[PATCH RFC v4 02/10] iio: core: support 64-bit register through debugfs

[Rodrigo Alencar via B4 Relay <devnull+rodrigo.alencar.analog.com@kernel.org>]

From: Rodrigo Alencar <rodrigo.alencar@analog.com>

Add debugfs_reg64_access function pointer field into iio_info and modify
file operation callbacks to favor 64-bit variant when it is available.

Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
---
 drivers/iio/industrialio-core.c | 33 ++++++++++++++++++++++++---------
 include/linux/iio/iio.h         |  4 ++++
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index bd6f4f9f4533..cb4e2ade25c0 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -386,6 +386,7 @@ static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
 	struct iio_dev *indio_dev = file->private_data;
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	unsigned int val = 0;
+	u64 val64 = 0;
 	int ret;
 
 	if (*ppos > 0)
@@ -393,9 +394,17 @@ static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
 					       iio_dev_opaque->read_buf,
 					       iio_dev_opaque->read_buf_len);
 
-	ret = indio_dev->info->debugfs_reg_access(indio_dev,
-						  iio_dev_opaque->cached_reg_addr,
-						  0, &val);
+	if (indio_dev->info->debugfs_reg64_access) {
+		ret = indio_dev->info->debugfs_reg64_access(indio_dev,
+							    iio_dev_opaque->cached_reg_addr,
+							    0, &val64);
+	} else {
+		ret = indio_dev->info->debugfs_reg_access(indio_dev,
+							  iio_dev_opaque->cached_reg_addr,
+							  0, &val);
+		val64 = val;
+	}
+
 	if (ret) {
 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
 		return ret;
@@ -403,7 +412,7 @@ static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
 
 	iio_dev_opaque->read_buf_len = snprintf(iio_dev_opaque->read_buf,
 						sizeof(iio_dev_opaque->read_buf),
-						"0x%X\n", val);
+						"0x%llX", val64);
 
 	return simple_read_from_buffer(userbuf, count, ppos,
 				       iio_dev_opaque->read_buf,
@@ -415,8 +424,9 @@ static ssize_t iio_debugfs_write_reg(struct file *file,
 {
 	struct iio_dev *indio_dev = file->private_data;
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
-	unsigned int reg, val;
+	unsigned int reg;
 	char buf[80];
+	u64 val64;
 	int ret;
 
 	if (count >= sizeof(buf))
@@ -429,7 +439,7 @@ static ssize_t iio_debugfs_write_reg(struct file *file,
 
 	buf[ret] = '\0';
 
-	ret = sscanf(buf, "%i %i", &reg, &val);
+	ret = sscanf(buf, "%i %lli", &reg, &val64);
 
 	switch (ret) {
 	case 1:
@@ -437,8 +447,12 @@ static ssize_t iio_debugfs_write_reg(struct file *file,
 		break;
 	case 2:
 		iio_dev_opaque->cached_reg_addr = reg;
-		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
-							  val, NULL);
+		if (indio_dev->info->debugfs_reg64_access)
+			ret = indio_dev->info->debugfs_reg64_access(indio_dev, reg,
+								    val64, NULL);
+		else
+			ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
+								  val64, NULL);
 		if (ret) {
 			dev_err(indio_dev->dev.parent, "%s: write failed\n",
 				__func__);
@@ -469,7 +483,8 @@ static void iio_device_register_debugfs(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque;
 
-	if (indio_dev->info->debugfs_reg_access == NULL)
+	if (!indio_dev->info->debugfs_reg_access &&
+	    !indio_dev->info->debugfs_reg64_access)
 		return;
 
 	if (!iio_debugfs_dentry)
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 96b05c86c325..86d17ee69e05 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -484,6 +484,7 @@ struct iio_trigger; /* forward declaration */
  * @update_scan_mode:	function to configure device and scan buffer when
  *			channels have changed
  * @debugfs_reg_access:	function to read or write register value of device
+ * @debugfs_reg64_access: function to read or write 64-bit register value of device
  * @fwnode_xlate:	fwnode based function pointer to obtain channel specifier index.
  * @hwfifo_set_watermark: function pointer to set the current hardware
  *			fifo watermark level; see hwfifo_* entries in
@@ -572,6 +573,9 @@ struct iio_info {
 	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
 				  unsigned int reg, unsigned int writeval,
 				  unsigned int *readval);
+	int (*debugfs_reg64_access)(struct iio_dev *indio_dev,
+				    unsigned int reg, u64 writeval,
+				    u64 *readval);
 	int (*fwnode_xlate)(struct iio_dev *indio_dev,
 			    const struct fwnode_reference_args *iiospec);
 	int (*hwfifo_set_watermark)(struct iio_dev *indio_dev, unsigned int val);

-- 
2.43.0