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linux_dsm_epyc7002/drivers/w1/slaves/w1_ds2408.c
Jean-Francois Dagenais d5528773e6 drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode 
Power-up timing

The DS2408 is sensitive to the power-on slew rate and can inadvertently
power up with a test mode feature enabled.  When this occurs, the P0 port
does not respond to the Channel Access Write command.  For most reliable
operation, it is recommended to disable the test mode after every power-on
reset using the Disable Test Mode sequence shown below.  The 64-bit ROM
code must be transmitted in the same bit sequence as with the Match ROM
command, i.e., least significant bit first.  This precaution is
recommended in parasite power mode (VCC pin connected to GND) as well as
with VCC power.

Disable Test Mode:
RST,PD,96h,<64-bit DS2408 ROM Code>,3Ch,RST,PD

[akpm@linux-foundation.org: don't use kerenldoc token to introduce a non-kerneldoc comment, tweak whitespace]
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:08:06 -07:00

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/*
* w1_ds2408.c - w1 family 29 (DS2408) driver
*
* Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#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/slab.h>
#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");
MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408));
#define W1_F29_RETRIES 3
#define W1_F29_REG_LOGIG_STATE 0x88 /* R */
#define W1_F29_REG_OUTPUT_LATCH_STATE 0x89 /* R */
#define W1_F29_REG_ACTIVITY_LATCH_STATE 0x8A /* R */
#define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */
#define W1_F29_REG_COND_SEARCH_POL_SELECT 0x8C /* RW */
#define W1_F29_REG_CONTROL_AND_STATUS 0x8D /* RW */
#define W1_F29_FUNC_READ_PIO_REGS 0xF0
#define W1_F29_FUNC_CHANN_ACCESS_READ 0xF5
#define W1_F29_FUNC_CHANN_ACCESS_WRITE 0x5A
/* also used to write the control/status reg (0x8D): */
#define W1_F29_FUNC_WRITE_COND_SEARCH_REG 0xCC
#define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC3
#define W1_F29_SUCCESS_CONFIRM_BYTE 0xAA
static int _read_reg(struct w1_slave *sl, u8 address, unsigned char* buf)
{
u8 wrbuf[3];
dev_dbg(&sl->dev,
"Reading with slave: %p, reg addr: %0#4x, buff addr: %p",
sl, (unsigned int)address, buf);
if (!buf)
return -EINVAL;
mutex_lock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex locked");
if (w1_reset_select_slave(sl)) {
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS;
wrbuf[1] = address;
wrbuf[2] = 0;
w1_write_block(sl->master, wrbuf, 3);
*buf = w1_read_8(sl->master);
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex unlocked");
return 1;
}
static ssize_t w1_f29_read_state(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
dev_dbg(&kobj_to_w1_slave(kobj)->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf);
}
static ssize_t w1_f29_read_output(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
dev_dbg(&kobj_to_w1_slave(kobj)->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj),
W1_F29_REG_OUTPUT_LATCH_STATE, buf);
}
static ssize_t w1_f29_read_activity(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
dev_dbg(&kobj_to_w1_slave(kobj)->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj),
W1_F29_REG_ACTIVITY_LATCH_STATE, buf);
}
static ssize_t w1_f29_read_cond_search_mask(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
dev_dbg(&kobj_to_w1_slave(kobj)->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj),
W1_F29_REG_COND_SEARCH_SELECT_MASK, buf);
}
static ssize_t w1_f29_read_cond_search_polarity(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj),
W1_F29_REG_COND_SEARCH_POL_SELECT, buf);
}
static ssize_t w1_f29_read_status_control(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
if (count != 1 || off != 0)
return -EFAULT;
return _read_reg(kobj_to_w1_slave(kobj),
W1_F29_REG_CONTROL_AND_STATUS, buf);
}
static ssize_t w1_f29_write_output(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 w1_buf[3];
u8 readBack;
unsigned int retries = W1_F29_RETRIES;
if (count != 1 || off != 0)
return -EFAULT;
dev_dbg(&sl->dev, "locking mutex for write_output");
mutex_lock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex locked");
if (w1_reset_select_slave(sl))
goto error;
while (retries--) {
w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;
w1_buf[1] = *buf;
w1_buf[2] = ~(*buf);
w1_write_block(sl->master, w1_buf, 3);
readBack = w1_read_8(sl->master);
if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) {
if (w1_reset_resume_command(sl->master))
goto error;
/* try again, the slave is ready for a command */
continue;
}
#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
/* here the master could read another byte which
would be the PIO reg (the actual pin logic state)
