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>
diff --git a/Documentation/hwmon/lm85 b/Documentation/hwmon/lm85
index 83cd5bb..239258a 100644
--- a/Documentation/hwmon/lm85
+++ b/Documentation/hwmon/lm85
@@ -101,6 +101,13 @@
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
diff --git a/drivers/hwmon/lm85.c b/drivers/hwmon/lm85.c
index 2e8f0c9..1e22984 100644
--- a/drivers/hwmon/lm85.c
+++ b/drivers/hwmon/lm85.c
@@ -64,9 +64,12 @@
#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 @@
{
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 @@
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;
}