On 3/14/21 5:42 AM, Wilken Gottwalt wrote:
> Adds support for reading the critical values of the temperature sensors
> and the rail sensors (voltage and current) once and caches them. Updates
> the naming of the constants following a more clear scheme. Also updates
> the documentation and fixes a typo.
> 
> The new sensors output of a Corsair HX850i will look like this:
> corsairpsu-hid-3-1
> Adapter: HID adapter
> v_in:        230.00 V
> v_out +12v:   12.14 V  (crit min =  +8.41 V, crit max = +15.59 V)
> v_out +5v:     5.03 V  (crit min =  +3.50 V, crit max =  +6.50 V)
> v_out +3.3v:   3.30 V  (crit min =  +2.31 V, crit max =  +4.30 V)
> psu fan:        0 RPM
> vrm temp:     +46.2°C  (crit = +70.0°C)
> case temp:    +39.8°C  (crit = +70.0°C)
> power total: 152.00 W
> power +12v:  108.00 W
> power +5v:    41.00 W
> power +3.3v:   5.00 W
> curr in:          N/A
> curr +12v:     9.00 A  (crit max = +85.00 A)
> curr +5v:      8.31 A  (crit max = +40.00 A)
> curr +3.3v:    1.62 A  (crit max = +40.00 A)
> 
> This patch changes:
> - hwmon corsair-psu documentation
> - hwmon corsair-psu driver
> 
> Signed-off-by: Wilken Gottwalt <[email protected]>
> ---
>  Documentation/hwmon/corsair-psu.rst |  13 +-
>  drivers/hwmon/corsair-psu.c         | 185 ++++++++++++++++++++++------
>  2 files changed, 157 insertions(+), 41 deletions(-)
> 
> diff --git a/Documentation/hwmon/corsair-psu.rst 
> b/Documentation/hwmon/corsair-psu.rst
> index 396b95c9a76a..b77e53810a13 100644
> --- a/Documentation/hwmon/corsair-psu.rst
> +++ b/Documentation/hwmon/corsair-psu.rst
> @@ -45,19 +45,30 @@ Sysfs entries
>  -------------
>  
>  =======================      
> ========================================================
> +curr2_crit           Current max critical value on the 12v psu rail
> +curr3_crit           Current max critical value on the 5v psu rail
> +curr4_crit           Current max critical value on the 3.3v psu rail
>  curr1_input          Total current usage
>  curr2_input          Current on the 12v psu rail
>  curr3_input          Current on the 5v psu rail
>  curr4_input          Current on the 3.3v psu rail
>  fan1_input           RPM of psu fan
> +in1_crit             Voltage max critical value on the 12v psu rail
> +in2_crit             Voltage max critical value on the 5v psu rail
> +in3_crit             Voltage max critical value on the 3.3v psu rail
>  in0_input            Voltage of the psu ac input
>  in1_input            Voltage of the 12v psu rail
>  in2_input            Voltage of the 5v psu rail
> -in3_input            Voltage of the 3.3 psu rail
> +in3_input            Voltage of the 3.3v psu rail
> +in1_lcrit            Voltage min critical value on the 12v psu rail
> +in2_lcrit            Voltage min critical value on the 5v psu rail
> +in3_lcrit            Voltage min critical value on the 3.3v psu rail
>  power1_input         Total power usage
>  power2_input         Power usage of the 12v psu rail
>  power3_input         Power usage of the 5v psu rail
>  power4_input         Power usage of the 3.3v psu rail
> +temp1_crit           Temperature max cirtical value of the psu vrm component
> +temp2_crit           Temperature max critical value of psu case
>  temp1_input          Temperature of the psu vrm component
>  temp2_input          Temperature of the psu case
>  =======================      
> ========================================================
> diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
> index b0953eeeb2d3..141a5079ea7e 100644
> --- a/drivers/hwmon/corsair-psu.c
> +++ b/drivers/hwmon/corsair-psu.c
> @@ -53,11 +53,21 @@
>  #define CMD_TIMEOUT_MS               250
>  #define SECONDS_PER_HOUR     (60 * 60)
>  #define SECONDS_PER_DAY              (SECONDS_PER_HOUR * 24)
> +#define RAIL_COUNT           3 /* 3v3 + 5v + 12v */
> +#define CRIT_VALUES_COUNT    11 /* 2 temp crit + 6 rail volts (low and high) 
