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    SubjectRE: [PATCH v3 1/2] i2c: add DMA support for freescale i2c driver
    Date
    On Wednesday, March 26, 2014 at 02:27:46 PM, Marek Vasut wrote:
    > On Wednesday, March 26, 2014 at 06:56:34 AM, Yao Yuan wrote:
    > > On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote:
    > > > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote:
    > > >
    > > > [...]
    > > >
    > > > > > > + i2c_imx->use_dma = false;
    > > > > > > + } else if (i2c_imx_dma_request(i2c_imx,
    > > > > > > +(dma_addr_t)phy_addr))
    > > >
    > > > {
    > > >
    > > > > > > + dev_info(&pdev->dev,
    > > > > > > + "can't request dma chan, faild use dma.
    > \n");
    > > > > > > + i2c_imx->use_dma = false;
    > > > > > > + } else {
    > > > > > > + i2c_imx->use_dma = true;
    > > > > > > + }
    > > > > >
    > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL
    > > >
    > > > pointer ?
    > > >
    > > > > > Then you won't need a separate variable, for this purpose ...
    > right ?
    > > > >
    > > > > Sorry and I think what I know is just to check whether it is NULL.
    > > > > Then for the second question, maybe there are some other ways, But
    > > > > I think it is more tidy and easier understanding for using a
    > > > > separate variable, for this purpose.
    > > >
    > > > You are just wasting space and duplicating data, unless I am wrong.
    > >
    > > Well, Do you have a better idea? Although I think it's necessary.
    >
    > I think we disconnected here, sorry. Why can you not use (i2c_imx->dma !=
    > NULL) instead of (i2c_imx->use_dma == true) please ?
    >

    But there are two judge conditions. But only the "i2c_imx->dma", but also whether "i2c_imx_dma_request" success.

    "i2c_imx->use_dma == true" be equivalent to "i2c_imx->dma != NULL && !i2c_imx_dma_request()"

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