[RFC PATCH 3/7] iio: adc: axp20x-adc: add support for AXP803

[Jonathan Cameron]

On Wed, 20 Sep 2017 23:18:10 +0800
Icenowy Zheng <icenowy at aosc.io> wrote:

> AXP803 SoC features an ADC part including these channels: GPADC (GPIO0)
> and TS pins, PMIC internal temperature sensor, battery voltage, battery
> charge/discharge current.
> 
> Add support for the battery-related channels and internal temperature
> channel in order to allow battery monitoring. The TS and GPADC channels
> are complex and will be support after more investigation.
> 
> Signed-off-by: Icenowy Zheng <icenowy at aosc.io>

A few comments inline but this looks good to me.

I will want to leave plenty of time for others to comment however, particularly
Quentin.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/axp20x_adc.c | 108 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 108 insertions(+)
> 
> diff --git a/drivers/iio/adc/axp20x_adc.c b/drivers/iio/adc/axp20x_adc.c
> index 93dd6b80059e..4f0cd98cf6ea 100644
> --- a/drivers/iio/adc/axp20x_adc.c
> +++ b/drivers/iio/adc/axp20x_adc.c
> @@ -28,6 +28,8 @@
>  
>  #define AXP20X_ADC_EN2_MASK			(GENMASK(3, 2) | BIT(7))
>  #define AXP22X_ADC_EN1_MASK			(GENMASK(7, 5) | BIT(0))
> +/* TODO: Enable TS and GPADC when supporting them */
> +#define AXP803_ADC_EN1_MASK			GENMASK(7, 5)
>  
>  #define AXP20X_GPIO10_IN_RANGE_GPIO0		BIT(0)
>  #define AXP20X_GPIO10_IN_RANGE_GPIO1		BIT(1)
> @@ -95,6 +97,17 @@ enum axp22x_adc_channel_i {
>  	AXP22X_BATT_DISCHRG_I,
>  };
>  
> +enum axp803_adc_channel_v {
> +	AXP803_TS_IN = 0,
> +	AXP803_GPADC_IN,
> +	AXP803_BATT_V,
> +};
> +
> +enum axp803_adc_channel_i {
> +	AXP803_BATT_CHRG_I = 2,
> +	AXP803_BATT_DISCHRG_I,
> +};
> +
>  static struct iio_map axp20x_maps[] = {
>  	{
>  		.consumer_dev_name = "axp20x-usb-power-supply",
> @@ -144,6 +157,11 @@ static struct iio_map axp22x_maps[] = {
>  };
>  
>  /*
> + * AXP803 shares the same consumer map with AXP22x, as it has no ADC for
> + * VBUS and ACIN inputs either.
> + */
> +
> +/*
>   * Channels are mapped by physical system. Their channels share the same index.
>   * i.e. acin_i is in_current0_raw and acin_v is in_voltage0_raw.
>   * The only exception is for the battery. batt_v will be in_voltage6_raw and
> @@ -197,6 +215,23 @@ static const struct iio_chan_spec axp22x_adc_channels[] = {
>  			   AXP20X_BATT_DISCHRG_I_H),
>  };
>  
> +static const struct iio_chan_spec axp803_adc_channels[] = {
> +	{
> +		.type = IIO_TEMP,
> +		.address = AXP288_PMIC_ADC_H,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE) |
> +				      BIT(IIO_CHAN_INFO_OFFSET),
> +		.datasheet_name = "pmic_temp",
> +	},
> +	AXP20X_ADC_CHANNEL(AXP803_BATT_V, "batt_v", IIO_VOLTAGE,
> +			   AXP20X_BATT_V_H),
> +	AXP20X_ADC_CHANNEL(AXP803_BATT_CHRG_I, "batt_chrg_i", IIO_CURRENT,
> +			   AXP20X_BATT_CHRG_I_H),
> +	AXP20X_ADC_CHANNEL(AXP803_BATT_DISCHRG_I, "batt_dischrg_i", IIO_CURRENT,
> +			   AXP20X_BATT_DISCHRG_I_H),
> +};
> +
>  static int axp20x_adc_raw(struct iio_dev *indio_dev,
>  			  struct iio_chan_spec const *chan, int *val)
>  {
> @@ -243,6 +278,19 @@ static int axp22x_adc_raw(struct iio_dev *indio_dev,
>  	return IIO_VAL_INT;
>  }
>  
> +static int axp803_adc_raw(struct iio_dev *indio_dev,
> +			  struct iio_chan_spec const *chan, int *val)
> +{
> +	struct axp20x_adc_iio *info = iio_priv(indio_dev);
> +
> +	/* All channels on AXP803 are stored on 12 bits. */
> +	*val = axp20x_read_variable_width(info->regmap, chan->address, 12);
> +	if (*val < 0)
> +		return *val;
> +
> +	return IIO_VAL_INT;
> +}
> +
>  static int axp20x_adc_scale_voltage(int channel, int *val, int *val2)
>  {
>  	switch (channel) {
> @@ -342,6 +390,31 @@ static int axp22x_adc_scale(struct iio_chan_spec const *chan, int *val,
>  	}
>  }
>  
> +static int axp803_adc_scale(struct iio_chan_spec const *chan, int *val,
> +			    int *val2)
> +{
> +	switch (chan->type) {
> +	case IIO_VOLTAGE:
> +		if (chan->channel != AXP803_BATT_V)
> +			return -EINVAL;
> +
> +		*val = 1;
> +		*val2 = 100000;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +
> +	case IIO_CURRENT:
> +		*val = 1;

