linux-kernel - Re: [PATCH v4 3/3] spi: geni-qcom: Use devm functions to simplify code

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Message-ID: <CAD=FV=XQ7uf_Y_WTv_6-DX1Mo=+RycKSyxf=E-f3TOKiuE5RMA@mail.gmail.com>
Date: Wed, 11 Sep 2024 15:53:20 -0700
From: Doug Anderson <dianders@...omium.org>
To: Jinjie Ruan <ruanjinjie@...wei.com>
Cc: broonie@...nel.org, akashast@...eaurora.org, vkoul@...nel.org, 
	linux-arm-msm@...r.kernel.org, linux-spi@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/3] spi: geni-qcom: Use devm functions to simplify code

Hi,

On Mon, Sep 9, 2024 at 6:19 AM Jinjie Ruan <ruanjinjie@...wei.com> wrote:
>
> Use devm_pm_runtime_enable(), devm_request_irq() and
> devm_spi_register_controller() to simplify code.
>
> And also register a callback spi_geni_release_dma_chan() with
> devm_add_action_or_reset(), to release dma channel in both error
> and device detach path, which can make sure the release sequence is
> consistent with the original one.
>
> 1. Unregister spi controller.
> 2. Free the IRQ.
> 3. Free DMA chans
> 4. Disable runtime PM.
>
> So the remove function can also be removed.
>
> Suggested-by: Doug Anderson <dianders@...omium.org>
> Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
> ---
> v4:
> - Correct the "data" of devm_add_action_or_reset().
> v3:
> - Land the rest of the cleanups afterwards.
> ---
>  drivers/spi/spi-geni-qcom.c | 37 +++++++++++++------------------------
>  1 file changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index 6f4057330444..5cb002d7d4a6 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -632,8 +632,10 @@ static int spi_geni_grab_gpi_chan(struct spi_geni_master *mas)
>         return ret;
>  }
>
> -static void spi_geni_release_dma_chan(struct spi_geni_master *mas)
> +static void spi_geni_release_dma_chan(void *data)
>  {
> +       struct spi_geni_master *mas = data;
> +
>         if (mas->rx) {
>                 dma_release_channel(mas->rx);
>                 mas->rx = NULL;
> @@ -1132,6 +1134,12 @@ static int spi_geni_probe(struct platform_device *pdev)
>         if (ret)
>                 return ret;
>
> +       ret = devm_add_action_or_reset(dev, spi_geni_release_dma_chan, mas);
> +       if (ret) {
> +               dev_err(dev, "Unable to add action.\n");
> +               return ret;
> +       }

Use dev_err_probe() to simplify.

ret = devm_add_action_or_reset(dev, spi_geni_release_dma_chan, mas);
if (ret)
  return dev_err_probe(dev, ret, "Unable to add action.\n");


Personally I'd also rather that you do the devm_add_action_or_reset()
call straight in spi_geni_grab_gpi_chan(). That makes it much more
obvious what's happening. You can still use dev_err_probe() in there
since it's called (indirectly) from probe. In that case you'd probably
replace the "return 0;" in that function with just "return
dev_err_probe(...)".


> @@ -1146,33 +1154,15 @@ static int spi_geni_probe(struct platform_device *pdev)
>         if (mas->cur_xfer_mode == GENI_GPI_DMA)
>                 spi->flags = SPI_CONTROLLER_MUST_TX;
>
> -       ret = request_irq(mas->irq, geni_spi_isr, 0, dev_name(dev), spi);
> +       ret = devm_request_irq(dev, mas->irq, geni_spi_isr, 0, dev_name(dev), spi);
>         if (ret)
> -               goto spi_geni_release_dma;
> +               return ret;
>
> -       ret = spi_register_controller(spi);
> +       ret = devm_spi_register_controller(dev, spi);
>         if (ret)
> -               goto spi_geni_probe_free_irq;
> +               return ret;
>
>         return 0;

You no longer need the "if" statement or even to assign to "ret". Just:

return devm_spi_register_controller(dev, spi);


Those are just nits, though. I'd be OK with:

Reviewed-by: Douglas Anderson <dianders@...omium.org>

...since Mark has already landed the first two patches, your v5 would
just contain this one patch.

-Doug