94 lines · plain
1CE4100 I2C2----------3 4CE4100 has one PCI device which is described as the I2C-Controller. This5PCI device has three PCI-bars, each bar contains a complete I2C6controller. So we have a total of three independent I2C-Controllers7which share only an interrupt line.8The driver is probed via the PCI-ID and is gathering the information of9attached devices from the devices tree.10Grant Likely recommended to use the ranges property to map the PCI-Bar11number to its physical address and to use this to find the child nodes12of the specific I2C controller. This were his exact words:13 14 Here's where the magic happens. Each entry in15 ranges describes how the parent pci address space16 (middle group of 3) is translated to the local17 address space (first group of 2) and the size of18 each range (last cell). In this particular case,19 the first cell of the local address is chosen to be20 1:1 mapped to the BARs, and the second is the21 offset from be base of the BAR (which would be22 non-zero if you had 2 or more devices mapped off23 the same BAR)24 25 ranges allows the address mapping to be described26 in a way that the OS can interpret without27 requiring custom device driver code.28 29This is an example which is used on FalconFalls:30------------------------------------------------31 i2c-controller@b,2 {32 #address-cells = <2>;33 #size-cells = <1>;34 compatible = "pci8086,2e68.2",35 "pci8086,2e68",36 "pciclass,ff0000",37 "pciclass,ff00";38 39 reg = <0x15a00 0x0 0x0 0x0 0x0>;40 interrupts = <16 1>;41 42 /* as described by Grant, the first number in the group of43 * three is the bar number followed by the 64bit bar address44 * followed by size of the mapping. The bar address45 * requires also a valid translation in parents ranges46 * property.47 */48 ranges = <0 0 0x02000000 0 0xdffe0500 0x10049 1 0 0x02000000 0 0xdffe0600 0x10050 2 0 0x02000000 0 0xdffe0700 0x100>;51 52 i2c@0 {53 #address-cells = <1>;54 #size-cells = <0>;55 compatible = "intel,ce4100-i2c-controller";56 57 /* The first number in the reg property is the58 * number of the bar59 */60 reg = <0 0 0x100>;61 62 /* This I2C controller has no devices */63 };64 65 i2c@1 {66 #address-cells = <1>;67 #size-cells = <0>;68 compatible = "intel,ce4100-i2c-controller";69 reg = <1 0 0x100>;70 71 /* This I2C controller has one gpio controller */72 gpio@26 {73 #gpio-cells = <2>;74 compatible = "nxp,pcf8575";75 reg = <0x26>;76 gpio-controller;77 };78 };79 80 i2c@2 {81 #address-cells = <1>;82 #size-cells = <0>;83 compatible = "intel,ce4100-i2c-controller";84 reg = <2 0 0x100>;85 86 gpio@26 {87 #gpio-cells = <2>;88 compatible = "nxp,pcf8575";89 reg = <0x26>;90 gpio-controller;91 };92 };93 };94