Re: [PATCH v2 03/25] power: supply: axp20x_usb_power: use IIO channels when available

[Jonathan Cameron <jic23@kernel.org>]

On 27/01/17 08:54, Quentin Schulz wrote:
> The X-Powers AXP20X PMIC exposes the current current and voltage
> measures via an internal ADC.
> 
> This adds the possibility to read IIO channels directly for processed
> values rather than reading the registers and computing the value.
> 
> For backward compatibility purpose, if the IIO driver is not compiled,
> this driver will fall back on previous behaviour which is direct
> register readings.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>

I (or someone else) really needs to find time to deal with deferred probing
properly in the IIO core. It's a mess as we need to revisit how the
channel map stuff works to make sure it's always there...

Anyhow, it's still on the todo list and we can tidy this up if it ever
happens!

Jonathan
> ---
> 
> added in v2
> 
>  drivers/power/supply/axp20x_usb_power.c | 70 +++++++++++++++++++++++++++++++--
>  1 file changed, 66 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/supply/axp20x_usb_power.c b/drivers/power/supply/axp20x_usb_power.c
> index 1bcb025..d8b1dc6 100644
> --- a/drivers/power/supply/axp20x_usb_power.c
> +++ b/drivers/power/supply/axp20x_usb_power.c
> @@ -22,6 +22,7 @@
>  #include <linux/power_supply.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
> +#include <linux/iio/consumer.h>
>  
>  #define DRVNAME "axp20x-usb-power-supply"
>  
> @@ -49,6 +50,8 @@ struct axp20x_usb_power {
>  	struct regmap *regmap;
>  	struct power_supply *supply;
>  	int axp20x_id;
> +	struct iio_channel *vbus_v;
> +	struct iio_channel *vbus_i;
>  };
>  
>  static irqreturn_t axp20x_usb_power_irq(int irq, void *devid)
> @@ -76,6 +79,20 @@ static int axp20x_usb_power_get_property(struct power_supply *psy,
>  		val->intval = AXP20X_VBUS_VHOLD_uV(v);
>  		return 0;
>  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +		if (IS_ENABLED(CONFIG_AXP20X_ADC)) {
> +			ret = iio_read_channel_processed(power->vbus_v,
> +							 &val->intval);
> +			if (ret)
> +				return ret;
> +
> +			/*
> +			 * IIO framework gives mV but Power Supply framework
> +			 * gives uV.
> +			 */
> +			val->intval *= 1000;
> +			return 0;
> +		}
> +
>  		ret = axp20x_read_variable_width(power->regmap,
>  						 AXP20X_VBUS_V_ADC_H, 12);
>  		if (ret < 0)
> @@ -107,6 +124,20 @@ static int axp20x_usb_power_get_property(struct power_supply *psy,
>  		}
>  		return 0;
>  	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +		if (IS_ENABLED(CONFIG_AXP20X_ADC)) {
> +			ret = iio_read_channel_processed(power->vbus_i,
> +							 &val->intval);
> +			if (ret)
> +				return ret;
> +
> +			/*
> +			 * IIO framework gives mA but Power Supply framework
> +			 * gives uA.
> +			 */
> +			val->intval *= 1000;
> +			return 0;
> +		}
> +
>  		ret = axp20x_read_variable_width(power->regmap,
>  						 AXP20X_VBUS_I_ADC_H, 12);
>  		if (ret < 0)
> @@ -269,6 +300,36 @@ static const struct power_supply_desc axp22x_usb_power_desc = {
>  	.set_property = axp20x_usb_power_set_property,
>  };
>  
> +static int configure_iio_channels(struct platform_device *pdev,
> +				  struct axp20x_usb_power *power)
> +{
> +	power->vbus_v = devm_iio_channel_get(&pdev->dev, "vbus_v");
> +	if (IS_ERR(power->vbus_v)) {
> +		if (PTR_ERR(power->vbus_v) == -ENODEV)
> +			return -EPROBE_DEFER;
> +		return PTR_ERR(power->vbus_v);
> +	}
> +
> +	power->vbus_i = devm_iio_channel_get(&pdev->dev, "vbus_i");
> +	if (IS_ERR(power->vbus_i)) {
> +		if (PTR_ERR(power->vbus_i) == -ENODEV)
> +			return -EPROBE_DEFER;
> +		return PTR_ERR(power->vbus_i);
> +	}
> +
> +	return 0;
> +}
> +
> +static int configure_adc_registers(struct axp20x_usb_power *power)
> +{
> +	/* Enable vbus voltage and current measurement */
> +	return regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
> +				  AXP20X_ADC_EN1_VBUS_CURR |
> +				  AXP20X_ADC_EN1_VBUS_VOLT,
> +				  AXP20X_ADC_EN1_VBUS_CURR |
> +				  AXP20X_ADC_EN1_VBUS_VOLT);
> +}
> +
>  static int axp20x_usb_power_probe(struct platform_device *pdev)
>  {
>  	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
> @@ -307,10 +368,11 @@ static int axp20x_usb_power_probe(struct platform_device *pdev)
>  		if (ret)
>  			return ret;
>  
> -		/* Enable vbus voltage and current measurement */
> -		ret = regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
> -			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT,
> -			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT);
> +		if (IS_ENABLED(CONFIG_AXP20X_ADC))
> +			ret = configure_iio_channels(pdev, power);
> +		else
> +			ret = configure_adc_registers(power);
> +
>  		if (ret)
>  			return ret;
>  
>