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Commit 8a95b252 authored by Kumar Gala's avatar Kumar Gala Committed by Linus Torvalds
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[PATCH] RTC subsystem: DS1672 oscillator handling 



* Always enable the oscillator when we set the time
* If the oscillator is disable when we probe the RTC report back a warning
  to the user
* Added sysfs attribute to represent the state of the oscillator

Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 389ed39b

drivers/rtc/rtc-ds1672.c

+58 −3
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ I2C_CLIENT_INSMOD; 


#define DS1672_REG_CNT_BASE	0

#define DS1672_REG_CONTROL	4

#define DS1672_REG_CONTROL_EOSC	0x80

#define DS1672_REG_TRICKLE	5
@@ -72,16 +73,17 @@ static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 
static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)

{

	int xfer;

	unsigned char buf[5];

	unsigned char buf[6];



	buf[0] = DS1672_REG_CNT_BASE;

	buf[1] = secs & 0x000000FF;

	buf[2] = (secs & 0x0000FF00) >> 8;

	buf[3] = (secs & 0x00FF0000) >> 16;

	buf[4] = (secs & 0xFF000000) >> 24;

	buf[5] = 0;	/* set control reg to enable counting */



	xfer = i2c_master_send(client, buf, 5);

	if (xfer != 5) {

	xfer = i2c_master_send(client, buf, 6);

	if (xfer != 6) {

		dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);

		return -EIO;

	}
@@ -120,6 +122,44 @@ static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 
	return ds1672_set_mmss(to_i2c_client(dev), secs);

}



static int ds1672_get_control(struct i2c_client *client, u8 *status)

{

	unsigned char addr = DS1672_REG_CONTROL;



	struct i2c_msg msgs[] = {

		{ client->addr, 0, 1, &addr },		/* setup read ptr */

		{ client->addr, I2C_M_RD, 1, status },	/* read control */

	};



	/* read control register */

	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		return -EIO;

	}



	return 0;

}



/* following are the sysfs callback functions */

static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	char *state = "enabled";

	u8 control;

	int err;



	err = ds1672_get_control(client, &control);

	if (err)

		return err;



	if (control & DS1672_REG_CONTROL_EOSC)

		state = "disabled";



	return sprintf(buf, "%s\n", state);

}



static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);



static struct rtc_class_ops ds1672_rtc_ops = {

	.read_time	= ds1672_rtc_read_time,

	.set_time	= ds1672_rtc_set_time,
@@ -162,6 +202,7 @@ static struct i2c_driver ds1672_driver = { 
static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)

{

	int err = 0;

	u8 control;

	struct i2c_client *client;

	struct rtc_device *rtc;
@@ -202,6 +243,20 @@ static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind) 


	i2c_set_clientdata(client, rtc);



	/* read control register */

	err = ds1672_get_control(client, &control);

	if (err) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		goto exit_detach;

	}



	if (control & DS1672_REG_CONTROL_EOSC)

		dev_warn(&client->dev, "Oscillator not enabled. "

					"Set time to enable.\n");



	/* Register sysfs hooks */

	device_create_file(&client->dev, &dev_attr_control);



	return 0;



exit_detach: