#define DRV_VERSION "0.0.1"
#define PCF85063_REG_CTRL1 0x00 /* status */
+#define PCF85063_REG_CTRL1_STOP BIT(5)
#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
#define PCF85063_REG_MO 0x09
#define PCF85063_REG_YR 0x0A
-#define PCF85063_MO_C 0x80 /* century */
-
static struct i2c_driver pcf85063_driver;
struct pcf85063 {
struct rtc_device *rtc;
- int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
int voltage_low; /* indicates if a low_voltage was detected */
};
+static int pcf85063_stop_clock(struct i2c_client *client, u8 *ctrl1)
+{
+ s32 ret;
+
+ ret = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to stop the clock\n");
+ return -EIO;
+ }
+
+ /* stop the clock */
+ ret |= PCF85063_REG_CTRL1_STOP;
+
+ ret = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ret);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failing to stop the clock\n");
+ return -EIO;
+ }
+
+ *ctrl1 = ret;
+
+ return 0;
+}
+
/*
* In the routines that deal directly with the pcf85063 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
- 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__);
+ int rc;
+ 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]);
+ /* 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(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) ?
- (tm->tm_year >= 100) : (tm->tm_year < 100);
return rtc_valid_tm(tm);
}
static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
- int i = 0, err = 0;
- unsigned char buf[11];
+ int rc;
+ u8 regs[8];
- /* Control & status */
- buf[PCF85063_REG_CTRL1] = 0;
- buf[PCF85063_REG_CTRL2] = 5;
+ /*
+ * to accurately set the time, reset the divider chain and keep it in
+ * reset state until all time/date registers are written
+ */
+ rc = pcf85063_stop_clock(client, ®s[7]);
+ if (rc != 0)
+ return rc;
/* hours, minutes and seconds */
- buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F;
+ regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */
- buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min);
- buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour);
+ regs[1] = bin2bcd(tm->tm_min);
+ regs[2] = bin2bcd(tm->tm_hour);
/* Day of month, 1 - 31 */
- buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday);
+ regs[3] = bin2bcd(tm->tm_mday);
/* Day, 0 - 6 */
- buf[PCF85063_REG_DW] = tm->tm_wday & 0x07;
+ regs[4] = tm->tm_wday & 0x07;
/* month, 1 - 12 */
- buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1);
+ regs[5] = bin2bcd(tm->tm_mon + 1);
/* year and century */
- buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100);
-
- /* write register's data */
- for (i = 0; i < sizeof(buf); i++) {
- unsigned char data[2] = { i, buf[i] };
-
- err = i2c_master_send(client, data, sizeof(data));
- if (err != sizeof(data)) {
- dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n",
- __func__, err, data[0], data[1]);
- return -EIO;
- }
+ regs[6] = bin2bcd(tm->tm_year % 100);
+
+ /*
+ * after all time/date registers are written, let the 'address auto
+ * increment' feature wrap around and write register CTRL1 to re-enable
+ * the clock divider chain again
+ */
+ regs[7] &= ~PCF85063_REG_CTRL1_STOP;
+
+ /* write all registers at once */
+ rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
+ sizeof(regs), regs);
+ if (rc < 0) {
+ dev_err(&client->dev, "date/time register write error\n");
+ return rc;
}
return 0;
projects / cascardo / linux.git / blobdiff