[话题]

【NanoPC-T4试用体验】2、点亮一盏LED

jackeyt

2018-10-15 10:17:11 5248

本帖最后由 jackeyt 于 2018-10-17 23:31 编辑

本系列帖子是为试用Nano PC T4开发板的帖子连载篇，以下为目录：

【NanoPC-T4试用体验】1、Nano PC T4开箱上电
【NanoPC-T4试用体验】2、点亮一盏LED

前面提到，RK3399是一个性能比较强大的CPU，所以其他在程序开发过程中，也为我们提供了极大的便捷，下面就是脑洞大开的做法，使用RK3399给自己编译内核，代码，以及开发程序的过程。

一、首先，先来检查下编译工具链：

gcc -v

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结果如下：

gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/aarch64-linux-gnu/7/lto-wrapper
Target: aarch64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 7.3.0-16ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --with-as=/usr/bin/aarch64-linux-gnu-as --with-ld=/usr/bin/aarch64-linux-gnu-ld --program-suffix=-7 --program-prefix=aarch64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libquadmath --disable-libquadmath-support --enable-plugin --enable-default-pie --with-system-zlib --enable-multiarch --enable-fix-cortex-a53-843419 --disable-werror --enable-checking=release --build=aarch64-linux-gnu --host=aarch64-linux-gnu --target=aarch64-linux-gnu
Thread model: posix
gcc version 7.3.0 (Ubuntu/Linaro 7.3.0-16ubuntu3)

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可以发现其实板子上的gcc就是对应于：aarch64-linux-gnu-gcc

root@NanoPC-T4:~# aarch64-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=aarch64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/aarch64-linux-gnu/7/lto-wrapper
Target: aarch64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 7.3.0-16ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --with-as=/usr/bin/aarch64-linux-gnu-as --with-ld=/usr/bin/aarch64-linux-gnu-ld --program-suffix=-7 --program-prefix=aarch64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libquadmath --disable-libquadmath-support --enable-plugin --enable-default-pie --with-system-zlib --enable-multiarch --enable-fix-cortex-a53-843419 --disable-werror --enable-checking=release --build=aarch64-linux-gnu --host=aarch64-linux-gnu --target=aarch64-linux-gnu
Thread model: posix
gcc version 7.3.0 (Ubuntu/Linaro 7.3.0-16ubuntu3)

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二、编译RK3399 Linux内核

首先安装git工具等(我刷入的FriendlyDesktop里面已经有了)：

sudo apt-get install git liblz4-tool

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接下来，下载友善提供的T4 3399的内核代码：

git clone https://github.com/friendlyARM/kernel-rockchip --depth 1 -b nanopi4-linux-v4.4.y

