Hi,
I'm having a problem with getting and freeing GPIOs. Please have a look at
this simple module:
-----------------------------8<--------------------------------
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/gpio.h>
#define DRV_NAME "GPIO Test"
#define PFX DRV_NAME ": "
#define GPIO_TEST_PIN 12
static int __init mymodule_init(void) {
int err;
printk (KERN_INFO PFX "requesting GPIO %d\n", GPIO_TEST_PIN);
err = gpio_request(GPIO_TEST_PIN, "GPIO TEST");
if (err ) {
printk (KERN_ERR PFX "didn't get %d\n", GPIO_TEST_PIN);
return -1;
}
return 0;
}
static void __exit mymodule_exit(void) {
printk (KERN_INFO PFX "freeing GPIO %d\n", GPIO_TEST_PIN);
gpio_free(GPIO_TEST_PIN);
return;
}
module_init(mymodule_init);
module_exit(mymodule_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mister X");
----------------------------->8--------------------------------
It just request a GPIO and freeing it at module unload. Here is the according
dmesg: (Carambola 1 with RT3052 using actual trunk)
insmod gpio-test
[ 3814.150000] GPIO Test: requesting GPIO 12
[ 3814.150000] rt2880-pinmux pinctrl.1: request pin 12 (io12) for pio:12
rmmod gpio-test
[ 3825.000000] GPIO Test: freeing GPIO 12
insmod gpio-test # again
[ 3832.250000] GPIO Test: requesting GPIO 12
[ 3832.250000] rt2880-pinmux pinctrl.1: request pin 12 (io12) for pio:12
[ 3832.250000] rt2880-pinmux pinctrl.1: pin io12 already requested by pio:12;
cannot claim for pio:12
[ 3832.260000] rt2880-pinmux pinctrl.1: pin-12 (pio:12) status -22
[ 3832.270000] GPIO Test: didn't get 12
Why is gpio_free() not enough ? Is there a missing peace in GPIO pinctrl glue ?
Any hint is greatly welcome ...
Regards
Gerd
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