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{{Message/Information Message|title=TITLE|message=This How-To was tested under Kernel 2.6.35.y but content are valid for Kernel 2.6.37.y}}
= Overview =
This How-To is meant to be a starting point for people to learn to set up UART2 for IGEPv2 J990 connector as quickly and easily as possible. In this how-to, we use [http://releases.linaro.org/platform/linaro-m/headless/final/linaro-m-headless-tar-20101108-2.tar.gz Linaro Headless] with [[Linux Kernel 2.6.35.y|Kernel 2.6.35.y]]. This How-To is focused for revisions RC1/RC3/RC4/RC6 (WIFI/BT versions). <br>
More information about UART: [http://en.wikipedia.org/wiki/UART UARTUniversal_asynchronous_receiver/transmitter <span style="text-decoration: underline;">here</span>] and [[How to use UARTs|here]].'''<br>'''
There are two three modes to configure UART2 in J990: via user space (fast modefirst way), editing only igep.ini (second way) or editing kernel source and compile it (slow modethird way). '''NOTE: '''UART2 in j990 connector has CMOS voltages (0V-1V8).
= Feedback and Contributing =
At any point, if you see a mistake you can contribute to this How-To.<br> = First way<br> = First way: this mode has an issue, when your system reboot or shutdown you will need to configure again. Using user space to configure mux and disable bluetooth.<br>
=== Configure IGEP ===
Logging with root user via SSH or Serial cable.<br> '''Disable BluethootNOTE:''' Poky distribution does not have debug filesystem enabled. Mount it: <pre>mount -t debugfs none /sys/kernel/debug</pre> Go to /sys/kernel/debug/omap_mux/<br>
Set sdmmc2_dat5 to GPIO137 gpio137 (mode(4):
<pre>echo 0x004 > sdmmc2_dat5 </pre>
<pre>root@localhost:/sys/kernel/debug/omap_mux# cat sdmmc2_dat5
name: sdmmc2_dat5.gpio_137 (0x48002166/0x136 = 0x0004), b ah3, t NA
signals: sdmmc2_dat5 | sdmmc2_dir_dat1 | cam_global_reset | sdmmc3_dat1 | gpio_137 | hsusb3_tll_stp | mm3_rxdp | safe_mode
</pre>
Go to: /sys/class/gpio/
export gpio137 gpio138 gpio139 gpio170 gpio64 gpiochip0 gpiochip128 gpiochip160 gpiochip192 gpiochip32 gpiochip64 gpiochip96 unexport
root@localhost:/sys/class/gpio#
</pre>
If you don't have it, you should export gpio137: <br>
<pre>echo 137 > /sys/class/gpio/export </pre>
Set gpio137 to low value to disable bluetooth:
<pre>echo 0 > /sys/class/gpio/gpio137/value</pre>
Revise that:
<pre>root@localhost:/sys/class/gpio# cat /sys/class/gpio/gpio137/value
0
root@localhost:/sys/class/gpio#
</pre>
'''Disable Bluetooth UART2 wires:'''
Go to /sys/kernel/debug/omap_mux/
Type:
<pre>echo 0x007 > uart2_cts
echo 0x007 > uart2_rts
echo 0x007 > uart2_rx
echo 0x007 > uart2_tx </pre>
Revise that:
<pre>root@localhost:/sys/kernel/debug/omap_mux# cat uart2_cts
name: uart2_cts.safe_mode (0x48002174/0x144 = 0x0007), b ab26, t NA
mode: OMAP_PIN_OUTPUT | OMAP_MUX_MODE7
signals: uart2_cts | mcbsp3_dx | gpt9_pwm_evt | NA | gpio_144 | NA | NA | safe_mode
root@localhost:/sys/kernel/debug/omap_mux# cat uart2_rts
name: uart2_rts.safe_mode (0x48002176/0x146 = 0x0007), b ab25, t NA
mode: OMAP_PIN_OUTPUT | OMAP_MUX_MODE7
signals: uart2_rts | mcbsp3_dr | gpt10_pwm_evt | NA | gpio_145 | NA | NA | safe_mode
root@localhost:/sys/kernel/debug/omap_mux# cat uart2_rx
name: uart2_rx.safe_mode (0x4800217a/0x14a = 0x0007), b ad25, t NA
mode: OMAP_PIN_OUTPUT | OMAP_MUX_MODE7
signals: uart2_rx | mcbsp3_fsx | gpt8_pwm_evt | NA | gpio_147 | NA | NA | safe_mode
root@localhost:/sys/kernel/debug/omap_mux# cat uart2_tx
name: uart2_tx.safe_mode (0x48002178/0x148 = 0x0007), b aa25, t NA
mode: OMAP_PIN_OUTPUT | OMAP_MUX_MODE7
signals: uart2_tx | mcbsp3_clkx | gpt11_pwm_evt | NA | gpio_146 | NA | NA | safe_mode
root@localhost:/sys/kernel/debug/omap_mux#
</pre>