Expose fanX_target, pwmX and pwmX_enable hwmon sysfs attributes.

Fans in a PMBus device are driven by the configuration of two registers:
FAN_CONFIG_x_y and FAN_COMMAND_x: FAN_CONFIG_x_y dictates how the fan
and the tacho operate (if installed), while FAN_COMMAND_x sets the
desired fan rate. The unit of FAN_COMMAND_x is dependent on the
operational fan mode, RPM or PWM percent duty, as determined by the
corresponding FAN_CONFIG_x_y.

The mapping of fanX_target, pwmX and pwmX_enable onto FAN_CONFIG_x_y and
FAN_COMMAND_x is implemented with the addition of virtual registers and
generic implementations in the core:

1. PMBUS_VIRT_FAN_TARGET_x
2. PMBUS_VIRT_PWM_x
3. PMBUS_VIRT_PWM_ENABLE_x

The facilitate the necessary side-effects of each access. Examples of
the read case, assuming m = 1, b = 0, R = 0:

             Read     |              With              || Gives
         -------------------------------------------------------
           Attribute  | FAN_CONFIG_x_y | FAN_COMMAND_y || Value
         ----------------------------------------------++-------
          fanX_target | ~PB_FAN_z_RPM  | 0x0001        || 1
          pwm1        | ~PB_FAN_z_RPM  | 0x0064        || 255
          pwmX_enable | ~PB_FAN_z_RPM  | 0x0001        || 1
          fanX_target |  PB_FAN_z_RPM  | 0x0001        || 1
          pwm1        |  PB_FAN_z_RPM  | 0x0064        || 0
          pwmX_enable |  PB_FAN_z_RPM  | 0x0001        || 1

And the write case:

             Write    | With  ||               Sets
         -------------+-------++----------------+---------------
           Attribute  | Value || FAN_CONFIG_x_y | FAN_COMMAND_x
         -------------+-------++----------------+---------------
          fanX_target | 1     ||  PB_FAN_z_RPM  | 0x0001
          pwmX        | 255   || ~PB_FAN_z_RPM  | 0x0064
          pwmX_enable | 1     || ~PB_FAN_z_RPM  | 0x0064

Also, the DIRECT mode scaling of some controllers is different between
RPM and PWM percent duty control modes, so PSC_PWM is introduced to
capture the necessary coefficients.

Signed-off-by: Andrew Jeffery <and...@aj.id.au>
---

v1 -> v2:
* Convert to using virtual registers
* Drop struct pmbus_fan_ctrl
* Introduce PSC_PWM
* Drop struct pmbus_coeffs
* Drop additional callbacks

 drivers/hwmon/pmbus/pmbus.h      |  19 ++++
 drivers/hwmon/pmbus/pmbus_core.c | 215 +++++++++++++++++++++++++++++++++++----
 2 files changed, 217 insertions(+), 17 deletions(-)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index bfcb13bae34b..226a37bd525f 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -190,6 +190,20 @@ enum pmbus_regs {
        PMBUS_VIRT_VMON_UV_FAULT_LIMIT,
        PMBUS_VIRT_VMON_OV_FAULT_LIMIT,
        PMBUS_VIRT_STATUS_VMON,
+
+       /* Fan control */
+       PMBUS_VIRT_FAN_TARGET_1,
+       PMBUS_VIRT_FAN_TARGET_2,
+       PMBUS_VIRT_FAN_TARGET_3,
+       PMBUS_VIRT_FAN_TARGET_4,
+       PMBUS_VIRT_PWM_1,
+       PMBUS_VIRT_PWM_2,
+       PMBUS_VIRT_PWM_3,
+       PMBUS_VIRT_PWM_4,
+       PMBUS_VIRT_PWM_ENABLE_1,
+       PMBUS_VIRT_PWM_ENABLE_2,
+       PMBUS_VIRT_PWM_ENABLE_3,
+       PMBUS_VIRT_PWM_ENABLE_4,
 };
 
 /*
@@ -223,6 +237,8 @@ enum pmbus_regs {
 #define PB_FAN_1_RPM                   BIT(6)
 #define PB_FAN_1_INSTALLED             BIT(7)
 
+enum pmbus_fan_mode { percent = 0, rpm };
+
 /*
  * STATUS_BYTE, STATUS_WORD (lower)
  */
@@ -313,6 +329,7 @@ enum pmbus_sensor_classes {
        PSC_POWER,
        PSC_TEMPERATURE,
        PSC_FAN,
+       PSC_PWM,
        PSC_NUM_CLASSES         /* Number of power sensor classes */
 };
 
