July 2016 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

gpio-led driver
by Raul Piper July 28, 2016

July 28, 2016

Hi, I wanted to know the part number for the leds-gpio.c in the driver/leds folder and the device tree bindings for this driver .Can some one point out to me where in Linux kernel it is? Also why below line has been used.Is it mandatory? ... .of_match_table = of_gpio_leds_match, }, thanks in advance , Rp

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Sample led driver dts file
by Raul Piper July 28, 2016

July 28, 2016

Hi, Can any one please send me the sample led driver dts file.I tried the sample from the /documentation/devicetree/bindings/leds/<dts file> but I am getting some parsing error from the dtc compiler. is "#" required while including the .dtsi file inside the dts while referring any include files. Also can we dynamically buil teh dts file and push/copy it to kernel? Reboot required? Thanks in advance , Rp

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Re: Feature Commit for Linux 4.7
by Rafael Westenberger July 28, 2016

July 28, 2016

DP++ ports allow for different signals (HDMI, VGA) to be passed thru the DisplayPort connector. A DP++ dongle offers the necessary pinnage for this to happen, very common are DP to HDMI adapters. By detecting capabilities of the dongles themselves, it will be possible to drive 4k displays or high frequency panels over this connection if the dongle so allows. On Wed, Jul 27, 2016 at 11:18 PM, <Valdis.Kletnieks(a)vt.edu> wrote: > On Mon, 25 Jul 2016 02:07:58 -0300, Rafael Westenberger said: > > > Please add this commit to wiki: > > > > Support for DP++ dongle detection > > There's *plenty* of stuff added every kernel release - adding every single > new feature and device supported would make the "new feature" list > unwieldy. > > In 2-3 sentences, explain what a DP++ dongle is, and why detecting one is > of general interest worth mentioning in an overview.... >

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help please first module
by hinawa July 26, 2016

July 26, 2016

hello i am starting to write modules and this code does not compile hello.c: /******************** Modulo experimental ********************/* #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Alberto Cerezo <ac90869(a)gmail.com>"); MODULE_DESCRIPTION("\"Hola Mundo\" Modulo experimental"); MODULE_VERSION("printk"); static int __init hola_init(void) { printk(KERN_INFO "Hola mundo\n"); return 0; } static void __exit hola_exit(void) { printk(KERN_INFO "Adios, me marcho\n"); } module_init(hola_init); module_exit(hola_exit); Makefile: obj-m += hello.o all: make -C /lib/modules/$(shell uname -r)/build M=${PWD} modules clean: make -C /lib/modules/$(shell uname -r)/build M=${PWD} clean error: In file included from /usr/src/linux-headers-4.6.0-1-common/include/linux/init.h:4:0, from /home/hinawa/Documentos/programasC/modulos/mod1/hello.c:9: /usr/src/linux-headers-4.6.0-1-common/include/linux/compiler.h:89:1: error: expected identifier or ‘(’ before ‘struct’ struct ftrace_branch_data { ^ make[4]: *** [/home/hinawa/Documentos/programasC/modulos/mod1/hello.o] Error 1 make[3]: *** [_module_/home/hinawa/Documentos/programasC/modulos/mod1] Error 2 make[2]: *** [sub-make] Error 2 make[1]: *** [all] Error 2 make: *** [all] Error 2 I do not get to find the error because the code appears to be correct ... thks

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Feature Commit for Linux 4.7
by Rafael Westenberger July 25, 2016

July 25, 2016

Please add this commit to wiki: Support for DP++ dongle detection https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=… Thanks

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File missing error
by SUNIL KHORWAL July 24, 2016

July 24, 2016

Hi I'm a beginner in linux's device driver. I am getting below errors - implicit declaration of function ‘ioperm' implicit declaration of function ‘sleep’ And when I am adding sys/io.h then i am getting "fatal error: sys/io.h: No such file or directory. One more question - How can I convert scan code to character. Please reply! Thanks Khorwal

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Is there a way to force probe to be called (etherned driver) ?
by Ran Shalit July 24, 2016

July 24, 2016

Hello, I write ethernet driver (mac controller is implemented in fpga connected to cpu) I see that the probe is not called on doing insmod. Is there a way to force the probe to be called on doing insmod ? I could not find in the board file (omap dart, kernel 3.4.0) any reference to ethernet. Best Regards, Ran

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Re: Mapping of Filename to allocated blocks
by Manoj Rao July 22, 2016

July 22, 2016

Thank you Valids. That worked! For others who may look for this info: If you have access to the struct file * then you could obtain this info with the following condition check: ============================================ struct file *filp = <blah blah>; if (filp->f_path.mnt->mnt_flags & MNT_NODEV) pr_info("ramfs node\n"); else pr_info("persist storage backed node\n"); ============================================ On Wed, Jul 20, 2016 at 7:49 PM, <Valdis.Kletnieks(a)vt.edu> wrote: > On Wed, 20 Jul 2016 18:46:47 -0700, Manoj Rao said: > > > However, I need to run this for each and every read system call which > > includes all the procfs, sysfs and other RAM fs based file reads. My > > code is causing the kernel to panic at some point due to an illegal > > memory access while trying to obtain the starting sector/block for the > > file that's currently being read. My hunch is the crash occurs when > > file being read is on a non-persistent fs such as a sysfs node > > I have gotten hold of the inode structure and I'm trying to find if > > a given inode is stored persistently or not and I've been unable to > > find this information so far. > > Hint: First, check if the filesystem is a pseudo filesystem before > bothering > to look for baking store. If you need to know how to do that, steal the > code from the code that prints /proc/filesystems - if it says 'nodev', > you'll > only find pain looking for backing storage. >

