21.02.2019 18:00, Jon Hunter пишет:
> From: Jonathan Hunter <jonathanh@xxxxxxxxxx>
>
> Commit 86c92b9965ff ("i2c: tegra: Add DMA support") added DMA support
> to the Tegra I2C driver for Tegra devices that support the APB DMA
> controller. One side-effect of this change is that even for Tegra
> devices that do not have an APB DMA controller and hence, cannot
> support DMA tranfers for I2C transactions, the following error messages
> are still displayed ...
>
> ERR KERN tegra-i2c 31c0000.i2c: cannot use DMA: -19
> ERR KERN tegra-i2c 31c0000.i2c: falling back to PIO
>
> There is no point displaying the above messages for devices that do not
> have an APB DMA controller and so fix this by returning from the
> tegra_i2c_init_dma() function if 'has_apb_dma' is not true.
>
> Furthermore, if CONFIG_TEGRA20_APB_DMA is not set, then rather than
> printing an error message, print an debug message as for whatever reason
> this could be intentional.
>
> Fixes: 86c92b9965ff ("i2c: tegra: Add DMA support")
>
> Signed-off-by: Jonathan Hunter <jonathanh@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-tegra.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 31ff67015255..ebaa78d17d6e 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -414,10 +414,12 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
> dma_addr_t dma_phys;
> int err;
>
> - if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA) ||
> - !i2c_dev->hw->has_apb_dma) {
> - err = -ENODEV;
> - goto err_out;
> + if (!i2c_dev->hw->has_apb_dma)
> + return 0;
> +
> + if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA)) {
> + dev_dbg(i2c_dev->dev, "Support for APB DMA not enabled!\n");
Nit: would be awesome if the common style of messages could be maintained across the driver, in particular starting the messages with the same upper/lower case. There is no real need to change it in this patch as the messages are already quite inconsistent. It probably won't hurt to clean up the driver's coding style and fix the checkpatch warnings in the future.
> + return 0;
> }
>
> chan = dma_request_slave_channel_reason(i2c_dev->dev, "rx");
>
Looks good. Thanks, Jon!
Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>
