From 897f6339893b741a5d68ae8e2475df65946041c2 Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Wed, 26 May 2021 08:40:17 -0700
Subject: [PATCH] hwmon: (max31790) Report correct current pwm duty cycles
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Git-commit: 897f6339893b741a5d68ae8e2475df65946041c2
Patch-mainline: v5.14-rc1
References: git-fixes
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>
Tested-by: Václav Kubernát <kubernat@ceesnet.cz>
Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/r/20210526154022.3223012-3-linux@roeck-us.net
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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];
--
2.26.2