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| − | == Overview ==
| + | #REDIRECT [[CM-X300: Linux: Kernel]] |
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| − | Linux kernel for CM-X300 modules provides support for on-board peripherals. Current support coverage is specified at [http://www.compulab.co.il/x300cm/html/x300-os-support.htm O/S support coverage map] page. CompuLab provides ready-to-run binary kernel images, and source code of the modifications and additions made to the Linux kernel to work properly with CM-X300 modules.
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| − | == Building Linux kernel for CM-X300 ==
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| − | <pre>
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| − | mkdir /home/development/cm-x300/kernel
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| − | cd /home/development/cm-x300/kernel
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| − | wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.31.tar.bz2
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| − | tar xjf linux-2.6.31.tar.bz2
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| − | cd linux-2.6.31
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| − | cat /path/to/x300-linux/kernel/linux-2.6.31-cm-x300.patch | patch -p1
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| − | export ARCH=arm
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| − | export CROSS_COMPILE=arm-linux-
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| − | make cm_x300_defconfig
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| − | make menuconfig
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| − | make && make uImage \
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| − | INSTALL_MOD_PATH=/home/development/cm-x300/rootfs make modules_install
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| − | </pre>
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| − | In the above example, the Linux kernel image ({{filename|uImage}}) will be created in {{filename|/home/development/cm-x300/kernel/linux-2.6.31/arch/arm/boot}}, and the loadable kernel modules will be installed into the {{filename|/home/development/cm-x300/rootfs/lib/modules}} directory.
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| − | Now, if you boot CM-X300 with newly created kernel image and with networked root filesysem at {{filename|/home/development/cm-x300/rootfs/}} the system will be able to properly load kernel modules and you avoid modules versioning problems.
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| − | === Creating Linux kernel JFFS2 image===
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| − | The Linux kernel should be stored in the CM-X300 NAND flash as a JFFS2 image. This image can be created as follows:
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| − | <pre>
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| − | mkdir /tmp/cm-x300-kernel/
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| − | cp /home/development/cm-x300/kernel/linux-2.6.31/arch/arm/boot/uImage
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| − | mkfs.jffs2 --no-cleanmarkers --pad --eraseblock=0x20000 --root=/tmp/cm-x300-kernel --output=/path/to/cm-x300-kernel.jffs2
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| − | </pre>
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| − | | |
| − | == Using mainline Linux kernel on CM-X300 ==
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| − | It is possible to use mainline Linux Kernel on CM-X300 "as is". Just keep in mind that features and fixes listed in below sections are still '''not present''' in the mainline kernel.
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| − | === CM-X300 specific additions and changes to Linux kernel 2.6.31 ===
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| − | * CM-X300 module revision 1.3 support
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| − | * PXA310 cpu support
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| − | * USB Host support
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| − | * Audio and Touchscreen support
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| − | * LCD and backlight support
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| − | * WIFI and Bluetooth support
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| − | * MMC binding fix
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| − | * DA9030 PMIC and battery charger support
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| − | | |
| − | === CM-X300 specific additions and changes to Linux kernel 2.6.26 ===
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| − | * Basic platform support
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| − | * NAND flash support
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| − | * PXA frame buffer and LCD support
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| − | * WIFI and Bluetooth support
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| − | * RTC support
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| − | * DA9030 PMIC support
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| − | * CPU frequency change support
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| − | * Audio and Touchscreen support
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| − | * USB Host support
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| − | == Device support details ==
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| − | === Basic platform support ===
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| − | The CM-X300 basic platform support is implemented in the {{filename|linux/arch/arm/mach-pxa/cm-x300.c}} file. This file includes default setup of multifunction pins, registration of the devices integrated in the CM-X300 module and definitions of platform-specific configuration of these devices. This file also includes several routines needed for proper operation of the WI2WI chip (WiFI and Bluetooth).
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| − | === I2C support ===
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| − | The I2C bus controller support is enabled in the default Linux Kernel for CM-X300.
