Hello everyone, I'm a newbie here!
I'm porting a custom PPC 405GP card based on a Walnut from Montavista
Linux 3.0 (kernel 2.4.18) to linux 2.6, and I was wondering if there is
a port of the IBM OCP GPIO driver (a char driver providing
device /dev/gpio, major 10 minor 185). The driver was written by Armin
Kuster, and it doesn't exist in the stock kernel 2.6.17.7.
Let me known if a port exists, or if there is a new way of accessing the
PPC 405GP GPIO under linux 2.6. Otherwise, I will port this driver using
the IBM IIC driver as an example (for the things about OCP). In this
case, do anybody know where I can have the last version of this driver
(I have v 1.7 (07/25/02)) ?
Thanks for all!
Jean-Baptiste Maneyrol
Teamlog - France
In article <1154603751.17247.10.camel@jb-portable> you write:
I'm porting a custom PPC 405GP card based on a Walnut from Montavista
Linux 3.0 (kernel 2.4.18) to linux 2.6, and I was wondering if there is
a port of the IBM OCP GPIO driver (a char driver providing
device /dev/gpio, major 10 minor 185). The driver was written by Armin
Kuster, and it doesn't exist in the stock kernel 2.6.17.7.
Let me known if a port exists, or if there is a new way of accessing the
PPC 405GP GPIO under linux 2.6.
The recommended way of accessing GPIO registers is to mmap them
and manipulate them directly in user space.
Below, I've included a quick hack that blinks a LED on a Walnut-like
board.
-Dale
#include <stdint.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#define GPIO_PAGE_ADDR 0xef600000
#define OUTPUT_REG 0x0700
#define TRISTATE_REG 0x0704
#define OPENDRAIN_REG 0x0718
#define INPUT_REG 0x071c
#define MEDIA_LED_BIT 0x20000000
#define reg_addr(p, o) ((uint32_t *)((void *)p + o))
int main(int argc, char *argv[])
{
int i;
uint32_t *p;
char *filename = "/dev/mem";
void *addr = 0;
size_t length = 4096;
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_SHARED;
int fd = open(filename, O_RDWR);
off_t offset = (off_t)GPIO_PAGE_ADDR;
if (fd < 0) {
perror("open");
return 1;
}
p = mmap(addr, length, prot, flags, fd, offset);
if (p == MAP_FAILED) {
perror("mmap");
return 4;
}
/* drive led output */
*reg_addr(p, TRISTATE_REG) |= MEDIA_LED_BIT;
/* blink media led 10 times */
for (i = 0; i < 10; i++) {
/* turn media led on */
*reg_addr(p, OUTPUT_REG) &= ~MEDIA_LED_BIT;
sleep(1);
/* turn media led off */
*reg_addr(p, OUTPUT_REG) |= MEDIA_LED_BIT;
sleep(1);
}
return 0;
}
On Thursday 03 August 2006 13:15, Jean-Baptiste Maneyrol wrote:
Let me known if a port exists, or if there is a new way of accessing the
PPC 405GP GPIO under linux 2.6. Otherwise, I will port this driver using
the IBM IIC driver as an example (for the things about OCP). In this
case, do anybody know where I can have the last version of this driver
(I have v 1.7 (07/25/02)) ?
The only OCP drivers that exist in the tree are for emac and iic.
Those will probably be converted to use something like of_platform_device
in the future, as soon as 4xx gets converted to arch/powerpc.
If you need to port the driver now, it's probably a good idea to use
a platform_driver instead of an ocp driver for it.
Arnd <><