From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: [PATCH 01/14] clk: update clk API documentation to clarify clk_round_rate() Date: Fri, 03 Apr 2015 18:12:27 +0100 Message-ID: References: <20150403171149.GC13898@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20150403171149.GC13898@n2100.arm.linux.org.uk> Content-Disposition: inline Sender: linux-sh-owner@vger.kernel.org To: alsa-devel@alsa-project.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-omap@vger.kernel.org, linux-sh@vger.kernel.org List-Id: alsa-devel@alsa-project.org The idea is that rate = clk_round_rate(clk, r) is equivalent to: clk_set_rate(clk, r); rate = clk_get_rate(clk); except that clk_round_rate() does not change the hardware in any way. Signed-off-by: Russell King --- include/linux/clk.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/linux/clk.h b/include/linux/clk.h index 8381bbfbc308..d1ac9f3ab24b 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -288,6 +288,20 @@ void devm_clk_put(struct device *dev, struct clk *clk); * @clk: clock source * @rate: desired clock rate in Hz * + * This answers the question "if I were to pass @rate to clk_set_rate(), + * what clock rate would I end up with?" without changing the hardware + * in any way. In other words: + * + * rate = clk_round_rate(clk, r); + * + * and: + * + * clk_set_rate(clk, r); + * rate = clk_get_rate(clk); + * + * are equivalent except the former does not modify the clock hardware + * in any way. + * * Returns rounded clock rate in Hz, or negative errno. */ long clk_round_rate(struct clk *clk, unsigned long rate); -- 1.8.3.1