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切换目录：

cd kernel-rockchip

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配置：

make ARCH=arm64 nanopi4_linux_defconfig

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编译：

make ARCH=arm64 CROSS_COMPILE＝aarch64-linux-gnu- nanopi4-images

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   （简选）编译过程如下：
  root@NanoPC-T4:/home/pi/t4_develop/t4_kernel# make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- nanopi4-images -j12
  CC    crypto/crc32.mod.o
  CC    crypto/cts.mod.o
  CC    crypto/michael_mic.mod.o
  CC    crypto/xor.mod.o
  CC    crypto/xts.mod.o
  CC    drivers/i2c/busses/i2c-cros-ec-tunnel.mod.o
  CC    drivers/gpu/arm/mali400/mali/mali.mod.o
  CC    drivers/input/keyboard/cros_ec_keyb.mod.o
  CC    drivers/input/touchscreen/elants_i2c.mod.o
  CC    drivers/input/mouse/cyapatp.mod.o
  CC    drivers/input/touchscreen/atmel_mxt_ts.mod.o
  CC    drivers/input/mouse/elan_i2c.mod.o
  CC    drivers/input/touchscreen/u***touchscreen.mod.o
  CC    drivers/mfd/cros_ec.mod.o
  CC    drivers/mfd/cros_ec_spi.mod.o
  CC    drivers/net/ppp/bsd_comp.mod.o
  CC    drivers/net/ppp/ppp_async.mod.o
  CC    drivers/net/ppp/ppp_deflate.mod.o
  CC    drivers/net/ppp/ppp_mppe.mod.o
  CC    drivers/net/ppp/ppp_synctty.mod.o
  CC    drivers/net/ppp/pppoe.mod.o
  CC    drivers/net/ppp/pppolac.mod.o
  CC    drivers/net/ppp/pppopns.mod.o
  CC    drivers/net/ppp/pppox.mod.o
  CC    drivers/net/u***/r8152.mod.o
  CC    drivers/net/u***/rtl8150.mod.o
  CC    drivers/net/wireless/at76c50x-u***.mod.o
  CC    drivers/net/wireless/brcm80211/brcmfmac/brcmfmac.mod.o
  CC    drivers/net/wireless/hostap/hostap.mod.o
  CC    drivers/net/wireless/brcm80211/brcmutil/brcmutil.mod.o
  CC    drivers/net/wireless/libertas_tf/libertas_tf.mod.o
  CC    drivers/net/wireless/mediatek/mt7601u/mt7601u.mod.o
  CC    drivers/net/wireless/mwifiex/mwifiex.mod.o
  CC    drivers/net/wireless/mwifiex/mwifiex_sdio.mod.o
  CC    drivers/net/wireless/p54/p54common.mod.o
  CC    drivers/net/wireless/p54/p54u***.mod.o
  CC    drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.mod.o
  CC    drivers/net/wireless/rndis_wlan.mod.o
  CC    drivers/net/wireless/rockchip_wlan/rtl8188eu/8188eu.mod.o
  CC    drivers/net/wireless/rt2x00/rt2500u***.mod.o
  CC    drivers/net/wireless/rt2x00/rt2800lib.mod.o
  CC    drivers/net/wireless/rt2x00/rt2800u***.mod.o
  CC    drivers/net/wireless/rt2x00/rt2x00lib.mod.o
  CC    drivers/net/wireless/rt2x00/rt2x00u***.mod.o
  CC    drivers/net/wireless/rt2x00/rt73u***.mod.o
  CC    drivers/net/wireless/zd1201.mod.o
  CC    drivers/net/wireless/zd1211rw/zd1211rw.mod.o
  CC    fs/btrfs/btrfs.mod.o
  CC    fs/cifs/cifs.mod.o
  CC    fs/crypto/fscrypto.mod.o
  CC    fs/f2fs/f2fs.mod.o
  CC    fs/nfsd/nfsd.mod.o
  CC    fs/ntfs/ntfs.mod.o
  CC    fs/xfs/xfs.mod.o
  CC    lib/raid6/raid6_pq.mod.o
  CC    lib/zlib_deflate/zlib_deflate.mod.o
  CC    net/sunrpc/auth_gss/rpcsec_gss_krb5.mod.o
  CC    net/wireless/lib80211.mod.o
  CC    net/wireless/lib80211_crypt_ccmp.mod.o
  CC    net/wireless/lib80211_crypt_tkip.mod.o
  CC    net/wireless/lib80211_crypt_wep.mod.o
  CC    security/keys/encrypted-keys/encrypted-keys.mod.o
  CC    sound/core/seq/snd-seq-midi-event.mod.o
  CC    sound/core/seq/snd-seq-midi.mod.o
  CC    sound/core/snd-hwdep.mod.o
  CC    sound/core/snd-rawmidi.mod.o
  CC    sound/soc/codecs/snd-soc-es8316.mod.o
  CC    sound/soc/codecs/snd-soc-max98090.mod.o
  CC    sound/soc/codecs/snd-soc-rk3308.mod.o
  CC    sound/soc/codecs/snd-soc-rk3328.mod.o
  CC    sound/soc/codecs/snd-soc-rk817.mod.o
  CC    sound/soc/codecs/snd-soc-rt5616.mod.o
  CC    sound/soc/rockchip/snd-soc-rockchip-max98090.mod.o
  CC    sound/u***/6fire/snd-u***-6fire.mod.o
