Re: [PATCH v3 4/5] Add ioctl to retrieve USBTMC-USB488 capabilities

[Andy Shevchenko]

On Wed, Nov 11, 2015 at 1:20 PM, Dave Penkler <dpenkler@xxxxxxxxx> wrote:
> This is a convenience function to obtain an instrument's capabilities
> from its file descriptor without having to access sysfs from the user
> program.
>
> Signed-off-by: Dave Penkler <dpenkler@xxxxxxxxx>
> ---
>  drivers/usb/class/usbtmc.c   | 12 ++++++++++++
>  include/uapi/linux/usb/tmc.h | 21 ++++++++++++++++++---
>  2 files changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
> index bb9a6ab..deca4b5 100644
> --- a/drivers/usb/class/usbtmc.c
> +++ b/drivers/usb/class/usbtmc.c
> @@ -103,6 +103,9 @@ struct usbtmc_device_data {
>         u16            iin_wMaxPacketSize;
>         atomic_t       srq_asserted;
>
> +       /* coalesced usb488_caps from usbtmc_dev_capabilities */
> +       u8 usb488_caps;
> +
>         u8 rigol_quirk;
>
>         /* attributes from the USB TMC spec for this device */
> @@ -1001,6 +1004,7 @@ static int get_capabilities(struct usbtmc_device_data *data)
>         data->capabilities.device_capabilities = buffer[5];
>         data->capabilities.usb488_interface_capabilities = buffer[14];
>         data->capabilities.usb488_device_capabilities = buffer[15];
> +       data->usb488_caps = (buffer[14] & 0x07) | ((buffer[15] & 0x0f) << 4);
>         rv = 0;
>
>  err_out:
> @@ -1176,6 +1180,14 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>                 retval = usbtmc_ioctl_abort_bulk_in(data);
>                 break;
>
> +       case USBTMC488_IOCTL_GET_CAPS:
> +               retval = copy_to_user((void __user *)arg,
> +                               &data->usb488_caps,
> +                               sizeof(data->usb488_caps));
> +               if (retval)
> +                       retval = -EFAULT;
> +               break;
> +
>         case USBTMC488_IOCTL_READ_STB:
>                 retval = usbtmc488_ioctl_read_stb(data, arg);
>                 break;
> diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
> index 49060ea..2606664 100644
> --- a/include/uapi/linux/usb/tmc.h
> +++ b/include/uapi/linux/usb/tmc.h
> @@ -2,12 +2,14 @@
>   * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
>   * Copyright (C) 2008 Novell, Inc.
>   * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@xxxxxxx>
> + * Copyright (C) 2015 Dave Penkler <dpenkler@xxxxxxxxx>
>   *
>   * This file holds USB constants defined by the USB Device Class
> - * Definition for Test and Measurement devices published by the USB-IF.
> + * and USB488 Subclass Definitions for Test and Measurement devices
> + * published by the USB-IF.
>   *

> - * It also has the ioctl definitions for the usbtmc kernel driver that
> - * userspace needs to know about.
> + * It also has the ioctl and capability definitions for the
> + * usbtmc kernel driver that userspace needs to know about.

Do not see what's changed here.

>   */
>
>  #ifndef __LINUX_USB_TMC_H
> @@ -40,6 +42,19 @@
>  #define USBTMC_IOCTL_ABORT_BULK_IN     _IO(USBTMC_IOC_NR, 4)
>  #define USBTMC_IOCTL_CLEAR_OUT_HALT    _IO(USBTMC_IOC_NR, 6)
>  #define USBTMC_IOCTL_CLEAR_IN_HALT     _IO(USBTMC_IOC_NR, 7)
> +#define USBTMC488_IOCTL_GET_CAPS       _IO(USBTMC_IOC_NR, 17)
>  #define USBTMC488_IOCTL_READ_STB       _IOR(USBTMC_IOC_NR, 18, unsigned char)
>
> +/* Driver encoded usb488 capabilities */
> +#define USBTMC488_CAPABILITY_TRIGGER         1
> +#define USBTMC488_CAPABILITY_SIMPLE          2
> +#define USBTMC488_CAPABILITY_REN_CONTROL     2
> +#define USBTMC488_CAPABILITY_GOTO_LOCAL      2
> +#define USBTMC488_CAPABILITY_LOCAL_LOCKOUT   2
> +#define USBTMC488_CAPABILITY_488_DOT_2       4
> +#define USBTMC488_CAPABILITY_DT1             16
> +#define USBTMC488_CAPABILITY_RL1             32
> +#define USBTMC488_CAPABILITY_SR1             64
> +#define USBTMC488_CAPABILITY_FULL_SCPI       128
> +
>  #endif
> --
> 2.5.1
> --
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-- 
With Best Regards,
Andy Shevchenko
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