[PATCH v5 6/6] iio: adc: meson: support reading from channel 7 mux inputs

George Stark
2023-07-11T20:02:06Z

Meson saradc channel 7 is connected to a mux that can switch input
to well-known sources like Vdd, GND and several Vdd dividers.
Add IIO channel for every channel 7 mux input.

Signed-off-by: George Stark <GNStark@sberdevices.ru>
---
drivers/iio/adc/meson_saradc.c | 77 +++++++++++++++++++++++++++++++++-
1 file changed, 75 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 918bd5da3605..2411cc864ccd 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -163,6 +163,7 @@
#define MESON_SAR_ADC_MAX_FIFO_SIZE 32
#define MESON_SAR_ADC_TIMEOUT 100 /* ms */
#define MESON_SAR_ADC_VOLTAGE_AND_TEMP_CHANNEL 6
+#define MESON_SAR_ADC_VOLTAGE_AND_MUX_CHANNEL 7
#define MESON_SAR_ADC_TEMP_OFFSET 27

/* temperature sensor calibration information in eFuse */
@@ -202,6 +203,19 @@
.datasheet_name = "TEMP_SENSOR", \
}

+#define MESON_SAR_ADC_MUX(_chan, _sel) { \
+ .type = IIO_VOLTAGE, \
+ .channel = _chan, \
+ .indexed = 1, \
+ .address = MESON_SAR_ADC_VOLTAGE_AND_MUX_CHANNEL, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_CALIBBIAS) | \
+ BIT(IIO_CHAN_INFO_CALIBSCALE), \
+ .datasheet_name = "SAR_ADC_MUX_"#_sel, \
+}
+
enum meson_sar_adc_avg_mode {
NO_AVERAGING = 0x0,
MEAN_AVERAGING = 0x1,
@@ -234,6 +248,27 @@ enum meson_sar_adc_channel_index {
NUM_CHAN_6,
NUM_CHAN_7,
NUM_CHAN_TEMP,
+ NUM_MUX_0_VSS,
+ NUM_MUX_1_VDD_DIV4,
+ NUM_MUX_2_VDD_DIV2,
+ NUM_MUX_3_VDD_MUL3_DIV4,
+ NUM_MUX_4_VDD,
+};
+
+static enum meson_sar_adc_chan7_mux_sel chan7_mux_values[] = {
+ CHAN7_MUX_VSS,
+ CHAN7_MUX_VDD_DIV4,
+ CHAN7_MUX_VDD_DIV2,
+ CHAN7_MUX_VDD_MUL3_DIV4,
+ CHAN7_MUX_VDD,
+};
+
+static const char * const chan7_mux_names[] = {
+ [CHAN7_MUX_VSS] = "gnd",
+ [CHAN7_MUX_VDD_DIV4] = "0.25vdd",
+ [CHAN7_MUX_VDD_DIV2] = "0.5vdd",
+ [CHAN7_MUX_VDD_MUL3_DIV4] = "0.75vdd",
+ [CHAN7_MUX_VDD] = "vdd",
};

static const struct iio_chan_spec meson_sar_adc_iio_channels[] = {
@@ -245,6 +280,11 @@ static const struct iio_chan_spec meson_sar_adc_iio_channels[] = {
MESON_SAR_ADC_CHAN(NUM_CHAN_5),
MESON_SAR_ADC_CHAN(NUM_CHAN_6),
MESON_SAR_ADC_CHAN(NUM_CHAN_7),
+ MESON_SAR_ADC_MUX(NUM_MUX_0_VSS, 0),
+ MESON_SAR_ADC_MUX(NUM_MUX_1_VDD_DIV4, 1),
+ MESON_SAR_ADC_MUX(NUM_MUX_2_VDD_DIV2, 2),
+ MESON_SAR_ADC_MUX(NUM_MUX_3_VDD_MUL3_DIV4, 3),
+ MESON_SAR_ADC_MUX(NUM_MUX_4_VDD, 4),
};

