From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chen-Yu Tsai Subject: [PATCH v3 09/14] regmap: add iopoll-like polling macro for regmap_field Date: Fri, 29 Sep 2017 16:23:01 +0800 Message-ID: <20170929082306.16193-10-wens@csie.org> References: <20170929082306.16193-1-wens@csie.org> Reply-To: wens-jdAy2FN1RRM@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20170929082306.16193-1-wens-jdAy2FN1RRM@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Mark Brown , Maxime Ripard , David Airlie , Michael Turquette , Stephen Boyd , Rob Herring , Mark Rutland Cc: Chen-Yu Tsai , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org 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 --- 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 { -- 2.14.2