/*
 *	w1_ds2423.c
 *
 * Copyright (c) 2010 Mika Laitio <lamikr@pilppa.org>
 *
 * This driver will read and write the value of 4 counters to w1_slave file in
 * sys filesystem.
 * Inspired by the w1_therm and w1_ds2431 drivers.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the therms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/crc16.h>

#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"

#define CRC16_VALID	0xb001
#define CRC16_INIT	0

#define COUNTER_COUNT 4
#define READ_BYTE_COUNT 42

static ssize_t w1_slave_show(struct device *device,
			     struct device_attribute *attr, char *out_buf)
{
	struct w1_slave *sl = dev_to_w1_slave(device);
	struct w1_master *dev = sl->master;
	u8 rbuf[COUNTER_COUNT * READ_BYTE_COUNT];
	u8 wrbuf[3];
	int rom_addr;
	int read_byte_count;
	int result;
	ssize_t c;
	int ii;
	int p;
	int crc;

	c		= PAGE_SIZE;
	rom_addr	= (12 << 5) + 31;
	wrbuf[0]	= 0xA5;
	wrbuf[1]	= rom_addr & 0xFF;
	wrbuf[2]	= rom_addr >> 8;
	mutex_lock(&dev->bus_mutex);
	if (!w1_reset_select_slave(sl)) {
		w1_write_block(dev, wrbuf, 3);
		read_byte_count = 0;
		for (p = 0; p < 4; p++) {
			/*
			 * 1 byte for first bytes in ram page read
			 * 4 bytes for counter
			 * 4 bytes for zero bits
			 * 2 bytes for crc
			 * 31 remaining bytes from the ram page
			 */
			read_byte_count += w1_read_block(dev,
				rbuf + (p * READ_BYTE_COUNT), READ_BYTE_COUNT);
			for (ii = 0; ii < READ_BYTE_COUNT; ++ii)
				c -= snprintf(out_buf + PAGE_SIZE - c,
					c, "%02x ",
					rbuf[(p * READ_BYTE_COUNT) + ii]);
			if (read_byte_count != (p + 1) * READ_BYTE_COUNT) {
				dev_warn(device,
					"w1_counter_read() returned %u bytes "
					"instead of %d bytes wanted.\n",
					read_byte_count,
					READ_BYTE_COUNT);
				c -= snprintf(out_buf + PAGE_SIZE - c,
					c, "crc=NO\n");
			} else {
				if (p == 0) {
					crc = crc16(CRC16_INIT, wrbuf, 3);
					crc = crc16(crc, rbuf, 11);
				} else {
					/*
					 * DS2423 calculates crc from all bytes
					 * read after the previous crc bytes.
					 */
					crc = crc16(CRC16_INIT,
						(rbuf + 11) +
						((p - 1) * READ_BYTE_COUNT),
						READ_BYTE_COUNT);
				}
				if (crc == CRC16_VALID) {
					result = 0;
					for (ii = 4; ii > 0; ii--) {
						result <<= 8;
						result |= rbuf[(p *
							READ_BYTE_COUNT) + ii];
					}
					c -= snprintf(out_buf + PAGE_SIZE - c,
						c, "crc=YES c=%d\n", result);
				} else {
					c -= snprintf(out_buf + PAGE_SIZE - c,
						c, "crc=NO\n");
				}
			}
		}
	} else {
		c -= snprintf(out_buf + PAGE_SIZE - c, c, "Connection error");
	}
	mutex_unlock(&dev->bus_mutex);
	return PAGE_SIZE - c;
}

static DEVICE_ATTR_RO(w1_slave);

static struct attribute *w1_f1d_attrs[] = {
	&dev_attr_w1_slave.attr,
	NULL,
};
ATTRIBUTE_GROUPS(w1_f1d);

static struct w1_family_ops w1_f1d_fops = {
	.groups		= w1_f1d_groups,
};

static struct w1_family w1_family_1d = {
	.fid = W1_COUNTER_DS2423,
	.fops = &w1_f1d_fops,
};
module_w1_family(w1_family_1d);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>");
MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram");
MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423));
 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>Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;</td><td class='right'>2017-02-03 14:18:39 -0800</td></tr>
<tr><th>committer</th><td>Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</td><td class='right'>2017-02-04 00:11:08 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/codecs/max9850.h?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>6e978b22efa1db9f6e71b24440b5f1d93e968ee3</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/soc/codecs/max9850.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>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=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>c666f7a26b860674848949e39a610222b0723f89</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/soc/codecs/max9850.h?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>sound/soc/codecs/max9850.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/codecs/max9850.h?h=nds-private-remove&amp;id=3c223c19aea85d3dda1416c187915f4a30b04b1f'>3c223c19aea85d3dda1416c187915f4a30b04b1f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/soc/codecs/max9850.h?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3&amp;id2=3c223c19aea85d3dda1416c187915f4a30b04b1f'>diff</a>)</td></tr></table>
<div class='commit-subject'>cpufreq: intel_pstate: Disable energy efficiency optimization</div><div class='commit-msg'>Some Kabylake desktop processors may not reach max turbo when running in
HWP mode, even if running under sustained 100% utilization.

This occurs when the HWP.EPP (Energy Performance Preference) is set to
"balance_power" (0x80) -- the default on most systems.

It occurs because the platform BIOS may erroneously enable an
energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not
recommended to be enabled on this SKU.

On the failing systems, this BIOS issue was not discovered when the
desktop motherboard was tested with Windows, because the BIOS also
neglects to provide the ACPI/CPPC table, that Windows requires to enable
HWP, and so Windows runs in legacy P-state mode, where this setting has
no effect.

Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and
so it runs in HWP mode, exposing this incorrect BIOS configuration.

There are several ways to address this problem.

First, Linux can also run in legacy P-state mode on this system.
As intel_pstate is how Linux enables HWP, booting with
"intel_pstate=disable"
will run in acpi-cpufreq/ondemand legacy p-state mode.

Or second, the "performance" governor can be used with intel_pstate,
which will modify HWP.EPP to 0.

Or third, starting in 4.10, the
/sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
attribute in can be updated from "balance_power" to "performance".

Or fourth, apply this patch, which fixes the erroneous setting of
MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default
configuration to function as designed.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Reviewed-by: Len Brown &lt;len.brown@intel.com&gt;
Cc: 4.6+ &lt;stable@vger.kernel.org&gt; # 4.6+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>Diffstat</a> (limited to 'sound/soc/codecs/max9850.h')</div><table summary='diffstat' class='diffstat'>