> + 3 rails amps */
> +#define TEMP_HCRIT           0
> +#define VOLTS_RAIL_HCRIT     2
> +#define VOLTS_RAIL_LCRIT     5
> +#define AMPS_RAIL_HCRIT              8
>  
>  #define PSU_CMD_SELECT_RAIL  0x00 /* expects length 2 */
> -#define PSU_CMD_IN_VOLTS     0x88 /* the rest of the commands expect length 
> 3 */
> +#define PSU_CMD_RAIL_VOLTS_HCRIT 0x40 /* the rest of the commands expect 
> length 3 */
> +#define PSU_CMD_RAIL_VOLTS_LCRIT 0x44
> +#define PSU_CMD_RAIL_AMPS_HCRIT      0x46
> +#define PSU_CMD_TEMP_HCRIT   0x4F
> +#define PSU_CMD_IN_VOLTS     0x88
>  #define PSU_CMD_IN_AMPS              0x89
> -#define PSU_CMD_RAIL_OUT_VOLTS       0x8B
> +#define PSU_CMD_RAIL_VOLTS   0x8B
>  #define PSU_CMD_RAIL_AMPS    0x8C
>  #define PSU_CMD_TEMP0                0x8D
>  #define PSU_CMD_TEMP1                0x8E
> @@ -113,6 +123,7 @@ struct corsairpsu_data {
>       struct dentry *debugfs;
>       struct completion wait_completion;
>       struct mutex lock; /* for locking access to cmd_buffer */
> +     long crit_values[CRIT_VALUES_COUNT];
>       u8 *cmd_buffer;
>       char vendor[REPLY_SIZE];
>       char product[REPLY_SIZE];
> @@ -193,7 +204,10 @@ static int corsairpsu_request(struct corsairpsu_data 
> *priv, u8 cmd, u8 rail, voi
>  
>       mutex_lock(&priv->lock);
>       switch (cmd) {
> -     case PSU_CMD_RAIL_OUT_VOLTS:
> +     case PSU_CMD_RAIL_VOLTS_HCRIT:
> +     case PSU_CMD_RAIL_VOLTS_LCRIT:
> +     case PSU_CMD_RAIL_AMPS_HCRIT:
> +     case PSU_CMD_RAIL_VOLTS:
>       case PSU_CMD_RAIL_AMPS:
>       case PSU_CMD_RAIL_WATTS:
>               ret = corsairpsu_usb_cmd(priv, 2, PSU_CMD_SELECT_RAIL, rail, 
> NULL);
> @@ -229,9 +243,13 @@ static int corsairpsu_get_value(struct corsairpsu_data 
> *priv, u8 cmd, u8 rail, l
>        */
>       tmp = ((long)data[3] << 24) + (data[2] << 16) + (data[1] << 8) + 
> data[0];
>       switch (cmd) {
> +     case PSU_CMD_RAIL_VOLTS_HCRIT:
> +     case PSU_CMD_RAIL_VOLTS_LCRIT:
> +     case PSU_CMD_RAIL_AMPS_HCRIT:
> +     case PSU_CMD_TEMP_HCRIT:
>       case PSU_CMD_IN_VOLTS:
>       case PSU_CMD_IN_AMPS:
> -     case PSU_CMD_RAIL_OUT_VOLTS:
> +     case PSU_CMD_RAIL_VOLTS:
>       case PSU_CMD_RAIL_AMPS:
>       case PSU_CMD_TEMP0:
>       case PSU_CMD_TEMP1:
> @@ -256,18 +274,70 @@ static int corsairpsu_get_value(struct corsairpsu_data 
> *priv, u8 cmd, u8 rail, l
>       return ret;
>  }
>  
> +static void corsairpsu_get_criticals(struct corsairpsu_data *priv)
> +{
> +     long tmp;
> +     int rail;
> +     int ret;
> +
> +     ret = corsairpsu_get_value(priv, PSU_CMD_TEMP_HCRIT, 0, &tmp);
> +     if (ret < 0)
> +             pr_debug("%s: unable to read temp0 critical value\n", 
> DRIVER_NAME);
> +     else
> +             priv->crit_values[TEMP_HCRIT] = tmp;
> +
> +     ret = corsairpsu_get_value(priv, PSU_CMD_TEMP_HCRIT, 1, &tmp);
> +     if (ret < 0)
> +             pr_debug("%s: unable to read temp1 cirtical value\n", 
> DRIVER_NAME);
> +     else
> +             priv->crit_values[TEMP_HCRIT + 1] = tmp;
> +
> +     for (rail = 0; rail < RAIL_COUNT; ++rail) {
> +             ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS_HCRIT, 
> rail, &tmp);
> +             if (ret < 0) {
> +                     pr_debug("%s: unable to read volts rail %d high 
> critical value\n",
> +                              DRIVER_NAME, rail);
> +             } else {
> +                     priv->crit_values[VOLTS_RAIL_HCRIT + rail] = tmp;
> +             }
> +     }
> +
> +     for (rail = 0; rail < RAIL_COUNT; ++rail) {
> +             ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS_LCRIT, 
> rail, &tmp);
> +             if (ret < 0) {
> +                     pr_debug("%s: unable to read volts rail %d low critical 
> value\n",
> +                              DRIVER_NAME, rail);
> +             } else {
> +                     priv->crit_values[VOLTS_RAIL_LCRIT + rail] = tmp;
> +             }

