2024-05-08 17:14:45

by Chris Packham

Subject: [PATCH 2/2] hwmon: (adt7475) Add support for configuring initial PWM duty cycle

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 <[email protected]>
---
drivers/hwmon/adt7475.c | 56 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 4224ffb30483..b0c7c1a95897 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -1662,6 +1662,54 @@ 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,
+ "pwm-initial-frequency", freqs,
+ ARRAY_SIZE(freqs));
+ if (ret)
+ return ret;
+
+ for (i = 0; i < ADT7475_PWM_COUNT; i++) {
+ 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 +1826,14 @@ 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)
+ return ret;
+
+ ret = adt7475_set_pwm_initial_duty(client);
+ if (ret)
+ return ret;
+
/* Start monitoring */
switch (chip) {
case adt7475:
--
2.43.2

2024-05-08 17:50:10

by Chris Packham

Subject: Re: [PATCH 2/2] hwmon: (adt7475) Add support for configuring initial PWM duty cycle

On 9/05/24 05:05, Chris Packham wrote:
> 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 <[email protected]>
> ---
> drivers/hwmon/adt7475.c | 56 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
> index 4224ffb30483..b0c7c1a95897 100644
> --- a/drivers/hwmon/adt7475.c
> +++ b/drivers/hwmon/adt7475.c
> @@ -1662,6 +1662,54 @@ 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,
> + "pwm-initial-frequency", freqs,
> + ARRAY_SIZE(freqs));
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < ADT7475_PWM_COUNT; i++) {
> + 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 +1826,14 @@ 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)
> + return ret;

Whoops I meant to send the version that handles -EINVAL. v2 will handle
errors the same way as pwm_polarity above. I'll wait for a bit before
sending that out.

> +
> + ret = adt7475_set_pwm_initial_duty(client);
> + if (ret)
> + return ret;
> +
> /* Start monitoring */
> switch (chip) {
> case adt7475: