Re: [PATCH 08/10] iio: adc: axp20x_adc: Add support for AXP192

From: Aidan MacDonald
Date: Sat Jun 04 2022 - 08:05:47 EST

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In reply to: Jonathan Cameron: "Re: [PATCH 08/10] iio: adc: axp20x_adc: Add support for AXP192"
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Jonathan Cameron <jic23@xxxxxxxxxx> writes:

> On Fri, 3 Jun 2022 14:57:12 +0100
> Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx> wrote:
>
>> The AXP192 is identical to the AXP20x, except for the addition of
>> two more GPIO ADC channels.
>>
>> Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx>
> Hi Aidan,
>
> A few minor questions and comments inline.
>
> Thanks,
>
> Jonathan
>
>> ---
>> drivers/iio/adc/axp20x_adc.c | 289 +++++++++++++++++++++++++++++++++--
>> 1 file changed, 280 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/iio/adc/axp20x_adc.c b/drivers/iio/adc/axp20x_adc.c
>> index 53bf7d4899d2..7d2bf9529420 100644
>> --- a/drivers/iio/adc/axp20x_adc.c
>> +++ b/drivers/iio/adc/axp20x_adc.c
>> @@ -21,6 +21,9 @@
>> #include <linux/iio/machine.h>
>> #include <linux/mfd/axp20x.h>
>>
>> +#define AXP192_ADC_EN1_MASK GENMASK(7, 0)
>> +#define AXP192_ADC_EN2_MASK (BIT(7) | GENMASK(3, 0))
>
> Obviously doesn't really mater, but for consistency, maybe match the
> ordering in AXP20X_ADC_EN2_MASK below?
>

Ack, will do

>> +
>> #define AXP20X_ADC_EN1_MASK GENMASK(7, 0)
>>
>> #define AXP20X_ADC_EN2_MASK (GENMASK(3, 2) | BIT(7))
>> @@ -31,6 +34,15 @@
>> #define AXP20X_GPIO10_IN_RANGE_GPIO0_VAL(x) ((x) & BIT(0))
>> #define AXP20X_GPIO10_IN_RANGE_GPIO1_VAL(x) (((x) & BIT(0)) << 1)
>>
>> +#define AXP192_GPIO30_IN_RANGE_GPIO0 BIT(0)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO1 BIT(1)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO2 BIT(2)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO3 BIT(3)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO0_VAL(x) ((x) & BIT(0))
>> +#define AXP192_GPIO30_IN_RANGE_GPIO1_VAL(x) (((x) & BIT(0)) << 1)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO2_VAL(x) (((x) & BIT(0)) << 2)
>> +#define AXP192_GPIO30_IN_RANGE_GPIO3_VAL(x) (((x) & BIT(0)) << 3)
>
> FIELD_PREP() using the masks is cleaner than hand rolling it.
> If you fancy updating the driver in general whilst here that would be great,
> but I don't mind if not.
>

Yeah, I don't mind, I'll include a cleanup patch in my v2.

