From a0175b9c76f59c1f5706f986d690e27ba06363dd Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Wed, 12 Aug 2015 10:22:41 +0200
Subject: [PATCH] iio: st_sensors: add debugfs register read hook

This adds a debugfs hook to read/write registers in the ST
sensors using debugfs. Proved to be awesome help when trying
to debug why IRQs do not arrive.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/accel/st_accel_core.c             |  1 +
 .../iio/common/st_sensors/st_sensors_core.c   | 22 +++++++++++++++++++
 drivers/iio/gyro/st_gyro_core.c               |  1 +
 drivers/iio/magnetometer/st_magn_core.c       |  1 +
 drivers/iio/pressure/st_pressure_core.c       |  1 +
 include/linux/iio/common/st_sensors.h         |  4 ++++
 6 files changed, 30 insertions(+)

diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index ff30f8806880..dab8b76c1427 100644
--- a/drivers/iio/accel/st_accel_core.c
+++ b/drivers/iio/accel/st_accel_core.c
@@ -618,6 +618,7 @@ static const struct iio_info accel_info = {
 	.attrs = &st_accel_attribute_group,
 	.read_raw = &st_accel_read_raw,
 	.write_raw = &st_accel_write_raw,
+	.debugfs_reg_access = &st_sensors_debugfs_reg_access,
 };
 
 #ifdef CONFIG_IIO_TRIGGER
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 2e7fdb502645..25258e2c1a82 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -44,6 +44,28 @@ st_sensors_write_data_with_mask_error:
 	return err;
 }
 
+int st_sensors_debugfs_reg_access(struct iio_dev *indio_dev,
+				  unsigned reg, unsigned writeval,
+				  unsigned *readval)
+{
+	struct st_sensor_data *sdata = iio_priv(indio_dev);
+	u8 readdata;
+	int err;
+
+	if (!readval)
+		return sdata->tf->write_byte(&sdata->tb, sdata->dev,
+					     (u8)reg, (u8)writeval);
+
+	err = sdata->tf->read_byte(&sdata->tb, sdata->dev, (u8)reg, &readdata);
+	if (err < 0)
+		return err;
+
+	*readval = (unsigned)readdata;
+
+	return 0;
+}
+EXPORT_SYMBOL(st_sensors_debugfs_reg_access);
+
 static int st_sensors_match_odr(struct st_sensor_settings *sensor_settings,
 			unsigned int odr, struct st_sensor_odr_avl *odr_out)
 {
diff --git a/drivers/iio/gyro/st_gyro_core.c b/drivers/iio/gyro/st_gyro_core.c
index 4b993a5bc9a1..02eddcebeea3 100644
--- a/drivers/iio/gyro/st_gyro_core.c
+++ b/drivers/iio/gyro/st_gyro_core.c
@@ -383,6 +383,7 @@ static const struct iio_info gyro_info = {
 	.attrs = &st_gyro_attribute_group,
 	.read_raw = &st_gyro_read_raw,
 	.write_raw = &st_gyro_write_raw,
+	.debugfs_reg_access = &st_sensors_debugfs_reg_access,
 };
 
 #ifdef CONFIG_IIO_TRIGGER
diff --git a/drivers/iio/magnetometer/st_magn_core.c b/drivers/iio/magnetometer/st_magn_core.c
index f8dc4b85d70c..b27f0146647b 100644
--- a/drivers/iio/magnetometer/st_magn_core.c
+++ b/drivers/iio/magnetometer/st_magn_core.c
@@ -560,6 +560,7 @@ static const struct iio_info magn_info = {
 	.attrs = &st_magn_attribute_group,
 	.read_raw = &st_magn_read_raw,
 	.write_raw = &st_magn_write_raw,
+	.debugfs_reg_access = &st_sensors_debugfs_reg_access,
 };
 
 #ifdef CONFIG_IIO_TRIGGER
diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c
index eb41d2b92c24..b39a2fb0671c 100644
--- a/drivers/iio/pressure/st_pressure_core.c
+++ b/drivers/iio/pressure/st_pressure_core.c
@@ -400,6 +400,7 @@ static const struct iio_info press_info = {
 	.attrs = &st_press_attribute_group,
 	.read_raw = &st_press_read_raw,
 	.write_raw = &st_press_write_raw,
+	.debugfs_reg_access = &st_sensors_debugfs_reg_access,
 };
 
 #ifdef CONFIG_IIO_TRIGGER
diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
index 3c17cd7fdf06..2fe939c73cd2 100644
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -271,6 +271,10 @@ void st_sensors_power_enable(struct iio_dev *indio_dev);
 
 void st_sensors_power_disable(struct iio_dev *indio_dev);
 
+int st_sensors_debugfs_reg_access(struct iio_dev *indio_dev,
+				  unsigned reg, unsigned writeval,
+				  unsigned *readval);
+
 int st_sensors_set_odr(struct iio_dev *indio_dev, unsigned int odr);
 
 int st_sensors_set_dataready_irq(struct iio_dev *indio_dev, bool enable);