On Thu, March 06, 2014 at 11:23:50 AM, Marek Vasut wrote: > On Wednesday, March 05, 2014 at 07:52:31 AM, Yuan Yao wrote: > > Add dma support for i2c. This function depend on DMA driver. > > You can turn on it by write both the dmas and dma-name properties in > > dts node. > > > > Signed-off-by: Yuan Yao <yao.y...@freescale.com> > > --- > > [...] > > > @@ -601,6 +826,7 @@ static int i2c_imx_probe(struct platform_device > *pdev) > > void __iomem *base; > > int irq, ret; > > u32 bitrate; > > + u32 phy_addr; > > > > dev_dbg(&pdev->dev, "<%s>\n", __func__); > > > > @@ -611,6 +837,7 @@ static int i2c_imx_probe(struct platform_device > *pdev) > > } > > > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + phy_addr = res->start; > > Uh ... Shawn, I really think I am lost here. Don't you need to map this > memory before you can use it for DMA ? The DMA mapping function should > give you the physical address and is the right way to go about this > instead of pulling the address from here, no ? > > I might be wrong here, I am rather uncertain, so please help me out. > Thanks!
Hi, Marek, Thanks for your suggestion. Here you can review the code in include/linux/ioport.h The resource->start describes the entity on the CPU bus as a starting physical address. So I thinks it can used for dma directly.
