Commit 777c97ff authored by Chris Packham's avatar Chris Packham Committed by Guenter Roeck
Browse files

hwmon: (adt7475) Add support for configuring initial PWM state 



By default the PWM duty cycle in hardware is 100%. On some systems this
can cause unwanted fan noise. Add the ability to specify the fan
connections and initial state of the PWMs via device properties.

Signed-off-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20240722221737.3407958-4-chris.packham@alliedtelesis.co.nz


[groeck: Cleaned up formatting]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 20705629

drivers/hwmon/adt7475.c

+130 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#include <linux/of.h>

#include <linux/util_macros.h>



#include <dt-bindings/pwm/pwm.h>



/* Indexes for the sysfs hooks */



#define INPUT		0
@@ -1662,6 +1664,130 @@ static int adt7475_set_pwm_polarity(struct i2c_client *client) 
	return 0;

}



struct adt7475_pwm_config {

	int index;

	int freq;

	int flags;

	int duty;

};



static int _adt7475_pwm_properties_parse_args(u32 args[4], struct adt7475_pwm_config *cfg)

{

	int freq_hz;

	int duty;



	if (args[1] == 0)

		return -EINVAL;



	freq_hz = 1000000000UL / args[1];

	if (args[3] >= args[1])

		duty = 255;

	else

		duty = div_u64(255ULL * args[3], args[1]);



	cfg->index = args[0];

	cfg->freq = find_closest(freq_hz, pwmfreq_table, ARRAY_SIZE(pwmfreq_table));

	cfg->flags = args[2];

	cfg->duty = duty;



	return 0;

}



static int adt7475_pwm_properties_parse_reference_args(struct fwnode_handle *fwnode,

						       struct adt7475_pwm_config *cfg)

{

	int ret, i;

	struct fwnode_reference_args rargs = {};

	u32 args[4] = {};



	ret = fwnode_property_get_reference_args(fwnode, "pwms", "#pwm-cells", 0, 0, &rargs);

	if (ret)

		return ret;



	if (rargs.nargs != 4) {

		fwnode_handle_put(rargs.fwnode);

		return -EINVAL;

	}



	for (i = 0; i < 4; i++)

		args[i] = rargs.args[i];



	ret = _adt7475_pwm_properties_parse_args(args, cfg);



	fwnode_handle_put(rargs.fwnode);



	return ret;

}



static int adt7475_pwm_properties_parse_args(struct fwnode_handle *fwnode,

					     struct adt7475_pwm_config *cfg)

{

	int ret;

	u32 args[4] = {};



	ret = fwnode_property_read_u32_array(fwnode, "pwms", args, ARRAY_SIZE(args));

	if (ret)

		return ret;



	return _adt7475_pwm_properties_parse_args(args, cfg);

}



static int adt7475_fan_pwm_config(struct i2c_client *client)

{

	struct adt7475_data *data = i2c_get_clientdata(client);

	struct fwnode_handle *child;

	struct adt7475_pwm_config cfg = {};

	int ret;



	device_for_each_child_node(&client->dev, child) {

		if (!fwnode_property_present(child, "pwms"))

			continue;



		if (is_of_node(child))

			ret = adt7475_pwm_properties_parse_reference_args(child, &cfg);

		else

			ret = adt7475_pwm_properties_parse_args(child, &cfg);



		if (cfg.index >= ADT7475_PWM_COUNT)

			return -EINVAL;



		ret = adt7475_read(PWM_CONFIG_REG(cfg.index));

		if (ret < 0)

			return ret;

		data->pwm[CONTROL][cfg.index] = ret;

		if (cfg.flags & PWM_POLARITY_INVERTED)

			data->pwm[CONTROL][cfg.index] |= BIT(4);

		else

			data->pwm[CONTROL][cfg.index] &= ~BIT(4);



		/* Force to manual mode so PWM values take effect */

		data->pwm[CONTROL][cfg.index] &= ~0xE0;

		data->pwm[CONTROL][cfg.index] |= 0x07 << 5;



		ret = i2c_smbus_write_byte_data(client, PWM_CONFIG_REG(cfg.index),

						data->pwm[CONTROL][cfg.index]);

		if (ret)

			return ret;



		data->pwm[INPUT][cfg.index] = cfg.duty;

		ret = i2c_smbus_write_byte_data(client, PWM_REG(cfg.index),

						data->pwm[INPUT][cfg.index]);

		if (ret)

			return ret;



		data->range[cfg.index] = adt7475_read(TEMP_TRANGE_REG(cfg.index));

		data->range[cfg.index] &= ~0xf;

		data->range[cfg.index] |= cfg.freq;



		ret = i2c_smbus_write_byte_data(client, TEMP_TRANGE_REG(cfg.index),

						data->range[cfg.index]);

		if (ret)

			return ret;

	}



	return 0;

}



static int adt7475_probe(struct i2c_client *client)

{

	enum chips chip;
@@ -1774,6 +1900,10 @@ static int adt7475_probe(struct i2c_client *client) 
	if (ret && ret != -EINVAL)

		dev_warn(&client->dev, "Error configuring pwm polarity\n");



	ret = adt7475_fan_pwm_config(client);

	if (ret)

		dev_warn(&client->dev, "Error %d configuring fan/pwm\n", ret);



	/* Start monitoring */

	switch (chip) {

	case adt7475: