On Sat, Sep 29, 2018 at 02:44:07PM -0700, Nicolin Chen wrote:
> Depending on the hardware design, an INA3221 chip might lose
> its power during system suspend/resume. So this patch adds
> a set of suspend and resume functions to cache the register
> values including config register value and limit settings.
>
> Signed-off-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx>
Applied to hwmon-next, with a minor change; see below.
Thanks,
Guenter
> ---
> Changelog
> v1->v2:
> * Added power-down setting during suspend for power saving
>
> drivers/hwmon/ina3221.c | 63 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 63 insertions(+)
>
> diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
> index e0c4f4d83f4e..877952efaa88 100644
> --- a/drivers/hwmon/ina3221.c
> +++ b/drivers/hwmon/ina3221.c
> @@ -38,6 +38,8 @@
> #define INA3221_WARN3 0x0c
> #define INA3221_MASK_ENABLE 0x0f
>
> +#define INA3221_CONFIG_MODE_MASK GENMASK(2, 0)
> +#define INA3221_CONFIG_MODE_POWERDOWN 0
> #define INA3221_CONFIG_MODE_SHUNT BIT(0)
> #define INA3221_CONFIG_MODE_BUS BIT(1)
> #define INA3221_CONFIG_MODE_CONTINUOUS BIT(2)
> @@ -91,11 +93,13 @@ 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,
> @@ -415,9 +419,67 @@ static int ina3221_probe(struct i2c_client *client,
> return PTR_ERR(hwmon_dev);
> }
>
> + dev_set_drvdata(dev, ina);
> +
It is better to call that function before registering the hwmon device,
to avoid the theroretical possibility that suspend is called before drvdata
is set. I moved the call accordingly.
> 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;
> +
> + /* Set to power-down mode for power saving */
> + ret = regmap_update_bits(ina->regmap, INA3221_CONFIG,
> + INA3221_CONFIG_MODE_MASK,
> + INA3221_CONFIG_MODE_POWERDOWN);
> + 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", },
> { /* sentinel */ }
> @@ -435,6 +497,7 @@ 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,
> };
