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power: supply: ltc2941-battery-gauge: Add LTC2944 support

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LTC2944 is compatible with LTC2943, but uses different
voltage and current computing constants.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Tested-by: Dragos Bogdan <dragos.bogdan@analog.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
This commit is contained in:
Dragos Bogdan 2017-07-16 11:35:32 +02:00 committed by Sebastian Reichel
parent a65df832f9
commit 17825ff6ec
2 changed files with 28 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
Documentation/devicetree/bindings/power/supply/ltc2941.txt
View file

@ -1,14 +1,14 @@
binding for LTC2941, LTC2942 and LTC2943 battery gauges
binding for LTC2941, LTC2942, LTC2943 and LTC2944 battery gauges
All chips measure battery capacity.
The LTC2942 is pin compatible with the LTC2941, it adds voltage and
temperature monitoring, and is runtime detected. LTC2943 is software
compatible, uses a slightly different conversion formula for the
charge counter and adds voltage, current and temperature monitoring.
temperature monitoring, and is runtime detected. LTC2943 and LTC2944
is software compatible, uses a slightly different conversion formula
for the charge counter and adds voltage, current and temperature monitoring.
Required properties:
- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942" or "lltc,ltc2943"
which also indicates the type of I2C chip attached.
- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942", "lltc,ltc2943"
or "lltc,ltc2944" which also indicates the type of I2C chip attached.
- reg: The 7-bit I2C address.
- lltc,resistor-sense: The sense resistor value in milli-ohms. Can be a 32-bit
negative value when the battery has been connected to the wrong end of the

27
drivers/power/supply/ltc2941-battery-gauge.c
View file

@ -1,6 +1,6 @@
/*
* I2C client/driver for the Linear Technology LTC2941, LTC2942 and LTC2943
* Battery Gas Gauge IC
* I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
* and LTC2944 Battery Gas Gauge IC
*
* Copyright (C) 2014 Topic Embedded Systems
*
@ -48,6 +48,7 @@ enum ltc294x_id {
LTC2941_ID,
LTC2942_ID,
LTC2943_ID,
LTC2944_ID,
};
#define LTC2941_REG_STATUS_CHIP_ID BIT(7)
@ -153,7 +154,8 @@ static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
case LTC2942_ID: /* 2942 measures every 2 sec */
control |= LTC2942_REG_CONTROL_MODE_SCAN;
break;
case LTC2943_ID: /* 2943 measures every 10 sec */
case LTC2943_ID:
case LTC2944_ID: /* 2943 and 2944 measure every 10 sec */
control |= LTC2943_REG_CONTROL_MODE_SCAN;
break;
default:
@ -269,6 +271,11 @@ static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
value /= 0xFFFF;
value *= 1000 / 2;
break;
case LTC2944_ID:
value *= 70800 / 5*4;
value /= 0xFFFF;
value *= 1000 * 5/4;
break;
default:
value *= 6000 * 10;
value /= 0xFFFF;
@ -289,10 +296,14 @@ static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
LTC2943_REG_CURRENT_MSB, &datar[0], 2);
value = (datar[0] << 8) | datar[1];
value -= 0x7FFF;
if (info->id == LTC2944_ID)
value *= 64000;
else
value *= 60000;
/* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
* the formula below keeps everything in s32 range while preserving
* enough digits */
*val = 1000 * ((60000 * value) / (info->r_sense * 0x7FFF)); /* in uA */
*val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
return ret;
}
@ -470,6 +481,7 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
info->supply_desc.properties = ltc294x_properties;
switch (info->id) {
case LTC2944_ID:
case LTC2943_ID:
info->supply_desc.num_properties =
ARRAY_SIZE(ltc294x_properties);
@ -543,6 +555,7 @@ static const struct i2c_device_id ltc294x_i2c_id[] = {
{ "ltc2941", LTC2941_ID, },
{ "ltc2942", LTC2942_ID, },
{ "ltc2943", LTC2943_ID, },
{ "ltc2944", LTC2944_ID, },
{ },
};
MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
@ -560,6 +573,10 @@ static const struct of_device_id ltc294x_i2c_of_match[] = {
.compatible = "lltc,ltc2943",
.data = (void *)LTC2943_ID,
},
{
.compatible = "lltc,ltc2944",
.data = (void *)LTC2944_ID,
},
{ },
};
MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
@ -578,5 +595,5 @@ module_i2c_driver(ltc294x_driver);
MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943 Battery Gas Gauge IC driver");
MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
MODULE_LICENSE("GPL");