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power: supply: ltc2941-battery-gauge: Add LTC2942 support

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LTC2942 is pin compatible with LTC2941 providing additional
informations about battery voltage and temperature. It can
be runtime detected using bit A7 in the Status register.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Dragos Bogdan <dragos.bogdan@analog.com>
Tested-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
This commit is contained in:
Ladislav Michl 2017-07-16 11:34:00 +02:00 committed by Sebastian Reichel
parent 63e67c5769
commit a65df832f9
2 changed files with 75 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
Documentation/devicetree/bindings/power/supply/ltc2941.txt
View File

@ -1,13 +1,14 @@
binding for LTC2941 and LTC2943 battery gauges binding for LTC2941, LTC2942 and LTC2943 battery gauges
Both the LTC2941 and LTC2943 measure battery capacity. All chips measure battery capacity.
The LTC2943 is compatible with the LTC2941, it adds voltage and The LTC2942 is pin compatible with the LTC2941, it adds voltage and
temperature monitoring, and uses a slightly different conversion temperature monitoring, and is runtime detected. LTC2943 is software
formula for the charge counter. compatible, uses a slightly different conversion formula for the
charge counter and adds voltage, current and temperature monitoring.
Required properties: Required properties:
- compatible: Should contain "lltc,ltc2941" or "lltc,ltc2943" which also - compatible: Should contain "lltc,ltc2941", "lltc,ltc2942" or "lltc,ltc2943"
indicates the type of I2C chip attached. which also indicates the type of I2C chip attached.
- reg: The 7-bit I2C address. - reg: The 7-bit I2C address.
- lltc,resistor-sense: The sense resistor value in milli-ohms. Can be a 32-bit - 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 negative value when the battery has been connected to the wrong end of the

