hwmon: (lm63) Add support for update_interval sysfs attribute

The update interval is configurable on LM63 and compatibles. Add
support for it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/Documentation/hwmon/lm63 b/Documentation/hwmon/lm63
index af3e8b0ad9c4ad6ff2f4f5aa7e5f4d7e52c16c71..0e695d3567ebd0873f07e11fc97a84a28e58e736 100644 (file)
--- a/Documentation/hwmon/lm63
+++ b/Documentation/hwmon/lm63
@@ -61,9 +61,9 @@ PWM modes: manual and automatic. Automatic mode is not fully implemented yet
 (you cannot define your custom PWM/temperature curve), and mode change isn't
 supported either.
 
-The lm63 driver will not update its values more frequently than every
-second; reading them more often will do no harm, but will return 'old'
-values.
+The lm63 driver will not update its values more frequently than configured with
+the update_interval sysfs attribute; reading them more often will do no harm,
+but will return 'old' values.
 
 The LM64 is effectively an LM63 with GPIO lines. The driver does not
 support these GPIO lines at present.

diff --git a/drivers/hwmon/lm63.c b/drivers/hwmon/lm63.c
index a9e6212ed54aa6e15ead82bbf1f3e0e9e2894229..5f6da52a7219a9b45c3ef38d58074c22a62a7332 100644 (file)
--- a/drivers/hwmon/lm63.c
+++ b/drivers/hwmon/lm63.c
@@ -61,6 +61,7 @@ static const unsigned short normal_i2c[] = { 0x18, 0x4c, 0x4e, I2C_CLIENT_END };
  */
 
 #define LM63_REG_CONFIG1               0x03
+#define LM63_REG_CONVRATE              0x04
 #define LM63_REG_CONFIG2               0xBF
 #define LM63_REG_CONFIG_FAN            0x4A
 
@@ -96,6 +97,11 @@ static const unsigned short normal_i2c[] = { 0x18, 0x4c, 0x4e, I2C_CLIENT_END };
 #define LM96163_REG_REMOTE_TEMP_U_LSB  0x32
 #define LM96163_REG_CONFIG_ENHANCED    0x45
 
+#define LM63_MAX_CONVRATE              9
+
+#define LM63_MAX_CONVRATE_HZ           32
+#define LM96163_MAX_CONVRATE_HZ                26
+
 /*
  * Conversions and various macros
  * For tachometer counts, the LM63 uses 16-bit values.
@@ -132,6 +138,9 @@ static const unsigned short normal_i2c[] = { 0x18, 0x4c, 0x4e, I2C_CLIENT_END };
                                 (val) >= 127000 ? 127 : \
                                 ((val) + 500) / 1000)
 
+#define UPDATE_INTERVAL(max, rate) \
+                       ((1000 << (LM63_MAX_CONVRATE - (rate))) / (max))
+
 /*
  * Functions declaration
  */
@@ -180,9 +189,12 @@ struct lm63_data {
        struct mutex update_lock;
        char valid; /* zero until following fields are valid */
        unsigned long last_updated; /* in jiffies */
-       int kind;
+       enum chips kind;
        int temp2_offset;
 
+       int update_interval;    /* in milliseconds */
+       int max_convrate_hz;
+
        /* registers values */
        u8 config, config_fan;
        u16 fan[2];     /* 0: input
@@ -449,6 +461,58 @@ static ssize_t set_temp2_crit_hyst(struct device *dev,
        return count;
 }
 
+/*
+ * Set conversion rate.
+ * client->update_lock must be held when calling this function.
+ */
+static void lm63_set_convrate(struct i2c_client *client, struct lm63_data *data,
+                             unsigned int interval)
+{
+       int i;
+       unsigned int update_interval;
+
+       /* Shift calculations to avoid rounding errors */
+       interval <<= 6;
+
+       /* find the nearest update rate */
+       update_interval = (1 << (LM63_MAX_CONVRATE + 6)) * 1000
+         / data->max_convrate_hz;
+       for (i = 0; i < LM63_MAX_CONVRATE; i++, update_interval >>= 1)
+               if (interval >= update_interval * 3 / 4)
+                       break;
+
+       i2c_smbus_write_byte_data(client, LM63_REG_CONVRATE, i);
+       data->update_interval = UPDATE_INTERVAL(data->max_convrate_hz, i);
+}
+
+static ssize_t show_update_interval(struct device *dev,
+                                   struct device_attribute *attr, char *buf)
+{
+       struct lm63_data *data = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%u\n", data->update_interval);
+}
+
+static ssize_t set_update_interval(struct device *dev,
+                                  struct device_attribute *attr,
+                                  const char *buf, size_t count)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct lm63_data *data = i2c_get_clientdata(client);
+       unsigned long val;
+       int err;
+
+       err = kstrtoul(buf, 10, &val);
+       if (err)
+               return err;
+
+       mutex_lock(&data->update_lock);
+       lm63_set_convrate(client, data, SENSORS_LIMIT(val, 0, 100000));
+       mutex_unlock(&data->update_lock);
+
+       return count;
+}
+
 static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
                           char *buf)
 {
@@ -499,6 +563,9 @@ static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
 /* Raw alarm file for compatibility */
 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 
+static DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR, show_update_interval,
+                  set_update_interval);
+
 static struct attribute *lm63_attributes[] = {
        &dev_attr_pwm1.attr,
        &dev_attr_pwm1_enable.attr,
@@ -517,6 +584,7 @@ static struct attribute *lm63_attributes[] = {
        &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &dev_attr_alarms.attr,
+       &dev_attr_update_interval.attr,
        NULL
 };
 
@@ -669,6 +737,7 @@ exit:
 static void lm63_init_client(struct i2c_client *client)
 {
        struct lm63_data *data = i2c_get_clientdata(client);
+       u8 convrate;
 
        data->config = i2c_smbus_read_byte_data(client, LM63_REG_CONFIG1);
        data->config_fan = i2c_smbus_read_byte_data(client,
@@ -687,6 +756,21 @@ static void lm63_init_client(struct i2c_client *client)
        if (data->pwm1_freq == 0)
                data->pwm1_freq = 1;
 
+       switch (data->kind) {
+       case lm63:
+       case lm64:
+               data->max_convrate_hz = LM63_MAX_CONVRATE_HZ;
+               break;
+       case lm96163:
+               data->max_convrate_hz = LM96163_MAX_CONVRATE_HZ;
+               break;
+       }
+       convrate = i2c_smbus_read_byte_data(client, LM63_REG_CONVRATE);
+       if (unlikely(convrate > LM63_MAX_CONVRATE))
+               convrate = LM63_MAX_CONVRATE;
+       data->update_interval = UPDATE_INTERVAL(data->max_convrate_hz,
+                                               convrate);
+
        /*
         * For LM96163, check if high resolution PWM
         * and unsigned temperature format is enabled.
@@ -730,10 +814,14 @@ static struct lm63_data *lm63_update_device(struct device *dev)
 {
        struct i2c_client *client = to_i2c_client(dev);
        struct lm63_data *data = i2c_get_clientdata(client);
+       unsigned long next_update;
 
        mutex_lock(&data->update_lock);
 
-       if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+       next_update = data->last_updated
+         + msecs_to_jiffies(data->update_interval) + 1;
+
+       if (time_after(jiffies, next_update) || !data->valid) {
                if (data->config & 0x04) { /* tachometer enabled  */
                        /* order matters for fan1_input */
                        data->fan[0] = i2c_smbus_read_byte_data(client,