[PATCH v3] spi: stm32-qspi: Update spi registering

[<patrice.chotard@foss.st.com>]

From: Patrice Chotard <patrice.chotard@foss.st.com>

Some device driver need to communicate to qspi device during the remove
process, qspi controller must be functional when spi_unregister_master()
is called.

To ensure this, replace devm_spi_register_master() by spi_register_master()
and spi_unregister_master() is called directly in .remove callback before
stopping the qspi controller.

This issue was put in evidence using kernel v5.11 and later
with a spi-nor which supports the software reset feature introduced
by commit d73ee7534cc5 ("mtd: spi-nor: core: perform a Soft Reset on
shutdown")

Fixes: c530cd1d9d5e ("spi: spi-mem: add stm32 qspi controller")

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: <stable@vger.kernel.org> # 5.8.x
---

v3: 
  _ Update error path due to devm_spi_alloc_master() usage

v2: 
  _ update commit message
  _ make usage of devm_spi_alloc_master() instead of spi_alloc_master()

 drivers/spi/spi-stm32-qspi.c | 47 +++++++++++++-----------------------
 1 file changed, 17 insertions(+), 30 deletions(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 514337c86d2c..ffdc55f87e82 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -688,7 +688,7 @@ static int stm32_qspi_probe(struct platform_device *pdev)
 	struct resource *res;
 	int ret, irq;
 
-	ctrl = spi_alloc_master(dev, sizeof(*qspi));
+	ctrl = devm_spi_alloc_master(dev, sizeof(*qspi));
 	if (!ctrl)
 		return -ENOMEM;
 
@@ -697,58 +697,46 @@ static int stm32_qspi_probe(struct platform_device *pdev)
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
 	qspi->io_base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(qspi->io_base)) {
-		ret = PTR_ERR(qspi->io_base);
-		goto err_master_put;
-	}
+	if (IS_ERR(qspi->io_base))
+		return PTR_ERR(qspi->io_base);
 
 	qspi->phys_base = res->start;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
 	qspi->mm_base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(qspi->mm_base)) {
-		ret = PTR_ERR(qspi->mm_base);
-		goto err_master_put;
-	}
+	if (IS_ERR(qspi->mm_base))
+		return PTR_ERR(qspi->mm_base);
 
 	qspi->mm_size = resource_size(res);
-	if (qspi->mm_size > STM32_QSPI_MAX_MMAP_SZ) {
-		ret = -EINVAL;
-		goto err_master_put;
-	}
+	if (qspi->mm_size > STM32_QSPI_MAX_MMAP_SZ)
+		return -EINVAL;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0) {
-		ret = irq;
-		goto err_master_put;
-	}
+	if (irq < 0)
+		return irq;
 
 	ret = devm_request_irq(dev, irq, stm32_qspi_irq, 0,
 			       dev_name(dev), qspi);
 	if (ret) {
 		dev_err(dev, "failed to request irq\n");
-		goto err_master_put;
+		return ret;
 	}
 
 	init_completion(&qspi->data_completion);
 	init_completion(&qspi->match_completion);
 
 	qspi->clk = devm_clk_get(dev, NULL);
-	if (IS_ERR(qspi->clk)) {
-		ret = PTR_ERR(qspi->clk);
-		goto err_master_put;
-	}
+	if (IS_ERR(qspi->clk))
+		return PTR_ERR(qspi->clk);
 
 	qspi->clk_rate = clk_get_rate(qspi->clk);
-	if (!qspi->clk_rate) {
-		ret = -EINVAL;
-		goto err_master_put;
-	}
+	if (!qspi->clk_rate)
+		return -EINVAL;
 
 	ret = clk_prepare_enable(qspi->clk);
 	if (ret) {
 		dev_err(dev, "can not enable the clock\n");
-		goto err_master_put;
+		return ret;
 	}
 
 	rstc = devm_reset_control_get_exclusive(dev, NULL);
@@ -784,7 +772,7 @@ static int stm32_qspi_probe(struct platform_device *pdev)
 	pm_runtime_enable(dev);
 	pm_runtime_get_noresume(dev);
 
-	ret = devm_spi_register_master(dev, ctrl);
+	ret = spi_register_master(ctrl);
 	if (ret)
 		goto err_pm_runtime_free;
 
@@ -806,8 +794,6 @@ static int stm32_qspi_probe(struct platform_device *pdev)
 	stm32_qspi_dma_free(qspi);
 err_clk_disable:
 	clk_disable_unprepare(qspi->clk);
-err_master_put:
-	spi_master_put(qspi->ctrl);
 
 	return ret;
 }
@@ -817,6 +803,7 @@ static int stm32_qspi_remove(struct platform_device *pdev)
 	struct stm32_qspi *qspi = platform_get_drvdata(pdev);
 
 	pm_runtime_get_sync(qspi->dev);
+	spi_unregister_master(qspi->ctrl);
 	/* disable qspi */
 	writel_relaxed(0, qspi->io_base + QSPI_CR);
 	stm32_qspi_dma_free(qspi);
-- 
2.17.1