On Wed, Sep 09, 2020 at 01:39:46AM +0300, Dmitry Osipenko wrote:
> The driver's probe function code is a bit difficult to read. This patch
> reorders code of the probe function, forming groups of code that are easy
> to work with. The probe tear-down order now matches the driver-removal
> order.
> 
> Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 100 ++++++++++++++++-----------------
>  1 file changed, 49 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 79d1cefdc901..7c91bbb3f95c 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -440,6 +440,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev 
> *i2c_dev)
>  
>       i2c_dev->tx_dma_chan = chan;
>  
> +     i2c_dev->dma_buf_size = i2c_dev->hw->quirks->max_write_len +
> +                             I2C_PACKET_HEADER_SIZE;
> +
>       dma_buf = dma_alloc_coherent(i2c_dev->dev, i2c_dev->dma_buf_size,
>                                    &dma_phys, GFP_KERNEL | __GFP_NOWARN);
>       if (!dma_buf) {
> @@ -1693,34 +1696,42 @@ static int tegra_i2c_probe(struct platform_device 
> *pdev)
>       struct device *dev = &pdev->dev;
>       struct tegra_i2c_dev *i2c_dev;
>       struct resource *res;
> -     void __iomem *base;
> -     phys_addr_t base_phys;
> -     int irq;
>       int ret;
>  
> -     base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> -     if (IS_ERR(base))
> -             return PTR_ERR(base);
> -
> -     base_phys = res->start;
> -
> -     irq = platform_get_irq(pdev, 0);
> -     if (irq < 0)
> -             return irq;
> -
>       i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
>       if (!i2c_dev)
>               return -ENOMEM;
>  
> -     i2c_dev->base = base;
> -     i2c_dev->base_phys = base_phys;
> -     i2c_dev->adapter.algo = &tegra_i2c_algo;
> -     i2c_dev->adapter.retries = 1;
> -     i2c_dev->adapter.timeout = 6 * HZ;
> -     i2c_dev->irq = irq;
> +     platform_set_drvdata(pdev, i2c_dev);
> +
> +     init_completion(&i2c_dev->msg_complete);
> +     init_completion(&i2c_dev->dma_complete);
> +
> +     i2c_dev->hw = of_device_get_match_data(&pdev->dev);
>       i2c_dev->cont_id = pdev->id;
>       i2c_dev->dev = &pdev->dev;
>  
> +     i2c_dev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> +     if (IS_ERR(i2c_dev->base))
> +             return PTR_ERR(i2c_dev->base);
> +
> +     i2c_dev->base_phys = res->start;
> +
> +     ret = platform_get_irq(pdev, 0);
> +     if (ret < 0)
> +             return ret;
> +
> +     i2c_dev->irq = ret;
> +
> +     /* interrupt will be enabled during of transfer time */
> +     irq_set_status_flags(i2c_dev->irq, IRQ_NOAUTOEN);
> +
> +     ret = devm_request_irq(&pdev->dev, i2c_dev->irq, tegra_i2c_isr,
> +                            IRQF_NO_SUSPEND, dev_name(&pdev->dev),
> +                            i2c_dev);
> +     if (ret)
> +             return ret;

Is it safe to install the interrupt handler at this point? What if,
perhaps because some bootloader didn't properly quiesce the I2C
controller, an interrupt triggers immediately after this?

Thierry

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