A scale of 1 is assumed so you could drop providing this attribute.
However, given there are scales for all other channels I guess that
would feel weird.  There is nothing in our ABI saying you can't
specify things that are the default so it makes sense to me to keep
this here.

> +		return IIO_VAL_INT;
> +
> +	case IIO_TEMP:
> +		*val = 106;
> +		return IIO_VAL_INT;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
>  static int axp20x_adc_offset_voltage(struct iio_dev *indio_dev, int channel,
>  				     int *val)
>  {
> @@ -425,6 +498,26 @@ static int axp22x_read_raw(struct iio_dev *indio_dev,
>  	}
>  }
>  
> +static int axp803_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan, int *val,
> +			   int *val2, long mask)
> +{
> +	switch (mask) {
> +	case IIO_CHAN_INFO_OFFSET:

I know it is impossible to get here unless we have a temperature channel,
but it still feels like this should be made apparent here.

Perhaps a comment rather than an explicit check in the code?

> +		*val = -2525;
> +		return IIO_VAL_INT;
> +
> +	case IIO_CHAN_INFO_SCALE:
> +		return axp803_adc_scale(chan, val, val2);
> +
> +	case IIO_CHAN_INFO_RAW:
> +		return axp803_adc_raw(indio_dev, chan, val);
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
>  static int axp20x_write_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan, int val, int val2,
>  			    long mask)
> @@ -472,6 +565,11 @@ static const struct iio_info axp22x_adc_iio_info = {
>  	.driver_module = THIS_MODULE,
>  };
>  
> +static const struct iio_info axp803_adc_iio_info = {
> +	.read_raw = axp803_read_raw,
> +	.driver_module = THIS_MODULE,

.driver_module is now gone from this structure, but as it hasn't gone
upstream from my tree yet I'll clean these up if they are still there
once we get to the point of applying this patch.

> +};
> +
>  static int axp20x_adc_rate(int rate)
>  {
>  	return AXP20X_ADC_RATE_HZ(rate);
> @@ -512,9 +610,19 @@ static const struct axp_data axp22x_data = {
>  	.maps = axp22x_maps,
>  };
>  
> +static const struct axp_data axp803_data = {
> +	.iio_info = &axp803_adc_iio_info,
> +	.num_channels = ARRAY_SIZE(axp803_adc_channels),
> +	.channels = axp803_adc_channels,
> +	.adc_en1_mask = AXP803_ADC_EN1_MASK,
> +	.adc_en2 = false,
> +	.maps = axp22x_maps,
> +};
> +
>  static const struct platform_device_id axp20x_adc_id_match[] = {
>  	{ .name = "axp20x-adc", .driver_data = (kernel_ulong_t)&axp20x_data, },
>  	{ .name = "axp22x-adc", .driver_data = (kernel_ulong_t)&axp22x_data, },
> +	{ .name = "axp803-adc", .driver_data = (kernel_ulong_t)&axp803_data, },
>  	{ /* sentinel */ },
>  };
>  MODULE_DEVICE_TABLE(platform, axp20x_adc_id_match);