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SubjectRe: [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@wanadoo.fr>

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

> ---
> 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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