[PATCH v3] mmc: pxamci: Simplify pxamci_probe() error handling using devm APIs

[Rakuram Eswaran <rakuram.e96@gmail.com>]

This patch refactors pxamci_probe() to use devm-managed resource
allocation (e.g. devm_dma_request_chan) and dev_err_probe() for
improved readability and automatic cleanup on probe failure.

It also removes redundant NULL assignments and manual resource release
logic from pxamci_probe(), and eliminates the corresponding release
calls from pxamci_remove().

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202510041841.pRlunIfl-lkp@intel.com/
Fixes: 58c40f3faf742c ("mmc: pxamci: Use devm_mmc_alloc_host() helper")
Suggested-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Rakuram Eswaran <rakuram.e96@gmail.com>
---

Changes since v2:
- Dropped redundant dma_release_channel() calls from pxamci_remove() as
  devm_dma_request_chan() automatically handles resource cleanup.
- Added link to v2 for reference:
  https://lore.kernel.org/linux-mmc/20251014184657.111144-1-rakuram.e96@gmail.com/

Changes since v1:
Following Uwe Kleine-König’s suggestion:
- Replaced dma_request_chan() with devm_dma_request_chan() to make DMA
  channel allocation devm-managed and avoid manual release paths.
- Adopted dev_err_probe() for improved error reporting and consistent
  probe failure handling.
- Removed redundant NULL assignments and obsolete goto-based cleanup logic.
- Updated commit message to better describe the intent of the change.
- Added link to v1 for reference:
  https://lore.kernel.org/linux-mmc/20251007161948.12442-1-rakuram.e96@gmail.com/

Testing note:
I do not have access to appropriate hardware for runtime testing.
Any help verifying on actual hardware would be appreciated.

Build and Analysis:
This patch was compiled against the configuration file reported by
0day CI in the above link (config: s390-randconfig-r071-20251004) using
`s390x-linux-gnu-gcc (Ubuntu 14.2.0-19ubuntu2) 14.2.0`.

Static analysis was performed with Smatch to ensure the reported warning
no longer reproduces after applying this fix.

Command used for verification:
  ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- \
  ~/project/smatch/smatch_scripts/kchecker ./drivers/mmc/host/pxamci.c

 drivers/mmc/host/pxamci.c | 56 +++++++++++++--------------------------
 1 file changed, 18 insertions(+), 38 deletions(-)

diff --git a/drivers/mmc/host/pxamci.c b/drivers/mmc/host/pxamci.c
index 26d03352af63..b5ea058ed467 100644
--- a/drivers/mmc/host/pxamci.c
+++ b/drivers/mmc/host/pxamci.c
@@ -652,10 +652,9 @@ static int pxamci_probe(struct platform_device *pdev)
 	host->clkrt = CLKRT_OFF;
 
 	host->clk = devm_clk_get(dev, NULL);
-	if (IS_ERR(host->clk)) {
-		host->clk = NULL;
-		return PTR_ERR(host->clk);
-	}
+	if (IS_ERR(host->clk))
+		return dev_err_probe(dev, PTR_ERR(host->clk),
+					"Failed to acquire clock\n");
 
 	host->clkrate = clk_get_rate(host->clk);
 
@@ -703,46 +702,37 @@ static int pxamci_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, mmc);
 
-	host->dma_chan_rx = dma_request_chan(dev, "rx");
-	if (IS_ERR(host->dma_chan_rx)) {
-		host->dma_chan_rx = NULL;
+	host->dma_chan_rx = devm_dma_request_chan(dev, "rx");
+	if (IS_ERR(host->dma_chan_rx))
 		return dev_err_probe(dev, PTR_ERR(host->dma_chan_rx),
 				     "unable to request rx dma channel\n");
-	}
 
-	host->dma_chan_tx = dma_request_chan(dev, "tx");
-	if (IS_ERR(host->dma_chan_tx)) {
-		dev_err(dev, "unable to request tx dma channel\n");
-		ret = PTR_ERR(host->dma_chan_tx);
-		host->dma_chan_tx = NULL;
-		goto out;
-	}
+
+	host->dma_chan_tx = devm_dma_request_chan(dev, "tx");
+	if (IS_ERR(host->dma_chan_tx))
+		return dev_err_probe(dev, PTR_ERR(host->dma_chan_tx),
+					"unable to request tx dma channel\n");
 
 	if (host->pdata) {
 		host->detect_delay_ms = host->pdata->detect_delay_ms;
 
 		host->power = devm_gpiod_get_optional(dev, "power", GPIOD_OUT_LOW);
-		if (IS_ERR(host->power)) {
-			ret = PTR_ERR(host->power);
-			dev_err(dev, "Failed requesting gpio_power\n");
-			goto out;
-		}
+		if (IS_ERR(host->power))
+			return dev_err_probe(dev, PTR_ERR(host->power),
+						"Failed requesting gpio_power\n");
 
 		/* FIXME: should we pass detection delay to debounce? */
 		ret = mmc_gpiod_request_cd(mmc, "cd", 0, false, 0);
-		if (ret && ret != -ENOENT) {
-			dev_err(dev, "Failed requesting gpio_cd\n");
-			goto out;
-		}
+		if (ret && ret != -ENOENT)
+			return dev_err_probe(dev, ret, "Failed requesting gpio_cd\n");
 
 		if (!host->pdata->gpio_card_ro_invert)
 			mmc->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
 
 		ret = mmc_gpiod_request_ro(mmc, "wp", 0, 0);
-		if (ret && ret != -ENOENT) {
-			dev_err(dev, "Failed requesting gpio_ro\n");
-			goto out;
-		}
+		if (ret && ret != -ENOENT)
+			return dev_err_probe(dev, ret, "Failed requesting gpio_ro\n");
+
 		if (!ret)
 			host->use_ro_gpio = true;
 
@@ -759,16 +749,8 @@ static int pxamci_probe(struct platform_device *pdev)
 	if (ret) {
 		if (host->pdata && host->pdata->exit)
 			host->pdata->exit(dev, mmc);
-		goto out;
 	}
 
-	return 0;
-
-out:
-	if (host->dma_chan_rx)
-		dma_release_channel(host->dma_chan_rx);
-	if (host->dma_chan_tx)
-		dma_release_channel(host->dma_chan_tx);
 	return ret;
 }
 
@@ -791,8 +773,6 @@ static void pxamci_remove(struct platform_device *pdev)
 
 		dmaengine_terminate_all(host->dma_chan_rx);
 		dmaengine_terminate_all(host->dma_chan_tx);
-		dma_release_channel(host->dma_chan_rx);
-		dma_release_channel(host->dma_chan_tx);
 	}
 }
 
-- 
2.48.1