@@ -413,6 +430,8 @@ int pmbus_write_byte_data(struct i2c_client *client, int 
page, u8 reg,
                          u8 value);
 int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
                           u8 mask, u8 value);
+int pmbus_update_fan(struct i2c_client *client, int page, int id,
+                    int config, int mask, int command);
 void pmbus_clear_faults(struct i2c_client *client);
 bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg);
 bool pmbus_check_word_register(struct i2c_client *client, int page, int reg);
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ba59eaef2e07..712a8b6c4bd6 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -63,6 +63,7 @@ struct pmbus_sensor {
        u16 reg;                /* register */
        enum pmbus_sensor_classes class;        /* sensor class */
        bool update;            /* runtime sensor update needed */
+       bool convert;           /* Whether or not to apply linear/vid/direct */
        int data;               /* Sensor data.
                                   Negative if there was a read error */
 };
@@ -118,6 +119,27 @@ struct pmbus_data {
        u8 currpage;
 };
 
+static const int pmbus_fan_rpm_mask[] = {
+       PB_FAN_1_RPM,
+       PB_FAN_2_RPM,
+       PB_FAN_1_RPM,
+       PB_FAN_2_RPM,
+};
+
+static const int pmbus_fan_config_registers[] = {
+       PMBUS_FAN_CONFIG_12,
+       PMBUS_FAN_CONFIG_12,
+       PMBUS_FAN_CONFIG_34,
+       PMBUS_FAN_CONFIG_34
+};
+
+static const int pmbus_fan_command_registers[] = {
+       PMBUS_FAN_COMMAND_1,
+       PMBUS_FAN_COMMAND_2,
+       PMBUS_FAN_COMMAND_3,
+       PMBUS_FAN_COMMAND_4,
+};
+
 void pmbus_clear_cache(struct i2c_client *client)
 {
        struct pmbus_data *data = i2c_get_clientdata(client);
@@ -188,6 +210,29 @@ int pmbus_write_word_data(struct i2c_client *client, u8 
page, u8 reg, u16 word)
 }
 EXPORT_SYMBOL_GPL(pmbus_write_word_data);
 
+int pmbus_update_fan(struct i2c_client *client, int page, int id,
+                              int config, int mask, int command)
+{
+       int from, to;
+       int rv;
+
+       from = pmbus_read_byte_data(client, page,
+                                   pmbus_fan_config_registers[id]);
+       if (from < 0)
+               return from;
+
+       to = (from & ~mask) | (config & mask);
+
+       rv = pmbus_write_byte_data(client, page,
+                                  pmbus_fan_config_registers[id], to);
+       if (rv < 0)
+               return rv;
+
+       return pmbus_write_word_data(client, page,
+                                    pmbus_fan_command_registers[id], command);
+}
+EXPORT_SYMBOL_GPL(pmbus_update_fan);
+
 /*
  * _pmbus_write_word_data() is similar to pmbus_write_word_data(), but checks 
if
  * a device specific mapping function exists and calls it if necessary.
@@ -197,15 +242,47 @@ static int _pmbus_write_word_data(struct i2c_client 
*client, int page, int reg,
 {
        struct pmbus_data *data = i2c_get_clientdata(client);
        const struct pmbus_driver_info *info = data->info;
-       int status;
+       int status = -ENODATA;
 
        if (info->write_word_data) {
                status = info->write_word_data(client, page, reg, word);
                if (status != -ENODATA)
                        return status;
        }
-       if (reg >= PMBUS_VIRT_BASE)
-               return -ENXIO;
+       if (status == -ENODATA && reg >= PMBUS_VIRT_BASE) {
+               int id, bit;
+
+               switch (reg) {
+               case PMBUS_VIRT_FAN_TARGET_1:
+               case PMBUS_VIRT_FAN_TARGET_2:
+               case PMBUS_VIRT_FAN_TARGET_3:
+               case PMBUS_VIRT_FAN_TARGET_4:
+                       id = reg - PMBUS_VIRT_FAN_TARGET_1;
+                       bit = pmbus_fan_rpm_mask[id];
+                       status = pmbus_update_fan(client, page, id, bit, bit,
+                                               word);
+                       break;
+               case PMBUS_VIRT_PWM_1:
+               case PMBUS_VIRT_PWM_2:
+               case PMBUS_VIRT_PWM_3:
+               case PMBUS_VIRT_PWM_4:
+               {
+                       long command = word;
+
+                       id = reg - PMBUS_VIRT_PWM_1;
+                       bit = pmbus_fan_rpm_mask[id];
+                       command *= 100;
+                       command /= 255;
+                       status = pmbus_update_fan(client, page, id, 0, bit,
+                                               command);
+                       break;
+               }
+               default:
+                       status = -ENXIO;
+                       break;
+               }
+               return status;
+       }
        return pmbus_write_word_data(client, page, reg, word);
 }
 
