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| author | Philipp Zabel <p.zabel@pengutronix.de> | 2016-07-06 17:19:41 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2016-07-15 15:44:22 +0300 |
| commit | 08188ba8822163922e6b9c600095d21ce02f6a84 (patch) | |
| tree | d30bb357aa98e64e4d4991e9efa539c98311e08b /include/linux | |
| parent | 1a695a905c18548062509178b98bc91e67510864 (diff) | |
| download | linux-08188ba8822163922e6b9c600095d21ce02f6a84.tar.xz | |
regmap: add iopoll-like polling macro
This patch adds a macro regmap_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_read.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/regmap.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 3dc08ce15426..26914dfcc9fc 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -95,6 +95,45 @@ struct reg_sequence { #define regmap_fields_force_update_bits(field, id, mask, val) \ regmap_fields_update_bits_base(field, id, mask, val, NULL, false, true) +/** + * 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) + * @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_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, sleep_us, timeout_us) \ +({ \ + ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ + int ret; \ + might_sleep_if(sleep_us); \ + 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 (sleep_us) \ + usleep_range((sleep_us >> 2) + 1, sleep_us); \ + } \ + ret ?: ((cond) ? 0 : -ETIMEDOUT); \ +}) + #ifdef CONFIG_REGMAP enum regmap_endian { |