// SPDX-License-Identifier: GPL-2.0-only
/*
* w1_ds2408.c - w1 family 29 (DS2408) driver
*
* Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>
*/
#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 <linux/w1.h>
#define W1_FAMILY_DS2408 0x29
#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 state_read(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 output_read(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 activity_read(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 cond_search_mask_read(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 cond_search_polarity_read(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 status_control_read(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);
}
#ifdef [31mCONFIG_W1_SLAVE_DS2408_READBACK[0m
static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
{
u8 w1_buf[3];
if (w1_reset_resume_command(sl->master))
return false;
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);
return (w1_read_8(sl->master) == expected);
}
#else
static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
{
return true;
}
#endif
static ssize_t output_write(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];
unsigned int retries = W1_F29_RETRIES;
ssize_t bytes_written = -EIO;
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 out;
do {
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);
if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE &&
optional_read_back_valid(sl, *buf)) {
bytes_written = 1;
goto out;
}
if (w1_reset_resume_command(sl->master))
goto out; /* unrecoverable error */
/* try again, the slave is ready for a command */
} while (--retries);
out:
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "%s, mutex unlocked retries:%d\n",
(bytes_written > 0) ? "succeeded" : "error", retries);
return bytes_written;
}
/**
* Writing to the activity file resets the activity latches.
*/
static ssize_t activity_write(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 status_control_write(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 BIN_ATTR_RO(state, 1);
static BIN_ATTR_RW(output, 1);
static BIN_ATTR_RW(activity, 1);
static BIN_ATTR_RO(cond_search_mask, 1);
static BIN_ATTR_RO(cond_search_polarity, 1);
static BIN_ATTR_RW(status_control, 1);
static struct bin_attribute *w1_f29_bin_attrs[] = {
&bin_attr_state,
&bin_attr_output,
&bin_attr_activity,
&bin_attr_cond_search_mask,
&bin_attr_cond_search_polarity,
&bin_attr_status_control,
NULL,
};
static const struct attribute_group w1_f29_group = {
.bin_attrs = w1_f29_bin_attrs,
};
static const struct attribute_group *w1_f29_groups[] = {
&w1_f29_group,
NULL,
};
static struct w1_family_ops w1_f29_fops = {
.add_slave = w1_f29_disable_test_mode,
.groups = w1_f29_groups,
};
static struct w1_family w1_family_29 = {
.fid = W1_FAMILY_DS2408,
.fops = &w1_f29_fops,
};
module_w1_family(w1_family_29);
MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");
MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408));