@@ -221,6 +298,9 @@ int pmbus_read_word_data(struct i2c_client *client, u8 
page, u8 reg)
 }
 EXPORT_SYMBOL_GPL(pmbus_read_word_data);
 
+static int pmbus_get_fan_command(struct i2c_client *client, int page, int id,
+                                enum pmbus_fan_mode mode);
+
 /*
  * _pmbus_read_word_data() is similar to pmbus_read_word_data(), but checks if
  * a device specific mapping function exists and calls it if necessary.
@@ -229,15 +309,49 @@ static int _pmbus_read_word_data(struct i2c_client 
*client, int page, int reg)
 {
        struct pmbus_data *data = i2c_get_clientdata(client);
        const struct pmbus_driver_info *info = data->info;
-       int status;
+       int status = -ENODATA;
 
        if (info->read_word_data) {
                status = info->read_word_data(client, page, reg);
                if (status != -ENODATA)
                        return status;
        }
-       if (reg >= PMBUS_VIRT_BASE)
-               return -ENXIO;
+       if (status == -ENODATA && reg >= PMBUS_VIRT_BASE) {
+               int id;
+
+               switch (reg) {
+               case PMBUS_VIRT_FAN_TARGET_1:
+               case PMBUS_VIRT_FAN_TARGET_2:
+               case PMBUS_VIRT_FAN_TARGET_3:
+               case PMBUS_VIRT_FAN_TARGET_4:
+                       id = reg - PMBUS_VIRT_FAN_TARGET_1;
+                       status = pmbus_get_fan_command(client, page, id, rpm);
+                       break;
+               case PMBUS_VIRT_PWM_1:
+               case PMBUS_VIRT_PWM_2:
+               case PMBUS_VIRT_PWM_3:
+               case PMBUS_VIRT_PWM_4:
+               {
+                       long rv;
+
+                       id = reg - PMBUS_VIRT_PWM_1;
+                       rv = pmbus_get_fan_command(client, page, id, percent);
+                       if (rv < 0)
+                               return rv;
+
+                       rv *= 255;
+                       rv /= 100;
+
+                       status = rv;
+                       break;
+               }
+               default:
+                       status = -ENXIO;
+                       break;
+               }
+
+               return status;
+       }
        return pmbus_read_word_data(client, page, reg);
 }
 
@@ -304,6 +418,23 @@ static int _pmbus_read_byte_data(struct i2c_client 
*client, int page, int reg)
        return pmbus_read_byte_data(client, page, reg);
 }
 
+static int pmbus_get_fan_command(struct i2c_client *client, int page, int id,
+                                enum pmbus_fan_mode mode)
+{
+       int config;
+
+       config = _pmbus_read_byte_data(client, page,
+                                      pmbus_fan_config_registers[id]);
+       if (config < 0)
+               return config;
+
+       if ((mode == rpm) != (!!(config & pmbus_fan_rpm_mask[id])))
+               return 0;
+
+       return _pmbus_read_word_data(client, page,
+                                    pmbus_fan_command_registers[id]);
+}
+
 static void pmbus_clear_fault_page(struct i2c_client *client, int page)
 {
        _pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
@@ -489,7 +620,7 @@ static long pmbus_reg2data_direct(struct pmbus_data *data,
        /* X = 1/m * (Y * 10^-R - b) */
        R = -R;
        /* scale result to milli-units for everything but fans */
-       if (sensor->class != PSC_FAN) {
+       if (!(sensor->class == PSC_FAN || sensor->class == PSC_PWM)) {
                R += 3;
                b *= 1000;
        }
@@ -539,6 +670,9 @@ static long pmbus_reg2data(struct pmbus_data *data, struct 
pmbus_sensor *sensor)
 {
        long val;
 
