diff options
| -rw-r--r-- | drivers/i2c/i2c-core.c | 63 | ||||
| -rw-r--r-- | include/linux/i2c.h | 9 |
2 files changed, 72 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 18124398b46..0fd4acbffb7 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1092,6 +1092,69 @@ int i2c_probe(struct i2c_adapter *adapter, } EXPORT_SYMBOL(i2c_probe); +struct i2c_client * +i2c_new_probed_device(struct i2c_adapter *adap, + struct i2c_board_info *info, + unsigned short const *addr_list) +{ + int i; + + /* Stop here if the bus doesn't support probing */ + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) { + dev_err(&adap->dev, "Probing not supported\n"); + return NULL; + } + + mutex_lock(&adap->clist_lock); + for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { + /* Check address validity */ + if (addr_list[i] < 0x03 || addr_list[i] > 0x77) { + dev_warn(&adap->dev, "Invalid 7-bit address " + "0x%02x\n", addr_list[i]); + continue; + } + + /* Check address availability */ + if (__i2c_check_addr(adap, addr_list[i])) { + dev_dbg(&adap->dev, "Address 0x%02x already in " + "use, not probing\n", addr_list[i]); + continue; + } + + /* Test address responsiveness + The default probe method is a quick write, but it is known + to corrupt the 24RF08 EEPROMs due to a state machine bug, + and could also irreversibly write-protect some EEPROMs, so + for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte + read instead. Also, some bus drivers don't implement + quick write, so we fallback to a byte read it that case + too. */ + if ((addr_list[i] & ~0x07) == 0x30 + || (addr_list[i] & ~0x0f) == 0x50 + || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) { + if (i2c_smbus_xfer(adap, addr_list[i], 0, + I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE, NULL) >= 0) + break; + } else { + if (i2c_smbus_xfer(adap, addr_list[i], 0, + I2C_SMBUS_WRITE, 0, + I2C_SMBUS_QUICK, NULL) >= 0) + break; + } + } + mutex_unlock(&adap->clist_lock); + + if (addr_list[i] == I2C_CLIENT_END) { + dev_dbg(&adap->dev, "Probing failed, no device found\n"); + return NULL; + } + + info->addr = addr_list[i]; + return i2c_new_device(adap, info); +} +EXPORT_SYMBOL_GPL(i2c_new_probed_device); + struct i2c_adapter* i2c_get_adapter(int id) { struct i2c_adapter *adapter; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 36d6814a6df..da95ce79d07 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -245,6 +245,15 @@ struct i2c_board_info { extern struct i2c_client * i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); +/* If you don't know the exact address of an I2C device, use this variant + * instead, which can probe for device presence in a list of possible + * addresses. + */ +extern struct i2c_client * +i2c_new_probed_device(struct i2c_adapter *adap, + struct i2c_board_info *info, + unsigned short const *addr_list); + extern void i2c_unregister_device(struct i2c_client *); /* Mainboard arch_initcall() code should register all its I2C devices. |