since in this driver we don't know which pins are
in and outs, there's no value to read the state and
compare. with (*buf) so end this command abruptly: */
if (w1_reset_resume_command(sl->master))
goto error;
/* go read back the output latches */
/* (the direct effect of the write above) */
w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
w1_buf[2] = 0;
w1_write_block(sl->master, w1_buf, 3);
/* read the result of the READ_PIO_REGS command */
if (w1_read_8(sl->master) == *buf)
#endif
{
/* success! */
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev,
"mutex unlocked, retries:%d", retries);
return 1;
}
}
error:
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
return -EIO;
}
/**
* Writing to the activity file resets the activity latches.
*/
static ssize_t w1_f29_write_activity(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
unsigned int retries = W1_F29_RETRIES;
if (count != 1 || off != 0)
return -EFAULT;
mutex_lock(&sl->master->bus_mutex);
if (w1_reset_select_slave(sl))
goto error;
while (retries--) {
w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES);
if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) {
mutex_unlock(&sl->master->bus_mutex);
return 1;
}
if (w1_reset_resume_command(sl->master))
goto error;
}
error:
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
static ssize_t w1_f29_write_status_control(
struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf,
loff_t off,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 w1_buf[4];
unsigned int retries = W1_F29_RETRIES;
if (count != 1 || off != 0)
return -EFAULT;
mutex_lock(&sl->master->bus_mutex);
if (w1_reset_select_slave(sl))
goto error;
while (retries--) {
w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG;
w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
w1_buf[2] = 0;
w1_buf[3] = *buf;
w1_write_block(sl->master, w1_buf, 4);
if (w1_reset_resume_command(sl->master))
goto error;
w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
w1_buf[2] = 0;
w1_write_block(sl->master, w1_buf, 3);
if (w1_read_8(sl->master) == *buf) {
/* success! */
mutex_unlock(&sl->master->bus_mutex);
return 1;
}
}
error:
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
/*
* This is a special sequence we must do to ensure the P0 output is not stuck
* in test mode. This is described in rev 2 of the ds2408's datasheet
* (http://datasheets.maximintegrated.com/en/ds/DS2408.pdf) under
* "APPLICATION INFORMATION/Power-up timing".
*/
static int w1_f29_disable_test_mode(struct w1_slave *sl)
{
int res;
u8 magic[10] = {0x96, };
u64 rn = le64_to_cpu(*((u64*)&sl->reg_num));
memcpy(&magic[1], &rn, 8);
magic[9] = 0x3C;
mutex_lock(&sl->master->bus_mutex);
res = w1_reset_bus(sl->master);
if (res)
goto out;
w1_write_block(sl->master, magic, ARRAY_SIZE(magic));
res = w1_reset_bus(sl->master);
out:
mutex_unlock(&sl->master->bus_mutex);
return res;
}
static struct bin_attribute w1_f29_sysfs_bin_files[] = {
{
.attr = {
.name = "state",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f29_read_state,
},
{
.attr = {
.name = "output",
.mode = S_IRUGO | S_IWUSR | S_IWGRP,
},
.size = 1,
.read = w1_f29_read_output,
.write = w1_f29_write_output,
},
{
.attr = {
.name = "activity",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f29_read_activity,
.write = w1_f29_write_activity,
},
{
.attr = {
.name = "cond_search_mask",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f29_read_cond_search_mask,
},
{
.attr = {
.name = "cond_search_polarity",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f29_read_cond_search_polarity,
},
{
.attr = {
.name = "status_control",
.mode = S_IRUGO | S_IWUSR | S_IWGRP,
},
.size = 1,
.read = w1_f29_read_status_control,
.write = w1_f29_write_status_control,
}
};
static int w1_f29_add_slave(struct w1_slave *sl)
{
int err = 0;
int i;
err = w1_f29_disable_test_mode(sl);
if (err)
return err;
for (i = 0; i < ARRAY_SIZE(w1_f29_sysfs_bin_files) && !err; ++i)
err = sysfs_create_bin_file(
&sl->dev.kobj,
&(w1_f29_sysfs_bin_files[i]));
if (err)
while (--i >= 0)
sysfs_remove_bin_file(&sl->dev.kobj,
&(w1_f29_sysfs_bin_files[i]));
return err;
}
static void w1_f29_remove_slave(struct w1_slave *sl)
{
int i;
for (i = ARRAY_SIZE(w1_f29_sysfs_bin_files) - 1; i >= 0; --i)
sysfs_remove_bin_file(&sl->dev.kobj,
&(w1_f29_sysfs_bin_files[i]));
}
static struct w1_family_ops w1_f29_fops = {
.add_slave = w1_f29_add_slave,
.remove_slave = w1_f29_remove_slave,
};
static struct w1_family w1_family_29 = {
.fid = W1_FAMILY_DS2408,
.fops = &w1_f29_fops,
};
static int __init w1_f29_init(void)
{
return w1_register_family(&w1_family_29);
}
static void __exit w1_f29_exit(void)
{
w1_unregister_family(&w1_family_29);
}
module_init(w1_f29_init);
module_exit(w1_f29_exit);
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