mtd: rawnand: stm32_fmc2: manage all errors cases at probe time

This patch defers its probe when the expected reset control is not
yet ready. This patch also handles properly all errors cases at probe
time.
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1588756279-17289-2-git-send-email-christophe.kerello@st.com

drivers/mtd/nand/raw/stm32_fmc2_nand.c

@@ -1967,7 +1967,11 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
 	}
 
 	rstc = devm_reset_control_get(dev, NULL);
-	if (!IS_ERR(rstc)) {
+	if (IS_ERR(rstc)) {
+		ret = PTR_ERR(rstc);
+		if (ret == -EPROBE_DEFER)
+			goto err_clk_disable;
+	} else {
 		reset_control_assert(rstc);
 		reset_control_deassert(rstc);
 	}
@@ -1975,7 +1979,7 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
 	/* DMA setup */
 	ret = stm32_fmc2_dma_setup(fmc2);
 	if (ret)
-		return ret;
+		goto err_release_dma;
 
 	/* FMC2 init routine */
 	stm32_fmc2_init(fmc2);
@@ -1997,20 +2001,20 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
 	/* Scan to find existence of the device */
 	ret = nand_scan(chip, nand->ncs);
 	if (ret)
-		goto err_scan;
+		goto err_release_dma;
 
 	ret = mtd_device_register(mtd, NULL, 0);
 	if (ret)
-		goto err_device_register;
+		goto err_nand_cleanup;
 
 	platform_set_drvdata(pdev, fmc2);
 
 	return 0;
 
-err_device_register:
+err_nand_cleanup:
 	nand_cleanup(chip);
 
-err_scan:
+err_release_dma:
 	if (fmc2->dma_ecc_ch)
 		dma_release_channel(fmc2->dma_ecc_ch);
 	if (fmc2->dma_tx_ch)
@@ -2021,6 +2025,7 @@ static int stm32_fmc2_probe(struct platform_device *pdev)
 	sg_free_table(&fmc2->dma_data_sg);
 	sg_free_table(&fmc2->dma_ecc_sg);
 
+err_clk_disable:
 	clk_disable_unprepare(fmc2->clk);
 
 	return ret;