[PATCH v3 2/3] iopoll: Add dealy to read poll

[Jagan Teki]

Some drivers and other bsp code not only poll the
register with timeout but also required to delay
on each transaction.

This patch add that requirement by adding sleep_us
variable so-that read_poll_timeout now support
delay as well.

This change is referenced from Linux from below commit:
commit <5f5323a14cad19323060a8cbf9d96f2280a462dd> ("iopoll:
introduce read_poll_timeout macro")

Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
---
Changes for v3:
- add delay header

 include/linux/iopoll.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index 51966d83da..76d2f951c1 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -6,6 +6,7 @@
 #ifndef _LINUX_IOPOLL_H
 #define _LINUX_IOPOLL_H
 
+#include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <time.h>
@@ -16,6 +17,7 @@
  * @addr: Address to poll
  * @val: Variable to read the value into
  * @cond: Break condition (usually involving @val)
+ * @sleep_us: Maximum time to sleep in us
  * @timeout_us: Timeout in us, 0 means never timeout
  *
  * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
@@ -24,7 +26,7 @@
  * When available, you'll probably want to use one of the specialized
  * macros defined below rather than this macro directly.
  */
-#define read_poll_timeout(op, addr, val, cond, timeout_us)	\
+#define read_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)	\
 ({ \
 	unsigned long timeout = timer_get_us() + timeout_us; \
 	for (;;) { \
@@ -35,12 +37,14 @@
 			(val) = op(addr); \
 			break; \
 		} \
+		if (sleep_us) \
+			udelay(sleep_us); \
 	} \
 	(cond) ? 0 : -ETIMEDOUT; \
 })
 
 #define readx_poll_timeout(op, addr, val, cond, timeout_us) \
-	read_poll_timeout(op, addr, val, cond, timeout_us)
+	read_poll_timeout(op, addr, val, cond, false, timeout_us)
 
 #define readb_poll_timeout(addr, val, cond, timeout_us) \
 	readx_poll_timeout(readb, addr, val, cond, timeout_us)
-- 
2.17.1