+/*
+ * Slots fan control loop
+ */
+static void do_monitor_slots(struct slots_pid_state *state)
+{
+ s32 temp, integral, derivative;
+ s64 integ_p, deriv_p, prop_p, sum;
+ int i, rc;
+
+ if (--state->ticks != 0)
+ return;
+ state->ticks = SLOTS_PID_INTERVAL;
+
+ DBG("slots:\n");
+
+ /* Check fan status */
+ rc = get_pwm_fan(SLOTS_FAN_PWM_INDEX);
+ if (rc < 0) {
+ printk(KERN_WARNING "Error %d reading slots fan !\n", rc);
+ /* XXX What do we do now ? */
+ } else
+ state->pwm = rc;
+ DBG(" current pwm: %d\n", state->pwm);
+
+ /* Get some sensor readings */
+ temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor,
+ DS1775_TEMP)) << 8;
+ state->last_temp = temp;
+ DBG(" temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
+ FIX32TOPRINT(SLOTS_PID_INPUT_TARGET));
+
+ /* Store temperature and error in history array */
+ state->cur_sample = (state->cur_sample + 1) % SLOTS_PID_HISTORY_SIZE;
+ state->sample_history[state->cur_sample] = temp;
+ state->error_history[state->cur_sample] = temp - SLOTS_PID_INPUT_TARGET;
+
+ /* If first loop, fill the history table */
+ if (state->first) {
+ for (i = 0; i < (SLOTS_PID_HISTORY_SIZE - 1); i++) {
+ state->cur_sample = (state->cur_sample + 1) %
+ SLOTS_PID_HISTORY_SIZE;
+ state->sample_history[state->cur_sample] = temp;
+ state->error_history[state->cur_sample] =
+ temp - SLOTS_PID_INPUT_TARGET;
+ }
+ state->first = 0;
+ }
+
+ /* Calculate the integral term */
+ sum = 0;
+ integral = 0;
+ for (i = 0; i < SLOTS_PID_HISTORY_SIZE; i++)
+ integral += state->error_history[i];
+ integral *= SLOTS_PID_INTERVAL;
+ DBG(" integral: %08x\n", integral);
+ integ_p = ((s64)SLOTS_PID_G_r) * (s64)integral;
+ DBG(" integ_p: %d\n", (int)(integ_p >> 36));
+ sum += integ_p;
+
+ /* Calculate the derivative term */
+ derivative = state->error_history[state->cur_sample] -
+ state->error_history[(state->cur_sample + SLOTS_PID_HISTORY_SIZE - 1)
+ % SLOTS_PID_HISTORY_SIZE];
+ derivative /= SLOTS_PID_INTERVAL;
+ deriv_p = ((s64)SLOTS_PID_G_d) * (s64)derivative;
+ DBG(" deriv_p: %d\n", (int)(deriv_p >> 36));
+ sum += deriv_p;
+
+ /* Calculate the proportional term */
+ prop_p = ((s64)SLOTS_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
+ DBG(" prop_p: %d\n", (int)(prop_p >> 36));
+ sum += prop_p;
+
+ /* Scale sum */
+ sum >>= 36;
+
+ DBG(" sum: %d\n", (int)sum);
+ state->pwm = (s32)sum;
+
+ state->pwm = max(state->pwm, SLOTS_PID_OUTPUT_MIN);
+ state->pwm = min(state->pwm, SLOTS_PID_OUTPUT_MAX);
+
+ DBG("** DRIVES PWM: %d\n", (int)state->pwm);
+ set_pwm_fan(SLOTS_FAN_PWM_INDEX, state->pwm);
+}
+
+/*
+ * Initialize the state structure for the slots bay fan control loop
+ */
+static int init_slots_state(struct slots_pid_state *state)
+{
+ state->ticks = 1;
+ state->first = 1;
+ state->pwm = 50;
+
+ state->monitor = attach_i2c_chip(XSERVE_SLOTS_LM75, "slots_temp");
+ if (state->monitor == NULL)
+ return -ENODEV;
+
+ device_create_file(&of_dev->dev, &dev_attr_slots_temperature);
+ device_create_file(&of_dev->dev, &dev_attr_slots_fan_pwm);
+
+ return 0;
+}
+
+/*
+ * Dispose of the state data for the slots control loop
+ */
+static void dispose_slots_state(struct slots_pid_state *state)
+{
+ if (state->monitor == NULL)
+ return;
+
+ device_remove_file(&of_dev->dev, &dev_attr_slots_temperature);
+ device_remove_file(&of_dev->dev, &dev_attr_slots_fan_pwm);
+
+ detach_i2c_chip(state->monitor);
+ state->monitor = NULL;
+}
+
+