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

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Message-ID: <c662f0b9-31dc-8b97-ef3f-ea33f9fc62af@huawei.com>
Date: Thu, 12 Sep 2024 11:53:19 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: Doug Anderson <dianders@...omium.org>
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



On 2024/9/12 6:53, Doug Anderson wrote:
> 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");

It seems that if it only return -ENOMEM or 0, using dev_err_probe() has
not not much value for many community maintainers.

> 
> 
> 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

Yes, it will be more clear.

> 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);

Right!

> 
> 
> 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