mpc-i2c.c in 2.6

mpc-i2c.c in 2.6

[Kumar Gala]

Adrian,

I was wondering if you had any opinions on the timeout between 
transactions in drivers/i2c/busses/mpc-i2c.  Looking at it, we 
currently set the timeout between transactions to 1 second (HZ).  Any 
reason its this high?

on 85xx, I'm able to set it to HZ/100 w/o any really issue.

thanks

- kumar

Re: mpc-i2c.c in 2.6

[Mark A. Greer]

Kumar Gala wrote:

> Adrian,
>
> I was wondering if you had any opinions on the timeout between 
> transactions in drivers/i2c/busses/mpc-i2c.  Looking at it, we 
> currently set the timeout between transactions to 1 second (HZ).  Any 
> reason its this high?
>
> on 85xx, I'm able to set it to HZ/100 w/o any really issue.


This is just an FYI since I've been in this code recently.  You can 
change the timeout from userspace with an ioctl.  Something like this 
should do it:

static char *usage_msg = "Usage: set_timeout <timeout value>\n";

int main(int argc, char **argv)
{
        uint    timeout;
        int     file;

        if (argc != 2) {
                fprintf(stderr, usage_msg);
                return 1;
        }

        timeout = strtoul(argv[1], NULL, 0);

        if ((file = open("/dev/i2c/0", O_RDWR)) < 0) {
                printf("Can't open device, errno: %d (%s)\n",
                        errno, strerror(errno));
                return 1;
        }

        if (ioctl(file, I2C_TIMEOUT, &timeout) < 0) {
                printf("Can't do TIMEOUT: %s\n", strerror(errno));
                return 1;
        }

        return 0;
}

Re: mpc-i2c.c in 2.6

[Adrian Cox]

On Thu, 2005-01-13 at 15:24 -0600, Kumar Gala wrote:
> I was wondering if you had any opinions on the timeout between 
> transactions in drivers/i2c/busses/mpc-i2c.  Looking at it, we 
> currently set the timeout between transactions to 1 second (HZ).  Any 
> reason its this high?

It only exists because when I started the driver I hadn't spotted the
timeout field in i2c_adapter. Your patch is fine.


-- 
Adrian Cox <adrian@humboldt.co.uk>