| Summit SMB137C Battery Charger |
| |
| The SMB137C is controlled via an I2C bus. Its 7-bit I2C slave address is |
| programmed during manufacturing. |
| |
| Required properties: |
| - compatible: Must be "summit,smb137c". |
| - reg: The device's 7-bit I2C address. |
| |
| Optional properties: |
| - summit,chg-current-ma Maximum battery charging current in milliamps. |
| Supported values are: 500, 650, 750, 850, 950, |
| 1100, 1300, and 1500. |
| - summit,term-current-ma Charging terminaton current in milliamps. |
| Supported values are: 0, 35, 50, 100, and 150. |
| A value of 0 means no termination current is |
| used. |
| - summit,pre-chg-current-ma Maximum battery pre-charging current in |
| milliamps. This current limit is applied while |
| the battery voltage is below the pre-charge / |
| fast-charge threshold. Supported values are: |
| 50, 100, 150, and 200. |
| - summit,float-voltage-mv Battery voltage threshold in millivolts at which |
| point charging switches from constant current to |
| constant voltage. Supported values are: 3460 up |
| through 4730 in 10 mV steps. |
| - summit,thresh-voltage-mv Threshold voltage in millivolts which is used to |
| switch between pre-charge and fast-charge |
| current limits. Supported values are: 2400 up |
| to 3100 in 100 mV steps. |
| - summit,recharge-thresh-mv Specifies the minimum voltage drop in millivolts |
| below the float voltage that is required in |
| order to initiate a new charging cycle. |
| Supported values are: 75 and 120. |
| - summit,system-voltage-mv Regulated voltage output on the VOUTL pin in |
| millivolts. Supported values are 4250 and 4460. |
| - summit,charging-timeout Maximum duration in minutes that a single charge |
| cycle may last. Supported values are: 0, 382, |
| 764, and 1527. A value of 0 means that no |
| charge cycle timeout is used and charging can |
| continue indefinitely. |
| - summit,pre-charge-timeout Maximum time in minutes spent in the pre-charge |
| state in any given charge cycle. Supports |
| values are: 0, 48, 95, and 191. A value of 0 |
| means that there is no limit to the amount of |
| time that may be spent in the pre-charge state. |
| - summit,therm-current-ua Thermistor current in microamps to be used for |
| battery temperature monitoring. Supported |
| values are 10, 20, 40, and 100. These values |
| correspond to 100, 50, 25, and 10 kohm NTC |
| thermistors respectively. |
| - summit,temperature-min Specifies the minimum temperature at which |
| charging is allowed. Supported values are |
| 0 to 7. These values correspond to -20 C to |
| +15 C in 5 C increments for an NTC thermistor |
| with beta = 4400. |
| - summit,temperature-max Specifies the maximum temperature at which |
| charging is allowed. Supported values are |
| 0 to 7. These values correspond to +30 C to |
| +65 C in 5 C increments for an NTC thermistor |
| with beta = 4400. |
| |
| Note: If an optional property is not specified, then the hardware default value |
| will be used. |
| |
| Example: |
| / { |
| i2c@f9925000 { |
| charger@57 { |
| compatible = "summit,smb137c"; |
| reg = <0x57>; |
| summit,chg-current-ma = <1500>; |
| summit,term-current-ma = <50>; |
| summit,pre-chg-current-ma = <100>; |
| summit,float-voltage-mv = <4200>; |
| summit,thresh-voltage-mv = <3000>; |
| summit,recharge-thresh-mv = <75>; |
| summit,system-voltage-mv = <4250>; |
| summit,charging-timeout = <382>; |
| summit,pre-charge-timeout = <48>; |
| summit,therm-current-ua = <10>; |
| summit,temperature-min = <4>; /* 0 C */ |
| summit,temperature-max = <3>; /* 45 C */ |
| }; |
| }; |
| }; |