Re: [PATCH] usb: cp210x: Added support for GPIO (CP2103/4/5)
From: Greg KH <hidden>
Date: 2012-05-16 23:42:03
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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 [off-list ref]
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 [off-list ref]Wow, that looks really nice and tiny, if that's all that is needed in the core, that's great.
quoted hunk ↗ jump to hunk
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?
quoted hunk ↗ jump to hunk
+ } + +#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 0x5451diff --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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html