Date:   Tue, 12 Jul 2022 20:50:54 +0000
From:   <Conor.Dooley@...rochip.com>
To:     <yangyingliang@...wei.com>
CC:     <Daire.McNamara@...rochip.com>, <broonie@...nel.org>,
        <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-riscv@...ts.infradead.org>
Subject: Re: [PATCH -next 2/2] spi: microchip-core: switch to use
 devm_spi_alloc_master()

On 12/07/2022 15:03, Conor.Dooley@...rochip.com wrote:
> On 12/07/2022 14:53, Yang Yingliang wrote:
>> [Some people who received this message don't often get email from yangyingliang@...wei.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> Switch to use devm_spi_alloc_master() to simpify error path.
> 
> Hey Yang,
> Thanks for trying to fix my mistakes!
> 
> Forgive my innocence here, but why is it okay to remove the
> spi_master_put() in remove() but not the one in the error path of
> the probe function?
> 
> If the devm_add_action_or_reset() in devm_spi_register_controller()
> fails won't the same thing apply to the probe error path?
> 
> IOW, I think this patch needs a fixes tag too b/c it also fixes a
> refcount underflow. Please correct me if I am misunderstanding.

Ahh, I just saw your revert of 59ebbe40fb51 ("spi: simplify
devm_spi register_controller"). With that, this makes a lot more
sense.

> 
> One other comment below.

This comment still applies for this patch. dev_err_probe would be
nice.

Thanks,
Conor.

> 
>>
>> Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
>> ---
>>   drivers/spi/spi-microchip-core.c | 20 +++++++-------------
>>   1 file changed, 7 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c
>> index c26767343176..1a24e47f8305 100644
>> --- a/drivers/spi/spi-microchip-core.c
>> +++ b/drivers/spi/spi-microchip-core.c
>> @@ -513,7 +513,7 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>          u32 num_cs;
>>          int ret = 0;
>>
>> -       master = spi_alloc_master(&pdev->dev, sizeof(*spi));
>> +       master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
>>          if (!master)
>>                  return dev_err_probe(&pdev->dev, -ENOMEM,
>>                                       "unable to allocate master for SPI controller\n");
>> @@ -535,36 +535,32 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>          spi = spi_master_get_devdata(master);
>>
>>          spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
>> -       if (IS_ERR(spi->regs)) {
>> -               ret = PTR_ERR(spi->regs);
>> -               goto error_release_master;
>> -       }
>> +       if (IS_ERR(spi->regs))
>> +               return PTR_ERR(spi->regs);
>>
>>          spi->irq = platform_get_irq(pdev, 0);
>>          if (spi->irq <= 0) {
>>                  dev_err(&pdev->dev, "invalid IRQ %d for SPI controller\n", spi->irq);
>> -               ret = -ENXIO;
>> -               goto error_release_master;
>> +               return -ENXIO;
> 
> Also these can now become dev_err_probe for further simplification?
> Thanks,
> Conor.
> 
>>          }
>>
>>          ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt,
>>                                 IRQF_SHARED, dev_name(&pdev->dev), master);
>>          if (ret) {
>>                  dev_err(&pdev->dev, "could not request irq: %d\n", ret);
>> -               goto error_release_master;
>> +               return ret;
>>          }
>>
>>          spi->clk = devm_clk_get(&pdev->dev, NULL);
>>          if (IS_ERR(spi->clk)) {
>> -               ret = PTR_ERR(spi->clk);
>>                  dev_err(&pdev->dev, "could not get clk: %d\n", ret);
>> -               goto error_release_master;
>> +               return PTR_ERR(spi->clk);
>>          }
>>
>>          ret = clk_prepare_enable(spi->clk);
>>          if (ret) {
>>                  dev_err(&pdev->dev, "failed to enable clock\n");
>> -               goto error_release_master;
>> +               return ret;
>>          }
>>
>>          mchp_corespi_init(master, spi);
>> @@ -583,8 +579,6 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>   error_release_hardware:
>>          mchp_corespi_disable(spi);
>>          clk_disable_unprepare(spi->clk);
>> -error_release_master:
>> -       spi_master_put(master);
>>
>>          return ret;
>>   }
>> --
>> 2.25.1
>>
> 
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