aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/lm90.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/hwmon/lm90.c')
-rw-r--r--drivers/hwmon/lm90.c72
1 files changed, 43 insertions, 29 deletions
diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index c24fe36ac787..73a1c622fb7a 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -1,7 +1,7 @@
1/* 1/*
2 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware 2 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring 3 * monitoring
4 * Copyright (C) 2003-2006 Jean Delvare <khali@linux-fr.org> 4 * Copyright (C) 2003-2008 Jean Delvare <khali@linux-fr.org>
5 * 5 *
6 * Based on the lm83 driver. The LM90 is a sensor chip made by National 6 * Based on the lm83 driver. The LM90 is a sensor chip made by National
7 * Semiconductor. It reports up to two temperatures (its own plus up to 7 * Semiconductor. It reports up to two temperatures (its own plus up to
@@ -736,6 +736,38 @@ static int lm90_remove(struct i2c_client *client)
736 return 0; 736 return 0;
737} 737}
738 738
739static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
740{
741 int err;
742 u8 oldh, newh, l;
743
744 /*
745 * There is a trick here. We have to read two registers to have the
746 * sensor temperature, but we have to beware a conversion could occur
747 * inbetween the readings. The datasheet says we should either use
748 * the one-shot conversion register, which we don't want to do
749 * (disables hardware monitoring) or monitor the busy bit, which is
750 * impossible (we can't read the values and monitor that bit at the
751 * exact same time). So the solution used here is to read the high
752 * byte once, then the low byte, then the high byte again. If the new
753 * high byte matches the old one, then we have a valid reading. Else
754 * we have to read the low byte again, and now we believe we have a
755 * correct reading.
756 */
757 if ((err = lm90_read_reg(client, regh, &oldh))
758 || (err = lm90_read_reg(client, regl, &l))
759 || (err = lm90_read_reg(client, regh, &newh)))
760 return err;
761 if (oldh != newh) {
762 err = lm90_read_reg(client, regl, &l);
763 if (err)
764 return err;
765 }
766 *value = (newh << 8) | l;
767
768 return 0;
769}
770
739static struct lm90_data *lm90_update_device(struct device *dev) 771static struct lm90_data *lm90_update_device(struct device *dev)
740{ 772{
741 struct i2c_client *client = to_i2c_client(dev); 773 struct i2c_client *client = to_i2c_client(dev);
@@ -744,7 +776,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
744 mutex_lock(&data->update_lock); 776 mutex_lock(&data->update_lock);
745 777
746 if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) { 778 if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
747 u8 oldh, newh, l; 779 u8 h, l;
748 780
749 dev_dbg(&client->dev, "Updating lm90 data.\n"); 781 dev_dbg(&client->dev, "Updating lm90 data.\n");
750 lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]); 782 lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
@@ -754,39 +786,21 @@ static struct lm90_data *lm90_update_device(struct device *dev)
754 lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]); 786 lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
755 lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst); 787 lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
756 788
757 /* 789 lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
758 * There is a trick here. We have to read two registers to 790 LM90_REG_R_REMOTE_TEMPL, &data->temp11[0]);
759 * have the remote sensor temperature, but we have to beware 791
760 * a conversion could occur inbetween the readings. The 792 if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0
761 * datasheet says we should either use the one-shot
762 * conversion register, which we don't want to do (disables
763 * hardware monitoring) or monitor the busy bit, which is
764 * impossible (we can't read the values and monitor that bit
765 * at the exact same time). So the solution used here is to
766 * read the high byte once, then the low byte, then the high
767 * byte again. If the new high byte matches the old one,
768 * then we have a valid reading. Else we have to read the low
769 * byte again, and now we believe we have a correct reading.
770 */
771 if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
772 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
773 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
774 && (newh == oldh
775 || lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
776 data->temp11[0] = (newh << 8) | l;
777
778 if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
779 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0) 793 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
780 data->temp11[1] = (newh << 8) | l; 794 data->temp11[1] = (h << 8) | l;
781 if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0 795 if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0
782 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0) 796 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
783 data->temp11[2] = (newh << 8) | l; 797 data->temp11[2] = (h << 8) | l;
784 if (data->kind != max6657) { 798 if (data->kind != max6657) {
785 if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH, 799 if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
786 &newh) == 0 800 &h) == 0
787 && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL, 801 && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
788 &l) == 0) 802 &l) == 0)
789 data->temp11[3] = (newh << 8) | l; 803 data->temp11[3] = (h << 8) | l;
790 } 804 }
791 lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms); 805 lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
792 806