Depending on the hardware design, an INA3221 chip might lose its power during system suspend/resume. So this patch adds a pair of suspend and resume functions to cache the register values including config register value and limit settings.
Signed-off-by: Nicolin Chen <[email protected]> --- drivers/hwmon/ina3221.c | 54 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c index cfe65ff01051..26f66f728b27 100644 --- a/drivers/hwmon/ina3221.c +++ b/drivers/hwmon/ina3221.c @@ -91,11 +91,13 @@ static const unsigned int register_channel[] = { * @regmap: Register map of the device * @fields: Register fields of the device * @shunt_resistors: Array of resistor values per channel + * @reg_config: Register value of INA3221_CONFIG */ struct ina3221_data { struct regmap *regmap; struct regmap_field *fields[F_MAX_FIELDS]; int shunt_resistors[INA3221_NUM_CHANNELS]; + u32 reg_config; }; static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg, @@ -415,8 +417,59 @@ static int ina3221_probe(struct i2c_client *client, return PTR_ERR(hwmon_dev); } + dev_set_drvdata(dev, ina); + + return 0; +} + +#ifdef CONFIG_PM +static int ina3221_suspend(struct device *dev) +{ + struct ina3221_data *ina = dev_get_drvdata(dev); + int ret; + + /* Save config register value and enable cache-only */ + ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config); + if (ret) + return ret; + + regcache_cache_only(ina->regmap, true); + regcache_mark_dirty(ina->regmap); + + return 0; +} + +static int ina3221_resume(struct device *dev) +{ + struct ina3221_data *ina = dev_get_drvdata(dev); + int ret; + + regcache_cache_only(ina->regmap, false); + + /* Software reset the chip */ + ret = regmap_field_write(ina->fields[F_RST], true); + if (ret) { + dev_err(dev, "Unable to reset device\n"); + return ret; + } + + /* Restore cached register values to hardware */ + ret = regcache_sync(ina->regmap); + if (ret) + return ret; + + /* Restore config register value to hardware */ + ret = regmap_write(ina->regmap, INA3221_CONFIG, ina->reg_config); + if (ret) + return ret; + return 0; } +#endif + +static const struct dev_pm_ops ina3221_pm = { + SET_SYSTEM_SLEEP_PM_OPS(ina3221_suspend, ina3221_resume) +}; static const struct of_device_id ina3221_of_match_table[] = { { .compatible = "ti,ina3221", }, @@ -435,6 +488,7 @@ static struct i2c_driver ina3221_i2c_driver = { .driver = { .name = INA3221_DRIVER_NAME, .of_match_table = ina3221_of_match_table, + .pm = &ina3221_pm, }, .id_table = ina3221_ids, }; -- 2.17.1
