin(data[RTC_DATE]);
	tm->tm_mon = bcd2bin(data[RTC_MONTH]);
	tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
	tm->tm_year -= 1900;
}

static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
{
	data[RTC_SEC] = bin2bcd(tm->tm_sec);
	data[RTC_MIN] = bin2bcd(tm->tm_min);
	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
	data[RTC_WEEKDAY] = tm->tm_wday;
	data[RTC_DATE] = bin2bcd(tm->tm_mday);
	data[RTC_MONTH] = bin2bcd(tm->tm_mon);
	data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
	data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
}

static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct max8998_rtc_info *info = dev_get_drvdata(dev);
	u8 data[8];
	int ret;

	ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
	if (ret < 0)
		return ret;

	max8998_data_to_tm(data, tm);

	return 0;
}

static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct max8998_rtc_info *info = dev_get_drvdata(dev);
	u8 data[8];
	int ret;

	max8998_tm_to_data(tm, data);

	ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);

	if (info->lp3974_bug_workaround)
		msleep(2000);

	return ret;
}

static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct max8998_rtc_info *info = dev_get_drvdata(dev);
	u8 data[8];
	u8 val;
	int ret;

	ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
	if (ret < 0)
		return ret;

	max8998_data_to_tm(data, &alrm->time);

	ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
	if (ret < 0)
		return ret;

	alrm->enabled = !!val;

	ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);

Annotation

Implementation Notes