From mboxrd@z Thu Jan 1 00:00:00 1970 From: raulpblooper@gmail.com (Raul Piper) Date: Thu, 28 Jul 2016 17:00:05 +0530 Subject: gpio-led driver In-Reply-To: <57922F36.3010505@samsung.com> References: <57906E60.6060703@samsung.com> <57922F36.3010505@samsung.com> Message-ID: To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- kirkwood-ns2.dtb This compiles fine.I was trying to compile only the "leds-ns2.dts" file, not knowing the actual dtb was kirkwood-ns2.dtb .Thanks !! This means I cant compile directly the files inside the Documentation/bindings/leds/ .They have to be associated as some node with some boards first . On Fri, Jul 22, 2016 at 8:05 PM, Jacek Anaszewski wrote: > On 07/22/2016 12:10 PM, Raul Piper wrote: >> >> On Thu, Jul 21, 2016 at 12:10 PM, Jacek Anaszewski >> wrote: >>> >>> Hi Raul, >>> >>> On 07/20/2016 01:17 PM, Raul Piper wrote: >>>> >>>> >>>> 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? >>> >>> >>> >>> What do you mean by part number? This is generic driver for LEDs >>> connected directly to a GPIO. >> >> >> Understood,I thought there is some specific part number of the led >> like all other led drivers in the same folder. >> >>> You can find DT documentation for it in the following location: >>> >>> Documentation/devicetree/bindings/leds/leds-gpio.txt >>> >> >> I tried compiling the sample dts file(leds-ns2.dts) using the dtc >> compiler . >> >> dtc -I dts -O dtb -o leds-ns2.dtb leds-ns2.dts >> >> but I am getting this error : >> >> DTC: dts->dtb on file "leds-ns2.dts" >> Error: leds-ns2.dts:1.1-2 syntax error >> FATAL ERROR: Unable to parse input tree > > > One minute of googling gives the answer: > > You can use the Makefile provided with the kernel: > > e.g. > > make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- kirkwood-ns2.dtb > > Make sure that CROSS_COMPILE matches your toolchain prefix. > >> Once it starts compiling fine I will modify it according to my >> driver.Can I build the dtb and load it the way I load the kernel >> driver.Do I have to do it before or after the insmod ? > > > dtb is required to properly boot the system. It must be appended to the > kernel image. You have to acquire some knowledge about bootloader > present on your board and at what address it expects DT blob. > > You can ask for details e.g. on linux-arm-kernel at lists.infradead.org > or try to search the Internet. > >> Right now I dont want to build dts as well as driver as a whole kernel >> and building it as a loadable module. >> Thanks in advance > > > > -- > Best regards, > Jacek Anaszewski