[PATCH v4 0/2] staging: axis-fifo: refactor and cleanup

[PATCH v4 0/2] staging: axis-fifo: refactor and cleanup

[Gustavo Piaz da Silva]

This series cleans up the axis-fifo driver probe function logic.

Patch 1 aligns the struct types with the OF API.
Patch 2 refactors the parsing logic.

Changes in v4:
 - Removed extra blank lines in commit messages.
 - Added "rx" and "tx" prefixes to error messages in Patch 2 to distinguish failures.
 - Explicitly listed changes in individual patches.

Changes in v3:
 - Split into two patches as requested.

Gustavo Piaz da Silva (2):
  staging: axis-fifo: align fifo depth types with OF API
  staging: axis-fifo: refactor device tree parsing

 drivers/staging/axis-fifo/axis-fifo.c | 81 +++++++++------------------
 1 file changed, 27 insertions(+), 54 deletions(-)

-- 
2.52.0

[PATCH v4 1/2] staging: axis-fifo: align fifo depth types with OF API

[Gustavo Piaz da Silva]

Change has_rx_fifo and has_tx_fifo types from int to u32 in struct
axis_fifo.

The of_property_read_u32() function expects a u32 pointer. While the
current code might work, aligning the types avoids potential mixed-type
issues and clarifies the data structure.

Signed-off-by: Gustavo Piaz da Silva <gustavopiazdasilva2102@gmail.com>
---
 drivers/staging/axis-fifo/axis-fifo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index 509d620d6ce7..7bc7bf191250 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -121,8 +121,8 @@ struct axis_fifo {
 
 	unsigned int rx_fifo_depth; /* max words in the receive fifo */
 	unsigned int tx_fifo_depth; /* max words in the transmit fifo */
-	int has_rx_fifo; /* whether the IP has the rx fifo enabled */
-	int has_tx_fifo; /* whether the IP has the tx fifo enabled */
+	u32 has_rx_fifo; /* whether the IP has the rx fifo enabled */
+	u32 has_tx_fifo; /* whether the IP has the tx fifo enabled */
 
 	wait_queue_head_t read_queue; /* wait queue for asynchronos read */
 	struct mutex read_lock; /* lock for reading */
-- 
2.52.0

[PATCH v4 2/2] staging: axis-fifo: refactor device tree parsing

[Gustavo Piaz da Silva]

Refactor the device tree parsing logic in axis_fifo_probe() to reduce
code duplication and improve readability.

Create a helper function axis_fifo_get_u32() to handle property reading
and error checking, replacing repetitive of_property_read_u32() calls.

This eliminates the goto logic for error handling in the probe path and
consolidates error logging.

Signed-off-by: Gustavo Piaz da Silva <gustavopiazdasilva2102@gmail.com>

Changes in v4:
 - Removed extra blank lines in the commit message.
 - Added "rx" and "tx" prefixes to error messages to distinguish between read and write width failures.

Changes in v3:
 - Split the original v2 patch into two separate patches.
 drivers/staging/axis-fifo/axis-fifo.c | 77 +++++++++------------------
 1 file changed, 25 insertions(+), 52 deletions(-)

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index 7bc7bf191250..779de1b22ef5 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -482,68 +482,41 @@ static void axis_fifo_debugfs_init(struct axis_fifo *fifo)
 			    &axis_fifo_debugfs_regs_fops);
 }
 
-static int axis_fifo_parse_dt(struct axis_fifo *fifo)
+static int axis_fifo_get_u32(struct axis_fifo *fifo, const char *prop, u32 *val)
 {
-	int ret;
-	unsigned int value;
-	struct device_node *node = fifo->dt_device->of_node;
+	int ret = of_property_read_u32(fifo->dt_device->of_node, prop, val);
 
-	ret = of_property_read_u32(node, "xlnx,axi-str-rxd-tdata-width",
-				   &value);
 	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,axi-str-rxd-tdata-width property\n");
-		goto end;
-	} else if (value != 32) {
-		dev_err(fifo->dt_device, "xlnx,axi-str-rxd-tdata-width only supports 32 bits\n");
-		ret = -EIO;
-		goto end;
+		dev_err(fifo->dt_device, "missing %s property\n", prop);
+		return ret;
 	}
+	return 0;
+}
 
-	ret = of_property_read_u32(node, "xlnx,axi-str-txd-tdata-width",
-				   &value);
-	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,axi-str-txd-tdata-width property\n");
-		goto end;
-	} else if (value != 32) {
-		dev_err(fifo->dt_device, "xlnx,axi-str-txd-tdata-width only supports 32 bits\n");
-		ret = -EIO;
-		goto end;
-	}
+static int axis_fifo_parse_dt(struct axis_fifo *fifo)
+{
+	u32 width;
 
-	ret = of_property_read_u32(node, "xlnx,rx-fifo-depth",
-				   &fifo->rx_fifo_depth);
-	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,rx-fifo-depth property\n");
-		ret = -EIO;
-		goto end;
+	if (axis_fifo_get_u32(fifo, "xlnx,axi-str-rxd-tdata-width", &width) || width != 32) {
+		dev_err(fifo->dt_device, "rx tdata-width only supports 32 bits\n");
+		return -EIO;
 	}
-
-	ret = of_property_read_u32(node, "xlnx,tx-fifo-depth",
-				   &fifo->tx_fifo_depth);
-	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,tx-fifo-depth property\n");
-		ret = -EIO;
-		goto end;
+	if (axis_fifo_get_u32(fifo, "xlnx,axi-str-txd-tdata-width", &width) || width != 32) {
+		dev_err(fifo->dt_device, "tx tdata-width only supports 32 bits\n");
+		return -EIO;
 	}
 
