diff mbox series

[2/7] hwmon: (max31790) Report correct current pwm duty cycles

Message ID 20210526154022.3223012-3-linux@roeck-us.net (mailing list archive)
State Accepted
Headers show
Series hwmon: (max31790) Fixes and improvements | expand

Commit Message

Guenter Roeck May 26, 2021, 3:40 p.m. UTC
The MAX31790 has two sets of registers for pwm duty cycles, one to request
a duty cycle and one to read the actual current duty cycle. Both do not
have to be the same.

When reporting the pwm duty cycle to the user, the actual pwm duty cycle
from pwm duty cycle registers needs to be reported. When setting it, the
pwm target duty cycle needs to be written. Since we don't know the actual
pwm duty cycle after a target pwm duty cycle has been written, set the
valid flag to false to indicate that actual pwm duty cycle should be read
from the chip instead of using cached values.

Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
Cc: Václav Kubernát <kubernat@cesnet.cz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 Documentation/hwmon/max31790.rst | 3 ++-
 drivers/hwmon/max31790.c         | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

Comments

Václav Kubernát June 1, 2021, 7:51 a.m. UTC | #1
PWM duty reading works.

Tested-by: Václav Kubernát <kubernat@ceesnet.cz>

st 26. 5. 2021 v 17:40 odesílatel Guenter Roeck <linux@roeck-us.net> napsal:
>
> The MAX31790 has two sets of registers for pwm duty cycles, one to request
> a duty cycle and one to read the actual current duty cycle. Both do not
> have to be the same.
>
> When reporting the pwm duty cycle to the user, the actual pwm duty cycle
> from pwm duty cycle registers needs to be reported. When setting it, the
> pwm target duty cycle needs to be written. Since we don't know the actual
> pwm duty cycle after a target pwm duty cycle has been written, set the
> valid flag to false to indicate that actual pwm duty cycle should be read
> from the chip instead of using cached values.
>
> Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
> Cc: Václav Kubernát <kubernat@cesnet.cz>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  Documentation/hwmon/max31790.rst | 3 ++-
>  drivers/hwmon/max31790.c         | 6 +++---
>  2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst
> index f301385d8cef..54ff0f49e28f 100644
> --- a/Documentation/hwmon/max31790.rst
> +++ b/Documentation/hwmon/max31790.rst
> @@ -39,5 +39,6 @@ fan[1-12]_input    RO  fan tachometer speed in RPM
>  fan[1-12]_fault    RO  fan experienced fault
>  fan[1-6]_target    RW  desired fan speed in RPM
>  pwm[1-6]_enable    RW  regulator mode, 0=disabled, 1=manual mode, 2=rpm mode
> -pwm[1-6]           RW  fan target duty cycle (0-255)
> +pwm[1-6]           RW  read: current pwm duty cycle,
> +                       write: target pwm duty cycle (0-255)
>  ================== === =======================================================
> diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
> index f6d4fc0a2f13..693497e09ac0 100644
> --- a/drivers/hwmon/max31790.c
> +++ b/drivers/hwmon/max31790.c
> @@ -104,7 +104,7 @@ static struct max31790_data *max31790_update_device(struct device *dev)
>                                 data->tach[NR_CHANNEL + i] = rv;
>                         } else {
>                                 rv = i2c_smbus_read_word_swapped(client,
> -                                               MAX31790_REG_PWMOUT(i));
> +                                               MAX31790_REG_PWM_DUTY_CYCLE(i));
>                                 if (rv < 0)
>                                         goto abort;
>                                 data->pwm[i] = rv;
> @@ -299,10 +299,10 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
>                         err = -EINVAL;
>                         break;
>                 }
> -               data->pwm[channel] = val << 8;
> +               data->valid = false;
>                 err = i2c_smbus_write_word_swapped(client,
>                                                    MAX31790_REG_PWMOUT(channel),
> -                                                  data->pwm[channel]);
> +                                                  val << 8);
>                 break;
>         case hwmon_pwm_enable:
>                 fan_config = data->fan_config[channel];
> --
> 2.25.1
>
Jan Kundrát June 2, 2021, 12:36 p.m. UTC | #2
On středa 26. května 2021 17:40:17 CEST, Guenter Roeck wrote:
> The MAX31790 has two sets of registers for pwm duty cycles, one to request
> a duty cycle and one to read the actual current duty cycle. Both do not
> have to be the same.
>
> When reporting the pwm duty cycle to the user, the actual pwm duty cycle
> from pwm duty cycle registers needs to be reported. When setting it, the
> pwm target duty cycle needs to be written. Since we don't know the actual
> pwm duty cycle after a target pwm duty cycle has been written, set the
> valid flag to false to indicate that actual pwm duty cycle should be read
> from the chip instead of using cached values.
>
> Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
> Cc: Václav Kubernát <kubernat@cesnet.cz>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>

Cheers,
Jan
diff mbox series

Patch

diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst
index f301385d8cef..54ff0f49e28f 100644
--- a/Documentation/hwmon/max31790.rst
+++ b/Documentation/hwmon/max31790.rst
@@ -39,5 +39,6 @@  fan[1-12]_input    RO  fan tachometer speed in RPM
 fan[1-12]_fault    RO  fan experienced fault
 fan[1-6]_target    RW  desired fan speed in RPM
 pwm[1-6]_enable    RW  regulator mode, 0=disabled, 1=manual mode, 2=rpm mode
-pwm[1-6]           RW  fan target duty cycle (0-255)
+pwm[1-6]           RW  read: current pwm duty cycle,
+                       write: target pwm duty cycle (0-255)
 ================== === =======================================================
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index f6d4fc0a2f13..693497e09ac0 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -104,7 +104,7 @@  static struct max31790_data *max31790_update_device(struct device *dev)
 				data->tach[NR_CHANNEL + i] = rv;
 			} else {
 				rv = i2c_smbus_read_word_swapped(client,
-						MAX31790_REG_PWMOUT(i));
+						MAX31790_REG_PWM_DUTY_CYCLE(i));
 				if (rv < 0)
 					goto abort;
 				data->pwm[i] = rv;
@@ -299,10 +299,10 @@  static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
 			err = -EINVAL;
 			break;
 		}
-		data->pwm[channel] = val << 8;
+		data->valid = false;
 		err = i2c_smbus_write_word_swapped(client,
 						   MAX31790_REG_PWMOUT(channel),
-						   data->pwm[channel]);
+						   val << 8);
 		break;
 	case hwmon_pwm_enable:
 		fan_config = data->fan_config[channel];