>> +
>> #define AXP20X_ADC_RATE_MASK GENMASK(7, 6)
>> #define AXP813_V_I_ADC_RATE_MASK GENMASK(5, 4)
>> #define AXP813_ADC_RATE_MASK (AXP20X_ADC_RATE_MASK | AXP813_V_I_ADC_RATE_MASK)
>> @@ -70,6 +82,25 @@ struct axp20x_adc_iio {
>> const struct axp_data *data;
>> };
>>
>> +enum axp192_adc_channel_v {
>> + AXP192_ACIN_V = 0,
>> + AXP192_VBUS_V,
>> + AXP192_TS_IN,
>> + AXP192_GPIO0_V,
>> + AXP192_GPIO1_V,
>> + AXP192_GPIO2_V,
>> + AXP192_GPIO3_V,
>> + AXP192_IPSOUT_V,
>> + AXP192_BATT_V,
>> +};
>> +
>> +enum axp192_adc_channel_i {
>> + AXP192_ACIN_I = 0,
>> + AXP192_VBUS_I,
>> + AXP192_BATT_CHRG_I,
>> + AXP192_BATT_DISCHRG_I,
>> +};
>> +
>> enum axp20x_adc_channel_v {
>> AXP20X_ACIN_V = 0,
>> AXP20X_VBUS_V,
>> @@ -157,6 +188,43 @@ static struct iio_map axp22x_maps[] = {
>> * The only exception is for the battery. batt_v will be in_voltage6_raw and
>> * charge current in_current6_raw and discharge current will be in_current7_raw.
>> */
>> +static const struct iio_chan_spec axp192_adc_channels[] = {
>> + AXP20X_ADC_CHANNEL(AXP192_ACIN_V, "acin_v", IIO_VOLTAGE,
>> + AXP20X_ACIN_V_ADC_H),
>> + AXP20X_ADC_CHANNEL(AXP192_ACIN_I, "acin_i", IIO_CURRENT,
>> + AXP20X_ACIN_I_ADC_H),
>> + AXP20X_ADC_CHANNEL(AXP192_VBUS_V, "vbus_v", IIO_VOLTAGE,
>> + AXP20X_VBUS_V_ADC_H),
>> + AXP20X_ADC_CHANNEL(AXP192_VBUS_I, "vbus_i", IIO_CURRENT,
>> + AXP20X_VBUS_I_ADC_H),
>> + {
>> + .type = IIO_TEMP,
>> + .address = AXP20X_TEMP_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_OFFSET(AXP192_GPIO0_V, "gpio0_v", IIO_VOLTAGE,
>> + AXP20X_GPIO0_V_ADC_H),
>> + AXP20X_ADC_CHANNEL_OFFSET(AXP192_GPIO1_V, "gpio1_v", IIO_VOLTAGE,
>> + AXP20X_GPIO1_V_ADC_H),
>> + AXP20X_ADC_CHANNEL_OFFSET(AXP192_GPIO2_V, "gpio2_v", IIO_VOLTAGE,
>> + AXP192_GPIO2_V_ADC_H),
>> + AXP20X_ADC_CHANNEL_OFFSET(AXP192_GPIO3_V, "gpio3_v", IIO_VOLTAGE,
>> + AXP192_GPIO3_V_ADC_H),
>> + AXP20X_ADC_CHANNEL(AXP192_IPSOUT_V, "ipsout_v", IIO_VOLTAGE,
>> + AXP20X_IPSOUT_V_HIGH_H),
>> + AXP20X_ADC_CHANNEL(AXP192_BATT_V, "batt_v", IIO_VOLTAGE,
>> + AXP20X_BATT_V_H),
>> + AXP20X_ADC_CHANNEL(AXP192_BATT_CHRG_I, "batt_chrg_i", IIO_CURRENT,
>> + AXP20X_BATT_CHRG_I_H),
>> + AXP20X_ADC_CHANNEL(AXP192_BATT_DISCHRG_I, "batt_dischrg_i", IIO_CURRENT,
>> + AXP20X_BATT_DISCHRG_I_H),
>> + AXP20X_ADC_CHANNEL(AXP192_TS_IN, "ts_v", IIO_VOLTAGE,
>> + AXP20X_TS_IN_H),
>> +};
>> +
>> static const struct iio_chan_spec axp20x_adc_channels[] = {
>> AXP20X_ADC_CHANNEL(AXP20X_ACIN_V, "acin_v", IIO_VOLTAGE,
>> AXP20X_ACIN_V_ADC_H),
>> @@ -277,6 +345,44 @@ static int axp813_adc_raw(struct iio_dev *indio_dev,
>> return IIO_VAL_INT;
>> }
>>
>> +static int axp192_adc_scale_voltage(int channel, int *val, int *val2)
>> +{
>> + switch (channel) {
>> + case AXP192_ACIN_V:
>> + case AXP192_VBUS_V:
>> + *val = 1;
>> + *val2 = 700000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> + case AXP192_GPIO0_V:
>> + case AXP192_GPIO1_V:
>> + case AXP192_GPIO2_V:
>> + case AXP192_GPIO3_V:
>> + *val = 0;
>> + *val2 = 500000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> + case AXP192_BATT_V:
>> + *val = 1;
>> + *val2 = 100000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> + case AXP192_IPSOUT_V:
>> + *val = 1;
>> + *val2 = 400000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> + case AXP192_TS_IN:
>> + /* 0.8 mV per LSB */
>> + *val = 0;
>> + *val2 = 800000;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> static int axp20x_adc_scale_voltage(int channel, int *val, int *val2)
>> {
>> switch (channel) {
>> @@ -380,6 +486,29 @@ static int axp20x_adc_scale_current(int channel, int *val, int *val2)
>> }
>> }
>>
>> +static int axp192_adc_scale(struct iio_chan_spec const *chan, int *val,
>> + int *val2)
>> +{
>> + switch (chan->type) {
>> + case IIO_VOLTAGE:
>> + return axp192_adc_scale_voltage(chan->channel, val, val2);
>> +
>> + case IIO_CURRENT:
>> + /*
>> + * AXP192 current channels are identical to the AXP20x,
>> + * therefore we can re-use the scaling function.
>> + */
>> + return axp20x_adc_scale_current(chan->channel, val, val2);
>> +
>> + case IIO_TEMP:
>> + *val = 100;
>> + return IIO_VAL_INT;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> static int axp20x_adc_scale(struct iio_chan_spec const *chan, int *val,
>> int *val2)
>> {
>> @@ -439,6 +568,42 @@ static int axp813_adc_scale(struct iio_chan_spec const *chan, int *val,
>> }
>> }
>>
>> +static int axp192_adc_offset_voltage(struct iio_dev *indio_dev, int channel,
>> + int *val)
>> +{
>> + struct axp20x_adc_iio *info = iio_priv(indio_dev);
>> + int ret;
>> +
>> + ret = regmap_read(info->regmap, AXP192_GPIO30_IN_RANGE, val);
>> + if (ret < 0)
>> + return ret;
>> +
>> + switch (channel) {
>> + case AXP192_GPIO0_V:
>> + *val &= AXP192_GPIO30_IN_RANGE_GPIO0;
>
> Obviously existing case does it this way, but I'd prefer a local variable
> and FIELD_GET() for these. Reusing *val for this is confusing.
>
> A precursor patch to tidy up earlier code would be great if you have
> time.
>

