Configuring LCD_DATA to GPIO2

Mangai M

Prodigy 20 points

Other Parts Discussed in Thread: TMDXEVM3358

I am trying to configure LCD_DATA to GPIO2 (LCD_DATA0 to GPIO2_6)

I have tried two methods

Method 1:

1. Using mmap configured LCD_DATA pins to GPIO using PAD Configuration.

2. Configured GPIO2_OE,GPIO2_DATAOUT using the same procedure.

Method 2:

1. Using Pin mux Utility configured LCD_DATA0 to GPIO2_6.The Pinmux.h file reads MUX_VAL(CONTROL_PADCONF_LCD_DATA0, (IEN | OFF | MODE7 ) ) /* GPIO2[6] */

2.Built the bootloader as per the pin mux utility guide.

3.Rebuilt the kernel with GPIO support.

With both the methods I am able to write into GPIO2_DATAOUT but I cannot see the output on the pin. We are using TMDXEVM3358 board and have tapped LCD_DATA0 pin on J6.

Kindly help me in solving this problem. Sample code for writing into GPIO2_6 and seeing it on LCD_DATA0 will be of great help.

over 12 years ago

0 Arturs Elksnis over 12 years ago

Intellectual 715 points

Have you seen this:

http://omappedia.org/wiki/GPIO

especially the "FAQ" part.

It worked for me.

0 Anil over 12 years ago

TI__Expert 6655 points

Hi Mangai,

These are the basic steps to toggle the GPIO line

Pinmux:-

Do pinmux configurations accordingly, follow the steps from psp user guide

http://processors.wiki.ti.com/index.php/AM335x_PSP_User%27s_Guide#Modifying_Pin_Mux_settings

Make sure that no other portion of the code modify the same pin. By using debugfs pinmux entries we can identify which pins are used for which purpose.

$ cat /sys/kernel/debug/omap_mux/lcd_data0
name: lcd_data0.lcd_data0 (0x44e108a0/0x8a0 = 0x0008), b NA, t NA
mode: OMAP_MUX_MODE0 | AM33XX_PULL_DISA
signals: lcd_data0 | gpmc_a0 | NA | NA | NA | NA | NA | gpio2_6

Method1:- Toggle GPIO pin (u-boot level)

GPIO Example:- Set gpio6 pin to high

Set GPIO value:

gpio_reg_val = (1 << 6); /* for GPIO70 */
writel(gpio_reg_val, GPIO2_BASE + 0x194);

Set GPIO direction:

gpio_reg_val = readl(GPIO2_BASE + 0x134);
gpio_reg_val &= ~(1 << 6);
writel(gpio_reg_val, GPIO2_BASE + 0x134);

Method2 & 3:- Toggle GPIO pin

http://processors.wiki.ti.com/index.php/GPIO_Driver_Guide#Driver_Usage

Note: Go through full details provided in each sections of the user guides.

Regards

AnilKumar

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Configuring LCD_DATA to GPIO2