From 7b5768486a910532885f01b9d2dad4818c8b3be1 Mon Sep 17 00:00:00 2001 From: Juergen Borleis Date: Tue, 9 Feb 2016 11:57:25 +0100 Subject: [PATCH] rtc: pcf85063: simplify code to read the current time By using i2c_smbus_read_i2c_block_data() the code is now much simpler. While at it: when reading the RTC's seconds register, all time/date registers are frozen until the RTC's year register is read. So it is important to read all time/date registers in one turn to not lose a second event. Make it more clear why the read must happen in this way. Signed-off-by: Juergen Borleis Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-pcf85063.c | 47 +++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 26 deletions(-) diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c index 63334cbeca41..7f9caee5f4ab 100644 --- a/drivers/rtc/rtc-pcf85063.c +++ b/drivers/rtc/rtc-pcf85063.c @@ -45,39 +45,34 @@ struct pcf85063 { */ 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 - }, - }; - - /* read registers */ - if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { - dev_err(&client->dev, "%s: read error\n", __func__); + u8 regs[7]; + + /* + * while reading, the time/date registers are blocked and not updated + * anymore until the access is finished. To not lose a second + * event, the access must be finished within one second. So, read all + * time/date registers in one turn. + */ + rc = i2c_smbus_read_i2c_block_data(client, PCF85063_REG_SC, + sizeof(regs), regs); + if (rc != sizeof(regs)) { + dev_err(&client->dev, "date/time register read error\n"); return -EIO; } - 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); -- 2.30.2