regmap: Add regmap_read_poll_timeout

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.barebox.org/20210602095507.24609-23-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/regmap.h b/include/regmap.h
index b43cd936fa..057370afc7 100644
--- a/include/regmap.h
+++ b/include/regmap.h
@@ -116,4 +116,28 @@ int regmap_write_bits(struct regmap *map, unsigned int reg,
 int regmap_update_bits(struct regmap *map, unsigned int reg,
 		       unsigned int mask, unsigned int val);
 
+/**
+ * regmap_read_poll_timeout - Poll until a condition is met or a timeout occurs
+ *
+ * @map: Regmap to read from
+ * @addr: Address to poll
+ * @val: Unsigned integer variable to read the value into
+ * @cond: Break condition (usually involving @val)
+ * @timeout_us: Timeout in us, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout or the regmap_read
+ * error return value in case of a error read. In the two former cases,
+ * 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.
+ *
+ * This is modelled after the readx_poll_timeout macros in linux/iopoll.h.
+ */
+#define regmap_read_poll_timeout(map, addr, val, cond, timeout_us) \
+({ \
+	int __ret, __tmp; \
+	__tmp = read_poll_timeout(regmap_read, __ret, __ret || (cond), \
+			timeout_us, (map), (addr), &(val)); \
+	__ret ?: __tmp; \
+})
+
 #endif /* __REGMAP_H */