+       if (!sensor->convert)
+               return sensor->data;
+
        switch (data->info->format[sensor->class]) {
        case direct:
                val = pmbus_reg2data_direct(data, sensor);
@@ -642,7 +776,7 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data,
        }
 
        /* Calculate Y = (m * X + b) * 10^R */
-       if (sensor->class != PSC_FAN) {
+       if (!(sensor->class == PSC_FAN || sensor->class == PSC_PWM)) {
                R -= 3;         /* Adjust R and b for data in milli-units */
                b *= 1000;
        }
@@ -673,6 +807,9 @@ static u16 pmbus_data2reg(struct pmbus_data *data,
 {
        u16 regval;
 
+       if (!sensor->convert)
+               return val;
+
        switch (data->info->format[sensor->class]) {
        case direct:
                regval = pmbus_data2reg_direct(data, sensor, val);
@@ -895,12 +1032,13 @@ static struct pmbus_sensor *pmbus_add_sensor(struct 
pmbus_data *data,
                return NULL;
        a = &sensor->attribute;
 
-       snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
-                name, seq, type);
+       snprintf(sensor->name, sizeof(sensor->name), "%s%d%s%s",
+                name, seq, type ? "_" : "", type ? type : "");
        sensor->page = page;
        sensor->reg = reg;
        sensor->class = class;
        sensor->update = update;
+       sensor->convert = true;
        pmbus_dev_attr_init(a, sensor->name,
                            readonly ? S_IRUGO : S_IRUGO | S_IWUSR,
                            pmbus_show_sensor, pmbus_set_sensor);
@@ -1558,13 +1696,6 @@ static const int pmbus_fan_registers[] = {
        PMBUS_READ_FAN_SPEED_4
 };
 
-static const int pmbus_fan_config_registers[] = {
-       PMBUS_FAN_CONFIG_12,
-       PMBUS_FAN_CONFIG_12,
-       PMBUS_FAN_CONFIG_34,
-       PMBUS_FAN_CONFIG_34
-};
-
 static const int pmbus_fan_status_registers[] = {
        PMBUS_STATUS_FAN_12,
        PMBUS_STATUS_FAN_12,
@@ -1587,6 +1718,47 @@ static const u32 pmbus_fan_status_flags[] = {
 };
 
 /* Fans */
+static int pmbus_add_fan_ctrl(struct i2c_client *client,
+               struct pmbus_data *data, int index, int page, int id,
+               u8 config)
+{
+       struct pmbus_sensor *sensor;
+       int rv;
+
+       rv = _pmbus_read_word_data(client, page,
+                                  pmbus_fan_command_registers[id]);
+       if (rv < 0)
+               return rv;
+
+       sensor = pmbus_add_sensor(data, "fan", "target", index, page,
+                                 PMBUS_VIRT_FAN_TARGET_1 + id, PSC_FAN,
+                                 true, false);
+
+       if (!sensor)
+               return -ENOMEM;
+
+       if (!data->info->m[PSC_PWM])
+               return 0;
+
+       sensor = pmbus_add_sensor(data, "pwm", NULL, index, page,
+                                 PMBUS_VIRT_PWM_1 + id, PSC_PWM,
+                                 true, false);
+
+       if (!sensor)
+               return -ENOMEM;
+
+       sensor = pmbus_add_sensor(data, "pwm", "enable", index, page,
+                                 PMBUS_VIRT_PWM_ENABLE_1 + id, PSC_PWM,
+                                 true, false);
+
+       if (!sensor)
+               return -ENOMEM;
+
+       sensor->convert = false;
+
+       return 0;
+}
+
 static int pmbus_add_fan_attributes(struct i2c_client *client,
                                    struct pmbus_data *data)
 {
@@ -1624,6 +1796,15 @@ static int pmbus_add_fan_attributes(struct i2c_client 
*client,
                                             PSC_FAN, true, true) == NULL)
                                return -ENOMEM;
 
+                       /* Fan control */
+                       if (pmbus_check_word_register(client, page,
+                                       pmbus_fan_command_registers[f])) {
+                               ret = pmbus_add_fan_ctrl(client, data, index,
+                                                        page, f, regval);
+                               if (ret < 0)
+                                       return ret;
+                       }
+
                        /*
                         * Each fan status register covers multiple fans,
                         * so we have to do some magic.
-- 
2.11.0

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