[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: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -23,6 +23,7 @@ I2C_CLIENT_INSMOD;
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#define DS1672_REG_CNT_BASE 0
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#define DS1672_REG_CONTROL 4
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#define DS1672_REG_CONTROL_EOSC 0x80
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#define DS1672_REG_TRICKLE 5
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@ -72,16 +73,17 @@ static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
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{
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int xfer;
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unsigned char buf[5];
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unsigned char buf[6];
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buf[0] = DS1672_REG_CNT_BASE;
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buf[1] = secs & 0x000000FF;
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buf[2] = (secs & 0x0000FF00) >> 8;
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buf[3] = (secs & 0x00FF0000) >> 16;
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buf[4] = (secs & 0xFF000000) >> 24;
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buf[5] = 0; /* set control reg to enable counting */
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xfer = i2c_master_send(client, buf, 5);
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if (xfer != 5) {
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xfer = i2c_master_send(client, buf, 6);
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if (xfer != 6) {
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dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);
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return -EIO;
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}
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@ -120,6 +122,44 @@ static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
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return ds1672_set_mmss(to_i2c_client(dev), secs);
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}
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static int ds1672_get_control(struct i2c_client *client, u8 *status)
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{
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unsigned char addr = DS1672_REG_CONTROL;
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struct i2c_msg msgs[] = {
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{ client->addr, 0, 1, &addr }, /* setup read ptr */
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{ client->addr, I2C_M_RD, 1, status }, /* read control */
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};
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/* read control register */
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if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
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dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
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return -EIO;
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}
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return 0;
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}
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/* following are the sysfs callback functions */
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static ssize_t show_control(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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char *state = "enabled";
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u8 control;
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int err;
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err = ds1672_get_control(client, &control);
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if (err)
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return err;
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if (control & DS1672_REG_CONTROL_EOSC)
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state = "disabled";
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return sprintf(buf, "%s\n", state);
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}
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static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
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static struct rtc_class_ops ds1672_rtc_ops = {
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.read_time = ds1672_rtc_read_time,
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.set_time = ds1672_rtc_set_time,
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@ -162,6 +202,7 @@ static struct i2c_driver ds1672_driver = {
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static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
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{
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int err = 0;
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u8 control;
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struct i2c_client *client;
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struct rtc_device *rtc;
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@ -202,6 +243,20 @@ static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
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i2c_set_clientdata(client, rtc);
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/* read control register */
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err = ds1672_get_control(client, &control);
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if (err) {
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dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
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goto exit_detach;
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}
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if (control & DS1672_REG_CONTROL_EOSC)
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dev_warn(&client->dev, "Oscillator not enabled. "
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"Set time to enable.\n");
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/* Register sysfs hooks */
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device_create_file(&client->dev, &dev_attr_control);
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return 0;
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exit_detach:
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