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power: supply: ltc2941-battery-gauge: Add LTC2942 support
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>
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63e67c5769
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2 changed files with 75 additions and 20 deletions
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@ -1,13 +1,14 @@
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binding for LTC2941 and LTC2943 battery gauges
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binding for LTC2941, LTC2942 and LTC2943 battery gauges
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Both the LTC2941 and LTC2943 measure battery capacity.
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The LTC2943 is compatible with the LTC2941, it adds voltage and
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temperature monitoring, and uses a slightly different conversion
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formula for the charge counter.
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All chips measure battery capacity.
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The LTC2942 is pin compatible with the LTC2941, it adds voltage and
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temperature monitoring, and is runtime detected. LTC2943 is software
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compatible, uses a slightly different conversion formula for the
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charge counter and adds voltage, current and temperature monitoring.
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Required properties:
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- compatible: Should contain "lltc,ltc2941" or "lltc,ltc2943" which also
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indicates the type of I2C chip attached.
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- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942" or "lltc,ltc2943"
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which also indicates the type of I2C chip attached.
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- reg: The 7-bit I2C address.
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- lltc,resistor-sense: The sense resistor value in milli-ohms. Can be a 32-bit
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negative value when the battery has been connected to the wrong end of the
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@ -1,5 +1,5 @@
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/*
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* I2C client/driver for the Linear Technology LTC2941 and LTC2943
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* I2C client/driver for the Linear Technology LTC2941, LTC2942 and LTC2943
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* Battery Gas Gauge IC
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*
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* Copyright (C) 2014 Topic Embedded Systems
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@ -46,11 +46,14 @@ enum ltc294x_reg {
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enum ltc294x_id {
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LTC2941_ID,
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LTC2942_ID,
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LTC2943_ID,
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};
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#define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) | BIT(6))
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#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
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#define LTC2941_REG_STATUS_CHIP_ID BIT(7)
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#define LTC2942_REG_CONTROL_MODE_SCAN (BIT(7) | BIT(6))
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#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
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#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3))
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#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
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#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
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@ -145,9 +148,17 @@ static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
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control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
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LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
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/* Put the 2943 into "monitor" mode, so it measures every 10 sec */
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if (info->id == LTC2941_ID)
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/* Put device into "monitor" mode */
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switch (info->id) {
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case LTC2942_ID: /* 2942 measures every 2 sec */
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control |= LTC2942_REG_CONTROL_MODE_SCAN;
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break;
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case LTC2943_ID: /* 2943 measures every 10 sec */
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control |= LTC2943_REG_CONTROL_MODE_SCAN;
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break;
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default:
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break;
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}
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if (value != control) {
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ret = ltc294x_write_regs(info->client,
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@ -252,7 +263,19 @@ static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
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ret = ltc294x_read_regs(info->client,
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LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
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value = (datar[0] << 8) | datar[1];
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*val = ((value * 23600) / 0xFFFF) * 1000; /* in uV */
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switch (info->id) {
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case LTC2943_ID:
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value *= 23600 * 2;
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value /= 0xFFFF;
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value *= 1000 / 2;
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break;
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default:
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value *= 6000 * 10;
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value /= 0xFFFF;
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value *= 1000 / 10;
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break;
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}
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*val = value;
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return ret;
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}
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@ -275,15 +298,22 @@ static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
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static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
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{
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enum ltc294x_reg reg;
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int ret;
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u8 datar[2];
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u32 value;
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ret = ltc294x_read_regs(info->client,
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LTC2943_REG_TEMPERATURE_MSB, &datar[0], 2);
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value = (datar[0] << 8) | datar[1];
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/* Full-scale is 510 Kelvin, convert to centidegrees */
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*val = (((51000 * value) / 0xFFFF) - 27215);
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if (info->id == LTC2942_ID) {
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reg = LTC2942_REG_TEMPERATURE_MSB;
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value = 60000; /* Full-scale is 600 Kelvin */
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} else {
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reg = LTC2943_REG_TEMPERATURE_MSB;
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value = 51000; /* Full-scale is 510 Kelvin */
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}
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ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
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value *= (datar[0] << 8) | datar[1];
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/* Convert to centidegrees */
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*val = value / 0xFFFF - 27215;
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return ret;
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}
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@ -375,10 +405,11 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
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{
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struct power_supply_config psy_cfg = {};
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struct ltc294x_info *info;
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struct device_node *np;
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int ret;
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u32 prescaler_exp;
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s32 r_sense;
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struct device_node *np;
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u8 status;
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info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
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if (info == NULL)
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@ -421,6 +452,20 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
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(128 / (1 << prescaler_exp));
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}
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/* Read status register to check for LTC2942 */
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if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
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ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
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if (ret < 0) {
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dev_err(&client->dev,
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"Could not read status register\n");
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return ret;
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}
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if (status & LTC2941_REG_STATUS_CHIP_ID)
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info->id = LTC2941_ID;
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else
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info->id = LTC2942_ID;
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}
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info->client = client;
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info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
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info->supply_desc.properties = ltc294x_properties;
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info->supply_desc.num_properties =
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ARRAY_SIZE(ltc294x_properties);
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break;
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case LTC2942_ID:
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info->supply_desc.num_properties =
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ARRAY_SIZE(ltc294x_properties) - 1;
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break;
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case LTC2941_ID:
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default:
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info->supply_desc.num_properties =
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@ -492,6 +541,7 @@ static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
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static const struct i2c_device_id ltc294x_i2c_id[] = {
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{ "ltc2941", LTC2941_ID, },
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{ "ltc2942", LTC2942_ID, },
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{ "ltc2943", LTC2943_ID, },
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{ },
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};
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.compatible = "lltc,ltc2941",
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.data = (void *)LTC2941_ID,
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},
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{
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.compatible = "lltc,ltc2942",
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.data = (void *)LTC2942_ID,
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},
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{
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.compatible = "lltc,ltc2943",
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.data = (void *)LTC2943_ID,
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@ -524,5 +578,5 @@ module_i2c_driver(ltc294x_driver);
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MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
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MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
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MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver");
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MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943 Battery Gas Gauge IC driver");
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MODULE_LICENSE("GPL");
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