drivers/rtc/rtc-m48t86.c

Source file repositories/reference/linux-study-clean/drivers/rtc/rtc-m48t86.c

File Facts

System
Linux kernel
Corpus path
drivers/rtc/rtc-m48t86.c
Extension
.c
Size
7749 bytes
Lines
293
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 m48t86_rtc_info {
	void __iomem *index_reg;
	void __iomem *data_reg;
};

static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
{
	struct m48t86_rtc_info *info = dev_get_drvdata(dev);
	unsigned char value;

	writeb(addr, info->index_reg);
	value = readb(info->data_reg);

	return value;
}

static void m48t86_writeb(struct device *dev,
			  unsigned char value, unsigned long addr)
{
	struct m48t86_rtc_info *info = dev_get_drvdata(dev);

	writeb(addr, info->index_reg);
	writeb(value, info->data_reg);
}

static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	unsigned char reg;

	reg = m48t86_readb(dev, M48T86_B);

	if (reg & M48T86_B_DM) {
		/* data (binary) mode */
		tm->tm_sec	= m48t86_readb(dev, M48T86_SEC);
		tm->tm_min	= m48t86_readb(dev, M48T86_MIN);
		tm->tm_hour	= m48t86_readb(dev, M48T86_HOUR) & 0x3f;
		tm->tm_mday	= m48t86_readb(dev, M48T86_DOM);
		/* tm_mon is 0-11 */
		tm->tm_mon	= m48t86_readb(dev, M48T86_MONTH) - 1;
		tm->tm_year	= m48t86_readb(dev, M48T86_YEAR) + 100;
		tm->tm_wday	= m48t86_readb(dev, M48T86_DOW);
	} else {
		/* bcd mode */
		tm->tm_sec	= bcd2bin(m48t86_readb(dev, M48T86_SEC));
		tm->tm_min	= bcd2bin(m48t86_readb(dev, M48T86_MIN));
		tm->tm_hour	= bcd2bin(m48t86_readb(dev, M48T86_HOUR) &
					  0x3f);
		tm->tm_mday	= bcd2bin(m48t86_readb(dev, M48T86_DOM));
		/* tm_mon is 0-11 */
		tm->tm_mon	= bcd2bin(m48t86_readb(dev, M48T86_MONTH)) - 1;
		tm->tm_year	= bcd2bin(m48t86_readb(dev, M48T86_YEAR)) + 100;
		tm->tm_wday	= bcd2bin(m48t86_readb(dev, M48T86_DOW));
	}

	/* correct the hour if the clock is in 12h mode */
	if (!(reg & M48T86_B_H24))
		if (m48t86_readb(dev, M48T86_HOUR) & 0x80)
			tm->tm_hour += 12;

	return 0;
}

static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned char reg;

	reg = m48t86_readb(dev, M48T86_B);

	/* update flag and 24h mode */
	reg |= M48T86_B_SET | M48T86_B_H24;
	m48t86_writeb(dev, reg, M48T86_B);

	if (reg & M48T86_B_DM) {
		/* data (binary) mode */
		m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
		m48t86_writeb(dev, tm->tm_min, M48T86_MIN);
		m48t86_writeb(dev, tm->tm_hour, M48T86_HOUR);
		m48t86_writeb(dev, tm->tm_mday, M48T86_DOM);
		m48t86_writeb(dev, tm->tm_mon + 1, M48T86_MONTH);
		m48t86_writeb(dev, tm->tm_year % 100, M48T86_YEAR);
		m48t86_writeb(dev, tm->tm_wday, M48T86_DOW);
	} else {
		/* bcd mode */
		m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
		m48t86_writeb(dev, bin2bcd(tm->tm_min), M48T86_MIN);
		m48t86_writeb(dev, bin2bcd(tm->tm_hour), M48T86_HOUR);
		m48t86_writeb(dev, bin2bcd(tm->tm_mday), M48T86_DOM);
		m48t86_writeb(dev, bin2bcd(tm->tm_mon + 1), M48T86_MONTH);
		m48t86_writeb(dev, bin2bcd(tm->tm_year % 100), M48T86_YEAR);
		m48t86_writeb(dev, bin2bcd(tm->tm_wday), M48T86_DOW);

Annotation

Implementation Notes