iio: core: iio_chan_spec_ext_info: Add private handle

There is currently no user, but we might need it in future.
So better add it now, before we have to convert drivers afterwards.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/industrialio-core.c

@@ -281,7 +281,7 @@ static ssize_t iio_read_channel_ext_info(struct device *dev,
 
 	ext_info = &this_attr->c->ext_info[this_attr->address];
 
-	return ext_info->read(indio_dev, this_attr->c, buf);
+	return ext_info->read(indio_dev, ext_info->private, this_attr->c, buf);
 }
 
 static ssize_t iio_write_channel_ext_info(struct device *dev,
@@ -295,7 +295,8 @@ static ssize_t iio_write_channel_ext_info(struct device *dev,
 
 	ext_info = &this_attr->c->ext_info[this_attr->address];
 
-	return ext_info->write(indio_dev, this_attr->c, buf, len);
+	return ext_info->write(indio_dev, ext_info->private,
+			       this_attr->c, buf, len);
 }
 
 static ssize_t iio_read_channel_info(struct device *dev,

drivers/staging/iio/dac/ad5064.c

@@ -144,14 +144,14 @@ static const char ad5064_powerdown_modes[][15] = {
 };
 
 static ssize_t ad5064_read_powerdown_mode_available(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, char *buf)
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	return sprintf(buf, "%s %s %s\n", ad5064_powerdown_modes[1],
 		ad5064_powerdown_modes[2], ad5064_powerdown_modes[3]);
 }
 
 static ssize_t ad5064_read_powerdown_mode(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, char *buf)
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	struct ad5064_state *st = iio_priv(indio_dev);
 
@@ -160,7 +160,8 @@ static ssize_t ad5064_read_powerdown_mode(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5064_write_powerdown_mode(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, const char *buf, size_t len)
+	uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
+	size_t len)
 {
 	struct ad5064_state *st = iio_priv(indio_dev);
 	unsigned int mode, i;
@@ -187,7 +188,7 @@ static ssize_t ad5064_write_powerdown_mode(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, char *buf)
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	struct ad5064_state *st = iio_priv(indio_dev);
 
@@ -195,7 +196,8 @@ static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5064_write_dac_powerdown(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, const char *buf, size_t len)
+	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
+	 size_t len)
 {
 	struct ad5064_state *st = iio_priv(indio_dev);
 	bool pwr_down;

drivers/staging/iio/dac/ad5446.c

@@ -46,13 +46,14 @@ static const char * const ad5446_powerdown_modes[] = {
 };
 
 static ssize_t ad5446_read_powerdown_mode_available(struct iio_dev *indio_dev,
-	const struct iio_chan_spec *chan, char *buf)
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
 	return sprintf(buf, "%s %s %s\n", ad5446_powerdown_modes[1],
 		ad5446_powerdown_modes[2], ad5446_powerdown_modes[3]);
 }
 
 static ssize_t ad5446_write_powerdown_mode(struct iio_dev *indio_dev,
+					    uintptr_t private,
 					    const struct iio_chan_spec *chan,
 					    const char *buf, size_t len)
 {
@@ -73,6 +74,7 @@ static ssize_t ad5446_write_powerdown_mode(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5446_read_powerdown_mode(struct iio_dev *indio_dev,
+					   uintptr_t private,
 					   const struct iio_chan_spec *chan,
 					   char *buf)
 {
@@ -82,6 +84,7 @@ static ssize_t ad5446_read_powerdown_mode(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5446_read_dac_powerdown(struct iio_dev *indio_dev,
+					   uintptr_t private,
 					   const struct iio_chan_spec *chan,
 					   char *buf)
 {
@@ -91,6 +94,7 @@ static ssize_t ad5446_read_dac_powerdown(struct iio_dev *indio_dev,
 }
 
 static ssize_t ad5446_write_dac_powerdown(struct iio_dev *indio_dev,
+					    uintptr_t private,
 					    const struct iio_chan_spec *chan,
 					    const char *buf, size_t len)
 {

include/linux/iio/iio.h

@@ -111,14 +111,17 @@ struct iio_dev;
  * @shared:	Whether this attribute is shared between all channels.
  * @read:	Read callback for this info attribute, may be NULL.
  * @write:	Write callback for this info attribute, may be NULL.
+ * @private:	Data private to the driver.
  */
 struct iio_chan_spec_ext_info {
 	const char *name;
 	bool shared;
-	ssize_t (*read)(struct iio_dev *, struct iio_chan_spec const *,
-			char *buf);
-	ssize_t (*write)(struct iio_dev *, struct iio_chan_spec const *,
-			const char *buf, size_t len);
+	ssize_t (*read)(struct iio_dev *, uintptr_t private,
+			struct iio_chan_spec const *, char *buf);
+	ssize_t (*write)(struct iio_dev *, uintptr_t private,
+			 struct iio_chan_spec const *, const char *buf,
+			 size_t len);
+	uintptr_t private;
 };
 
 /**