[rtc-linux] [PATCH 2/3] RTC/PCF85063: fix time/date reading (part II)
From: Juergen Borleis <hidden>
Date: 2015-12-07 13:49:31
Also in:
lkml
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
Use the function to read the whole time/date register in one turn and now check if the RTC signals an invalid time/date (due to a battery power loss for example). In this case ignore the time/date until it is really set again. Signed-off-by: Juergen Borleis <redacted> --- drivers/rtc/rtc-pcf85063.c | 45 +++++++++++++++++++-------------------------- 1 file changed, 19 insertions(+), 26 deletions(-)
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 75f2866..abed934 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c@@ -22,6 +22,7 @@ #define PCF85063_REG_CTRL2 0x01 #define PCF85063_REG_SC 0x04 /* datetime */ +#define PCF85063_REG_SC_OS 0x80 #define PCF85063_REG_MN 0x05 #define PCF85063_REG_HR 0x06 #define PCF85063_REG_DM 0x07
@@ -77,39 +78,31 @@ static int pcf85063_read_time(struct i2c_client *client, u8 *buf, u16 size) */ static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm) { + int rc; struct pcf85063 *pcf85063 = i2c_get_clientdata(client); - unsigned char buf[13] = { PCF85063_REG_CTRL1 }; - struct i2c_msg msgs[] = { - {/* setup read ptr */ - .addr = client->addr, - .len = 1, - .buf = buf - }, - {/* read status + date */ - .addr = client->addr, - .flags = I2C_M_RD, - .len = 13, - .buf = buf - }, - }; + u8 regs[7]; - /* read registers */ - if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { - dev_err(&client->dev, "%s: read error\n", __func__); - return -EIO; + rc = pcf85063_read_time(client, regs, sizeof(regs)); + if (rc < 0) + return rc; + + /* if the clock has lost its power it makes no sense to use its time */ + if (regs[0] & PCF85063_REG_SC_OS) { + dev_warn(&client->dev, "Power loss detected, invalid time\n"); + return -EINVAL; } - tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F); - tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F); - tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */ - tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F); - tm->tm_wday = buf[PCF85063_REG_DW] & 0x07; - tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ - tm->tm_year = bcd2bin(buf[PCF85063_REG_YR]); + tm->tm_sec = bcd2bin(regs[0] & 0x7F); + tm->tm_min = bcd2bin(regs[1] & 0x7F); + tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */ + tm->tm_mday = bcd2bin(regs[3] & 0x3F); + tm->tm_wday = regs[4] & 0x07; + tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */ + tm->tm_year = bcd2bin(regs[6]); if (tm->tm_year < 70) tm->tm_year += 100; /* assume we are in 1970...2069 */ /* detect the polarity heuristically. see note above. */ - pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ? + pcf85063->c_polarity = (regs[5] & PCF85063_MO_C) ? (tm->tm_year >= 100) : (tm->tm_year < 100); return rtc_valid_tm(tm);
--
2.6.2
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