Linux Device Drivers Development

Consumer binding

According to the SDMA event-mapping table, the following code shows DMA request signals for peripherals in i.MX 6Dual/ 6Quad:

uart1: serial@02020000 { 
    compatible = "fsl,imx6sx-uart", "fsl,imx21-uart"; 
    reg = <0x02020000 0x4000>; 
    interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>; 
    clocks = <&clks IMX6SX_CLK_UART_IPG>, 
                <&clks IMX6SX_CLK_UART_SERIAL>; 
    clock-names = "ipg", "per"; 
    dmas = <&sdma 25 4 0>, <&sdma 26 4 0>; 
    dma-names = "rx", "tx"; 
    status = "disabled"; 
}; 

The second cells (25 and 26) in the DMA property correspond to the DMA request/event ID. Those values come from the SoC manuals (i.MX53 in our case). Please have a look at https://community.nxp.com/servlet/JiveServlet/download/614186-1-373516/iMX6_Firmware_Guide.pdf, and ...