/*
 * pid.c PID controller for testing cooling devices
 *
 *
 *
 * Copyright (C) 2012 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 or later as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Author Name Jacob Pan <jacob.jun.pan@linux.intel.com>
 *
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <dirent.h>
#include <libintl.h>
#include <ctype.h>
#include <assert.h>
#include <time.h>
#include <limits.h>
#include <math.h>
#include <sys/stat.h>
#include <syslog.h>

#include "tmon.h"

/**************************************************************************
 * PID (Proportional-Integral-Derivative) controller is commonly used in
 * linear control system, consider the the process.
 * G(s) = U(s)/E(s)
 * kp = proportional gain
 * ki = integral gain
 * kd = derivative gain
 * Ts
 * We use type C Alan Bradley equation which takes set point off the
 * output dependency in P and D term.
 *
 *   y[k] = y[k-1] - kp*(x[k] - x[k-1]) + Ki*Ts*e[k] - Kd*(x[k]
 *          - 2*x[k-1]+x[k-2])/Ts
 *
 *
 ***********************************************************************/
struct pid_params p_param;
/* cached data from previous loop */
static double xk_1, xk_2; /* input temperature x[k-#] */

/*
 * TODO: make PID parameters tuned automatically,
 * 1. use CPU burn to produce open loop unit step response
 * 2. calculate PID based on Ziegler-Nichols rule
 *
 * add a flag for tuning PID
 */
int init_thermal_controller(void)
{
	int ret = 0;

	/* init pid params */
	p_param.ts = ticktime;
	/* TODO: get it from TUI tuning tab */
	p_param.kp = .36;
	p_param.ki = 5.0;
	p_param.kd = 0.19;

	p_param.t_target = target_temp_user;

	return ret;
}

void controller_reset(void)
{
	/* TODO: relax control data when not over thermal limit */
	syslog(LOG_DEBUG, "TC inactive, relax p-state\n");
	p_param.y_k = 0.0;
	xk_1 = 0.0;
	xk_2 = 0.0;
	set_ctrl_state(0);
}

/* To be called at time interval Ts. Type C PID controller.
 *    y[k] = y[k-1] - kp*(x[k] - x[k-1]) + Ki*Ts*e[k] - Kd*(x[k]
 *          - 2*x[k-1]+x[k-2])/Ts
 * TODO: add low pass filter for D term
 */
#define GUARD_BAND (2)
void controller_handler(const double xk, double *yk)
{
	double ek;
	double p_term, i_term, d_term;

	ek = p_param.t_target - xk; /* error */
	if (ek >= 3.0) {
		syslog(LOG_DEBUG, "PID: %3.1f Below set point %3.1f, stop\n",
			xk, p_param.t_target);
		controller_reset();
		*yk = 0.0;
		return;
	}
	/* compute intermediate PID terms */
	p_term = -p_param.kp * (xk - xk_1);
	i_term = p_param.kp * p_param.ki * p_param.ts * ek;
	d_term = -p_param.kp * p_param.kd * (xk - 2 * xk_1 + xk_2) / p_param.ts;
	/* compute output */
	*yk += p_term + i_term + d_term;
	/* update sample data */
	xk_1 = xk;
	xk_2 = xk_1;

	/* clamp output adjustment range */
	if (*yk < -LIMIT_HIGH)
		*yk = -LIMIT_HIGH;
	else if (*yk > -LIMIT_LOW)
		*yk = -LIMIT_LOW;

	p_param.y_k = *yk;

	set_ctrl_state(lround(fabs(p_param.y_k)));

}
ds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b'>perf.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='0263d4ebd94b36280608e296cba39b924b6e832b'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-24 12:38:43 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-24 12:38:43 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/perf.h?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b'>0263d4ebd94b36280608e296cba39b924b6e832b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/perf/perf.h?id=0263d4ebd94b36280608e296cba39b924b6e832b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b'>6e21b4b3d8e8fb12cdfcfd185d46992487265a9b</a> /<a href='/cgit.cgi/linux/net-next.git/tree/tools/perf/perf.h?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b'>tools/perf/perf.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/perf.h?h=nds-private-remove&amp;id=19ca2c8fecb1592d623fe5e82d6796f8d446268d'>19ca2c8fecb1592d623fe5e82d6796f8d446268d</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/perf/perf.h?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b&amp;id2=19ca2c8fecb1592d623fe5e82d6796f8d446268d'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/perf.h?h=nds-private-remove&amp;id=7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b'>7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/perf/perf.h?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b&amp;id2=7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'platform-drivers-x86-v4.10-4' of git://git.infradead.org/linux-platform-drivers-x86</div><div class='commit-msg'>Pull x86 platform-driver fixes from Andy Shevchenko:
 "This is my first pull request since I become a co-maintainer of
  Platform Drivers x86 subsystem. It's a bit bigger than usual due to
  material collected for almost two weeks in a row.

  MAINTAINERS:
   - Add myself to X86 PLATFORM DRIVERS as a co-maintainer

  ideapad-laptop:
   - handle ACPI event 1

  intel_mid_powerbtn:
   - Set IRQ_ONESHOT

  surface3-wmi:
   - fix uninitialized symbol
   - Shut up unused-function warning

  mlx-platform:
   - free first dev on error"

* tag 'platform-drivers-x86-v4.10-4' of git://git.infradead.org/linux-platform-drivers-x86:
  MAINTAINERS: Add myself to X86 PLATFORM DRIVERS as a co-maintainer
  platform/x86: ideapad-laptop: handle ACPI event 1
  platform/x86: intel_mid_powerbtn: Set IRQ_ONESHOT
  platform/x86: surface3-wmi: fix uninitialized symbol
  platform/x86: surface3-wmi: Shut up unused-function warning
  platform/x86: mlx-platform: free first dev on error
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=0263d4ebd94b36280608e296cba39b924b6e832b'>Diffstat</a> (limited to 'tools/perf/perf.h')</div><table summary='diffstat' class='diffstat'>