-	ret = of_property_read_u32(node, "xlnx,use-rx-data",
-				   &fifo->has_rx_fifo);
-	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,use-rx-data property\n");
-		ret = -EIO;
-		goto end;
-	}
+	if (axis_fifo_get_u32(fifo, "xlnx,rx-fifo-depth", &fifo->rx_fifo_depth))
+		return -EIO;
+	if (axis_fifo_get_u32(fifo, "xlnx,tx-fifo-depth", &fifo->tx_fifo_depth))
+		return -EIO;
 
-	ret = of_property_read_u32(node, "xlnx,use-tx-data",
-				   &fifo->has_tx_fifo);
-	if (ret) {
-		dev_err(fifo->dt_device, "missing xlnx,use-tx-data property\n");
-		ret = -EIO;
-		goto end;
-	}
+	if (axis_fifo_get_u32(fifo, "xlnx,use-rx-data", &fifo->has_rx_fifo))
+		return -EIO;
+	if (axis_fifo_get_u32(fifo, "xlnx,use-tx-data", &fifo->has_tx_fifo))
+		return -EIO;
 
-end:
-	return ret;
+	return 0;
 }
 
 static int axis_fifo_probe(struct platform_device *pdev)
@@ -700,4 +673,4 @@ module_exit(axis_fifo_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Jacob Feder <jacobsfeder@gmail.com>");
-MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO IP core driver");
+MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO IP core driver");
\ No newline at end of file
-- 
2.52.0

Re: [PATCH v4 2/2] staging: axis-fifo: refactor device tree parsing

[Dan Carpenter]

On Mon, Feb 02, 2026 at 09:23:17AM -0300, Gustavo Piaz da Silva wrote:
> @@ -700,4 +673,4 @@ module_exit(axis_fifo_exit);
>  
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Jacob Feder <jacobsfeder@gmail.com>");
> -MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO IP core driver");
> +MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO IP core driver");
> \ No newline at end of file

I guess you accidentally deleted the newline?

regards,
dan carpenter

Re: [PATCH v4 2/2] staging: axis-fifo: refactor device tree parsing

[Greg KH]

On Mon, Feb 02, 2026 at 09:23:17AM -0300, Gustavo Piaz da Silva wrote:
> Refactor the device tree parsing logic in axis_fifo_probe() to reduce
> code duplication and improve readability.
> 
> Create a helper function axis_fifo_get_u32() to handle property reading
> and error checking, replacing repetitive of_property_read_u32() calls.
> 
> This eliminates the goto logic for error handling in the probe path and
> consolidates error logging.
> 
> Signed-off-by: Gustavo Piaz da Silva <gustavopiazdasilva2102@gmail.com>
> 
> Changes in v4:
>  - Removed extra blank lines in the commit message.
>  - Added "rx" and "tx" prefixes to error messages to distinguish between read and write width failures.
> 
> Changes in v3:
>  - Split the original v2 patch into two separate patches.
>  drivers/staging/axis-fifo/axis-fifo.c | 77 +++++++++------------------
>  1 file changed, 25 insertions(+), 52 deletions(-)

You are missing a --- line after the signed-off-by :(

> +static int axis_fifo_parse_dt(struct axis_fifo *fifo)
> +{
> +	u32 width;
>  
> -	ret = of_property_read_u32(node, "xlnx,rx-fifo-depth",
> -				   &fifo->rx_fifo_depth);
> -	if (ret) {
> -		dev_err(fifo->dt_device, "missing xlnx,rx-fifo-depth property\n");
> -		ret = -EIO;
> -		goto end;
> +	if (axis_fifo_get_u32(fifo, "xlnx,axi-str-rxd-tdata-width", &width) || width != 32) {
> +		dev_err(fifo->dt_device, "rx tdata-width only supports 32 bits\n");
> +		return -EIO;
>  	}
> -
> -	ret = of_property_read_u32(node, "xlnx,tx-fifo-depth",
> -				   &fifo->tx_fifo_depth);
> -	if (ret) {
> -		dev_err(fifo->dt_device, "missing xlnx,tx-fifo-depth property\n");
> -		ret = -EIO;
> -		goto end;
> +	if (axis_fifo_get_u32(fifo, "xlnx,axi-str-txd-tdata-width", &width) || width != 32) {
> +		dev_err(fifo->dt_device, "tx tdata-width only supports 32 bits\n");

Now you have 2 errors printed out?

And really, the helper function isn't needed, just get rid of the
dev_err() lines, why would they be needed anymore?  No other driver uses
this type of error reporting that I have noticed.

Also, do you have this hardware to test this with?

thanks,

greg k-h

Re: [PATCH v4 2/2] staging: axis-fifo: refactor device tree parsing

[Gustavo Piaz]

Hi Greg,

Our emails crossed paths. I had just sent v5 to fix a missing newline
pointed out by Dan Carpenter when your review arrived.

Since v5 still contains the helper function you asked to remove,
please ignore it.

I will prepare and send v6 shortly to address your feedback: I'll
remove the helper function and the dev_err() calls, and fix the
missing separator line.

Regarding the hardware: No, I don't have it. I am build-testing only.

Regards,
Gustavo


Gustavo Piaz <gustavopiazdasilva2102@gmail.com> escreveu (segunda,
2/02/2026 à(s) 10:49):
>>
>>
>> Hi Greg,
>>
>> Our emails crossed paths. I had just sent v5 to fix a missing newline pointed out by Dan Carpenter when your review arrived.
>>
>> Since v5 still contains the helper function you asked to remove, please ignore it.
>>
>> I will prepare and send v6 shortly to address your feedback: I'll remove the helper function and the dev_err() calls, and fix the missing separator line.
>>
>> Regarding the hardware: No, I don't have it. I am build-testing only.
>>
>> Regards,
>> Gustavo