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Subject[PATCH v1] meson saradc: add iio device attrib to switch channel 7 mux
Date
Patch adds two sysfs nodes: chan7_mux to set mux state
and chan7_mux_available to show available mux states.
Mux can be used to debug and calibrate adc by
switching and measuring well-known inputs like gnd, vdd etc.

Signed-off-by: George Stark <GNStark@sberdevices.ru>
---
drivers/iio/adc/meson_saradc.c | 66 ++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index e05e51900c35..77ef2b55f6f4 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -11,6 +11,7 @@
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nvmem-consumer.h>
@@ -320,6 +321,7 @@ struct meson_sar_adc_priv {
bool temperature_sensor_calibrated;
u8 temperature_sensor_coefficient;
u16 temperature_sensor_adc_val;
+ u8 chan7_mux_sel;
};

static const struct regmap_config meson_sar_adc_regmap_config_gxbb = {
@@ -483,6 +485,7 @@ static void meson_sar_adc_set_chan7_mux(struct iio_dev *indio_dev,
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval);

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

@@ -1130,8 +1133,71 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
return ret;
}

+static const char * const chan7_vol[] = {
+ "gnd",
+ "vdd/4",
+ "vdd/2",
+ "vdd*3/4",
+ "vdd",
+ "ch7_input",
+};
+
+static ssize_t chan7_mux_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+ unsigned int index = priv->chan7_mux_sel;
+
+ if (index >= ARRAY_SIZE(chan7_vol))
+ index = ARRAY_SIZE(chan7_vol) - 1;
+
+ return sysfs_emit(buf, "%s\n", chan7_vol[index]);
+}
+
+static ssize_t chan7_mux_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(chan7_vol); i++)
+ if (!strcmp(chan7_vol[i], buf)) {
+ meson_sar_adc_set_chan7_mux(indio_dev, i);
+ return count;
+ }
+
+ return -EINVAL;
+}
+
+static ssize_t chan7_mux_available_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int i, len = 0;
+
+ for (i = 0; i < ARRAY_SIZE(chan7_vol); i++)
+ len += sysfs_emit_at(buf, len, "%s ", chan7_vol[i]);
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR_RW(chan7_mux, -1);
+static IIO_DEVICE_ATTR_RO(chan7_mux_available, -1);
+
+static struct attribute *meson_sar_adc_attrs[] = {
+ &iio_dev_attr_chan7_mux_available.dev_attr.attr,
+ &iio_dev_attr_chan7_mux.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group meson_sar_adc_attr_group = {
+ .attrs = meson_sar_adc_attrs,
+};
+
static const struct iio_info meson_sar_adc_iio_info = {
.read_raw = meson_sar_adc_iio_info_read_raw,
+ .attrs = &meson_sar_adc_attr_group,
};

static const struct meson_sar_adc_param meson_sar_adc_meson8_param = {
--
2.38.4
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