how to set gpio in am335x linux kernel?

jery0711 jery

Hi everyone:

i want to set gpio3_21 to output with high in kernel. but i don't know how to do it. whether anyone can give me a example? i used am335x_evm 05.05 sdk.

{"mcasp0_ahclkx.gpio3_21", OMAP_MUX_MODE7 | AM33XX_PIN_OUTPUT},this is the pin i initialized. i tracked it found it just wrote to 0x9ac(reg offset) with 7.

[    0.976287] muxmode=7
[    0.978698] partitionname=core
[    0.981903] partitionflag=0
[    0.984893] partitionbase=f9e10000
[    0.988464] muxregoffset=2476(0x9ac)

over 12 years ago

0 Sandhya Satyanarayana over 12 years ago

TI__Intellectual 1165 points

Hi,

Please refer

http://processors.wiki.ti.com/index.php/Sitara_GPIO_Driver_User_Guide

Regards

Sandhya

0 Miroslav Kiradzhiyski XID over 12 years ago

TI__Mastermind 25235 points

Hi Jery,

Please read the <linux_folder>/Documentation/gpio.txt for more information on how to use the GPIO interface.

This is an excerpt from the document:

/* GPIO OUTPUT */
void gpio_set_value(unsigned gpio, int value);

You can use the GPIO_TO_PIN built-in macro to get the gpio pin number:

/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))

Depending on the platform you are using (GP EVM, Starter Kit or BeagleBone) the initialization happens in different functions. For the GP EVM it is in the setup_general_purpose_evm() function. You can put your code inside it.

Best regards,
Miroslav

0 jery0711 jery over 12 years ago in reply to Miroslav Kiradzhiyski XID

Intellectual 340 points

Hi Sandhya , Miroslav

Thank you very much, i solved the problem.

Best regards.

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how to set gpio in am335x linux kernel?