hwmon: (it87) Display fan outputs in automatic mode as such

The it87 driver doesn't yet support automatic fan control. Let it at
least tell the user when a fan output is in automatic mode. Also let
the user switch from automatic mode (possibly set by the BIOS) to
manual mode and back without losing the settings.

Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 0ffe84d..49022bd 100644 (file)
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -281,7 +281,14 @@ struct it87_data {
        u32 alarms;             /* Register encoding, combined */
        u8 fan_main_ctrl;       /* Register value */
        u8 fan_ctl;             /* Register value */
-       u8 manual_pwm_ctl[3];   /* manual PWM value set by user */
+
+       /* The following 3 arrays correspond to the same registers. The
+        * meaning of bits 6-0 depends on the value of bit 7, and we want
+        * to preserve settings on mode changes, so we have to track all
+        * values separately. */
+       u8 pwm_ctrl[3];         /* Register value */
+       u8 pwm_duty[3];         /* Manual PWM value set by user (bit 6-0) */
+       u8 pwm_temp_map[3];     /* PWM to temp. chan. mapping (bits 1-0) */
 };
 
 static inline int has_16bit_fans(const struct it87_data *data)
@@ -531,6 +538,19 @@ show_sensor_offset(2);
 show_sensor_offset(3);
 
 /* 3 Fans */
+
+static int pwm_mode(const struct it87_data *data, int nr)
+{
+       int ctrl = data->fan_main_ctrl & (1 << nr);
+
+       if (ctrl == 0)                                  /* Full speed */
+               return 0;
+       if (data->pwm_ctrl[nr] & 0x80)                  /* Automatic mode */
+               return 2;
+       else                                            /* Manual mode */
+               return 1;
+}
+
 static ssize_t show_fan(struct device *dev, struct device_attribute *attr,
                char *buf)
 {
@@ -567,7 +587,7 @@ static ssize_t show_pwm_enable(struct device *dev, struct device_attribute *attr
        int nr = sensor_attr->index;
 
        struct it87_data *data = it87_update_device(dev);
-       return sprintf(buf,"%d\n", (data->fan_main_ctrl & (1 << nr)) ? 1 : 0);
+       return sprintf(buf, "%d\n", pwm_mode(data, nr));
 }
 static ssize_t show_pwm(struct device *dev, struct device_attribute *attr,
                char *buf)
@@ -576,7 +596,7 @@ static ssize_t show_pwm(struct device *dev, struct device_attribute *attr,
        int nr = sensor_attr->index;
 
        struct it87_data *data = it87_update_device(dev);
-       return sprintf(buf,"%d\n", data->manual_pwm_ctl[nr]);
+       return sprintf(buf, "%d\n", PWM_FROM_REG(data->pwm_duty[nr]));
 }
 static ssize_t show_pwm_freq(struct device *dev, struct device_attribute *attr,
                char *buf)
@@ -660,6 +680,9 @@ static ssize_t set_pwm_enable(struct device *dev,
        struct it87_data *data = dev_get_drvdata(dev);
        int val = simple_strtol(buf, NULL, 10);
 
+       if (val < 0 || val > 2)
+               return -EINVAL;
+
        mutex_lock(&data->update_lock);
 
        if (val == 0) {
@@ -670,15 +693,15 @@ static ssize_t set_pwm_enable(struct device *dev,
                /* set on/off mode */
                data->fan_main_ctrl &= ~(1 << nr);
                it87_write_value(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
-       } else if (val == 1) {
+       } else {
+               if (val == 1)                           /* Manual mode */
+                       data->pwm_ctrl[nr] = data->pwm_duty[nr];
+               else                                    /* Automatic mode */
+                       data->pwm_ctrl[nr] = 0x80 | data->pwm_temp_map[nr];
+               it87_write_value(data, IT87_REG_PWM(nr), data->pwm_ctrl[nr]);
                /* set SmartGuardian mode */
                data->fan_main_ctrl |= (1 << nr);
                it87_write_value(data, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
-               /* set saved pwm value, clear FAN_CTLX PWM mode bit */
-               it87_write_value(data, IT87_REG_PWM(nr), PWM_TO_REG(data->manual_pwm_ctl[nr]));
-       } else {
-               mutex_unlock(&data->update_lock);
-               return -EINVAL;
        }
 
        mutex_unlock(&data->update_lock);
@@ -697,9 +720,13 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
                return -EINVAL;
 
