Re: [PATCH 2/4] spi: mt7621: Use the devm_clk_get_enabled() helper to simplify error handling

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On 27/08/2022 13:42, Christophe JAILLET wrote:
The devm_clk_get_enabled() helper:
    - calls devm_clk_get()
    - calls clk_prepare_enable() and registers what is needed in order to
      call clk_disable_unprepare() when needed, as a managed resource.

This helper is well suited for cases where the clock would be kept
prepared or enabled for the whole lifetime of the driver.

This simplifies the error handling a lot.

The order between spi_unregister_controller() (in the remove function) and
the clk_disable_unprepare() (now handle by a  managed resource) is kept
the same.
(see commit 46b5c4fb87ce ("spi: mt7621: Don't leak SPI master in probe
error path") to see why it matters)

Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>

Reviewed-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>

---
The order with  devm_spi_release_controller() (which undoes
devm_spi_alloc_master()) is reversed, but I don't think it is an issue.
---
  drivers/spi/spi-mt7621.c | 14 +-------------
  1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/drivers/spi/spi-mt7621.c b/drivers/spi/spi-mt7621.c
index 351b0ef52bbc..2580b28042be 100644
--- a/drivers/spi/spi-mt7621.c
+++ b/drivers/spi/spi-mt7621.c
@@ -327,7 +327,6 @@ static int mt7621_spi_probe(struct platform_device *pdev)
  	struct spi_controller *master;
  	struct mt7621_spi *rs;
  	void __iomem *base;
-	int status = 0;
  	struct clk *clk;
  	int ret;
@@ -339,19 +338,14 @@ static int mt7621_spi_probe(struct platform_device *pdev)
  	if (IS_ERR(base))
  		return PTR_ERR(base);
- clk = devm_clk_get(&pdev->dev, NULL);
+	clk = devm_clk_get_enabled(&pdev->dev, NULL);
  	if (IS_ERR(clk))
  		return dev_err_probe(&pdev->dev, PTR_ERR(clk),
  				     "unable to get SYS clock\n");
- status = clk_prepare_enable(clk);
-	if (status)
-		return status;
-
  	master = devm_spi_alloc_master(&pdev->dev, sizeof(*rs));
  	if (!master) {
  		dev_info(&pdev->dev, "master allocation failed\n");
-		clk_disable_unprepare(clk);
  		return -ENOMEM;
  	}
@@ -376,13 +370,10 @@ static int mt7621_spi_probe(struct platform_device *pdev)
  	ret = device_reset(&pdev->dev);
  	if (ret) {
  		dev_err(&pdev->dev, "SPI reset failed!\n");
-		clk_disable_unprepare(clk);
  		return ret;
  	}
ret = spi_register_controller(master);
-	if (ret)
-		clk_disable_unprepare(clk);
return ret;
  }
@@ -390,13 +381,10 @@ static int mt7621_spi_probe(struct platform_device *pdev)
  static int mt7621_spi_remove(struct platform_device *pdev)
  {
  	struct spi_controller *master;
-	struct mt7621_spi *rs;
master = dev_get_drvdata(&pdev->dev);
-	rs = spi_controller_get_devdata(master);
spi_unregister_controller(master);
-	clk_disable_unprepare(rs->clk);
return 0;
  }



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