Ack

>> + break;
>> +
>> + case AXP192_GPIO1_V:
>> + *val &= AXP192_GPIO30_IN_RANGE_GPIO1;
>> + break;
>> +
>> + case AXP192_GPIO2_V:
>> + *val &= AXP192_GPIO30_IN_RANGE_GPIO2;
>> + break;
>> +
>> + case AXP192_GPIO3_V:
>> + *val &= AXP192_GPIO30_IN_RANGE_GPIO3;
>> + break;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + *val = *val ? 700000 : 0;
>> +
>> + return IIO_VAL_INT;
>> +}
>> +
>> static int axp20x_adc_offset_voltage(struct iio_dev *indio_dev, int channel,
>> int *val)
>> {
>> @@ -467,6 +632,22 @@ static int axp20x_adc_offset_voltage(struct iio_dev *indio_dev, int channel,
>> return IIO_VAL_INT;
>> }
>>
>> +static int axp192_adc_offset(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan, int *val)
>> +{
>> + switch (chan->type) {
>> + case IIO_VOLTAGE:
>> + return axp192_adc_offset_voltage(indio_dev, chan->channel, val);
>> +
>> + case IIO_TEMP:
>> + *val = -1447;
>> + return IIO_VAL_INT;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> static int axp20x_adc_offset(struct iio_dev *indio_dev,
>> struct iio_chan_spec const *chan, int *val)
>> {
>> @@ -483,6 +664,25 @@ static int axp20x_adc_offset(struct iio_dev *indio_dev,
>> }
>> }
>>
>> +static int axp192_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:
>> + return axp192_adc_offset(indio_dev, chan, val);
>> +
>> + case IIO_CHAN_INFO_SCALE:
>> + return axp192_adc_scale(chan, val, val2);
>> +
>> + case IIO_CHAN_INFO_RAW:
>> + return axp20x_adc_raw(indio_dev, chan, val);
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> static int axp20x_read_raw(struct iio_dev *indio_dev,
>> struct iio_chan_spec const *chan, int *val,
>> int *val2, long mask)
>> @@ -543,6 +743,54 @@ static int axp813_read_raw(struct iio_dev *indio_dev,
>> }
>> }
>>
>> +static int axp192_write_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan, int val, int val2,
>> + long mask)
>> +{
>> + struct axp20x_adc_iio *info = iio_priv(indio_dev);
>> + unsigned int reg, regval;
>> +
>> + /*
>> + * The AXP192 PMIC allows the user to choose between 0V and 0.7V offsets
>> + * for (independently) GPIO0-3 when in ADC mode.
>> + */
>> + if (mask != IIO_CHAN_INFO_OFFSET)
>> + return -EINVAL;
>> +
>> + if (val != 0 && val != 700000)
>> + return -EINVAL;
>> +
>> + val = val ? 1 : 0;
>
> Use a local variable for this. It's no longer val in any way so the
> reuse is confusing.
>

