RE: [PATCH V9 3/5] i2c: tegra: Add DMA support

[Sowjanya Komatineni]

> > +static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) {
> > +   struct dma_chan *dma_chan;
> > +   u32 *dma_buf;
> > +   dma_addr_t dma_phys;
> > +   int err = 0;
> > +
> > +   if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA))
> > +           return -ENODEV;
>
> Driver shall not fail to probe if DMA driver is disabled, but to continue 
> with the PIO-only mode available.
>
> Should be:
>
>       if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA))
>               return 0;
>
Except EPROBE_DEFER, anything else returned from tegra_i2c_init_dma 
(ENODEV/ENOMEM) is ignored in i2c_probe
DMA mode decision is based on xfer size and availability of dma channel or can 
be changed based on valid dma buf to shorten the line.