topic Adding GPIO support in i.MX Processors

Adding GPIO support

divyardharan — Tue, 06 Jan 2015 04:16:35 GMT

Hi All,

I am using imx6Q Sabre SD board,

I am a beginner in this.

I wants to implement GPIO support in U-Boot.

Plz advice me from where to start.

Regards

Divya

Re: Adding GPIO support

saurabh206 — Tue, 06 Jan 2015 04:20:42 GMT

Divya

You need to first setup PAD for GPIO.

Than you can use gpio_direction_output or gpio_direction_input according to your GPIO functionality.

I hope this helps.

Thanks

Saurabh

Re: Adding GPIO support

divyardharan — Tue, 06 Jan 2015 04:32:54 GMT

Hi Saurabh,

Thanks for your quick reply.

As I mentioned in the earlier message ,am a beginner in this.

So could you plz provide any helpful link or note on how to set up all these PAD and how I can use gpio_direction_output or gpio_direction_input .

Regards

Divya

Re: Adding GPIO support

saurabh206 — Tue, 06 Jan 2015 04:44:01 GMT

Divya

uboot-imx\board\freescale\mx6q_sabreauto\mx6q_sabreauto.c

GPIO can be configured in input or output according to our requirement.

Suppose if I want to control LED using GPIO than I need to setup gpio_direction_output.

Thanks

Saurabh

Re: Adding GPIO support

divyardharan — Tue, 06 Jan 2015 05:07:03 GMT

Hi Saurabh,

Thanks for your quick reply.

I found the file mx6q_sabreauto.c.In that file there is no method named gpio_direction_output or gpio_direction_input .

Only i could found below code snippet

#ifdef CONFIG_I2C_MXC

if (!mx6_board_is_reva()) {

mxc_iomux_v3_setup_multiple_pads(gpio_pads,

ARRAY_SIZE(gpio_pads));

gpio_direction_output(I2C_EXP_RST, 1);

gpio_direction_output(I2C3_STEER, 1);

}

setup_i2c(CONFIG_SYS_I2C_PORT);

/* Enable lvds power */

setup_lvds_poweron();

/* restore path for weim/spi nor */

if (!mx6_board_is_reva())

gpio_direction_output(I2C3_STEER, 0);

#endif

void udc_pins_setting(void)

{

mxc_iomux_v3_setup_pad(MX6X_IOMUX(PAD_ENET_RX_ER__ANATOP_USBOTG_ID));

/* USB_OTG_PWR = 0 */

gpio_direction_output(SABREAUTO_USB_OTG_PWR, 0);

/* USB_H1_POWER = 1 */

gpio_direction_output(SABREAUTO_USB_HOST1_PWR, 1);

mxc_iomux_set_gpr_register(1, 13, 1, 0);

}

if I want to control LED using GPIO then how will i setup gpio_direction_output.

Regards

Divya

Re: Adding GPIO support

saurabh206 — Tue, 06 Jan 2015 05:10:48 GMT

If gpio_direction_output(SABREAUTO_USB_OTG_PWR, 0); mean SABREAUTO_USB_OTG_PWR GPIO set to Low.

And gpio_direction_output(SABREAUTO_USB_OTG_PWR, 1) mean SABREAUTO_USB_OTG_PWR GPIO set to High.

Same way you can set your GPIO.

Re: Adding GPIO support

jayaramks — Tue, 06 Jan 2015 09:49:26 GMT

As Saurabh said, you can configure GPIOs using:

gpio_direction_output(IMX_GPIO_NR((bank,number), 0));

gpio_direction_output(IMX_GPIO_NR((bank,number), 1));

gpio_direction_output is defined in u-boot\drivers\gpio\mxc_gpio.c

Regards,

Jayaram