On 07/16/2017 12:34 PM, Ladislav Michl wrote:
> 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@xxxxxxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
Acked-by: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx>
Tested-by: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx>
> ---
> Changes:
> - v2: reworked voltage computing to not overflow and keep presision
> - v3: update devicetree binding documentation
> - v4: add ltc2942 devicetree compatible
> - v5: make use of info->id introduced in previous patch
> - v6: collect devicetree ack from Rob
>
> .../devicetree/bindings/power/supply/ltc2941.txt | 15 ++--
> drivers/power/supply/ltc2941-battery-gauge.c | 80 ++++++++++++++++++----
> 2 files changed, 75 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/power/supply/ltc2941.txt b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> index a9d7aa60558b..8ec10366295d 100644
> --- a/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> +++ b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> @@ -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.
> -The LTC2943 is compatible with the LTC2941, it adds voltage and
> -temperature monitoring, and uses a slightly different conversion
> -formula for the charge counter.
> +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.
>
> Required properties:
> -- compatible: Should contain "lltc,ltc2941" or "lltc,ltc2943" which also
> - indicates the type of I2C chip attached.
> +- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942" or "lltc,ltc2943"
> + 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
> diff --git a/drivers/power/supply/ltc2941-battery-gauge.c b/drivers/power/supply/ltc2941-battery-gauge.c
> index b0de448a226b..42ff4e3daf35 100644
> --- a/drivers/power/supply/ltc2941-battery-gauge.c
> +++ b/drivers/power/supply/ltc2941-battery-gauge.c
> @@ -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
> *
> * Copyright (C) 2014 Topic Embedded Systems
> @@ -46,11 +46,14 @@ enum ltc294x_reg {
>
> enum ltc294x_id {
> LTC2941_ID,
> + LTC2942_ID,
> LTC2943_ID,
> };
>
> -#define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) | BIT(6))
> -#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
> +#define LTC2941_REG_STATUS_CHIP_ID 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_SHUTDOWN_MASK (BIT(0))
> #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) |
> LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
> - /* Put the 2943 into "monitor" mode, so it measures every 10 sec */
> - if (info->id == LTC2941_ID)
> + /* Put device into "monitor" mode */
> + 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;
> + break;
> + default:
> + break;
> + }
>
> if (value != control) {
> 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,
> LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
> 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;
> }
>
> @@ -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)
> {
> + enum ltc294x_reg reg;
> int ret;
> u8 datar[2];
> u32 value;
>
> - ret = ltc294x_read_regs(info->client,
> - LTC2943_REG_TEMPERATURE_MSB, &datar[0], 2);
> - value = (datar[0] << 8) | datar[1];
> - /* Full-scale is 510 Kelvin, convert to centidegrees */
> - *val = (((51000 * value) / 0xFFFF) - 27215);
> + if (info->id == LTC2942_ID) {
> + reg = LTC2942_REG_TEMPERATURE_MSB;
> + value = 60000; /* Full-scale is 600 Kelvin */
> + } else {
> + 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;
> }
>
> @@ -375,10 +405,11 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
> {
> struct power_supply_config psy_cfg = {};
> struct ltc294x_info *info;
> + struct device_node *np;
> int ret;
> u32 prescaler_exp;
> s32 r_sense;
> - struct device_node *np;
> + u8 status;
>
> info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
> if (info == NULL)
> @@ -421,6 +452,20 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
> (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->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
> info->supply_desc.properties = ltc294x_properties;
> @@ -429,6 +474,10 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
> info->supply_desc.num_properties =
> ARRAY_SIZE(ltc294x_properties);
> break;
> + case LTC2942_ID:
> + info->supply_desc.num_properties =
> + ARRAY_SIZE(ltc294x_properties) - 1;
> + break;
> case LTC2941_ID:
> default:
> 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[] = {
> { "ltc2941", LTC2941_ID, },
> + { "ltc2942", LTC2942_ID, },
> { "ltc2943", LTC2943_ID, },
> { },
> };
> @@ -503,6 +553,10 @@ static const struct of_device_id ltc294x_i2c_of_match[] = {
> .data = (void *)LTC2941_ID,
> },
> {
> + .compatible = "lltc,ltc2942",
> + .data = (void *)LTC2942_ID,
> + },
> + {
> .compatible = "lltc,ltc2943",
> .data = (void *)LTC2943_ID,
> },
> @@ -524,5 +578,5 @@ module_i2c_driver(ltc294x_driver);
>
> MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
> 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");
--
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