| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 1 | Kernel driver ltc4261 |
| 2 | ===================== |
| 3 | |
| 4 | Supported chips: |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 5 | |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 6 | * Linear Technology LTC4261 |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 7 | |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 8 | Prefix: 'ltc4261' |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 9 | |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 10 | Addresses scanned: - |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 11 | |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 12 | Datasheet: |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 13 | |
| 14 | http://cds.linear.com/docs/Datasheet/42612fb.pdf |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 15 | |
| Guenter Roeck | e3333e5 | 2013-02-20 20:58:42 -0800 | [diff] [blame] | 16 | Author: Guenter Roeck <linux@roeck-us.net> |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 17 | |
| 18 | |
| 19 | Description |
| 20 | ----------- |
| 21 | |
| 22 | The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board |
| 23 | to be safely inserted and removed from a live backplane. |
| 24 | |
| 25 | |
| 26 | Usage Notes |
| 27 | ----------- |
| 28 | |
| 29 | This driver does not probe for LTC4261 devices, since there is no register |
| 30 | which can be safely used to identify the chip. You will have to instantiate |
| 31 | the devices explicitly. |
| 32 | |
| 33 | Example: the following will load the driver for an LTC4261 at address 0x10 |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 34 | on I2C bus #1:: |
| 35 | |
| 36 | $ modprobe ltc4261 |
| 37 | $ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 38 | |
| 39 | |
| 40 | Sysfs entries |
| 41 | ------------- |
| 42 | |
| 43 | Voltage readings provided by this driver are reported as obtained from the ADC |
| 44 | registers. If a set of voltage divider resistors is installed, calculate the |
| 45 | real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the |
| 46 | value of the divider resistor against the measured voltage and R2 is the value |
| 47 | of the divider resistor against Ground. |
| 48 | |
| 49 | Current reading provided by this driver is reported as obtained from the ADC |
| 50 | Current Sense register. The reported value assumes that a 1 mOhm sense resistor |
| 51 | is installed. If a different sense resistor is installed, calculate the real |
| 52 | current by dividing the reported value by the sense resistor value in mOhm. |
| 53 | |
| 54 | The chip has two voltage sensors, but only one set of voltage alarm status bits. |
| 55 | In many many designs, those alarms are associated with the ADIN2 sensor, due to |
| 56 | the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available |
| 57 | on all chip variants. To ensure that the alarm condition is reported to the user, |
| 58 | report it with both voltage sensors. |
| 59 | |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 60 | ======================= ============================= |
| Guenter Roeck | e5f5c99 | 2010-06-25 11:59:54 -0700 | [diff] [blame] | 61 | in1_input ADIN2 voltage (mV) |
| 62 | in1_min_alarm ADIN/ADIN2 Undervoltage alarm |
| 63 | in1_max_alarm ADIN/ADIN2 Overvoltage alarm |
| 64 | |
| 65 | in2_input ADIN voltage (mV) |
| 66 | in2_min_alarm ADIN/ADIN2 Undervoltage alarm |
| 67 | in2_max_alarm ADIN/ADIN2 Overvoltage alarm |
| 68 | |
| 69 | curr1_input SENSE current (mA) |
| 70 | curr1_alarm SENSE overcurrent alarm |
| Mauro Carvalho Chehab | b32570a | 2019-04-17 06:46:27 -0300 | [diff] [blame] | 71 | ======================= ============================= |