80
drivers/power/supply/ltc2941-battery-gauge.c
View File

@ -1,5 +1,5 @@
/* /*
* I2C client/driver for the Linear Technology LTC2941 and LTC2943 * I2C client/driver for the Linear Technology LTC2941, LTC2942 and LTC2943
* Battery Gas Gauge IC * Battery Gas Gauge IC
* *
* Copyright (C) 2014 Topic Embedded Systems * Copyright (C) 2014 Topic Embedded Systems
@ -46,11 +46,14 @@ enum ltc294x_reg {
enum ltc294x_id { enum ltc294x_id {
LTC2941_ID, LTC2941_ID,
LTC2942_ID,
LTC2943_ID, LTC2943_ID,
}; };
#define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) | BIT(6)) #define LTC2941_REG_STATUS_CHIP_ID BIT(7)
#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
#define LTC2942_REG_CONTROL_MODE_SCAN (BIT(7) | BIT(6))
#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3)) #define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3))
#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0)) #define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \ #define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
@ -145,9 +148,17 @@ static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) | control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED; LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
/* Put the 2943 into "monitor" mode, so it measures every 10 sec */ /* Put device into "monitor" mode */
if (info->id == LTC2941_ID) switch (info->id) {
case LTC2942_ID: /* 2942 measures every 2 sec */
control |= LTC2942_REG_CONTROL_MODE_SCAN;
break;
case LTC2943_ID: /* 2943 measures every 10 sec */
control |= LTC2943_REG_CONTROL_MODE_SCAN; control |= LTC2943_REG_CONTROL_MODE_SCAN;
break;
default:
break;
}
if (value != control) { if (value != control) {
ret = ltc294x_write_regs(info->client, ret = ltc294x_write_regs(info->client,
@ -252,7 +263,19 @@ static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
ret = ltc294x_read_regs(info->client, ret = ltc294x_read_regs(info->client,
LTC294X_REG_VOLTAGE_MSB, &datar[0], 2); LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
value = (datar[0] << 8) | datar[1]; value = (datar[0] << 8) | datar[1];
*val = ((value * 23600) / 0xFFFF) * 1000; /* in uV */ switch (info->id) {
case LTC2943_ID:
value *= 23600 * 2;
value /= 0xFFFF;
value *= 1000 / 2;
break;
default:
value *= 6000 * 10;
value /= 0xFFFF;
value *= 1000 / 10;
break;
}
*val = value;
return ret; return ret;
} }
@ -275,15 +298,22 @@ static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val) static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
{ {
enum ltc294x_reg reg;
int ret; int ret;
u8 datar[2]; u8 datar[2];
u32 value; u32 value;
ret = ltc294x_read_regs(info->client, if (info->id == LTC2942_ID) {
LTC2943_REG_TEMPERATURE_MSB, &datar[0], 2); reg = LTC2942_REG_TEMPERATURE_MSB;
value = (datar[0] << 8) | datar[1]; value = 60000; /* Full-scale is 600 Kelvin */
/* Full-scale is 510 Kelvin, convert to centidegrees */ } else {
*val = (((51000 * value) / 0xFFFF) - 27215); reg = LTC2943_REG_TEMPERATURE_MSB;
value = 51000; /* Full-scale is 510 Kelvin */
}
ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
value *= (datar[0] << 8) | datar[1];
/* Convert to centidegrees */
*val = value / 0xFFFF - 27215;
return ret; return ret;
} }
@ -375,10 +405,11 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
{ {
struct power_supply_config psy_cfg = {}; struct power_supply_config psy_cfg = {};
struct ltc294x_info *info; struct ltc294x_info *info;
struct device_node *np;
int ret; int ret;
u32 prescaler_exp; u32 prescaler_exp;
s32 r_sense; s32 r_sense;
struct device_node *np; u8 status;
info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL); info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
if (info == NULL) if (info == NULL)
@ -421,6 +452,20 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
(128 / (1 << prescaler_exp)); (128 / (1 << prescaler_exp));
} }
/* Read status register to check for LTC2942 */
if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
if (ret < 0) {
dev_err(&client->dev,
"Could not read status register\n");
return ret;
}
if (status & LTC2941_REG_STATUS_CHIP_ID)
info->id = LTC2941_ID;
else
info->id = LTC2942_ID;
}
info->client = client; info->client = client;
info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY; info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
info->supply_desc.properties = ltc294x_properties; info->supply_desc.properties = ltc294x_properties;
@ -429,6 +474,10 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
info->supply_desc.num_properties = info->supply_desc.num_properties =
ARRAY_SIZE(ltc294x_properties); ARRAY_SIZE(ltc294x_properties);
break; break;
case LTC2942_ID:
info->supply_desc.num_properties =
ARRAY_SIZE(ltc294x_properties) - 1;
break;
case LTC2941_ID: case LTC2941_ID:
default: default:
info->supply_desc.num_properties = info->supply_desc.num_properties =
@ -492,6 +541,7 @@ static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
static const struct i2c_device_id ltc294x_i2c_id[] = { static const struct i2c_device_id ltc294x_i2c_id[] = {
{ "ltc2941", LTC2941_ID, }, { "ltc2941", LTC2941_ID, },
{ "ltc2942", LTC2942_ID, },
{ "ltc2943", LTC2943_ID, }, { "ltc2943", LTC2943_ID, },
{ }, { },
}; };
@ -502,6 +552,10 @@ static const struct of_device_id ltc294x_i2c_of_match[] = {
.compatible = "lltc,ltc2941", .compatible = "lltc,ltc2941",
.data = (void *)LTC2941_ID, .data = (void *)LTC2941_ID,
}, },
{
.compatible = "lltc,ltc2942",
.data = (void *)LTC2942_ID,
},
{ {
.compatible = "lltc,ltc2943", .compatible = "lltc,ltc2943",
.data = (void *)LTC2943_ID, .data = (void *)LTC2943_ID,
@ -524,5 +578,5 @@ module_i2c_driver(ltc294x_driver);
MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems"); MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products"); MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver"); MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943 Battery Gas Gauge IC driver");
MODULE_LICENSE("GPL"); MODULE_LICENSE("GPL");