  CC    sound/u***/caiaq/snd-u***-caiaq.mod.o
  CC    sound/u***/hiface/snd-u***-hiface.mod.o
  CC    sound/u***/misc/snd-ua101.mod.o
  CC    sound/u***/snd-u***-audio.mod.o
  CC    sound/u***/snd-u***midi-lib.mod.o
  LD [M]  crypto/crc32.ko
  LD [M]  crypto/cts.ko
  LD [M]  crypto/michael_mic.ko
  LD [M]  crypto/xts.ko
  LD [M]  crypto/xor.ko
  LD [M]  drivers/gpu/arm/mali400/mali/mali.ko
  LD [M]  drivers/i2c/busses/i2c-cros-ec-tunnel.ko
  LD [M]  drivers/input/keyboard/cros_ec_keyb.ko
  LD [M]  drivers/input/mouse/elan_i2c.ko
  LD [M]  drivers/input/mouse/cyapatp.ko
  LD [M]  drivers/input/touchscreen/atmel_mxt_ts.ko
  LD [M]  drivers/input/touchscreen/elants_i2c.ko
  LD [M]  drivers/input/touchscreen/u***touchscreen.ko
  LD [M]  drivers/mfd/cros_ec_spi.ko
  LD [M]  drivers/mfd/cros_ec.ko
  LD [M]  drivers/net/ppp/bsd_comp.ko
  LD [M]  drivers/net/ppp/ppp_async.ko
  LD [M]  drivers/net/ppp/ppp_deflate.ko
  LD [M]  drivers/net/ppp/ppp_mppe.ko
  LD [M]  drivers/net/ppp/ppp_synctty.ko
  LD [M]  drivers/net/ppp/pppoe.ko
  LD [M]  drivers/net/ppp/pppolac.ko
  LD [M]  drivers/net/ppp/pppopns.ko
  LD [M]  drivers/net/ppp/pppox.ko
  LD [M]  drivers/net/u***/r8152.ko
  LD [M]  drivers/net/u***/rtl8150.ko
  LD [M]  drivers/net/wireless/at76c50x-u***.ko
  LD [M]  drivers/net/wireless/brcm80211/brcmfmac/brcmfmac.ko
  LD [M]  drivers/net/wireless/brcm80211/brcmutil/brcmutil.ko
  LD [M]  drivers/net/wireless/hostap/hostap.ko
  LD [M]  drivers/net/wireless/libertas_tf/libertas_tf.ko
  LD [M]  drivers/net/wireless/mediatek/mt7601u/mt7601u.ko
  LD [M]  drivers/net/wireless/mwifiex/mwifiex.ko
  LD [M]  drivers/net/wireless/mwifiex/mwifiex_sdio.ko
  LD [M]  drivers/net/wireless/p54/p54common.ko
  LD [M]  drivers/net/wireless/p54/p54u***.ko
  LD [M]  drivers/net/wireless/rndis_wlan.ko
  LD [M]  drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.ko
  LD [M]  drivers/net/wireless/rockchip_wlan/rtl8188eu/8188eu.ko
  LD [M]  drivers/net/wireless/rt2x00/rt2500u***.ko
  LD [M]  drivers/net/wireless/rt2x00/rt2800lib.ko
  LD [M]  drivers/net/wireless/rt2x00/rt2800u***.ko
  LD [M]  drivers/net/wireless/rt2x00/rt2x00lib.ko
  LD [M]  drivers/net/wireless/rt2x00/rt2x00u***.ko
  LD [M]  drivers/net/wireless/rt2x00/rt73u***.ko
  LD [M]  drivers/net/wireless/zd1201.ko
  LD [M]  drivers/net/wireless/zd1211rw/zd1211rw.ko
  LD [M]  fs/btrfs/btrfs.ko
  LD [M]  fs/cifs/cifs.ko
  LD [M]  fs/crypto/fscrypto.ko
  LD [M]  fs/nfsd/nfsd.ko
  LD [M]  fs/f2fs/f2fs.ko
  LD [M]  fs/ntfs/ntfs.ko
  LD [M]  fs/xfs/xfs.ko
  LD [M]  lib/zlib_deflate/zlib_deflate.ko
  LD [M]  lib/raid6/raid6_pq.ko
  LD [M]  net/sunrpc/auth_gss/rpcsec_gss_krb5.ko
  LD [M]  net/wireless/lib80211.ko
  LD [M]  net/wireless/lib80211_crypt_ccmp.ko
  LD [M]  net/wireless/lib80211_crypt_tkip.ko
  LD [M]  security/keys/encrypted-keys/encrypted-keys.ko
  LD [M]  net/wireless/lib80211_crypt_wep.ko
  LD [M]  sound/core/seq/snd-seq-midi-event.ko
  LD [M]  sound/core/seq/snd-seq-midi.ko
  LD [M]  sound/core/snd-hwdep.ko
  LD [M]  sound/core/snd-rawmidi.ko
  LD [M]  sound/soc/codecs/snd-soc-rk3308.ko
  LD [M]  sound/soc/codecs/snd-soc-es8316.ko
  LD [M]  sound/soc/codecs/snd-soc-max98090.ko
  LD [M]  sound/soc/codecs/snd-soc-rk3328.ko
  LD [M]  sound/soc/codecs/snd-soc-rk817.ko
  LD [M]  sound/soc/codecs/snd-soc-rt5616.ko
  LD [M]  sound/soc/rockchip/snd-soc-rockchip-max98090.ko
  LD [M]  sound/u***/6fire/snd-u***-6fire.ko
  LD [M]  sound/u***/caiaq/snd-u***-caiaq.ko
  LD [M]  sound/u***/hiface/snd-u***-hiface.ko
  LD [M]  sound/u***/snd-u***midi-lib.ko
  LD [M]  sound/u***/misc/snd-ua101.ko
  LD [M]  sound/u***/snd-u***-audio.ko
  Pack to resource.img successed!
  Image:  resource.img (with rockchip/rk3399-nanopi4-rev*.dtb logo.bmp logo_kernel.bmp) is ready

