调试 W1 总线时, 设备注册没有问题
但是在查看 eeprom 数据时报错
/system/bin/sh: cat: eeprom: I/O error
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命令行是啥? 驱动是怎么写的, 跟踪一下驱动的 write 函数.
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lrwxrwxrwx root root 2021-01-01 00:21 driver -> ../../../bus/w1/drivers/w1_slave_driver
-rw-rw-rw- root root 128 2021-01-01 00:21 eeprom
-r--r--r-- root root 4096 2021-01-01 00:21 id
-r--r--r-- root root 4096 2021-01-01 00:21 name
lrwxrwxrwx root root 2021-01-01 00:21 subsystem -> ../../../bus/w1
-rw-r--r-- root root 4096 2021-01-01 00:21 uevent
cat eeprom
/system/bin/sh: cat: eeprom: I/O error
static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
int tries = W1_F0D_READ_RETRIES;
u8 wrbuf[3];
u8 rdbuf[W1_F0D_SCRATCH_SIZE];
u8 cs;
if ((addr & 1) || (len != 2)) {
dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n",
__func__, addr, len);
return -1;
}
retry:
if (w1_reset_select_slave(sl)) {
if (--tries)
goto retry;
}
wrbuf[0] = W1_F0D_WRITE_EEPROM;
wrbuf[1] = addr & 0xff;
wrbuf[2] = 0xff;
w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
w1_write_block(sl->master, data, len);
w1_read_block(sl->master, rdbuf, sizeof(rdbuf));
if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) {
if (--tries)
goto retry;
dev_err(&sl->dev,
"could not write to eeprom, scratchpad compare failed %d times\n",
W1_F0D_READ_RETRIES);
pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n",
__func__, rdbuf[0], rdbuf[1], data[0], data[1]);
return -1;
}
w1_write_8(sl->master, W1_F0D_RELEASE);
msleep(W1_F0D_TPROG_MS);
cs = w1_read_8(sl->master);
if (cs != W1_F0D_CS_OK) {
if (--tries)
goto retry;
dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs);
return -1;
}
return 0;
}
static ssize_t w1_f0d_write_bin(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);
int addr, len;
int copy;
count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);
if (count == 0)
return 0;
mutex_lock(&sl->master->mutex);
addr = off;
len = count;
while (len > 0) {
if (len < W1_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) {
char tmp[W1_F0D_SCRATCH_SIZE];
if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK,
W1_F0D_SCRATCH_SIZE, tmp)) {
count = -EIO;
goto out_up;
}
copy = W1_F0D_SCRATCH_SIZE -
(addr & W1_F0D_SCRATCH_MASK);
if (copy > len)
copy = len;
memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy);
if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK,
W1_F0D_SCRATCH_SIZE, tmp) < 0) {
count = -EIO;
goto out_up;
}
} else {
copy = W1_F0D_SCRATCH_SIZE;
if (w1_f0d_write(sl, addr, copy, buf) < 0) {
count = -EIO;
goto out_up;
}
}
buf += copy;
addr += copy;
len -= copy;
}
out_up:
mutex_unlock(&sl->master->mutex);
return count;
}
读写权限是开放的
static struct bin_attribute w1_f0d_bin_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO | S_IWUGO,
//.mode = S_IRUSR|S_IRGRP|S_IROTH | S_IWUSR|S_IWGRP|S_IWOTH,
},
.size = W1_F0D_EEPROM_SIZE,
.read = w1_f0d_read_bin,
.write = w1_f0d_write_bin,
};
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w1_f0d_write_bin( )
这里面加点调试语句看看
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添加调试节点定位问题点定位在
w1_reset_select_slave(sl) -> w1_reset_bus(sl->master)
从代码来看应该是复位时序导致的问题,继续。。。
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