drivers/rtc/rtc-wilco-ec.c

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

File Facts

System
Linux kernel
Corpus path
drivers/rtc/rtc-wilco-ec.c
Extension
.c
Size
4712 bytes
Lines
195
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 ec_rtc_read_request {
	u8 command;
	u8 reserved;
	u8 param;
} __packed;
static struct ec_rtc_read_request read_rq = {
	.command = EC_COMMAND_CMOS,
	.param = EC_CMOS_TOD_READ,
};

/**
 * struct ec_rtc_read_response - Format of RTC returned by EC.
 * @reserved: Unused byte
 * @second: Second value (0..59)
 * @minute: Minute value (0..59)
 * @hour: Hour value (0..23)
 * @day: Day value (1..31)
 * @month: Month value (1..12)
 * @year: Year value (full year % 100)
 * @century: Century value (full year / 100)
 *
 * All values are presented in binary (not BCD).
 */
struct ec_rtc_read_response {
	u8 reserved;
	u8 second;
	u8 minute;
	u8 hour;
	u8 day;
	u8 month;
	u8 year;
	u8 century;
} __packed;

/**
 * struct ec_rtc_write_request - Format of RTC sent to the EC.
 * @command: Always EC_COMMAND_CMOS
 * @reserved: Unused byte
 * @param: Always EC_CMOS_TOD_WRITE
 * @century: Century value (full year / 100)
 * @year: Year value (full year % 100)
 * @month: Month value (1..12)
 * @day: Day value (1..31)
 * @hour: Hour value (0..23)
 * @minute: Minute value (0..59)
 * @second: Second value (0..59)
 * @weekday: Day of the week (0=Saturday)
 *
 * All values are presented in BCD.
 */
struct ec_rtc_write_request {
	u8 command;
	u8 reserved;
	u8 param;
	u8 century;
	u8 year;
	u8 month;
	u8 day;
	u8 hour;
	u8 minute;
	u8 second;
	u8 weekday;
} __packed;

static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
{
	struct wilco_ec_device *ec = dev_get_drvdata(dev->parent);
	struct ec_rtc_read_response rtc;
	struct wilco_ec_message msg;
	int ret;

	memset(&msg, 0, sizeof(msg));
	msg.type = WILCO_EC_MSG_LEGACY;
	msg.request_data = &read_rq;
	msg.request_size = sizeof(read_rq);
	msg.response_data = &rtc;
	msg.response_size = sizeof(rtc);

	ret = wilco_ec_mailbox(ec, &msg);
	if (ret < 0)
		return ret;

	tm->tm_sec	= rtc.second;
	tm->tm_min	= rtc.minute;
	tm->tm_hour	= rtc.hour;
	tm->tm_mday	= rtc.day;
	tm->tm_mon	= rtc.month - 1;
	tm->tm_year	= rtc.year + (rtc.century * 100) - 1900;
	/* Ignore other tm fields, man rtc says userspace shouldn't use them. */

Annotation

Implementation Notes