Ack, I'll also clean up the existing code that I copied this from.

>> +
>> + switch (chan->channel) {
>> + case AXP192_GPIO0_V:
>> + reg = AXP192_GPIO30_IN_RANGE_GPIO0;
>> + regval = AXP192_GPIO30_IN_RANGE_GPIO0_VAL(val);
>
> FIELD_PREP()
>

Ack

>> + break;
>> +
>> + case AXP192_GPIO1_V:
>> + reg = AXP192_GPIO30_IN_RANGE_GPIO1;
>> + regval = AXP192_GPIO30_IN_RANGE_GPIO1_VAL(val);
>> + break;
>> +
>> + case AXP192_GPIO2_V:
>> + reg = AXP192_GPIO30_IN_RANGE_GPIO2;
>> + regval = AXP192_GPIO30_IN_RANGE_GPIO2_VAL(val);
>> + break;
>> +
>> + case AXP192_GPIO3_V:
>> + reg = AXP192_GPIO30_IN_RANGE_GPIO3;
>> + regval = AXP192_GPIO30_IN_RANGE_GPIO3_VAL(val);
>> + break;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + return regmap_update_bits(info->regmap, AXP192_GPIO30_IN_RANGE, reg,
>> + regval);
>> +}
>> +
>> static int axp20x_write_raw(struct iio_dev *indio_dev,
>> struct iio_chan_spec const *chan, int val, int val2,
>> long mask)
>> @@ -581,6 +829,18 @@ static int axp20x_write_raw(struct iio_dev *indio_dev,
>> regval);
>> }
>>
>> +static int axp192_read_label(struct iio_dev *iio_dev,
>> + const struct iio_chan_spec *chan, char *label)
>> +{
>> + return snprintf(label, PAGE_SIZE, "%s\n", chan->datasheet_name);
>> +}
>
> Unless I missed a previous patch adding labels to the other devices supported,
> this is the first driver to use these. Why do they make sense here but not
> to add to existing supported devices?
>
> I don't particularly mind this addition, just looking for an explanation.
>

That'd be because 1d4ef9b39ebecca8 ("iio: core: Add optional symbolic
label to a device channel") added read_label in 2020, while the AXP
driver was introduced in 2017. I could add read_label for the other
chips while I'm here, for consistency.

One question I have is why read_label exists when the kernel already has
unique names for IIO channels. Why not just expose the datasheet_name to
userspace from the IIO core instead of making drivers do it?

