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regmap: add regmap_read_poll_timeout() helper

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Add the regmap_read_poll_timeout() macro based on the Linux implementation
to simplify register polling with configurable timeout and sleep.

Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Jagan Teki <jagan@openedev.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
This commit is contained in:
Neil Armstrong 2018-11-22 11:01:03 +01:00 committed by Jagan Teki
parent d821e5edfb
commit d13801ef1d
1 changed files with 38 additions and 0 deletions
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38
include/regmap.h
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@ -239,6 +239,44 @@ int regmap_raw_read_range(struct regmap *map, uint range_num, uint offset,
#define regmap_get(map, type, member, valp) \
regmap_range_get(map, 0, type, member, valp)
/**
* regmap_read_poll_timeout - Poll until a condition is met or a timeout occurs
*
* @map: Regmap to read from
* @addr: Offset to poll
* @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).
* @timeout_ms: Timeout in ms, 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 regmap_read_poll_timeout macros in linux but
* with millisecond timeout.
*/
#define regmap_read_poll_timeout(map, addr, val, cond, sleep_us, timeout_ms) \
({ \
unsigned long __start = get_timer(0); \
int __ret; \
for (;;) { \
__ret = regmap_read((map), (addr), &(val)); \
if (__ret) \
break; \
if (cond) \
break; \
if ((timeout_ms) && get_timer(__start) > (timeout_ms)) { \
__ret = regmap_read((map), (addr), &(val)); \
break; \
} \
if ((sleep_us)) \
udelay((sleep_us)); \
} \
__ret ?: ((cond) ? 0 : -ETIMEDOUT); \
})
/**
* regmap_update_bits() - Perform a read/modify/write using a mask
*