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hwmon: (mlxreg-fan) Extend driver to support multiply PWM
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Add additional PWM attributes in order to support the systems, which
can be equipped with up-to four PWM controllers. System capability of
additional PWM support is validated through the reading of relevant
registers.

Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20210916194719.871413-3-vadimp@nvidia.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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@vadimp-nvidia @groeck
vadimp-nvidia authored and groeck committed Oct 12, 2021
1 parent bc8de07 commit 150f1e0
Showing 1 changed file with 43 additions and 12 deletions.
55 changes: 43 additions & 12 deletions drivers/hwmon/mlxreg-fan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
#include <linux/thermal.h>

#define MLXREG_FAN_MAX_TACHO 14
#define MLXREG_FAN_MAX_PWM 4
#define MLXREG_FAN_PWM_NOT_CONNECTED 0xff
#define MLXREG_FAN_MAX_STATE 10
#define MLXREG_FAN_MIN_DUTY 51 /* 20% */
#define MLXREG_FAN_MAX_DUTY 255 /* 100% */
Expand Down Expand Up @@ -105,7 +107,7 @@ struct mlxreg_fan {
void *regmap;
struct mlxreg_core_platform_data *pdata;
struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
struct mlxreg_fan_pwm pwm;
struct mlxreg_fan_pwm pwm[MLXREG_FAN_MAX_PWM];
int tachos_per_drwr;
int samples;
int divider;
Expand All @@ -119,6 +121,7 @@ mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
{
struct mlxreg_fan *fan = dev_get_drvdata(dev);
struct mlxreg_fan_tacho *tacho;
struct mlxreg_fan_pwm *pwm;
u32 regval;
int err;

Expand Down Expand Up @@ -169,9 +172,10 @@ mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
break;

case hwmon_pwm:
pwm = &fan->pwm[channel];
switch (attr) {
case hwmon_pwm_input:
err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
err = regmap_read(fan->regmap, pwm->reg, &regval);
if (err)
return err;

Expand All @@ -195,6 +199,7 @@ mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long val)
{
struct mlxreg_fan *fan = dev_get_drvdata(dev);
struct mlxreg_fan_pwm *pwm;

switch (type) {
case hwmon_pwm:
Expand All @@ -203,7 +208,8 @@ mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
if (val < MLXREG_FAN_MIN_DUTY ||
val > MLXREG_FAN_MAX_DUTY)
return -EINVAL;
return regmap_write(fan->regmap, fan->pwm.reg, val);
pwm = &fan->pwm[channel];
return regmap_write(fan->regmap, pwm->reg, val);
default:
return -EOPNOTSUPP;
}
Expand Down Expand Up @@ -235,7 +241,7 @@ mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
break;

case hwmon_pwm:
if (!(((struct mlxreg_fan *)data)->pwm.connected))
if (!(((struct mlxreg_fan *)data)->pwm[channel].connected))
return 0;

switch (attr) {
Expand Down Expand Up @@ -270,6 +276,9 @@ static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT),
HWMON_CHANNEL_INFO(pwm,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT),
NULL
};
Expand Down Expand Up @@ -300,7 +309,7 @@ static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
u32 regval;
int err;

err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
err = regmap_read(fan->regmap, fan->pwm[0].reg, &regval);
if (err) {
dev_err(fan->dev, "Failed to query PWM duty\n");
return err;
Expand Down Expand Up @@ -343,7 +352,7 @@ static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
for (i = state; i <= MLXREG_FAN_MAX_STATE; i++)
fan->cooling_levels[i] = i;

err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
err = regmap_read(fan->regmap, fan->pwm[0].reg, &regval);
if (err) {
dev_err(fan->dev, "Failed to query PWM duty\n");
return err;
Expand All @@ -361,7 +370,7 @@ static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,

/* Normalize the state to the valid speed range. */
state = fan->cooling_levels[state];
err = regmap_write(fan->regmap, fan->pwm.reg,
err = regmap_write(fan->regmap, fan->pwm[0].reg,
MLXREG_FAN_PWM_STATE2DUTY(state));
if (err) {
dev_err(fan->dev, "Failed to write PWM duty\n");
Expand Down Expand Up @@ -392,6 +401,22 @@ static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
return !!(regval & data->bit);
}

static int mlxreg_pwm_connect_verify(struct mlxreg_fan *fan,
struct mlxreg_core_data *data)
{
u32 regval;
int err;

err = regmap_read(fan->regmap, data->reg, &regval);
if (err) {
dev_err(fan->dev, "Failed to query pwm register 0x%08x\n",
data->reg);
return err;
}

return regval != MLXREG_FAN_PWM_NOT_CONNECTED;
}

static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
struct mlxreg_core_data *data)
{
Expand Down Expand Up @@ -420,8 +445,8 @@ static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
static int mlxreg_fan_config(struct mlxreg_fan *fan,
struct mlxreg_core_platform_data *pdata)
{
int tacho_num = 0, tacho_avail = 0, pwm_num = 0, i;
struct mlxreg_core_data *data = pdata->data;
int tacho_num = 0, tacho_avail = 0, i;
bool configured = false;
int err;

Expand Down Expand Up @@ -451,13 +476,19 @@ static int mlxreg_fan_config(struct mlxreg_fan *fan,
fan->tacho[tacho_num++].connected = true;
tacho_avail++;
} else if (strnstr(data->label, "pwm", sizeof(data->label))) {
if (fan->pwm.connected) {
dev_err(fan->dev, "duplicate pwm entry: %s\n",
if (pwm_num == MLXREG_FAN_MAX_TACHO) {
dev_err(fan->dev, "too many pwm entries: %s\n",
data->label);
return -EINVAL;
}
fan->pwm.reg = data->reg;
fan->pwm.connected = true;

err = mlxreg_pwm_connect_verify(fan, data);
if (err)
return err;

fan->pwm[pwm_num].reg = data->reg;
fan->pwm[pwm_num].connected = true;
pwm_num++;
} else if (strnstr(data->label, "conf", sizeof(data->label))) {
if (configured) {
dev_err(fan->dev, "duplicate conf entry: %s\n",
Expand Down

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