Re: [PATCH v7 14/34] i2c: tegra: Clean up probe function

Thierry Reding
2020-09-17T13:03:52Z

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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 <digetx@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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