I am not happy with this code. First, it is quite complex. Second,
it uses crit_values[] to indicate both valid limits and error codes.
That is mostly fine until there is ever a negative limit (which can happen
if there is ever a low temperature limit).

It would be much better to have a limit_supported bit map as well as limit 
arrays.
On top of that, I am not sure if bundling all limits into a single array is 
worth it.
Something like

                ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS_LCRIT, 
rail, &tmp);
                if (ret == 0) {
                        priv->lcrit_in_supported |= BIT(rail);
                        priv->lcrit_in[rail] = tmp;
                }

would be much easier to understand, and it would and be much less error prone.

The is_visible function could then simply check for
                if (priv->lcrit_in_supported & BIT(channel))
to determine if limits are supported for a channel.

I also don't see a value in the debug messages. That is either is a bug, or it 
is
normal operation for some PSUs. If it is a bug, it should be reported as such
and result in an error. If it is normal operation, the result can be seen
in the non-existing attribute, and there is no need for an extra message.

> +     }
> +
> +     for (rail = 0; rail < RAIL_COUNT; ++rail) {
> +             ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS_HCRIT, rail, 
> &tmp);
> +             if (ret < 0) {
> +                     pr_debug("%s: unable to read amps rail %d hight 
> critical value\n",
> +                              DRIVER_NAME, rail);
> +             } else {
> +                     priv->crit_values[AMPS_RAIL_HCRIT + rail] = tmp;
> +             }
> +     }
> +}
> +
>  static umode_t corsairpsu_hwmon_ops_is_visible(const void *data, enum 
> hwmon_sensor_types type,
>                                              u32 attr, int channel)
>  {
> -     if (type == hwmon_temp && (attr == hwmon_temp_input || attr == 
> hwmon_temp_label))
> +     if (type == hwmon_temp && (attr == hwmon_temp_input || attr == 
> hwmon_temp_label ||
> +                                attr == hwmon_temp_crit))
>               return 0444;
>       else if (type == hwmon_fan && (attr == hwmon_fan_input || attr == 
> hwmon_fan_label))
>               return 0444;
>       else if (type == hwmon_power && (attr == hwmon_power_input || attr == 
> hwmon_power_label))
>               return 0444;
> -     else if (type == hwmon_in && (attr == hwmon_in_input || attr == 
> hwmon_in_label))
> +     else if (type == hwmon_in && (attr == hwmon_in_input || attr == 
> hwmon_in_label ||
> +                                   attr == hwmon_in_lcrit || attr == 
> hwmon_in_crit))
>               return 0444;
> -     else if (type == hwmon_curr && (attr == hwmon_curr_input || attr == 
> hwmon_curr_label))
> +     else if (type == hwmon_curr && (attr == hwmon_curr_input || attr == 
> hwmon_curr_label ||
> +                                     attr == hwmon_curr_crit))
>               return 0444;
>  
>       return 0;
> @@ -277,11 +347,18 @@ static int corsairpsu_hwmon_ops_read(struct device 
> *dev, enum hwmon_sensor_types
>                                    int channel, long *val)
>  {
>       struct corsairpsu_data *priv = dev_get_drvdata(dev);
> -     int ret;
> -
> -     if (type == hwmon_temp && attr == hwmon_temp_input && channel < 2) {
> -             ret = corsairpsu_get_value(priv, channel ? PSU_CMD_TEMP1 : 
> PSU_CMD_TEMP0, channel,
> -                                        val);
> +     int ret = 0;
> +
> +     if (type == hwmon_temp && channel < 2) {
> +             if (attr == hwmon_temp_input) {
> +                     ret = corsairpsu_get_value(priv, channel ? 
> PSU_CMD_TEMP1 : PSU_CMD_TEMP0,
> +                                                channel, val);
> +             } else if (attr == hwmon_temp_crit) {
> +                     if (priv->crit_values[TEMP_HCRIT + channel] != 
