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hwmon: (lm85) Add support for ADT7468 high-frequency PWM mode 

The ADT7468 supports a high-frequency PWM output mode where all PWM
outputs are driven by a 22.5 kHz clock. Add support for this mode, and
document it, as it may surprise the user that setting one PWM output
frequency also affects the other PWM outputs.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
This commit is contained in:
Jean Delvare 2010-10-28 20:31:50 +02:00 committed by Jean Delvare
parent c36364dbf3
commit f6c61cff8b
2 changed files with 35 additions and 7 deletions
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7
Documentation/hwmon/lm85
View File

@ -101,6 +101,13 @@ Devices has confirmed this "bug". The ADT7463 is reported to work as
described in the documentation. The current lm85 driver does not show the
offset register.
The ADT7468 has a high-frequency PWM mode, where all PWM outputs are
driven by a 22.5 kHz clock. This is a global mode, not per-PWM output,
which means that setting any PWM frequency above 11.3 kHz will switch
all 3 PWM outputs to a 22.5 kHz frequency. Conversely, setting any PWM
frequency below 11.3 kHz will switch all 3 PWM outputs to a frequency
between 10 and 100 Hz, which can then be tuned separately.
See the vendor datasheets for more information. There is application note
from National (AN-1260) with some additional information about the LM85.
The Analog Devices datasheet is very detailed and describes a procedure for

35
drivers/hwmon/lm85.c
View File

@ -64,9 +64,12 @@ enum chips {
#define LM85_REG_VERSTEP 0x3f
#define ADT7468_REG_CFG5 0x7c
#define ADT7468_OFF64 0x01
#define ADT7468_OFF64 (1 << 0)
#define ADT7468_HFPWM (1 << 1)
#define IS_ADT7468_OFF64(data) \
((data)->type == adt7468 && !((data)->cfg5 & ADT7468_OFF64))
#define IS_ADT7468_HFPWM(data) \
((data)->type == adt7468 && !((data)->cfg5 & ADT7468_HFPWM))
/* These are the recognized values for the above regs */
#define LM85_COMPANY_NATIONAL 0x01
@ -567,8 +570,14 @@ static ssize_t show_pwm_freq(struct device *dev,
{
int nr = to_sensor_dev_attr(attr)->index;
struct lm85_data *data = lm85_update_device(dev);
return sprintf(buf, "%d\n", FREQ_FROM_REG(data->freq_map,
data->pwm_freq[nr]));
int freq;
if (IS_ADT7468_HFPWM(data))
freq = 22500;
else
freq = FREQ_FROM_REG(data->freq_map, data->pwm_freq[nr]);
return sprintf(buf, "%d\n", freq);
}
static ssize_t set_pwm_freq(struct device *dev,
@ -580,10 +589,22 @@ static ssize_t set_pwm_freq(struct device *dev,
long val = simple_strtol(buf, NULL, 10);
mutex_lock(&data->update_lock);
data->pwm_freq[nr] = FREQ_TO_REG(data->freq_map, val);
lm85_write_value(client, LM85_REG_AFAN_RANGE(nr),
(data->zone[nr].range << 4)
| data->pwm_freq[nr]);
/* The ADT7468 has a special high-frequency PWM output mode,
* where all PWM outputs are driven by a 22.5 kHz clock.
* This might confuse the user, but there's not much we can do. */
if (data->type == adt7468 && val >= 11300) { /* High freq. mode */
data->cfg5 &= ~ADT7468_HFPWM;
lm85_write_value(client, ADT7468_REG_CFG5, data->cfg5);
} else { /* Low freq. mode */
data->pwm_freq[nr] = FREQ_TO_REG(data->freq_map, val);
lm85_write_value(client, LM85_REG_AFAN_RANGE(nr),
(data->zone[nr].range << 4)
| data->pwm_freq[nr]);
if (data->type == adt7468) {
data->cfg5 |= ADT7468_HFPWM;
lm85_write_value(client, ADT7468_REG_CFG5, data->cfg5);
}
}
mutex_unlock(&data->update_lock);
return count;
}