dmaengine: dw: fix regression in dw_probe() function

The commit dbde5c2 "dw_dmac: use devm_* functions to simplify code" turns
probe function to use devm_* helpers and simultaneously brings a regression.

We have to 1) call clk_disable_unprepare() on error path, and 2) check error
code of clk_enable_prepare(). First part was done in the original code, second
one is an update.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dw/core.c

@@ -1496,7 +1496,9 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dw->clk = devm_clk_get(chip->dev, "hclk");
 	if (IS_ERR(dw->clk))
 		return PTR_ERR(dw->clk);
-	clk_prepare_enable(dw->clk);
+	err = clk_prepare_enable(dw->clk);
+	if (err)
+		return err;
 
 	dw_params = dma_read_byaddr(chip->regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
@@ -1505,15 +1507,19 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 
 	if (!pdata && autocfg) {
 		pdata = devm_kzalloc(chip->dev, sizeof(*pdata), GFP_KERNEL);
-		if (!pdata)
-			return -ENOMEM;
+		if (!pdata) {
+			err = -ENOMEM;
+			goto err_pdata;
+		}
 
 		/* Fill platform data with the default values */
 		pdata->is_private = true;
 		pdata->chan_allocation_order = CHAN_ALLOCATION_ASCENDING;
 		pdata->chan_priority = CHAN_PRIORITY_ASCENDING;
-	} else if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
-		return -EINVAL;
+	} else if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS) {
+		err = -EINVAL;
+		goto err_pdata;
+	}
 
 	if (autocfg)
 		nr_channels = (dw_params >> DW_PARAMS_NR_CHAN & 0x7) + 1;
@@ -1522,8 +1528,10 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 
 	dw->chan = devm_kcalloc(chip->dev, nr_channels, sizeof(*dw->chan),
 				GFP_KERNEL);
-	if (!dw->chan)
-		return -ENOMEM;
+	if (!dw->chan) {
+		err = -ENOMEM;
+		goto err_pdata;
+	}
 
 	/* Get hardware configuration parameters */
 	if (autocfg) {
@@ -1553,15 +1561,16 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 					 sizeof(struct dw_desc), 4, 0);
 	if (!dw->desc_pool) {
 		dev_err(chip->dev, "No memory for descriptors dma pool\n");
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto err_pdata;
 	}
 
 	tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);
 
 	err = request_irq(chip->irq, dw_dma_interrupt, IRQF_SHARED,
 			  "dw_dmac", dw);
 	if (err)
-		return err;
+		goto err_pdata;
 
 	INIT_LIST_HEAD(&dw->dma.channels);
 	for (i = 0; i < nr_channels; i++) {
@@ -1656,6 +1665,10 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dma_async_device_register(&dw->dma);
 
 	return 0;
+
+err_pdata:
+	clk_disable_unprepare(dw->clk);
+	return err;
 }
 EXPORT_SYMBOL_GPL(dw_dma_probe);
 
@@ -1676,6 +1689,8 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 		channel_clear_bit(dw, CH_EN, dwc->mask);
 	}
 
+	clk_disable_unprepare(dw->clk);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_dma_remove);