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From: Chris Packham <chris.packham@alliedtelesis.co.nz>
To: jdelvare@suse.com,
	linux@roeck-us.net,
	robh@kernel.org,
	krzk+dt@kernel.org,
	conor+dt@kernel.org,
	ukleinek@kernel.org
Cc: linux-hwmon@vger.kernel.org,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-pwm@vger.kernel.org,
	Chris Packham <chris.packham@alliedtelesis.co.nz>
Subject: [PATCH v4 3/3] hwmon: (adt7475) Add support for configuring initial PWM state
Date: Wed, 29 May 2024 10:56:38 +1200
Message-ID: <20240528225638.1211676-4-chris.packham@alliedtelesis.co.nz>
In-Reply-To: <20240528225638.1211676-1-chris.packham@alliedtelesis.co.nz>
References: <20240528225638.1211676-1-chris.packham@alliedtelesis.co.nz>
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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: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v4:
    - Support DT and ACPI fwnodes
    - Put PWM into manual mode
    Changes in v3:
    - Use the pwm provider/consumer bindings
    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 a=
s-is

 drivers/hwmon/adt7475.c | 112 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index 4224ffb30483..b5c58e3cda03 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -21,6 +21,8 @@
 #include <linux/of.h>
 #include <linux/util_macros.h>
=20
+#include <dt-bindings/pwm/pwm.h>
+
 /* Indexes for the sysfs hooks */
=20
 #define INPUT		0
@@ -1662,6 +1664,112 @@ static int adt7475_set_pwm_polarity(struct i2c_cl=
ient *client)
 	return 0;
 }
=20
+struct adt7475_pwm_config {
+	int index;
+	int freq;
+	int flags;
+	int duty;
+};
+
+static int adt7475_pwm_properties_parse_reference_args(struct fwnode_han=
dle *fwnode,
+						       struct adt7475_pwm_config *cfg)
+{
+	int ret;
+	struct fwnode_reference_args args =3D {};
+
+	ret =3D fwnode_property_get_reference_args(fwnode, "pwms", "#pwm-cells"=
, 0, 0, &args);
+	if (ret)
+		return ret;
+
+	if (args.nargs !=3D 4) {
+		fwnode_handle_put(args.fwnode);
+		return -EINVAL;
+	}
+
+	cfg->index =3D args.args[0];
+	cfg->freq =3D find_closest(args.args[1], pwmfreq_table, ARRAY_SIZE(pwmf=
req_table));
+	cfg->flags =3D args.args[2];
+	cfg->duty =3D clamp_val(args.args[3], 0, 0xFF);
+
+	fwnode_handle_put(args.fwnode);
+
+	return 0;
+}
+
+static int adt7475_pwm_properties_parse_args(struct fwnode_handle *fwnod=
e,
+					     struct adt7475_pwm_config *cfg)
+{
+	int ret;
+	u32 args[4] =3D {};
+
+	ret =3D fwnode_property_read_u32_array(fwnode, "pwms", args, ARRAY_SIZE=
(args));
+	if (ret)
+		return ret;
+
+	cfg->index =3D args[0];
+	cfg->freq =3D find_closest(args[1], pwmfreq_table, ARRAY_SIZE(pwmfreq_t=
able));
+	cfg->flags =3D args[2];
+	cfg->duty =3D clamp_val(args[3], 0, 0xFF);
+
+	return 0;
+}
+
+static int adt7475_fan_pwm_config(struct i2c_client *client)
+{
+	struct adt7475_data *data =3D i2c_get_clientdata(client);
+	struct fwnode_handle *child;
+	struct adt7475_pwm_config cfg =3D {};
+	int ret;
+
+	device_for_each_child_node(&client->dev, child) {
+		if (!fwnode_property_present(child, "pwms"))
+			continue;
+
+		if (is_of_node(child))
+			ret =3D adt7475_pwm_properties_parse_reference_args(child, &cfg);
+		else
+			ret =3D adt7475_pwm_properties_parse_args(child, &cfg);
+
+		if (cfg.index >=3D ADT7475_PWM_COUNT)
+			return -EINVAL;
+
+		ret =3D adt7475_read(PWM_CONFIG_REG(cfg.index));
+		if (ret < 0)
+			return ret;
+		data->pwm[CONTROL][cfg.index] =3D ret;
+		if (cfg.flags & PWM_POLARITY_INVERTED)
+			data->pwm[CONTROL][cfg.index] |=3D BIT(4);
+		else
+			data->pwm[CONTROL][cfg.index] &=3D ~BIT(4);
+
+		/* Force to manual mode so PWM values take effect */
+		data->pwm[CONTROL][cfg.index] &=3D ~0xE0;
+		data->pwm[CONTROL][cfg.index] |=3D 0x07 << 5;
+
+		ret =3D 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] =3D cfg.duty;
+		ret =3D i2c_smbus_write_byte_data(client, PWM_REG(cfg.index),
+						data->pwm[INPUT][cfg.index]);
+		if (ret)
+			return ret;
+
+		data->range[cfg.index] =3D adt7475_read(TEMP_TRANGE_REG(cfg.index));
+		data->range[cfg.index] &=3D ~0xf;
+		data->range[cfg.index] |=3D cfg.freq;
+
+		ret =3D 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;
@@ -1778,6 +1886,10 @@ static int adt7475_probe(struct i2c_client *client=
)
 	if (ret && ret !=3D -EINVAL)
 		dev_warn(&client->dev, "Error configuring pwm polarity\n");
=20
+	ret =3D adt7475_fan_pwm_config(client);
+	if (ret)
+		dev_warn(&client->dev, "Error %d configuring fan/pwm\n", ret);
+
 	/* Start monitoring */
 	switch (chip) {
 	case adt7475:
--=20
2.45.1