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hwmon: (amc6821) Add PWM polarity configuration with OF

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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: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20250402102146.65406-3-francesco@dolcini.it
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Francesco Dolcini 2025-04-02 12:21:46 +02:00 committed by Guenter Roeck
parent ce66422118
commit cd17587272
1 changed files with 45 additions and 5 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

50
drivers/hwmon/amc6821.c
View file

@ -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;