[PATCH 4/7] hwmon: (max31790) Add support for fanX_enable attributes

Guenter Roeck
2021-05-26T15:40:47Z

Since pwmX_enable is now fixed and only handles pwm support instead
of also enabling/disabling fan tachometers, we need an explicit means
to do that.

For fan channels 7..12, display the enable status if the channel
is configured for fan speed reporting. The displayed status matches
the value of the companion channel but is read-only.

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 | 55 ++++++++++++++++++++++++--------
2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst
index 7b097c3b9b90..b43aa32813fd 100644
--- a/Documentation/hwmon/max31790.rst
+++ b/Documentation/hwmon/max31790.rst
@@ -35,6 +35,9 @@ Sysfs entries
-------------

================== === =======================================================
+fan[1-12]_enable RW 0=disable fan speed monitoring, 1=enable fan speed monitoring
+ The value is RO for companion channels (7-12). For those
+ channels, the value matches the value of the primary channel.
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
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index 67677c437768..19651feb40fb 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -170,6 +170,9 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel,
return PTR_ERR(data);

switch (attr) {
+ case hwmon_fan_enable:
+ *val = !!(data->fan_config[channel % NR_CHANNEL] & MAX31790_FAN_CFG_TACH_INPUT_EN);
+ return 0;
case hwmon_fan_input:
sr = get_tach_period(data->fan_dynamics[channel % NR_CHANNEL]);
rpm = RPM_FROM_REG(data->tach[channel], sr);
@@ -195,12 +198,32 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
struct i2c_client *client = data->client;
int target_count;
int err = 0;
- u8 bits;
+ u8 bits, config;
int sr;

mutex_lock(&data->update_lock);

switch (attr) {
+ case hwmon_fan_enable:
+ config = data->fan_config[channel];
+ if (val == 0) {
+ /* Disabling TACH_INPUT_EN has no effect in RPM_MODE */
+ if (!(config & MAX31790_FAN_CFG_RPM_MODE))
+ config &= ~MAX31790_FAN_CFG_TACH_INPUT_EN;
+ } else if (val == 1) {
+ config |= MAX31790_FAN_CFG_TACH_INPUT_EN;
+ } else {
+ err = -EINVAL;
+ break;
+ }
+ if (config != data->fan_config[channel]) {
+ err = i2c_smbus_write_byte_data(client,
+ MAX31790_REG_FAN_CONFIG(channel),
+ config);
+ if (!err)
+ data->fan_config[channel] = config;
+ }
+ break;
case hwmon_fan_target:
val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
bits = bits_for_tach_period(val);
@@ -240,6 +263,12 @@ static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
u8 fan_config = data->fan_config[channel % NR_CHANNEL];

switch (attr) {
+ case hwmon_fan_enable:
+ if (channel < NR_CHANNEL)
+ return 0644;
+ if (fan_config & MAX31790_FAN_CFG_TACH_INPUT)
+ return 0444;
+ return 0;
case hwmon_fan_input:
case hwmon_fan_fault:
if (channel < NR_CHANNEL ||
@@ -404,18 +433,18 @@ static umode_t max31790_is_visible(const void *data,

static const struct hwmon_channel_info *max31790_info[] = {
HWMON_CHANNEL_INFO(fan,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT,
- HWMON_F_INPUT | HWMON_F_FAULT),
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+ HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT),
HWMON_CHANNEL_INFO(pwm,
HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
--
2.25.1