By default the PWM duty cycle in hardware is 100%. On some systems this
can cause unwanted fan noise. Add the ability to take an initial PWM
duty cycle and frequency via device properties.
Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
---
Notes:
Changes in v2:
- Use correct device property string for frequency
- Allow -EINVAL and only warn on error
- Use a frequency of 0 to indicate that the hardware should be left as-is
drivers/hwmon/adt7475.c | 58 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 4224ffb30483..14bd618488f8 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -1662,6 +1662,56 @@ static int adt7475_set_pwm_polarity(struct i2c_client *client)
return 0;
}
+static int adt7475_set_pwm_initial_freq(struct i2c_client *client)
+{
+ int ret, out, i;
+ u32 freqs[ADT7475_PWM_COUNT];
+ int data;
+
+ ret = device_property_read_u32_array(&client->dev,
+ "adi,pwm-initial-frequency", freqs,
+ ARRAY_SIZE(freqs));
+ if (ret)
+ return ret;
+
+ for (i = 0; i < ADT7475_PWM_COUNT; i++) {
+ if (!freqs[i])
+ continue;
+ out = find_closest(freqs[i], pwmfreq_table, ARRAY_SIZE(pwmfreq_table));
+ data = adt7475_read(TEMP_TRANGE_REG(i));
+ if (data < 0)
+ return data;
+ data &= ~0xf;
+ data |= out;
+
+ ret = i2c_smbus_write_byte_data(client, TEMP_TRANGE_REG(i), data);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int adt7475_set_pwm_initial_duty(struct i2c_client *client)
+{
+ int ret, i;
+ u32 dutys[ADT7475_PWM_COUNT];
+
+ ret = device_property_read_u32_array(&client->dev,
+ "adi,pwm-initial-duty-cycle", dutys,
+ ARRAY_SIZE(dutys));
+ if (ret)
+ return ret;
+
+ for (i = 0; i < ADT7475_PWM_COUNT; i++) {
+ ret = i2c_smbus_write_byte_data(client, PWM_MAX_REG(i), dutys[i] & 0xff);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
static int adt7475_probe(struct i2c_client *client)
{
enum chips chip;
@@ -1778,6 +1828,14 @@ static int adt7475_probe(struct i2c_client *client)
if (ret && ret != -EINVAL)
dev_warn(&client->dev, "Error configuring pwm polarity\n");
+ ret = adt7475_set_pwm_initial_freq(client);
+ if (ret && ret != -EINVAL)
+ dev_warn(&client->dev, "Error configuring pwm frequency\n");
+
+ ret = adt7475_set_pwm_initial_duty(client);
+ if (ret && ret != -EINVAL)
+ dev_warn(&client->dev, "Error configuring pwm duty cycle\n");
+
/* Start monitoring */
switch (chip) {
case adt7475:
--
2.43.2
