diff options
| -rw-r--r-- | drivers/w1/w1.c | 39 |
1 files changed, 37 insertions, 2 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 15a2ee32f116..f2ae2e563dc5 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -25,6 +25,8 @@ #include "w1_netlink.h" #define W1_FAMILY_DEFAULT 0 +#define W1_FAMILY_DS28E04 0x1C /* for crc quirk */ + static int w1_timeout = 10; module_param_named(timeout, w1_timeout, int, 0); @@ -913,11 +915,44 @@ void w1_reconnect_slaves(struct w1_family *f, int attach) mutex_unlock(&w1_mlock); } +static int w1_addr_crc_is_valid(struct w1_master *dev, u64 rn) +{ + u64 rn_le = cpu_to_le64(rn); + struct w1_reg_num *tmp = (struct w1_reg_num *)&rn; + u8 crc; + + crc = w1_calc_crc8((u8 *)&rn_le, 7); + + /* quirk: + * DS28E04 (1w eeprom) has strapping pins to change + * address, but will not update the crc. So normal rules + * for consistent w1 addresses are violated. We test + * with the 7 LSBs of the address forced high. + * + * (char*)&rn_le = { family, addr_lsb, ..., addr_msb, crc }. + */ + if (crc != tmp->crc && tmp->family == W1_FAMILY_DS28E04) { + u64 corr_le = rn_le; + + ((u8 *)&corr_le)[1] |= 0x7f; + crc = w1_calc_crc8((u8 *)&corr_le, 7); + + dev_info(&dev->dev, "DS28E04 crc workaround on %02x.%012llx.%02x\n", + tmp->family, (unsigned long long)tmp->id, tmp->crc); + } + + if (crc != tmp->crc) { + dev_dbg(&dev->dev, "w1 addr crc mismatch: %02x.%012llx.%02x != 0x%02x.\n", + tmp->family, (unsigned long long)tmp->id, tmp->crc, crc); + return 0; + } + return 1; +} + void w1_slave_found(struct w1_master *dev, u64 rn) { struct w1_slave *sl; struct w1_reg_num *tmp; - u64 rn_le = cpu_to_le64(rn); atomic_inc(&dev->refcnt); @@ -927,7 +962,7 @@ void w1_slave_found(struct w1_master *dev, u64 rn) if (sl) { set_bit(W1_SLAVE_ACTIVE, &sl->flags); } else { - if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7)) + if (rn && w1_addr_crc_is_valid(dev, rn)) w1_attach_slave_device(dev, tmp); } |