Merge branch 'introduce-read_poll_timeout'

Dejin Zheng says:

====================
introduce read_poll_timeout

This patch sets is introduce read_poll_timeout macro, it is an extension
of readx_poll_timeout macro. the accessor function op just supports only
one parameter in the readx_poll_timeout macro, but this macro can
supports multiple variable parameters for it. so functions like
phy_read(struct phy_device *phydev, u32 regnum) and
phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum) can
use this poll timeout framework.

the first patch introduce read_poll_timeout macro, and the second patch
redefined readx_poll_timeout macro by read_poll_timeout(), and the other
patches are examples using read_poll_timeout macro.

v6 -> v7:
	- add a parameter to supports that it can sleep some time
	  before read operation in read_poll_timeout macro.
	- add prefix with double underscores for some variable to avoid
	  any variable re-declaration or shadowing in patch 3 and patch
	  7.
v5 -> v6:
	- add some check to keep the code more similar in patch 8
v4 -> v5:
	- add some msleep() before call phy_read_mmd_poll_timeout() to
	  keep the code more similar in patch 6 and patch 9.
	- add a patch of drop by v4, it can add msleep before call
	  phy_read_poll_timeout() to keep the code more similar.
v3 -> v4:
	- add 3 examples of using new functions.
	- deal with precedence issues for parameter cond.
	- drop a patch about phy_poll_reset() function.
v2 -> v3:
	- modify the parameter order of newly added functions.
	  phy_read_mmd_poll_timeout(val, cond, sleep_us, timeout_us, \
				     phydev, devaddr, regnum)
				||
				\/
	  phy_read_mmd_poll_timeout(phydev, devaddr regnum, val, cond, \
				    sleep_us, timeout_us)

	  phy_read_poll_timeout(val, cond, sleep_us, timeout_us, \
				phydev, regnum)
				||
				\/
	  phy_read_poll_timeout(phydev, regnum, val, cond, sleep_us, \
				timeout_us)
v1 -> v2:
	- passed a phydev, device address and a reg to replace args...
	  parameter in phy_read_mmd_poll_timeout() by Andrew Lunn 's
	  suggestion in patch 3. Andrew Lunn <andrew@lunn.ch>, Thanks
	  very much for your help!
	- also in patch 3, handle phy_read_mmd return an error(the return
	  value < 0) in phy_read_mmd_poll_timeout(). Thanks Andrew
	  again.
	- in patch 6, pass a phydev and a reg to replace args...
	  parameter in phy_read_poll_timeout(), and also handle the
	  phy_read() function's return error.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 60 insertions, 7 deletions

diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index 35e15dfd4155..cb20c733b15a 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -14,36 +14,41 @@
 #include <linux/io.h>
 
 /**
- * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
- * @op: accessor function (takes @addr as its only argument)
- * @addr: Address to poll
+ * read_poll_timeout - Periodically poll an address until a condition is
+ *			met or a timeout occurs
+ * @op: accessor function (takes @args as its arguments)
  * @val: Variable to read the value into
  * @cond: Break condition (usually involving @val)
  * @sleep_us: Maximum time to sleep between reads in us (0
  *            tight-loops).  Should be less than ~20ms since usleep_range
  *            is used (see Documentation/timers/timers-howto.rst).
  * @timeout_us: Timeout in us, 0 means never timeout
+ * @sleep_before_read: if it is true, sleep @sleep_us before read.
+ * @args: arguments for @op poll
  *
  * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
- * case, the last read value at @addr is stored in @val. Must not
+ * case, the last read value at @args is stored in @val. Must not
  * be called from atomic context if sleep_us or timeout_us are used.
  *
  * When available, you'll probably want to use one of the specialized
  * macros defined below rather than this macro directly.
  */
-#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)	\
+#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
+				sleep_before_read, args...) \
 ({ \
 	u64 __timeout_us = (timeout_us); \
 	unsigned long __sleep_us = (sleep_us); \
 	ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
 	might_sleep_if((__sleep_us) != 0); \
+	if (sleep_before_read && __sleep_us) \
+		usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
 	for (;;) { \
-		(val) = op(addr); \
+		(val) = op(args); \
 		if (cond) \
 			break; \
 		if (__timeout_us && \
 		    ktime_compare(ktime_get(), __timeout) > 0) { \
-			(val) = op(addr); \
+			(val) = op(args); \
 			break; \
 		} \
 		if (__sleep_us) \
@@ -53,6 +58,27 @@
 })
 
 /**
+ * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
+ * @op: accessor function (takes @addr as its only argument)
+ * @addr: Address to poll
+ * @val: Variable to read the value into
+ * @cond: Break condition (usually involving @val)
+ * @sleep_us: Maximum time to sleep between reads in us (0
+ *            tight-loops).  Should be less than ~20ms since usleep_range
+ *            is used (see Documentation/timers/timers-howto.rst).
+ * @timeout_us: Timeout in us, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @addr is stored in @val. Must not
+ * be called from atomic context if sleep_us or timeout_us are used.
+ *
+ * When available, you'll probably want to use one of the specialized
+ * macros defined below rather than this macro directly.
+ */
+#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)	\
+	read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
+
+/**
  * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
  * @op: accessor function (takes @addr as its only argument)
  * @addr: Address to poll
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 99b5e3c4b621..2432ca463ddc 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -24,6 +24,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/u64_stats_sync.h>
 #include <linux/irqreturn.h>
+#include <linux/iopoll.h>
 
 #include <linux/atomic.h>
 
@@ -716,6 +717,19 @@ static inline int phy_read(struct phy_device *phydev, u32 regnum)
 	return mdiobus_read(phydev->mdio.bus, phydev->mdio.addr, regnum);
 }
 
+#define phy_read_poll_timeout(phydev, regnum, val, cond, sleep_us, \
+				timeout_us, sleep_before_read) \
+({ \
+	int __ret = read_poll_timeout(phy_read, val, (cond) || val < 0, \
+		sleep_us, timeout_us, sleep_before_read, phydev, regnum); \
+	if (val <  0) \
+		__ret = val; \
+	if (__ret) \
+		phydev_err(phydev, "%s failed: %d\n", __func__, __ret); \
+	__ret; \
+})
+
+
 /**
  * __phy_read - convenience function for reading a given PHY register
  * @phydev: the phy_device struct
@@ -787,6 +801,19 @@ static inline int __phy_modify_changed(struct phy_device *phydev, u32 regnum,
  */
 int phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum);
 
+#define phy_read_mmd_poll_timeout(phydev, devaddr, regnum, val, cond, \
+				  sleep_us, timeout_us, sleep_before_read) \
+({ \
+	int __ret = read_poll_timeout(phy_read_mmd, val, (cond) || val < 0, \
+				  sleep_us, timeout_us, sleep_before_read, \
+				  phydev, devaddr, regnum); \
+	if (val <  0) \
+		__ret = val; \
+	if (__ret) \
+		phydev_err(phydev, "%s failed: %d\n", __func__, __ret); \
+	__ret; \
+})
+
 /**
  * __phy_read_mmd - Convenience function for reading a register
  * from an MMD on a given PHY.