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>
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@ -1,7 +1,7 @@
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/*
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* lm90.c - Part of lm_sensors, Linux kernel modules for hardware
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* monitoring
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* Copyright (C) 2003-2006 Jean Delvare <khali@linux-fr.org>
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* Copyright (C) 2003-2008 Jean Delvare <khali@linux-fr.org>
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*
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* Based on the lm83 driver. The LM90 is a sensor chip made by National
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* Semiconductor. It reports up to two temperatures (its own plus up to
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@ -736,6 +736,38 @@ static int lm90_remove(struct i2c_client *client)
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return 0;
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}
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static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
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{
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int err;
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u8 oldh, newh, l;
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/*
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* There is a trick here. We have to read two registers to have the
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* sensor temperature, but we have to beware a conversion could occur
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* inbetween the readings. The datasheet says we should either use
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* the one-shot conversion register, which we don't want to do
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* (disables hardware monitoring) or monitor the busy bit, which is
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* impossible (we can't read the values and monitor that bit at the
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* exact same time). So the solution used here is to read the high
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* byte once, then the low byte, then the high byte again. If the new
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* high byte matches the old one, then we have a valid reading. Else
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* we have to read the low byte again, and now we believe we have a
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* correct reading.
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*/
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if ((err = lm90_read_reg(client, regh, &oldh))
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|| (err = lm90_read_reg(client, regl, &l))
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|| (err = lm90_read_reg(client, regh, &newh)))
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return err;
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if (oldh != newh) {
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err = lm90_read_reg(client, regl, &l);
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if (err)
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return err;
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}
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*value = (newh << 8) | l;
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return 0;
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}
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static struct lm90_data *lm90_update_device(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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@ -744,7 +776,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
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u8 oldh, newh, l;
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u8 h, l;
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dev_dbg(&client->dev, "Updating lm90 data.\n");
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lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
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@ -754,39 +786,21 @@ static struct lm90_data *lm90_update_device(struct device *dev)
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lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
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lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
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/*
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* There is a trick here. We have to read two registers to
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* have the remote sensor temperature, but we have to beware
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* a conversion could occur inbetween the readings. The
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* datasheet says we should either use the one-shot
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* conversion register, which we don't want to do (disables
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* hardware monitoring) or monitor the busy bit, which is
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* impossible (we can't read the values and monitor that bit
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* at the exact same time). So the solution used here is to
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* read the high byte once, then the low byte, then the high
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* byte again. If the new high byte matches the old one,
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* then we have a valid reading. Else we have to read the low
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* byte again, and now we believe we have a correct reading.
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*/
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
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&& lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
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&& lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
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&& (newh == oldh
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|| lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
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data->temp11[0] = (newh << 8) | l;
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lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
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LM90_REG_R_REMOTE_TEMPL, &data->temp11[0]);
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0
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&& lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
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data->temp11[1] = (newh << 8) | l;
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0
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data->temp11[1] = (h << 8) | l;
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0
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&& lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
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data->temp11[2] = (newh << 8) | l;
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data->temp11[2] = (h << 8) | l;
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if (data->kind != max6657) {
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if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
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&newh) == 0
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&h) == 0
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&& lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
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&l) == 0)
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data->temp11[3] = (newh << 8) | l;
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data->temp11[3] = (h << 8) | l;
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}
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lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
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