        mutex_lock(&data->update_lock);
-       data->manual_pwm_ctl[nr] = val;
-       if (data->fan_main_ctrl & (1 << nr))
-               it87_write_value(data, IT87_REG_PWM(nr), PWM_TO_REG(data->manual_pwm_ctl[nr]));
+       data->pwm_duty[nr] = PWM_TO_REG(val);
+       /* If we are in manual mode, write the duty cycle immediately;
+        * otherwise, just store it for later use. */
+       if (!(data->pwm_ctrl[nr] & 0x80)) {
+               data->pwm_ctrl[nr] = data->pwm_duty[nr];
+               it87_write_value(data, IT87_REG_PWM(nr), data->pwm_ctrl[nr]);
+       }
        mutex_unlock(&data->update_lock);
        return count;
 }
@@ -1387,15 +1414,17 @@ static void __devinit it87_init_device(struct platform_device *pdev)
        int tmp, i;
        u8 mask;
 
-       /* initialize to sane defaults:
-        * - if the chip is in manual pwm mode, this will be overwritten with
-        *   the actual settings on the chip (so in this case, initialization
-        *   is not needed)
-        * - if in automatic or on/off mode, we could switch to manual mode,
-        *   read the registers and set manual_pwm_ctl accordingly, but currently
-        *   this is not implemented, so we initialize to something sane */
+       /* For each PWM channel:
+        * - If it is in automatic mode, setting to manual mode should set
+        *   the fan to full speed by default.
+        * - If it is in manual mode, we need a mapping to temperature
+        *   channels to use when later setting to automatic mode later.
+        *   Use a 1:1 mapping by default (we are clueless.)
+        * In both cases, the value can (and should) be changed by the user
+        * prior to switching to a different mode. */
        for (i = 0; i < 3; i++) {
-               data->manual_pwm_ctl[i] = 0xff;
+               data->pwm_temp_map[i] = i;
+               data->pwm_duty[i] = 0x7f;       /* Full speed */
        }
 
        /* Some chips seem to have default value 0xff for all limit
@@ -1461,30 +1490,21 @@ static void __devinit it87_init_device(struct platform_device *pdev)
        /* Fan input pins may be used for alternative functions */
        data->has_fan &= ~sio_data->skip_fan;
 
-       /* Set current fan mode registers and the default settings for the
-        * other mode registers */
-       for (i = 0; i < 3; i++) {
-               if (data->fan_main_ctrl & (1 << i)) {
-                       /* pwm mode */
-                       tmp = it87_read_value(data, IT87_REG_PWM(i));
-                       if (tmp & 0x80) {
-                               /* automatic pwm - not yet implemented, but
-                                * leave the settings made by the BIOS alone
-                                * until a change is requested via the sysfs
-                                * interface */
-                       } else {
-                               /* manual pwm */
-                               data->manual_pwm_ctl[i] = PWM_FROM_REG(tmp);
-                       }
-               }
-       }
-
        /* Start monitoring */
        it87_write_value(data, IT87_REG_CONFIG,
                         (it87_read_value(data, IT87_REG_CONFIG) & 0x36)
                         | (update_vbat ? 0x41 : 0x01));
 }
 
+static void it87_update_pwm_ctrl(struct it87_data *data, int nr)
+{
+       data->pwm_ctrl[nr] = it87_read_value(data, IT87_REG_PWM(nr));
+       if (data->pwm_ctrl[nr] & 0x80)  /* Automatic mode */
+               data->pwm_temp_map[nr] = data->pwm_ctrl[nr] & 0x03;
+       else                            /* Manual mode */
+               data->pwm_duty[nr] = data->pwm_ctrl[nr] & 0x7f;
+}
+
 static struct it87_data *it87_update_device(struct device *dev)
 {
        struct it87_data *data = dev_get_drvdata(dev);
@@ -1551,9 +1571,12 @@ static struct it87_data *it87_update_device(struct device *dev)
                        it87_read_value(data, IT87_REG_ALARM1) |
                        (it87_read_value(data, IT87_REG_ALARM2) << 8) |
                        (it87_read_value(data, IT87_REG_ALARM3) << 16);
+
                data->fan_main_ctrl = it87_read_value(data,
                                IT87_REG_FAN_MAIN_CTRL);
                data->fan_ctl = it87_read_value(data, IT87_REG_FAN_CTL);
+               for (i = 0; i < 3; i++)
+                       it87_update_pwm_ctrl(data, i);
 
                data->sensor = it87_read_value(data, IT87_REG_TEMP_ENABLE);
                /* The 8705 does not have VID capability.