static const struct iio_chan_spec meson_sar_adc_and_temp_iio_channels[] = {
@@ -257,6 +297,11 @@ static const struct iio_chan_spec meson_sar_adc_and_temp_iio_channels[] = {
MESON_SAR_ADC_CHAN(NUM_CHAN_6),
MESON_SAR_ADC_CHAN(NUM_CHAN_7),
MESON_SAR_ADC_TEMP_CHAN(NUM_CHAN_TEMP),
+ MESON_SAR_ADC_MUX(NUM_MUX_0_VSS, 0),
+ MESON_SAR_ADC_MUX(NUM_MUX_1_VDD_DIV4, 1),
+ MESON_SAR_ADC_MUX(NUM_MUX_2_VDD_DIV2, 2),
+ MESON_SAR_ADC_MUX(NUM_MUX_3_VDD_MUL3_DIV4, 3),
+ MESON_SAR_ADC_MUX(NUM_MUX_4_VDD, 4),
};

struct meson_sar_adc_param {
@@ -295,6 +340,7 @@ struct meson_sar_adc_priv {
bool temperature_sensor_calibrated;
u8 temperature_sensor_coefficient;
u16 temperature_sensor_adc_val;
+ enum meson_sar_adc_chan7_mux_sel chan7_mux_sel;
};

static const struct regmap_config meson_sar_adc_regmap_config_gxbb = {
@@ -311,6 +357,17 @@ static const struct regmap_config meson_sar_adc_regmap_config_meson8 = {
.max_register = MESON_SAR_ADC_DELTA_10,
};

+static const struct iio_chan_spec *
+find_channel_by_num(struct iio_dev *indio_dev, int num)
+{
+ int i;
+
+ for (i = 0; i < indio_dev->num_channels; i++)
+ if (indio_dev->channels[i].channel == num)
+ return &indio_dev->channels[i];
+ return NULL;
+}
+
static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
@@ -359,6 +416,8 @@ static void meson_sar_adc_set_chan7_mux(struct iio_dev *indio_dev,
MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval);

usleep_range(10, 20);
+
+ priv->chan7_mux_sel = sel;
}

static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
@@ -454,6 +513,15 @@ static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
regmap_update_bits(priv->regmap,
MESON_SAR_ADC_DELTA_10,
MESON_SAR_ADC_DELTA_10_TEMP_SEL, regval);
+ } else if (chan->address == MESON_SAR_ADC_VOLTAGE_AND_MUX_CHANNEL) {
+ enum meson_sar_adc_chan7_mux_sel sel;
+
+ if (chan->channel == NUM_CHAN_7)
+ sel = CHAN7_MUX_CH7_INPUT;
+ else
+ sel = chan7_mux_values[chan->channel - NUM_MUX_0_VSS];
+ if (sel != priv->chan7_mux_sel)
+ meson_sar_adc_set_chan7_mux(indio_dev, sel);
}
}

@@ -1026,7 +1094,8 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
usleep_range(10, 20);
ret = meson_sar_adc_get_sample(indio_dev,
- &indio_dev->channels[7],
+ find_channel_by_num(indio_dev,
+ NUM_MUX_1_VDD_DIV4),
MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
if (ret < 0)
goto out;
@@ -1034,7 +1103,8 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
usleep_range(10, 20);
ret = meson_sar_adc_get_sample(indio_dev,
- &indio_dev->channels[7],
+ find_channel_by_num(indio_dev,
+ NUM_MUX_3_VDD_MUL3_DIV4),
MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
if (ret < 0)
goto out;
@@ -1061,6 +1131,9 @@ static int read_label(struct iio_dev *indio_dev,
{
if (chan->type == IIO_TEMP)
return sprintf(label, "temp-sensor\n");
+ if (chan->type == IIO_VOLTAGE && chan->channel >= NUM_MUX_0_VSS)
+ return sprintf(label, "%s\n",
+ chan7_mux_names[chan->channel - NUM_MUX_0_VSS]);
if (chan->type == IIO_VOLTAGE)
return sprintf(label, "channel-%d\n", chan->channel);
return 0;
--
2.38.4