[PATCH v3 09/14] regmap: add iopoll-like polling macro for regmap_field
From: Chen-Yu Tsai <hidden>
Date: 2017-09-29 08:25:09
Also in:
dri-devel, linux-clk, linux-devicetree, lkml
Subsystem:
register map abstraction, the rest · Maintainers:
Mark Brown, Linus Torvalds
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 <redacted> --- 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 {
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2.14.2