gpio driver for hawkboard help

[abhi]

Hi,

I am trying to write the driver for the GPIO. I write the code but I
am not understading the multiplexing configuration how can I use the
bank 5 i.e. GPIO5 port please help

here is the code(I am interested only in writing so don't include the
read routine)

/*
HEADER FILES
*/

MODULE_LICENSE("GPL");

char *ker_buf;
dev_t devid;
struct cdev ab_cdev;

unsigned int *GPIO54;

static int ab_open(struct inode *inode, struct file *file);
static int ab_release(struct inode *inode, struct file *file);
static ssize_t ab_read(struct file *file, char __user *buf, size_t
count, loff_t *ppos);
static ssize_t ab_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos);

struct file_operations ab_fops = {
.owner = THIS_MODULE,
.read = ab_read,
.write = ab_write,
.open = ab_open,
.release = ab_release,
};

static int ab_open(struct inode *inode, struct file *file)
{
unsigned int tmp;
int ret;
printk(KERN_INFO "Opening the device\n");

tmp = readb(GPIO54+3);
printk("GPIO Banks 4 and 5 Direction Register: 0x%x\n",tmp);
ret = writeb((tmp & 0xf0),GPIO54+3);
if(ret < 0) printk(" failed to write to data register\n");
else printk("GPIO5 8,9,10,11 set as output\n");

return 0;
}

static int ab_release(struct inode *inode, struct file *file)
{
unsigned int tmp;
int ret;
printk(KERN_INFO "Closing the device\n");

tmp = readb(GPIO54+3);
printk("GPIO Banks 4 and 5 Direction Register: 0x%x\n",tmp);
ret = writeb((tmp & 0xff),GPIO54+3);
if(ret < 0) printk(" failed to write to data register\n");
else printk("GPIO5 8,9,10,11 set as default\n");

return 0;
}

static ssize_t ab_read(struct file *file, char __user *buf, size_t
count, loff_t *ppos)
{

printk(KERN_INFO "Reading the device\n");

return 0;
}

static ssize_t ab_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
unsigned int tmp;
int ret;
char data = *buf;

printk(KERN_INFO "Writing the device\n");

tmp = readb(GPIO54+4+3);
printk("Current GPIO54 status: 0x%x\n",tmp);

if(count == 1 && data == 0x01)
{
tmp = readb(GPIO54+8+3);
printk("data 0x%x\n",tmp);
ret = writeb((0xff),GPIO54+8+3);
if(ret < 0) printk(" failed to write to data register\n");
else
{
tmp = readb(GPIO54+8+3);
printk("GPIO5 8,9,10,11 set to high: 0x%x\n",tmp);
tmp = readb(GPIO54+4+3);
printk("GPIO5 Status: 0x%x\n",tmp);
}
}
else
{
tmp = readb(GPIO54+12+3);
ret = writeb((0xff),GPIO54+12+3);
if(ret < 0) printk(" failed to write to data register\n");
else
{
tmp = readb(GPIO54+12+3);
printk("GPIO5 8,9,10,11 set to low: 0x%x\n",tmp);
tmp = readb(GPIO54+4+3);
printk("GPIO5 Status: 0x%x\n",tmp);
}
}


return 0;
}

static int hello_init(void)
{
unsigned short int major,minor;
unsigned int tmp;
void *ret;


printk(KERN_ALERT "Here we GO .............\nStarting GPIO\n");

ret = request_mem_region(0x01e26060,24,"GPIO_region");
// ret = request_region(0x01e26000,16,"GPIO_region");
if(!ret){ printk("request region failed\n"); return -1; }


GPIO54 = ioremap(0x01e26060,24+4);

if(alloc_chrdev_region(&devid, 0, 1,"GPIO_B1"))
{
printk("failed to register\n");
return -1;
}


major = MAJOR(devid);
minor = MINOR(devid);

printk(KERN_INFO"Major no. : %d MInor no. : %d\n",major,minor);

cdev_init(&ab_cdev, &ab_fops);
ab_cdev.owner = THIS_MODULE;

ab_cdev.ops = &ab_fops;
kobject_set_name(&ab_cdev.kobj,"GPIO");

if (cdev_add(&ab_cdev, devid, 1))
{
kobject_put(&ab_cdev.kobj);
unregister_chrdev_region(devid, 1);
return -1;
}


printk(KERN_INFO"GPIO INITIALISED\n");

return 0;
}

static void hello_exit(void)
{
printk(KERN_ALERT "Goodbye, cruel world\n");

iounmap(GPIO54);
release_mem_region(0x01e26060,24);
printk("Realising memory region\n");

cdev_del(&ab_cdev);
unregister_chrdev_region(devid, 1);
printk("Unregistered the device");

printk(KERN_ALERT "abhijit Exiting\n");

}

module_init(hello_init);
module_exit(hello_exit);

[Harishkumar V]

Hi,

check da850.c for pinmux configuration.

Also, in ti omapl138 website, u can find pinmux utility, which runs on windows, from that tool, u can get it.

--
Thanks and Regards,
Harish Kumar. V

[abhi]

but how I use them in the driver code.

How I do this??

I don't understand the configuration settings

Thanks
Abhijit

[Nikhil Varghese]

Hi abhi,

Go throug the Kernel/Documentation/gpio once
You ll Get it

--
With,
Thanks and Regards
Nikhil Varghese
+91- 8861218092