>> +
>> +static const struct iio_info axp192_adc_iio_info = {
>> + .read_raw = axp192_read_raw,
>> + .write_raw = axp192_write_raw,
>> + .read_label = axp192_read_label,
>> +};
>> +
>> static const struct iio_info axp20x_adc_iio_info = {
>> .read_raw = axp20x_read_raw,
>> .write_raw = axp20x_write_raw,
>> @@ -620,19 +880,29 @@ struct axp_data {
>> int num_channels;
>> struct iio_chan_spec const *channels;
>> unsigned long adc_en1_mask;
>> + unsigned long adc_en2_mask;
>> int (*adc_rate)(struct axp20x_adc_iio *info,
>> int rate);
>> - bool adc_en2;
>> struct iio_map *maps;
>> };
>>
>> +static const struct axp_data axp192_data = {
>> + .iio_info = &axp192_adc_iio_info,
>> + .num_channels = ARRAY_SIZE(axp192_adc_channels),
>> + .channels = axp192_adc_channels,
>> + .adc_en1_mask = AXP192_ADC_EN1_MASK,
>> + .adc_en2_mask = AXP192_ADC_EN2_MASK,
>> + .adc_rate = axp20x_adc_rate,
>> + .maps = axp20x_maps,
>> +};
>> +
>> static const struct axp_data axp20x_data = {
>> .iio_info = &axp20x_adc_iio_info,
>> .num_channels = ARRAY_SIZE(axp20x_adc_channels),
>> .channels = axp20x_adc_channels,
>> .adc_en1_mask = AXP20X_ADC_EN1_MASK,
>> + .adc_en2_mask = AXP20X_ADC_EN2_MASK,
>> .adc_rate = axp20x_adc_rate,
>> - .adc_en2 = true,
>> .maps = axp20x_maps,
>> };
>>
>> @@ -642,7 +912,6 @@ static const struct axp_data axp22x_data = {
>> .channels = axp22x_adc_channels,
>> .adc_en1_mask = AXP22X_ADC_EN1_MASK,
>> .adc_rate = axp22x_adc_rate,
>> - .adc_en2 = false,
>> .maps = axp22x_maps,
>> };
>>
>> @@ -652,11 +921,11 @@ static const struct axp_data axp813_data = {
>> .channels = axp813_adc_channels,
>> .adc_en1_mask = AXP22X_ADC_EN1_MASK,
>> .adc_rate = axp813_adc_rate,
>> - .adc_en2 = false,
>> .maps = axp22x_maps,
>> };
>>
>> static const struct of_device_id axp20x_adc_of_match[] = {
>> + { .compatible = "x-powers,axp192-adc", .data = (void *)&axp192_data, },
>> { .compatible = "x-powers,axp209-adc", .data = (void *)&axp20x_data, },
>> { .compatible = "x-powers,axp221-adc", .data = (void *)&axp22x_data, },
>> { .compatible = "x-powers,axp813-adc", .data = (void *)&axp813_data, },
>> @@ -665,6 +934,7 @@ static const struct of_device_id axp20x_adc_of_match[] = {
>> MODULE_DEVICE_TABLE(of, axp20x_adc_of_match);
>>
>> static const struct platform_device_id axp20x_adc_id_match[] = {
>> + { .name = "axp192-adc", .driver_data = (kernel_ulong_t)&axp192_data, },
>> { .name = "axp20x-adc", .driver_data = (kernel_ulong_t)&axp20x_data, },
>> { .name = "axp22x-adc", .driver_data = (kernel_ulong_t)&axp22x_data, },
>> { .name = "axp813-adc", .driver_data = (kernel_ulong_t)&axp813_data, },
>> @@ -710,10 +980,11 @@ static int axp20x_probe(struct platform_device *pdev)
>> /* Enable the ADCs on IP */
>> regmap_write(info->regmap, AXP20X_ADC_EN1, info->data->adc_en1_mask);
>>
>> - if (info->data->adc_en2)
>> - /* Enable GPIO0/1 and internal temperature ADCs */
>> + if (info->data->adc_en2_mask)
>> + /* Enable GPIO and internal temperature ADCs */
>> regmap_update_bits(info->regmap, AXP20X_ADC_EN2,
>> - AXP20X_ADC_EN2_MASK, AXP20X_ADC_EN2_MASK);
>> + info->data->adc_en2_mask,
>> + info->data->adc_en2_mask);
>>
>> /* Configure ADCs rate */
>> info->data->adc_rate(info, 100);
>> @@ -738,7 +1009,7 @@ static int axp20x_probe(struct platform_device *pdev)
>> fail_map:
>> regmap_write(info->regmap, AXP20X_ADC_EN1, 0);
>>
>> - if (info->data->adc_en2)
>> + if (info->data->adc_en2_mask)
>> regmap_write(info->regmap, AXP20X_ADC_EN2, 0);
>>
>> return ret;
>> @@ -754,7 +1025,7 @@ static int axp20x_remove(struct platform_device *pdev)
>>
>> regmap_write(info->regmap, AXP20X_ADC_EN1, 0);
>>
>> - if (info->data->adc_en2)
>> + if (info->data->adc_en2_mask)
>> regmap_write(info->regmap, AXP20X_ADC_EN2, 0);
>>
>> return 0;

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