On Wed, May 16, 2012 at 04:33:47PM +0100, Alan Cox wrote:
> So the patch looks like this, which seems nice and compact (UNTESTED)
>
> commit 4164f9b7074e682fe71dad3b57e78521ef9df492
> Author: Alan Cox <alan@xxxxxxxxxxxxxxx>
> Date: Wed May 16 15:13:02 2012 +0100
>
> tty: Add a gpio helper set
>
> Various tty devices have additional control lines which are sometimes used
> as GPIO pins and sometimes also tied with the serial port to implement
> protocols such as ISO7816.
>
> This code provides a kernel interface for querying the GPIO range of a tty,
> and to describe the mapping between GPIO pins and control lines. The latter
> will be needed for some upcoming line discipline support.
>
> [Proposal do not merge yet]
>
> Not-Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Wow, that looks really nice and tiny, if that's all that is needed in
the core, that's great.
> diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
> index a1b9a2f..60550e7 100644
> --- a/drivers/tty/tty_ioctl.c
> +++ b/drivers/tty/tty_ioctl.c
> @@ -1071,6 +1071,39 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
> case TCSETXF:
> return set_termiox(real_tty, p, TERMIOS_FLUSH);
> #endif
> +#ifdef TCGGPIO
> + case TCGGPIO: {
> + struct tcgpio gpio;
> +
> + if (tty->gpio == NULL)
> + return -EOPNOTSUPP;
> + mutex_lock(&real_tty->termios_mutex);
> + memset(&gpio, 0, sizeof(gpio));
> + gpio.base = tty->gpio->base;
> + gpio.num = tty->gpio->num;
> + memcpy(gpio.map, tty->gpio->map, sizeof(gpio.map));
> + mutex_unlock(&real_tty->termios_mutex);
> + if (copy_to_user(p, &gpio, sizeof(gpio)))
> + return -EFAULT;
> + return 0;
> + }
> + case TCSGPIO:
> + {
> + struct tcgpio gpio;
> +
> + if (tty->gpio == NULL)
> + return -EOPNOTSUPP;
> + if (copy_from_user(&gpio, p, sizeof(gpio)))
> + return -EFAULT;
> + mutex_lock(&real_tty->termios_mutex);
> + memcpy(tty->gpio->map, gpio.map, sizeof(tty->gpio->map));
> + /* An ldisc can see this by watching the ioctl go through
> + but we may want to add a hook */
> + mutex_unlock(&real_tty->termios_mutex);
> + return 0;
So how would the lower tty driver get the ioctl to know to now set these
values to the hardware? I think we at least need a hook for that,
right? Or would that go through the ldisc?
> + }
> +
> +#endif
> case TIOCGSOFTCAR:
> copy_termios(real_tty, &kterm);
> ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
> diff --git a/include/asm-generic/ioctls.h b/include/asm-generic/ioctls.h
> index 199975f..fee17d3 100644
> --- a/include/asm-generic/ioctls.h
> +++ b/include/asm-generic/ioctls.h
> @@ -74,6 +74,8 @@
> #define TCSETXW 0x5435
> #define TIOCSIG _IOW('T', 0x36, int) /* pty: generate signal */
> #define TIOCVHANGUP 0x5437
> +#define TCGGPIO _IOR('T', 0x38, struct tcgpio)
> +#define TCSGPIO _IOW('T', 0x39, struct tcgpio)
>
> #define FIONCLEX 0x5450
> #define FIOCLEX 0x5451
> diff --git a/include/asm-generic/termios.h b/include/asm-generic/termios.h
> index d0922ad..3adda38 100644
> --- a/include/asm-generic/termios.h
> +++ b/include/asm-generic/termios.h
> @@ -18,6 +18,18 @@ struct winsize {
> unsigned short ws_ypixel;
> };
>
> +
> +/* GPIO handling */
> +#define NR_TTY_GPIOMAP 8
> +struct tcgpio /* User copied version */
> +{
> + u32 base;
> + u16 num;
> + u16 reserved;
> + u32 map[NR_TTY_GPIOMAP];
> + u32 reserved2[6];
> +};
__u32 and friends instead?
greg k-h
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