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| − | Standard I2C drivers can be used to access I2C bus on CM-X300 module.<br>
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| − | In particular, you can enable the [[Linux_Kernel_for_CM-X300#Generic_i2c-dev_driver|generic i2c-dev driver]] that allows issuing read/write requests to i2c device through {{filename|/dev/i2c-X}} interface or
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| − | you can use/implement in-kernel device driver.<br>
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| − | ==== Registering an I2C device ====
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| − | To register an I2C device, some code needs to be added to the platform initialization file {{filename|arch/arm/mach-pxa/cm-x300.c}}:
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| − | * Add '''''struct''' i2c_board_info'' and initialize it using the macro (defined in {{filename|linux/i2c.h}}) {{parameter|I2C_BOARD_INFO}}:
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| − | <pre>
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| − | static struct i2c_board_info cm_x300_i2c_device = {
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| − | I2C_BOARD_INFO("device name", <7 bit address>),
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| − | /* here initialize other fields if used */
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| − | ...
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| − | };
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| − | </pre>
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| − | * Register the device with I2C bus controller:
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| − | <pre>
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| − | static void __init cm_x300_init_i2c(void)
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| − | {
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| − | ...
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| − | i2c_register_board_info(<i2c bus number>, &cm_x300_i2c_device, 1);
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| − | }
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| − | </pre>
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| − | ==== Generic {{filename|i2c-dev}} driver ====
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| − | To enable the generic {{filename|i2c-dev}} driver, in Linux Kernel configuration, in ''Device Drivers'' ---> ''I2C support'' select "''I2C device interface''" either as built-in driver or a module:
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| − | <pre>
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| − | ┌─────────────────────────────────────────── I2C support ────────────────────────────────────────────┐
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| − | │ Arrow keys navigate the menu. <Enter> selects submenus --->. Highlighted letters are hotkeys. │
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| − | │ Pressing <Y> includes, <N> excludes, <M> modularizes features. Press <Esc><Esc> to exit, <?> for │
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| − | │ Help, </> for Search. Legend: [*] built-in [ ] excluded <M> module < > module capable │
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| − | │ │
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| − | │ ┌────────────────────────────────────────────────────────────────────────────────────────────────┐ │
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| − | │ │ --- I2C support │ │
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| − | │ │ <M> I2C device interface │ │
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| − | │ │ [*] Autoselect pertinent helper modules │ │
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| − | │ │ I2C Hardware Bus support ---> │ │
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| − | │ │ Miscellaneous I2C Chip support ---> │ │
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| − | │ │ [ ] I2C Core debugging messages │ │
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| − | │ │ [ ] I2C Algorithm debugging messages │ │
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| − | │ │ [ ] I2C Bus debugging messages │ │
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| − | │ │ [ ] I2C Chip debugging messages │ │
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| − | │ └────────────────────────────────────────────────────────────────────────────────────────────────┘ │
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| − | ├────────────────────────────────────────────────────────────────────────────────────────────────────┤
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| − | │ <Select> < Exit > < Help > │
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| − | └────────────────────────────────────────────────────────────────────────────────────────────────────┘
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| − | </pre>
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| − | If you choose to compile the driver as a module, the module will be called {{filename|i2c-dev}}.<br>
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| − | This will create {{filename|/dev/i2c-X}} files for each registered I2C adapter.<br>
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| − | Information on accessing the I2C devices via the generic {{filename|i2c-dev}} driver could be found in {{filename|Documentation/i2c/dev-interface}} in the Linux Kernel tree.
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| − | === SPI support ===
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| − | PXA3xx SPI controller is backward compatible with PXA2xx and it is handled on CM-X300 the same way as on CM-X270. Please refer to [[SPI support for CM-X270]] article.
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| − | == See also ==
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| − | * [[Getting started with Linux on CM-X300]]
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| − | * [[Linux Development for XScale modules]]
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| − | * [[Debian Linux for CM-X300]]
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