Commit 31d4d33e authored by Juergen Borleis's avatar Juergen Borleis Committed by Alexandre Belloni
Browse files

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: default avatarJuergen Borleis <jbe@pengutronix.de>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 6cc4c8b1

drivers/rtc/rtc-pcf85063.c

+55 −23
Original line number Diff line number Diff line
@@ -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;