device-tree

问题 I have two device tree nodes, one sets a gpio pin and the other one configures one i2c bus, ex: &gpio2 { en-gpio { gpio-hog; gpios = <5 0>; output-high; }; }; &i2c1 { gpiom1: gpio@27 { compatible = "microchip,mcp23008"; gpio-controller; #gpio-cells = <2>; reg = <0x27>; }; }; How can i add a dependency between the i2c node and gpio one? What i want to achieve is that the gpio pin should be set before the devices on i2c are initialized. 回答1: Short answer You can't provide dependency between

问题 I have developped a kernel module to manage a nf4 tag as a char device. I have developped this module outside of the kernel and tested it compiled as a loadable kernel module (i.e. .ko) during the development phase. Once the driver has been functional and stable enough I have inserted it into linux kernel source (v4.9.30) using patches so it's built as part of the kernel. Here I'm in the situation where the module is loaded probed at boot by kernel as it's builtin and it appears into the

问题 I have developped a kernel module to manage a nf4 tag as a char device. I have developped this module outside of the kernel and tested it compiled as a loadable kernel module (i.e. .ko) during the development phase. Once the driver has been functional and stable enough I have inserted it into linux kernel source (v4.9.30) using patches so it's built as part of the kernel. Here I'm in the situation where the module is loaded probed at boot by kernel as it's builtin and it appears into the

问题 I have developped a kernel module to manage a nf4 tag as a char device. I have developped this module outside of the kernel and tested it compiled as a loadable kernel module (i.e. .ko) during the development phase. Once the driver has been functional and stable enough I have inserted it into linux kernel source (v4.9.30) using patches so it's built as part of the kernel. Here I'm in the situation where the module is loaded probed at boot by kernel as it's builtin and it appears into the

问题 I have developped a kernel module to manage a nf4 tag as a char device. I have developped this module outside of the kernel and tested it compiled as a loadable kernel module (i.e. .ko) during the development phase. Once the driver has been functional and stable enough I have inserted it into linux kernel source (v4.9.30) using patches so it's built as part of the kernel. Here I'm in the situation where the module is loaded probed at boot by kernel as it's builtin and it appears into the

问题 I have developped a kernel module to manage a nf4 tag as a char device. I have developped this module outside of the kernel and tested it compiled as a loadable kernel module (i.e. .ko) during the development phase. Once the driver has been functional and stable enough I have inserted it into linux kernel source (v4.9.30) using patches so it's built as part of the kernel. Here I'm in the situation where the module is loaded probed at boot by kernel as it's builtin and it appears into the

问题 I am using SAMA5D27-SOM1-EK1 Microchip embedded board. I am using Linux kernel 4.14.73 version that I build using Yocto project. That board has a J27 connector that is used as Image Sensor Interface as shown in 4.3.2 Title, page 31 from the board user guide document, besides, Table 4-16. ISC Connector J27 Pin Assignment, page 32 , shows the connector PIN features. This is a link to the board document : SAMA5D27_User_guide My goal is to change some PIN features of this connector, in order to

问题 I am using SAMA5D27-SOM1-EK1 Microchip embedded board. I am using Linux kernel 4.14.73 version that I build using Yocto project. That board has a J27 connector that is used as Image Sensor Interface as shown in 4.3.2 Title, page 31 from the board user guide document, besides, Table 4-16. ISC Connector J27 Pin Assignment, page 32 , shows the connector PIN features. This is a link to the board document : SAMA5D27_User_guide My goal is to change some PIN features of this connector, in order to

问题 Can any one explain what each value in ranges property represent. my_pcie_0: pcie@10000000 { #address-cells = <1>; #size-cells = <1>; compatible = "mypcie"; device_type = "pcie"; reg = < 0x40000000 0x00100000 >; ranges = < 0x02000000 0 0xf0000000 0xf00000000 0x0 0x08000000>; } 回答1: This question has been up for a while but I ran into the same issue and found the answer after searching for a while. my_pcie_0: pcie@10000000 { #address-cells = <1>; #size-cells = <1>; compatible = "mypcie";

问题 Can any one explain what each value in ranges property represent. my_pcie_0: pcie@10000000 { #address-cells = <1>; #size-cells = <1>; compatible = "mypcie"; device_type = "pcie"; reg = < 0x40000000 0x00100000 >; ranges = < 0x02000000 0 0xf0000000 0xf00000000 0x0 0x08000000>; } 回答1: This question has been up for a while but I ran into the same issue and found the answer after searching for a while. my_pcie_0: pcie@10000000 { #address-cells = <1>; #size-cells = <1>; compatible = "mypcie";