[PATCH 4/5] iio: accel: adxl372: Add sysfs for g thresholds

[Alexandru Tachici <alexandru.tachici@analog.com>]

Adxl372 has configurable thresholds for all 3 axis
that define activity and inactivity.
The driver sets the default inactivity threshold to 100mg
and the activity threshold to 1g. These values are not
ideal for all applications.

This patch adds device attributes for activity and inactivity
thresholds for each axis.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/iio/accel/adxl372.c | 91 +++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
index 8bef6f2030ff..ab154699e23a 100644
--- a/drivers/iio/accel/adxl372.c
+++ b/drivers/iio/accel/adxl372.c
@@ -5,6 +5,7 @@
  * Copyright 2018 Analog Devices Inc.
  */
 
+#include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
@@ -131,6 +132,14 @@
 #define ADXL372_INT1_MAP_LOW_MSK		BIT(7)
 #define ADXL372_INT1_MAP_LOW_MODE(x)		(((x) & 0x1) << 7)
 
+/* ADX372_THRESH */
+#define ADXL372_THRESH_VAL_H_MSK		GENMASK(10, 3)
+#define ADXL372_THRESH_VAL_H_SEL(x)		\
+		FIELD_GET(ADXL372_THRESH_VAL_H_MSK, x)
+#define ADXL372_THRESH_VAL_L_MSK		GENMASK(2, 0)
+#define ADXL372_THRESH_VAL_L_SEL(x)		\
+		FIELD_GET(ADXL372_THRESH_VAL_L_MSK, x)
+
 /* The ADXL372 includes a deep, 512 sample FIFO buffer */
 #define ADXL372_FIFO_SIZE			512
 
@@ -222,6 +231,32 @@ static const struct adxl372_axis_lookup adxl372_axis_lookup_table[] = {
 	{ BIT(0) | BIT(1) | BIT(2), ADXL372_XYZ_FIFO },
 };
 
+static ssize_t adxl372_read_threshold_value(struct iio_dev *, uintptr_t,
+					    const struct iio_chan_spec *,
+					    char *);
+
+static ssize_t adxl372_write_threshold_value(struct iio_dev *, uintptr_t,
+					     struct iio_chan_spec const *,
+					     const char *, size_t);
+
+static const struct iio_chan_spec_ext_info adxl372_ext_info[] = {
+	{
+		.name = "threshold_activity",
+		.shared = IIO_SEPARATE,
+		.read = adxl372_read_threshold_value,
+		.write = adxl372_write_threshold_value,
+		.private = ADXL372_X_THRESH_ACT_H,
+	},
+	{
+		.name = "threshold_inactivity",
+		.shared = IIO_SEPARATE,
+		.read = adxl372_read_threshold_value,
+		.write = adxl372_write_threshold_value,
+		.private = ADXL372_X_THRESH_INACT_H,
+	},
+	{},
+};
+
 #define ADXL372_ACCEL_CHANNEL(index, reg, axis) {			\
 	.type = IIO_ACCEL,						\
 	.address = reg,							\
@@ -239,6 +274,7 @@ static const struct adxl372_axis_lookup adxl372_axis_lookup_table[] = {
 		.shift = 4,						\
 		.endianness = IIO_BE,					\
 	},								\
+	.ext_info = adxl372_ext_info,					\
 }
 
 static const struct iio_chan_spec adxl372_channels[] = {
@@ -277,6 +313,61 @@ static const unsigned long adxl372_channel_masks[] = {
 	0
 };
 
+static ssize_t adxl372_read_threshold_value(struct iio_dev *indio_dev,
+					    uintptr_t private,
+					    const struct iio_chan_spec *chan,
+					    char *buf)
+{
+	struct adxl372_state *st = iio_priv(indio_dev);
+	unsigned int addr;
+	__be16 __regval;
+	u16 regval;
+	int ret;
+
+	addr = (unsigned int)chan->ext_info->private;
+	addr = addr + chan->scan_index * 2;
+
+	ret = regmap_bulk_read(st->regmap, addr, &__regval, sizeof(__regval));
+	if (ret < 0)
+		return ret;
+
+	regval = be16_to_cpu(__regval);
+	regval >>= 5;
+
+	return sprintf(buf, "%d\n", regval);
+}
+
+static ssize_t adxl372_write_threshold_value(struct iio_dev *indio_dev,
+					     uintptr_t private,
+					     const struct iio_chan_spec *chan,
+					     const char *buf,
+					     size_t len)
+{
+	struct adxl372_state *st = iio_priv(indio_dev);
+	unsigned int addr;
+	u16 threshold;
+	int ret;
+
+	ret = kstrtou16(buf, 0, &threshold);
+	if (ret < 0)
+		return ret;
+
+	addr = chan->ext_info->private;
+	addr = addr + chan->scan_index * 2;
+
+	ret = regmap_write(st->regmap, addr,
+			   ADXL372_THRESH_VAL_H_SEL(threshold));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(st->regmap, addr + 1, GENMASK(7, 5),
+				 ADXL372_THRESH_VAL_L_SEL(threshold) << 5);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
 static int adxl372_read_axis(struct adxl372_state *st, u8 addr)
 {
 	__be16 regval;
-- 
2.20.1