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rtc: pcf85063: fix time/date setting 

When setting a new time/date the RTC's clock must be stopped first, in
order to write the time/date registers in an atomic manner.
So, this change stops the clock first and then writes the time/date
registers and the clock control register (to re-enable the clock) in one
turn.

Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Juergen Borleis 2016-02-09 11:57:27 +01:00 committed by Alexandre Belloni
parent 6cc4c8b1e3
commit 31d4d33ef4
1 changed files with 53 additions and 21 deletions
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74
drivers/rtc/rtc-pcf85063.c
View File

@ -19,6 +19,7 @@
#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 */
@ -40,6 +41,30 @@ struct pcf85063 {
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.
@ -87,41 +112,48 @@ static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *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, &regs[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);
regs[6] = bin2bcd(tm->tm_year % 100);
/* write register's data */
for (i = 0; i < sizeof(buf); i++) {
unsigned char data[2] = { i, buf[i] };
/*
* 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;
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;
}
/* 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;