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