> -EOPNOTSUPP)
> +                             *val = priv->crit_values[TEMP_HCRIT + channel];
> +                     else
> +                             ret = -EOPNOTSUPP;
> +             }
>       } else if (type == hwmon_fan && attr == hwmon_fan_input) {
>               ret = corsairpsu_get_value(priv, PSU_CMD_FAN, 0, val);
>       } else if (type == hwmon_power && attr == hwmon_power_input) {
> @@ -295,27 +372,48 @@ static int corsairpsu_hwmon_ops_read(struct device 
> *dev, enum hwmon_sensor_types
>               default:
>                       return -EOPNOTSUPP;
>               }
> -     } else if (type == hwmon_in && attr == hwmon_in_input) {
> -             switch (channel) {
> -             case 0:
> -                     ret = corsairpsu_get_value(priv, PSU_CMD_IN_VOLTS, 0, 
> val);
> -                     break;
> -             case 1 ... 3:
> -                     ret = corsairpsu_get_value(priv, 
> PSU_CMD_RAIL_OUT_VOLTS, channel - 1, val);
> -                     break;
> -             default:
> -                     return -EOPNOTSUPP;
> +     } else if (type == hwmon_in) {
> +             if (attr == hwmon_in_input) {
> +                     switch (channel) {
> +                     case 0:
> +                             ret = corsairpsu_get_value(priv, 
> PSU_CMD_IN_VOLTS, 0, val);
> +                             break;
> +                     case 1 ... 3:
> +                             ret = corsairpsu_get_value(priv, 
> PSU_CMD_RAIL_VOLTS, channel - 1,
> +                                                        val);
> +                             break;
> +                     default:
> +                             return -EOPNOTSUPP;
> +                     }
> +             } else if (attr == hwmon_in_crit && channel > 0 && channel < 4) 
> {
> +                     if (priv->crit_values[VOLTS_RAIL_HCRIT + channel - 1] 
> != -EOPNOTSUPP)
> +                             *val = priv->crit_values[VOLTS_RAIL_HCRIT + 
> channel - 1];
> +                     else
> +                             ret = -EOPNOTSUPP;
> +             } else if (attr == hwmon_in_lcrit && channel > 0 && channel < 
> 4) {
> +                     if (priv->crit_values[VOLTS_RAIL_LCRIT + channel - 1] 
> != -EOPNOTSUPP)
> +                             *val = priv->crit_values[VOLTS_RAIL_LCRIT + 
> channel - 1];
> +                     else
> +                             ret = -EOPNOTSUPP;
>               }
> -     } else if (type == hwmon_curr && attr == hwmon_curr_input) {
> -             switch (channel) {
> -             case 0:
> -                     ret = corsairpsu_get_value(priv, PSU_CMD_IN_AMPS, 0, 
> val);
> -                     break;
> -             case 1 ... 3:
> -                     ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS, 
> channel - 1, val);
> -                     break;
> -             default:
> -                     return -EOPNOTSUPP;
> +     } else if (type == hwmon_curr) {
> +             if (attr == hwmon_curr_input) {
> +                     switch (channel) {
> +                     case 0:
> +                             ret = corsairpsu_get_value(priv, 
> PSU_CMD_IN_AMPS, 0, val);
> +                             break;
> +                     case 1 ... 3:
> +                             ret = corsairpsu_get_value(priv, 
> PSU_CMD_RAIL_AMPS, channel - 1,
> +                                                        val);
> +                             break;
> +                     default:
> +                             return -EOPNOTSUPP;
> +                     }
> +             } else if (attr == hwmon_curr_crit && channel > 0 && channel < 
> 4) {
> +                     if (priv->crit_values[AMPS_RAIL_HCRIT + channel - 1] != 
> -EOPNOTSUPP)
> +                             *val = priv->crit_values[AMPS_RAIL_HCRIT + 
> channel - 1];
> +                     else
> +                             ret = -EOPNOTSUPP;
>               }

