mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
rtc: ds1307: Fix relying on reset value for weekday
The reset value of weekday is 0x1. This is wrong since
the reset values of the day/month/year make up to Jan 1 2001.
When computed weekday comes out to be Monday. On a scale
of 1-7(Sunday - Saturday) it should be 0x2. So we should not
be relying on the reset value.
Hence compute the wday using the current date/month/year values.
Check if reset wday is any different from the computed wday,
If different then set the wday which we computed using
date/month/year values.
Document Referred:
http://ww1.microchip.com/downloads/en/DeviceDoc/20002266F.pdf
Fixes: 1d1945d261
"drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips"
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
parent
cd9b518b98
commit
e29385fab0
1 changed files with 27 additions and 1 deletions
|
@ -602,6 +602,8 @@ static const struct rtc_class_ops ds13xx_rtc_ops = {
|
|||
* Alarm support for mcp794xx devices.
|
||||
*/
|
||||
|
||||
#define MCP794XX_REG_WEEKDAY 0x3
|
||||
#define MCP794XX_REG_WEEKDAY_WDAY_MASK 0x7
|
||||
#define MCP794XX_REG_CONTROL 0x07
|
||||
# define MCP794XX_BIT_ALM0_EN 0x10
|
||||
# define MCP794XX_BIT_ALM1_EN 0x20
|
||||
|
@ -1231,13 +1233,16 @@ static int ds1307_probe(struct i2c_client *client,
|
|||
{
|
||||
struct ds1307 *ds1307;
|
||||
int err = -ENODEV;
|
||||
int tmp;
|
||||
int tmp, wday;
|
||||
struct chip_desc *chip = &chips[id->driver_data];
|
||||
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
|
||||
bool want_irq = false;
|
||||
bool ds1307_can_wakeup_device = false;
|
||||
unsigned char *buf;
|
||||
struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
|
||||
struct rtc_time tm;
|
||||
unsigned long timestamp;
|
||||
|
||||
irq_handler_t irq_handler = ds1307_irq;
|
||||
|
||||
static const int bbsqi_bitpos[] = {
|
||||
|
@ -1526,6 +1531,27 @@ static int ds1307_probe(struct i2c_client *client,
|
|||
bin2bcd(tmp));
|
||||
}
|
||||
|
||||
/*
|
||||
* Some IPs have weekday reset value = 0x1 which might not correct
|
||||
* hence compute the wday using the current date/month/year values
|
||||
*/
|
||||
ds1307_get_time(&client->dev, &tm);
|
||||
wday = tm.tm_wday;
|
||||
timestamp = rtc_tm_to_time64(&tm);
|
||||
rtc_time64_to_tm(timestamp, &tm);
|
||||
|
||||
/*
|
||||
* Check if reset wday is different from the computed wday
|
||||
* If different then set the wday which we computed using
|
||||
* timestamp
|
||||
*/
|
||||
if (wday != tm.tm_wday) {
|
||||
wday = i2c_smbus_read_byte_data(client, MCP794XX_REG_WEEKDAY);
|
||||
wday = wday & ~MCP794XX_REG_WEEKDAY_WDAY_MASK;
|
||||
wday = wday | (tm.tm_wday + 1);
|
||||
i2c_smbus_write_byte_data(client, MCP794XX_REG_WEEKDAY, wday);
|
||||
}
|
||||
|
||||
if (want_irq) {
|
||||
device_set_wakeup_capable(&client->dev, true);
|
||||
set_bit(HAS_ALARM, &ds1307->flags);
|
||||
|
|
Loading…
Reference in a new issue