drivers/rtc/rtc-bq4802.c

Source file repositories/reference/linux-study-clean/drivers/rtc/rtc-bq4802.c

File Facts

System
Linux kernel
Corpus path
drivers/rtc/rtc-bq4802.c
Extension
.c
Size
4267 bytes
Lines
203
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 bq4802 {
	void __iomem		*regs;
	unsigned long		ioport;
	struct rtc_device	*rtc;
	spinlock_t		lock;
	struct resource		*r;
	u8 (*read)(struct bq4802 *, int);
	void (*write)(struct bq4802 *, int, u8);
};

static u8 bq4802_read_io(struct bq4802 *p, int off)
{
	return inb(p->ioport + off);
}

static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
{
	outb(val, p->ioport + off);
}

static u8 bq4802_read_mem(struct bq4802 *p, int off)
{
	return readb(p->regs + off);
}

static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
{
	writeb(val, p->regs + off);
}

static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
{
	struct bq4802 *p = dev_get_drvdata(dev);
	unsigned long flags;
	unsigned int century;
	u8 val;

	spin_lock_irqsave(&p->lock, flags);

	val = p->read(p, 0x0e);
	p->write(p, 0xe, val | 0x08);

	tm->tm_sec = p->read(p, 0x00);
	tm->tm_min = p->read(p, 0x02);
	tm->tm_hour = p->read(p, 0x04);
	tm->tm_mday = p->read(p, 0x06);
	tm->tm_mon = p->read(p, 0x09);
	tm->tm_year = p->read(p, 0x0a);
	tm->tm_wday = p->read(p, 0x08);
	century = p->read(p, 0x0f);

	p->write(p, 0x0e, val);

	spin_unlock_irqrestore(&p->lock, flags);

	tm->tm_sec = bcd2bin(tm->tm_sec);
	tm->tm_min = bcd2bin(tm->tm_min);
	tm->tm_hour = bcd2bin(tm->tm_hour);
	tm->tm_mday = bcd2bin(tm->tm_mday);
	tm->tm_mon = bcd2bin(tm->tm_mon);
	tm->tm_year = bcd2bin(tm->tm_year);
	tm->tm_wday = bcd2bin(tm->tm_wday);
	century = bcd2bin(century);

	tm->tm_year += (century * 100);
	tm->tm_year -= 1900;

	tm->tm_mon--;

	return 0;
}

static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
{
	struct bq4802 *p = dev_get_drvdata(dev);
	u8 sec, min, hrs, day, mon, yrs, century, val;
	unsigned long flags;
	unsigned int year;

	year = tm->tm_year + 1900;
	century = year / 100;
	yrs = year % 100;

	mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
	day = tm->tm_mday;
	hrs = tm->tm_hour;
	min = tm->tm_min;
	sec = tm->tm_sec;

	sec = bin2bcd(sec);

Annotation

Implementation Notes