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>

1 files changed, 61 insertions, 38 deletions

diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 0ffe84d190bb..49022bd2a0a5 100644
--- 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.