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Commit 5f2f0d61 authored by Mike Looijmans's avatar Mike Looijmans Committed by Sebastian Reichel
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power: ltc2941-battery-gauge: Disable continuous monitoring on shutdown 



The driver sets the fuel gauge to continuous monitoring on startup, for
the models that support this. When the board shuts down, the chip remains
in that mode, causing a few mA drain on the battery every 2 or 10 seconds.

This patch registers a shutdown handler that turns off the monitoring to
prevent this battery drain.

Signed-off-by: default avatarMike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.co.uk>
parent 68204f2f

drivers/power/supply/ltc2941-battery-gauge.c

+25 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ enum ltc294x_id { 
#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \

	((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)

#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED	0

#define LTC294X_REG_CONTROL_ADC_DISABLE(x)	((x) & ~(BIT(7) | BIT(6)))



struct ltc294x_info {

	struct i2c_client *client;	/* I2C Client pointer */
@@ -523,6 +524,29 @@ static int ltc294x_i2c_probe(struct i2c_client *client, 
	return 0;

}



static void ltc294x_i2c_shutdown(struct i2c_client *client)

{

	struct ltc294x_info *info = i2c_get_clientdata(client);

	int ret;

	u8 value;

	u8 control;



	/* The LTC2941 does not need any special handling */

	if (info->id == LTC2941_ID)

		return;



	/* Read control register */

	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);

	if (ret < 0)

		return;



	/* Disable continuous ADC conversion as this drains the battery */

	control = LTC294X_REG_CONTROL_ADC_DISABLE(value);

	if (control != value)

		ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,

			&control, 1);

}



#ifdef CONFIG_PM_SLEEP



static int ltc294x_suspend(struct device *dev)
@@ -589,6 +613,7 @@ static struct i2c_driver ltc294x_driver = { 
	},

	.probe		= ltc294x_i2c_probe,

	.remove		= ltc294x_i2c_remove,

	.shutdown	= ltc294x_i2c_shutdown,

	.id_table	= ltc294x_i2c_id,

};

module_i2c_driver(ltc294x_driver);