Commit cd175872 authored by Francesco Dolcini's avatar Francesco Dolcini Committed by Guenter Roeck
Browse files

hwmon: (amc6821) Add PWM polarity configuration with OF 



Add support to configure the PWM-Out pin polarity based on the device
tree. The binding would allow also to configure the PWM period, this is
currently not implemented by the driver.

The driver has a module option to set the PWM polarity (normal=0,
inverted=1), when specified it always takes the precedence over the DT.

Signed-off-by: default avatarFrancesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20250402102146.65406-3-francesco@dolcini.it


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent ce664221

drivers/hwmon/amc6821.c

+45 −5
Original line number Diff line number Diff line
@@ -23,9 +23,12 @@ 
#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of_platform.h>

#include <linux/pwm.h>

#include <linux/regmap.h>

#include <linux/slab.h>



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



/*

 * Addresses to scan.

 */
@@ -37,7 +40,7 @@ static const unsigned short normal_i2c[] = {0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 
 * Insmod parameters

 */



static int pwminv;	/*Inverted PWM output. */

static int pwminv = -1; /*Inverted PWM output. */

module_param(pwminv, int, 0444);



static int init = 1; /*Power-on initialization.*/
@@ -845,9 +848,43 @@ static int amc6821_detect(struct i2c_client *client, struct i2c_board_info *info 
	return 0;

}



static int amc6821_init_client(struct amc6821_data *data)

static enum pwm_polarity amc6821_pwm_polarity(struct i2c_client *client)

{

	enum pwm_polarity polarity = PWM_POLARITY_NORMAL;

	struct of_phandle_args args;

	struct device_node *fan_np;



	/*

	 * For backward compatibility, the pwminv module parameter takes

	 * always the precedence over any other device description

	 */

	if (pwminv == 0)

		return PWM_POLARITY_NORMAL;

	if (pwminv > 0)

		return PWM_POLARITY_INVERSED;



	fan_np = of_get_child_by_name(client->dev.of_node, "fan");

	if (!fan_np)

		return PWM_POLARITY_NORMAL;



	if (of_parse_phandle_with_args(fan_np, "pwms", "#pwm-cells", 0, &args))

		goto out;

	of_node_put(args.np);



	if (args.args_count != 2)

		goto out;



	if (args.args[1] & PWM_POLARITY_INVERTED)

		polarity = PWM_POLARITY_INVERSED;

out:

	of_node_put(fan_np);

	return polarity;

}



static int amc6821_init_client(struct i2c_client *client, struct amc6821_data *data)

{

	struct regmap *regmap = data->regmap;

	u32 regval;

	int err;



	if (init) {
@@ -864,11 +901,14 @@ static int amc6821_init_client(struct amc6821_data *data) 
		if (err)

			return err;



		regval = AMC6821_CONF1_START;

		if (amc6821_pwm_polarity(client) == PWM_POLARITY_INVERSED)

			regval |= AMC6821_CONF1_PWMINV;



		err = regmap_update_bits(regmap, AMC6821_REG_CONF1,

					 AMC6821_CONF1_THERMOVIE | AMC6821_CONF1_FANIE |

					 AMC6821_CONF1_START | AMC6821_CONF1_PWMINV,

					 AMC6821_CONF1_START |

					 (pwminv ? AMC6821_CONF1_PWMINV : 0));

					 regval);

		if (err)

			return err;

	}
@@ -916,7 +956,7 @@ static int amc6821_probe(struct i2c_client *client) 
				     "Failed to initialize regmap\n");

	data->regmap = regmap;



	err = amc6821_init_client(data);

	err = amc6821_init_client(client, data);

	if (err)

		return err;