halfkay: Replace usleep with udelay based on nanosleep

A point was raised that usleep is deprecated, a new function was written
to replace it: udelay.

1 files changed, 18 insertions, 2 deletions

diff --git a/halfkay.c b/halfkay.c
index 8158888..3f0aeec 100644
--- a/halfkay.c
+++ b/halfkay.c
@@ -86,16 +86,32 @@ static void usbclose(void)
 	hk_usb_hnd = NULL;
 }
 
+/* TODO: move somewhere or consider a cleaner replacement */
+/* udelay: usleep replacement */
+static void udelay(unsigned long usec)
+{
+	enum { USECSEC = 1000000, NSECUSEC = 1000, };
+	struct timespec ts = {
+		.tv_sec = usec / USECSEC,
+		.tv_nsec = usec % USECSEC * NSECUSEC,
+	};
+	/* If we get interrupted, oh well */
+	nanosleep(&ts, NULL);
+}
+
 static void usbsendcmd(void *data, size_t size, bool firstxfer)
 {
 	unsigned int timeout = firstxfer ? TIMEOUT_FIRST : TIMEOUT;
 	int rc, attempt = 0;
-	useconds_t delay = SEND_DELAY;
+	unsigned long delay = SEND_DELAY;
+
+	_Static_assert(SEND_DELAY << SEND_ATTEMPTS <= (1UL << 32) - 1,
+		       "SEND_DELAY << SEND_ATTEMPTS > 2^32 - 1");
 
 	do {
 		rc = libusb_control_transfer(hk_usb_hnd, HK_USB_REQTYP, HK_USB_REQ,
 					     HK_USB_VAL, 0, data, size, timeout);
-		usleep(delay);
+		udelay(delay);
 		delay *= 2;
 	} while (rc == LIBUSB_ERROR_PIPE && ++attempt < SEND_ATTEMPTS);