add ioctl USBTMC_IOCTL_MSG_IN_ATTR that returns the specific
bmTransferAttributes field of the last DEV_DEP_MSG_IN Bulk-IN
header. This header is received by the read() function. The
meaning of the (u8) bitmap bmTransferAttributes is:
Bit 0 = EOM flag is set when the last transfer of a USBTMC
message is received.
Bit 1 = is set when the last byte is a termchar (e.g. '\n').
Note that this bit is always zero when the device does not support
the termchar feature or when termchar detection is not enabled
(see ioctl USBTMC_IOCTL_CONFIG_TERMCHAR).
Signed-off-by: Guido Kiener <guido.kiener@xxxxxxxxxxxxxxxxx>
Reviewed-by: Steve Bayless <steve_bayless@xxxxxxxxxxxx>
---
drivers/usb/class/usbtmc.c | 8 ++++++++
include/uapi/linux/usb/tmc.h | 2 ++
2 files changed, 10 insertions(+)
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 8ab8c6f33cec..1e6cecf9e981 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -131,6 +131,7 @@ struct usbtmc_file_data {
u8 srq_byte;
atomic_t srq_asserted;
atomic_t closing;
+ u8 bmTransferAttributes; /* member of DEV_DEP_MSG_IN */
u8 eom_val;
u8 term_char;
@@ -1503,6 +1504,8 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf,
(buffer[6] << 16) +
(buffer[7] << 24);
+ file_data->bmTransferAttributes = buffer[8];
+
if (n_characters > this_part) {
dev_err(dev, "Device wants to return more data than requested: %u > %zu\n", n_characters, count);
if (data->auto_abort)
@@ -2347,6 +2350,11 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
(__u32 __user *)arg);
break;
+ case USBTMC_IOCTL_MSG_IN_ATTR:
+ retval = put_user(file_data->bmTransferAttributes,
+ (__u8 __user *)arg);
+ break;
+
case USBTMC_IOCTL_CANCEL_IO:
retval = usbtmc_ioctl_cancel_io(file_data);
break;
diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
index 76d11af19aaa..35c115e68775 100644
--- a/include/uapi/linux/usb/tmc.h
+++ b/include/uapi/linux/usb/tmc.h
@@ -98,6 +98,8 @@ struct usbtmc_message {
#define USBTMC488_IOCTL_TRIGGER _IO(USBTMC_IOC_NR, 22)
#define USBTMC488_IOCTL_WAIT_SRQ _IOW(USBTMC_IOC_NR, 23, __u32)
+#define USBTMC_IOCTL_MSG_IN_ATTR _IOR(USBTMC_IOC_NR, 24, __u8)
+
/* Cancel and cleanup asynchronous calls */
#define USBTMC_IOCTL_CANCEL_IO _IO(USBTMC_IOC_NR, 35)
#define USBTMC_IOCTL_CLEANUP_IO _IO(USBTMC_IOC_NR, 36)
--
2.17.1
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