Re: [PATCH v8 1/4] i2c: tegra: Do not configure DMA if not supported

Kartik Rajput
2025-09-18T07:10:43Z

On 17/09/25 19:38, Jon Hunter wrote:
>
> On 17/09/2025 09:56, Kartik Rajput wrote:
>> On Tegra264, not all I2C controllers have the necessary interface to
>> GPC DMA, this causes failures when function tegra_i2c_init_dma()
>> is called.
>>
>> Ensure that "dmas" device-tree property is present before initializing
>> DMA in function tegra_i2c_init_dma().
>>
>> Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
>> ---
>> v2 -> v4:
>>     * Add debug print if DMA is not supported by the I2C controller.
>> v1 -> v2:
>>     * Update commit message to clarify that some I2C controllers may
>>       not have the necessary interface to GPC DMA.
>> ---
>>   drivers/i2c/busses/i2c-tegra.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
>> index e533460bccc3..d908e5e3f0af 100644
>> --- a/drivers/i2c/busses/i2c-tegra.c
>> +++ b/drivers/i2c/busses/i2c-tegra.c
>> @@ -446,6 +446,11 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
>>       u32 *dma_buf;
>>       int err;
>> +    if (!of_property_present(i2c_dev->dev->of_node, "dmas")) {
>> +        dev_dbg(i2c_dev->dev, "DMA not available, falling back to PIO\n");
>> +        return 0;
>> +    }
>> +
>>       if (IS_VI(i2c_dev))
>>           return 0;
>
> No issue with this change, but we have a few checks for DMA support in this function and so it would be nice to have them altogether.
>
> Jon
>

Ack.

Thanks,
Kartik