Applied "regmap: add iopoll-like polling macro for regmap_field" to the regmap tree

[Mark Brown <broonie@kernel.org>]

The patch

   regmap: add iopoll-like polling macro for regmap_field

has been applied to the regmap tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 667063acb81931e2f8fd0cb91df9fcccad131d9a Mon Sep 17 00:00:00 2001
From: Chen-Yu Tsai <wens@csie.org>
Date: Fri, 29 Sep 2017 16:23:01 +0800
Subject: [PATCH] regmap: add iopoll-like polling macro for regmap_field

This patch adds a macro regmap_field_read_poll_timeout that works
similar to the readx_poll_timeout defined in linux/iopoll.h, except
that this can also return the error value returned by a failed
regmap_field_read.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 include/linux/regmap.h | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 978abfbac617..93a4663d7acb 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -139,6 +139,45 @@ struct reg_sequence {
 	pollret ?: ((cond) ? 0 : -ETIMEDOUT); \
 })
 
+/**
+ * regmap_field_read_poll_timeout - Poll until a condition is met or timeout
+ *
+ * @field: Regmap field to read from
+ * @val: Unsigned integer 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.txt).
+ * @timeout_us: Timeout in us, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout or the regmap_field_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_field_read_poll_timeout(field, val, cond, sleep_us, timeout_us) \
+({ \
+	ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
+	int pollret; \
+	might_sleep_if(sleep_us); \
+	for (;;) { \
+		pollret = regmap_field_read((field), &(val)); \
+		if (pollret) \
+			break; \
+		if (cond) \
+			break; \
+		if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+			pollret = regmap_field_read((field), &(val)); \
+			break; \
+		} \
+		if (sleep_us) \
+			usleep_range((sleep_us >> 2) + 1, sleep_us); \
+	} \
+	pollret ?: ((cond) ? 0 : -ETIMEDOUT); \
+})
+
 #ifdef CONFIG_REGMAP
 
 enum regmap_endian {
-- 
2.14.1