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lightweight live os for bisect
by Matwey V. Kornilov July 21, 2016

July 21, 2016

Hello, I would like to make a long-range bisect (unfortunately) to find where an issue appeared. The issue is present only on single one laptop, where I don't want to alter OS or somehow intrude things. Moreover, when I usually do `git bisect' between subsequent releases, I am fine with ordinarily 'make install', which is not the case now, because, for instance, 2.6.xx just won't run with modern systemd things (or, correctly, systemd things won't run with 2.6.xx). So, I would like to discover a way to compile USB live image with as simple as possible OS using precompiled ./linux tree. Only my test executable is required to run after the boot to show whether the issue here. So, what would you recommend? Or, how do you solve such problem usually?

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Re: gpio-led driver
by Gadre Nayan July 21, 2016

July 21, 2016

Hi, I used this: /* * XXX: Use a flat representation of the AM33XX interconnect. * The real AM33XX interconnect network is quite complex.Since * that will not bring real advantage to represent that in DT * for the moment, just use a fake OCP bus entry to represent * the whole bus hierarchy. */ ocp { compatible = "simple-bus"; #address-cells = <1>; #size-cells = <1>; ranges; ti,hwmods = "l3_main"; . . . dali_gpio { compatible = "arm,dali_gpio"; dali_TX = <9>; dali_RX = <10>; }; } Thanks Nayan Gadre. On Thu, Jul 21, 2016 at 11:19 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: > kindly cc the previous people in "To" .Sorry I missed in while replying you. > > On Thu, Jul 21, 2016 at 11:17 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: >> HI, >> >> On Thu, Jul 21, 2016 at 9:43 AM, Gadre Nayan <gadrenayan(a)gmail.com> wrote: >>> Hi, >>> >>> OF stands for open firmware, OF uses a format to represent platform >>> information, which is called a device tree. >>> >>> An example of how the driver extracts information from device tree: >>> >>> #if defined(CONFIG_OF) >>> static const struct of_device_id dali_of_ids[] = >>> { >>> { .compatible = "arm,dali_gpio", }, >>> {}, >>> }; >>> >>> MODULE_DEVICE_TABLE(of, dali_of_ids); >>> #endif >>> >>> static struct platform_driver dali_driver = { >>> .driver = { >>> .name = "dali_gpio", >>> .of_match_table = of_match_ptr(dali_of_ids), >>> }, >>> .probe = Dali_probe, >>> .remove = Dali_remove, >>> }; >>> >>> The driver is going to fetch information from the device tree later on >>> (in probe) using the compatible property mentioned. So if the tree has >>> the same compatible string then subsequent information can be obtained >>> from that device tree node. >>> >>> Thanks >>> >> Can you please post the coresponding dt binding code? >> >>> On Thu, Jul 21, 2016 at 9:42 AM, Gadre Nayan <gadrenayan(a)gmail.com> wrote: >>>> Hi, >>>> >>>> OF stands for open firmware, OF uses a format to represent platform >>>> information, which is called a device tree. >>>> >>>> An example of how the driver extracts information from device tree: >>>> >>>> #if defined(CONFIG_OF) >>>> static const struct of_device_id dali_of_ids[] = >>>> { >>>> { .compatible = "arm,dali_gpio", }, >>>> {}, >>>> }; >>>> >>>> MODULE_DEVICE_TABLE(of, dali_of_ids); >>>> #endif >>>> >>>> static struct platform_driver dali_driver = { >>>> .driver = { >>>> .name = "dali_gpio", >>>> .of_match_table = of_match_ptr(dali_of_ids), >>>> }, >>>> .probe = Dali_probe, >>>> .remove = Dali_remove, >>>> }; >>>> >>>> The driver is going to fetch information from the device tree later on >>>> (in probe) using the compatible property mentioned. So if the tree has >>>> the same compatible string then subsequent information can be obtained >>>> from that device tree node. >>>> >>>> Thanks >>>> Nayan Gadre >>>> >>>> On Wed, Jul 20, 2016 at 8:30 PM, Anish Kumar >>>> <anish198519851985(a)gmail.com> wrote: >>>>> >>>>> >>>>> On Jul 20, 2016, at 4:15 AM, Raul Piper <raulpblooper(a)gmail.com> wrote: >>>>> >>>>> Hi, >>>>> I wanted to know the part number >>>>> >>>>> >>>>> What is part number? >>>>> >>>>> for the leds-gpio.c in the driver/leds folder and the device tree bindings >>>>> for this driver .Can some one point out to me where in Linux kernel it is? >>>>> >>>>> Also why below line has been used.Is it mandatory? >>>>> ... >>>>> .of_match_table = of_gpio_leds_match, >>>>> >>>>> >>>>> This is needed when you are using device tree for getting the board settings >>>>> but you can also do the same without this as well. Read up on device tree in >>>>> kernel Documentation folder. >>>>> >>>>> }, >>>>> >>>>> thanks in advance , >>>>> Rp >>>>> >>>>> _______________________________________________ >>>>> Kernelnewbies mailing list >>>>> Kernelnewbies(a)kernelnewbies.org >>>>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>>>> >>>>> >>>>> _______________________________________________ >>>>> Kernelnewbies mailing list >>>>> Kernelnewbies(a)kernelnewbies.org >>>>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>>>>

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