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hwmon: (lm90) Move 16-bit value read to a separate function 

Move the code which aggregates two 8-bit register values into a 16-bit
value to a separate function. We'll need to do it a second time soon and
I don't want to duplicate the code.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Martyn Welch <martyn.welch@gefanuc.com>
hifive-unleashed-5.1
Jean Delvare 2008-10-17 17:51:09 +02:00 committed by Jean Delvare
parent 2e532d68a2
commit 6388a388ff
1 changed files with 42 additions and 28 deletions
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70
drivers/hwmon/lm90.c
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@ -1,7 +1,7 @@
/*
* lm90.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring
* Copyright (C) 2003-2006 Jean Delvare <khali@linux-fr.org>
* Copyright (C) 2003-2008 Jean Delvare <khali@linux-fr.org>
*
* Based on the lm83 driver. The LM90 is a sensor chip made by National
* Semiconductor. It reports up to two temperatures (its own plus up to
@ -736,6 +736,38 @@ static int lm90_remove(struct i2c_client *client)
return 0;
}
static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
{
int err;
u8 oldh, newh, l;
/*
* There is a trick here. We have to read two registers to have the
* sensor temperature, but we have to beware a conversion could occur
* inbetween the readings. The datasheet says we should either use
* the one-shot conversion register, which we don't want to do
* (disables hardware monitoring) or monitor the busy bit, which is
* impossible (we can't read the values and monitor that bit at the
* exact same time). So the solution used here is to read the high
* byte once, then the low byte, then the high byte again. If the new
* high byte matches the old one, then we have a valid reading. Else
* we have to read the low byte again, and now we believe we have a
* correct reading.
*/
if ((err = lm90_read_reg(client, regh, &oldh))
|| (err = lm90_read_reg(client, regl, &l))
|| (err = lm90_read_reg(client, regh, &newh)))
return err;
if (oldh != newh) {
err = lm90_read_reg(client, regl, &l);
if (err)
return err;
}
*value = (newh << 8) | l;
return 0;
}
static struct lm90_data *lm90_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
@ -744,7 +776,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
u8 oldh, newh, l;
u8 h, l;
dev_dbg(&client->dev, "Updating lm90 data.\n");
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)
lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
/*
* There is a trick here. We have to read two registers to
* have the remote sensor temperature, but we have to beware
* a conversion could occur inbetween the readings. The
* datasheet says we should either use the one-shot
* conversion register, which we don't want to do (disables
* hardware monitoring) or monitor the busy bit, which is
* impossible (we can't read the values and monitor that bit
* at the exact same time). So the solution used here is to
* read the high byte once, then the low byte, then the high
* byte again. If the new high byte matches the old one,
* then we have a valid reading. Else we have to read the low
* byte again, and now we believe we have a correct reading.
*/
if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
&& lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
&& lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
&& (newh == oldh
|| lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
data->temp11[0] = (newh << 8) | l;
lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
LM90_REG_R_REMOTE_TEMPL, &data->temp11[0]);
if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0
&& lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
data->temp11[1] = (newh << 8) | l;
if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0
data->temp11[1] = (h << 8) | l;
if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0
&& lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
data->temp11[2] = (newh << 8) | l;
data->temp11[2] = (h << 8) | l;
if (data->kind != max6657) {
if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
&newh) == 0
&h) == 0
&& lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
&l) == 0)
data->temp11[3] = (newh << 8) | l;
data->temp11[3] = (h << 8) | l;
}
lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);