update readme file

README.md

@@ -1 +1,65 @@
 #seeed-voicecard
+
+Firstly, get an updated kernel 4.9 :
+```
+sudo apt update
+sudo apt dist-upgrade
+sudo apt install git rpi-update bc dkms
+sudo BRANCH=next rpi-update
+sudo reboot
+```
+
+Install matching kernel header files:
+eg. Get your kernel verson "uname -r", then
+```
+wget  https://www.niksula.hut.fi/~mhiienka/Rpi/linux-headers-rpi/linux-headers-4.9.13-v7%2B_4.9.13-v7%2B-2_armhf.deb 
+```
+Next, while the upstream wm8960 codec is not currently supported by current Pi kernel builds, upstream wm8960 has some bugs, we had fixed it. we must it build manually.
+
+Get the seeed voice card source code.
+```
+git clone http://git.oschina.net/seeed-se/seeed-voicecard
+cd seeed-voicecard
+sudo  make all install
+```
+Next, copy then voice card overlay to boot dir, then apply it.
+```
+sudo cp seeed-voicecard.dtbo /boot/overlays
+sudo reboot
+sudo modprobe  wm8960
+sudo dtoverlay seeed-voicecard
+```
+Check that the sound card name matches the source code seeed-voicecard.
+
+```
+pi@raspberrypi:~/seeed-voicecard$ aplay -l
+**** List of PLAYBACK Hardware Devices ****
+card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
+  Subdevices: 8/8
+  Subdevice #0: subdevice #0
+  Subdevice #1: subdevice #1
+  Subdevice #2: subdevice #2
+  Subdevice #3: subdevice #3
+  Subdevice #4: subdevice #4
+  Subdevice #5: subdevice #5
+  Subdevice #6: subdevice #6
+  Subdevice #7: subdevice #7
+card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 1: seeedvoicecard [seeed-voicecard], device 0: bcm2835-i2s-wm8960-hifi wm8960-hifi-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+pi@raspberrypi:~/seeed-voicecard$ 
+```
+Next apply the alsa controls setting
+```
+alsactl --file ./asound.state restore
+```
+
+Test:
+``` 
+arecord -f cd -Dhw:1 | aplay -Dhw:1
+
+```
+Enjoy !