Due to the channel range check, this returns a random value if the function is 
ever called
with attr == hwmon_curr_crit && channel == 0. This shows that the channel check 
is
really unnecessary (but also that the code is getting dificult to understand).

>       } else {
>               return -EOPNOTSUPP;

I think it is time to split this code into per-type functions. It is getting 
unreadable.

> @@ -360,8 +458,8 @@ static const struct hwmon_channel_info *corsairpsu_info[] 
> = {
>       HWMON_CHANNEL_INFO(chip,
>                          HWMON_C_REGISTER_TZ),
>       HWMON_CHANNEL_INFO(temp,
> -                        HWMON_T_INPUT | HWMON_T_LABEL,
> -                        HWMON_T_INPUT | HWMON_T_LABEL),
> +                        HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
> +                        HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT),
>       HWMON_CHANNEL_INFO(fan,
>                          HWMON_F_INPUT | HWMON_F_LABEL),
>       HWMON_CHANNEL_INFO(power,
> @@ -371,14 +469,14 @@ static const struct hwmon_channel_info 
> *corsairpsu_info[] = {
>                          HWMON_P_INPUT | HWMON_P_LABEL),
>       HWMON_CHANNEL_INFO(in,
>                          HWMON_I_INPUT | HWMON_I_LABEL,
> -                        HWMON_I_INPUT | HWMON_I_LABEL,
> -                        HWMON_I_INPUT | HWMON_I_LABEL,
> -                        HWMON_I_INPUT | HWMON_I_LABEL),
> +                        HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | 
> HWMON_I_CRIT,
> +                        HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | 
> HWMON_I_CRIT,
> +                        HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | 
> HWMON_I_CRIT),
>       HWMON_CHANNEL_INFO(curr,
>                          HWMON_C_INPUT | HWMON_C_LABEL,
> -                        HWMON_C_INPUT | HWMON_C_LABEL,
> -                        HWMON_C_INPUT | HWMON_C_LABEL,
> -                        HWMON_C_INPUT | HWMON_C_LABEL),
> +                        HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT,
> +                        HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT,
> +                        HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT),
>       NULL
>  };
>  
> @@ -472,6 +570,7 @@ static void corsairpsu_debugfs_init(struct 
> corsairpsu_data *priv)
>  static int corsairpsu_probe(struct hid_device *hdev, const struct 
> hid_device_id *id)
>  {
>       struct corsairpsu_data *priv;
> +     int i;
>       int ret;
>  
>       priv = devm_kzalloc(&hdev->dev, sizeof(struct corsairpsu_data), 
> GFP_KERNEL);
> @@ -482,6 +581,9 @@ static int corsairpsu_probe(struct hid_device *hdev, 
> const struct hid_device_id
>       if (!priv->cmd_buffer)
>               return -ENOMEM;
>  
> +     for (i = 0; i < CRIT_VALUES_COUNT; ++i)
> +             priv->crit_values[i] = -EOPNOTSUPP;
> +
>       ret = hid_parse(hdev);
>       if (ret)
>               return ret;
> @@ -513,6 +615,9 @@ static int corsairpsu_probe(struct hid_device *hdev, 
> const struct hid_device_id
>               goto fail_and_stop;
>       }
>  
> +     /* this can fail and is considered non-fatal */
> +     corsairpsu_get_criticals(priv);
> +

The comment does not add value, but it does add confusion. "Fail" implies
that something is wrong. However, I suspect that it only means that not all
power supplies report limits. That is not a failure, it is normal operation.

Thanks,
Guenter

>       priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, 
> "corsairpsu", priv,
>                                                         
> &corsairpsu_chip_info, 0);
>  
> 

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