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SubjectRe: [PATCH v4 5/5] Add ioctls to enable and disable local controls on an instrument
From
On Sun, Nov 15, 2015 at 8:40 PM, Dave Penkler <dpenkler@gmail.com> wrote:
> These ioctls provide support for the USBTMC-USB488 control requests
> for REN_CONTROL, GO_TO_LOCAL and LOCAL_LOCKOUT
>

Nitpicks below.

> Signed-off-by: Dave Penkler <dpenkler@gmail.com>
> ---
> drivers/usb/class/usbtmc.c | 76 ++++++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/usb/tmc.h | 6 ++++
> 2 files changed, 82 insertions(+)
>
> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
> index add0ce2..79caa78 100644
> --- a/drivers/usb/class/usbtmc.c
> +++ b/drivers/usb/class/usbtmc.c
> @@ -478,6 +478,68 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_device_data *data,
> return rv;
> }
>
> +static int usbtmc488_ioctl_simple(struct usbtmc_device_data *data,
> + unsigned long arg,
> + unsigned int cmd)
> +{
> + u8 *buffer;
> + struct device *dev;
> + int rv;
> + unsigned int val;
> + u16 wValue;
> +
> + dev = &data->intf->dev;

Could be assigned above.

> +
> + if (!(data->usb488_caps & USBTMC488_CAPABILITY_SIMPLE))
> + return -EINVAL;
> +
> + buffer = kmalloc(8, GFP_KERNEL);
> + if (!buffer)
> + return -ENOMEM;
> +
> + if (cmd == USBTMC488_REQUEST_REN_CONTROL) {
> + rv = copy_from_user(&val, (void __user *)arg, sizeof(val));
> + if (rv) {
> + rv = -EFAULT;
> + goto exit;
> + }
> + wValue = (val) ? 1 : 0;

Redundant parens.

> + } else {
> + wValue = 0;
> + }
> +
> + dev_warn(dev, "wValue is %d\n", wValue);
> +
> + rv = usb_control_msg(data->usb_dev,
> + usb_rcvctrlpipe(data->usb_dev, 0),
> + cmd,
> + USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> + wValue,
> + data->ifnum,
> + buffer, 0x01, USBTMC_TIMEOUT);
> +
> + if (rv < 0) {
> + dev_err(dev, "simple usb_control_msg failed %d\n", rv);
> + goto exit;
> + } else if (rv != 1) {
> + dev_warn(dev, "simple usb_control_msg returned %d\n", rv);
> + rv = -EIO;

Hmm… Does usb_control_msg() return a proper error code? If it does,
perhaps better to propagate it.

> + goto exit;
> + }
> +
> + if (buffer[0] != USBTMC_STATUS_SUCCESS) {
> + dev_err(dev, "simple control status returned %x\n", buffer[0]);
> + rv = -EIO;
> + goto exit;

> + } else {

Redundant else.

> + rv = 0;
> + }


> +
> + exit:
> + kfree(buffer);
> + return rv;
> +}
> +
> /*
> * Sends a REQUEST_DEV_DEP_MSG_IN message on the Bulk-IN endpoint.
> * @transfer_size: number of bytes to request from the device.
> @@ -1188,6 +1250,20 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> retval = usbtmc488_ioctl_read_stb(data, arg);
> break;
>
> + case USBTMC488_IOCTL_REN_CONTROL:
> + retval = usbtmc488_ioctl_simple(data, arg,
> + USBTMC488_REQUEST_REN_CONTROL);
> + break;
> +
> + case USBTMC488_IOCTL_GOTO_LOCAL:
> + retval = usbtmc488_ioctl_simple(data, arg,
> + USBTMC488_REQUEST_GOTO_LOCAL);
> + break;
> +
> + case USBTMC488_IOCTL_LOCAL_LOCKOUT:
> + retval = usbtmc488_ioctl_simple(data, arg,
> + USBTMC488_REQUEST_LOCAL_LOCKOUT);
> + break;
> }
>
> skip_io_on_zombie:
> diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
> index 1dc3af1..0d852c9 100644
> --- a/include/uapi/linux/usb/tmc.h
> +++ b/include/uapi/linux/usb/tmc.h
> @@ -33,6 +33,9 @@
> #define USBTMC_REQUEST_GET_CAPABILITIES 7
> #define USBTMC_REQUEST_INDICATOR_PULSE 64
> #define USBTMC488_REQUEST_READ_STATUS_BYTE 128
> +#define USBTMC488_REQUEST_REN_CONTROL 160
> +#define USBTMC488_REQUEST_GOTO_LOCAL 161
> +#define USBTMC488_REQUEST_LOCAL_LOCKOUT 162
>
> /* Request values for USBTMC driver's ioctl entry point */
> #define USBTMC_IOC_NR 91
> @@ -44,6 +47,9 @@
> #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)
> +#define USBTMC488_IOCTL_REN_CONTROL _IOW(USBTMC_IOC_NR, 19, unsigned char)
> +#define USBTMC488_IOCTL_GOTO_LOCAL _IO(USBTMC_IOC_NR, 20)
> +#define USBTMC488_IOCTL_LOCAL_LOCKOUT _IO(USBTMC_IOC_NR, 21)
>
> /* Driver encoded usb488 capabilities */
> #define USBTMC488_CAPABILITY_TRIGGER 1
> --
> 2.5.1
> --
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--
With Best Regards,
Andy Shevchenko


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