DART-SD410 Android Examples
This WIKI describes how to use some simple peripheral devices available on VAR-DT410CustomBoard.
Using User LED1
User LED1 (D6) connected to GPIO21 of the CPU. The LED1 is defined in the apq8016-var-dt410.dtsi file under gpio-leds section.
general1 {
gpios = <&msm_gpio 21 0>;
label = "led1";
linux,default-trigger = "none";
default-state = "off";
retain-state-suspended;
};
You can access the LED device via serial console by:
$ su # cd /sys/class/leds/led1 # echo 1 > brightness Writing any value other then 0 will turn the led on # echo 0 > brightness The led will turn off
You can view available triggers by typing:
# cat trigger The output will be: [none] boot-indication usb-online mmc0 mmc1 battery-charging-or-full battery-charging battery-full battery-charging-blink-full-solid wlan-indication-led
Set the trigger to mmc0 device by typing:
# echo mmc0 > trigger
Test it by reading mmc0 device:
# dd if=/dev/block/mmcblk0 of=/dev/null bs=128 count=1000000
Using GPIO
User LED2 (D9) connected to GPIO120 of the CPU. The LED1 is not defined in the apq8016-var-dt410.dtsi file under gpio-leds section.
This allow user acces to this LED as GPIO device.
To change the state of the LED via serial console type:
$ su # cd /sys/class/gpio # echo 1022 > export This line creates a new directory gpio1022 The number 1022 calculated as 120 + 902. 120 is the GPIO number, 902 is static offset for CPU gpio. So changing any other GPIO will lead to 902 + GPIO number. # cd gpio1022 # echo out > direction # echo 1 > value The led will turn on #echo 0 > value The led will turn off
To read the current state type:
# cat value The output will be 0
You can change active state to active low.
# echo 1 > active_low # echo 0 > value The led is active low, writing 0 will turn on the led. # echo 1 > value The led is active low, writing 1 will turn off the led.
To see all allocated GPIOs in the system type:
# cat /sys/kernel/debug/gpio The output will be: GPIOs 577-608, platform/qcom,smp2pgpio-ssr-smp2p-4-out.19, master-kernel: GPIOs 609-640, platform/qcom,smp2pgpio-ssr-smp2p-4-in.18, slave-kernel: GPIOs 641-672, platform/qcom,smp2pgpio-ssr-smp2p-1-out.13, master-kernel: GPIOs 673-704, platform/qcom,smp2pgpio-ssr-smp2p-1-in.12, slave-kernel: GPIOs 705-736, platform/qcom,smp2pgpio-smp2p-4-out.16, smp2p: GPIOs 737-768, platform/qcom,smp2pgpio-smp2p-4-in.14, smp2p: GPIOs 769-800, platform/qcom,smp2pgpio-smp2p-1-out.10, smp2p: GPIOs 801-832, platform/qcom,smp2pgpio-smp2p-1-in.8, smp2p: GPIOs 833-864, platform/qcom,smp2pgpio-smp2p-7-out.6, smp2p: GPIOs 865-896, platform/qcom,smp2pgpio-smp2p-7-in.4, smp2p: GPIOs 897-900, spmi/qpnp-pin-ffffffc0319b4c00, pm8916-gpio: gpio-899 (qcom,hub-reset-gpio ) out hi gpio-900 (qcom,sw-sel-gpio ) in lo GPIOs 901-901, spmi/qpnp-pin-ffffffc0319b4800, pm8916-mpp: GPIOs 902-1023, platform/1000000.pinctrl, msm_tlmm_gpio: gpio-914 (ft5x06_reset_gpio ) out hi gpio-915 (ft5x06_irq_gpio ) in hi gpio-922 (adv7533_hpd_irq_gpio) in lo gpio-923 (led1 ) out lo gpio-933 (adv7533_irq_gpio ) in hi gpio-934 (disp_rst_n ) in hi gpio-940 (7864900.sdhci cd ) in lo gpio-1009 (volume_up ) in hi gpio-1010 (home ) in hi gpio-1011 (back ) in hi gpio-1022 (sysfs ) out lo gpio-1023 (USB_ID_GPIO ) in hi
From this table you can see that offsets are:
- CPU gpio is 902
- PMIC gpio is 897
- PMIC mpp is 901