Merge tag 'regmap-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

Pull regmap updates from Mark Brown:
 "This is quite a busy release for a subsystem that's usually very
  quiet, though still a small set of updates in the grand scheme of
  things:

   - A fix for writes to non-incrementing registers.

   - An iopoll() style helper for use with atomic safe regmaps, making
     it easier to transition from raw memory mapped I/O.

   - Some constification"

* tag 'regmap-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: fix writes to non incrementing registers
  regmap: add iopoll-like atomic polling macro
  regmap-i2c: constify regmap_bus structures

1 files changed, 45 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index dfe493ac692d..f0a092a1a96d 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -145,6 +145,51 @@ struct reg_sequence {
 })
 
 /**
+ * regmap_read_poll_timeout_atomic - 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)
+ * @delay_us: Time to udelay between reads in us (0 tight-loops).
+ *            Should be less than ~10us since udelay 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 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.
+ *
+ * This is modelled after the readx_poll_timeout_atomic macros in linux/iopoll.h.
+ *
+ * Note: In general regmap cannot be used in atomic context. If you want to use
+ * this macro then first setup your regmap for atomic use (flat or no cache
+ * and MMIO regmap).
+ */
+#define regmap_read_poll_timeout_atomic(map, addr, val, cond, delay_us, timeout_us) \
+({ \
+	u64 __timeout_us = (timeout_us); \
+	unsigned long __delay_us = (delay_us); \
+	ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
+	int __ret; \
+	for (;;) { \
+		__ret = regmap_read((map), (addr), &(val)); \
+		if (__ret) \
+			break; \
+		if (cond) \
+			break; \
+		if ((__timeout_us) && \
+		    ktime_compare(ktime_get(), __timeout) > 0) { \
+			__ret = regmap_read((map), (addr), &(val)); \
+			break; \
+		} \
+		if (__delay_us) \
+			udelay(__delay_us); \
+	} \
+	__ret ?: ((cond) ? 0 : -ETIMEDOUT); \
+})
+
+/**
  * regmap_field_read_poll_timeout - Poll until a condition is met or timeout
  *
  * @field: Regmap field to read from