从最后的输出语句里面可以看出，resource.img打包成功了，是由设备树、logo.bmp logo_kernel.bmp组成的，所以这个resource.img是接下来开发所必要的，因为我们修改的设备树等信息就是从这里面打包的。

二、点亮LED

2.1、硬件准备

   首先，我们通过友善的WIKI 资料，确认有哪些可以使用的你GPIO口，这里我们随便取个IO口：GPIO1_A0(3V)
   将该IO口接上，LED与一个限流电阻，串接到地。
   其次，我们需要来编写我们的设备树节点。
   我们可以参考板子运行的例子：

leds: gpio-leds {

            compatible = "gpio-leds";

            pinctrl-names = "default";

            pinctrl-0 =<&leds_gpio>;

            led@1 {

                     gpios = <&gpio0 13 GPIO_ACTIVE_HIGH>;

                     label = "status_led1";

                     linux,default-trigger = "heartbeat";

                     linux,default-trigger-delay-ms = <0>;

            };

      };gpio-leds {

  leds_gpio: leds-gpio {

rockchip,pins = <0 13 RK_FUNC_GPIO &pcfg_pull_none>;

  };

};
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我们明白，设备树的语法是一种十分自然，附合人类阅读习惯的一种语法，因此，我们可以看到，参考中的例子中的LED是接到了GPIO0 13,我们通过原理图可以发现：硬件上该LED是接到了：GPIO0_B5， 如下图所示：

那么，GPIO0_B5是如何转换成了GPIO0 13呢？我们可以通过datasheet发现：

B5对应为GPIO0组中的第13个位置（从0开始编号）。

那么，对应于我们上面所选的：GPIO1_A0(3V) 那就对应为gpio1 0

那因此，我们的设备树节点可参考上面所说的，写成如下：

myleds: mygpio-leds {
            compatible = "mygpio-leds";
            pinctrl-names = "default";
            pinctrl-0 =<&myleds_gpio>;

            led@1 {
                     gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
                     label = "my_led";
                     linux,default-trigger = "heartbeat";
                     linux,default-trigger-delay-ms = <0>;
            };
      };
mygpio-leds {
            myleds_gpio: myleds-gpio {
                     rockchip,pins = <1 0 RK_FUNC_GPIO &pcfg_pull_none>;
            };
      };

将上述的设备树信息写入后，编译：

make ARCH=arm64 CROSS_COMPILE＝aarch64-linux-gnu- nanopi4-images
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得到：resource.img
现可以利用量产更新工具进行更新，首先要保障板子进入loader模式，插上type C线：

更新成功之后，系统重启，我们可以利用调试信息，确保设备树已经正常修改了！如下图所示：


可以看到，我们已经可以将我们的写的设备树信息写入到了系统中！接下来，就需要我们写代码去实现了！