[PATCH net-next v3 6/7] net: phy: introduce phy_read_poll_timeout macro

[Dejin Zheng <zhengdejin5@gmail.com>]

it is sometimes necessary to poll a phy register by phy_read()
function until its value satisfies some condition. introduce
phy_read_poll_timeout() macros that do this.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
---
v2 -> v3:
	- modify the parameter order of newly added functions.
	  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:
	- pass a phydev and a regnum to replace args... parameter in
	  the phy_read_poll_timeout(), and also handle the
	  phy_read() function's return error.
 
 include/linux/phy.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 29718865242d..a23d6caf5c2c 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -714,6 +714,19 @@ 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) \
+({ \
+	int ret = 0; \
+	ret = read_poll_timeout(phy_read, val, cond || val < 0, sleep_us, \
+				timeout_us, 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
-- 
2.25.0