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From: Stephen Boyd <sboyd@codeaurora.org>
To: Mike Turquette <mturquette@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Viresh Kumar <viresh.kumar@linaro.org>,
	linux-pm@vger.kernel.org
Subject: [PATCH v2 03/15] clk: Add __clk_mux_determine_rate_closest
Date: Fri,  5 Sep 2014 15:47:22 -0700	[thread overview]
Message-ID: <1409957256-23729-4-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1409957256-23729-1-git-send-email-sboyd@codeaurora.org>

Some clock drivers want to find the closest rate on the input of
a mux instead of a rate that's less than or equal to the desired
rate. Add a generic mux function to support this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clk/clk.c            | 47 +++++++++++++++++++++++++++++++++++---------
 include/linux/clk-provider.h |  9 +++++++--
 2 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b76fa69b44cb..255ec8c92919 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -712,14 +712,20 @@ struct clk *__clk_lookup(const char *name)
 	return NULL;
 }
 
-/*
- * Helper for finding best parent to provide a given frequency. This can be used
- * directly as a determine_rate callback (e.g. for a mux), or from a more
- * complex clock that may combine a mux with other operations.
- */
-long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
-			      unsigned long *best_parent_rate,
-			      struct clk **best_parent_p)
+static bool mux_is_better_rate(unsigned long rate, unsigned long now,
+			   unsigned long best, unsigned long flags)
+{
+	if (flags & CLK_MUX_ROUND_CLOSEST)
+		return abs(now - rate) < abs(best - rate);
+
+	return now <= rate && now > best;
+}
+
+static long
+clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
+			     unsigned long *best_parent_rate,
+			     struct clk **best_parent_p,
+			     unsigned long flags)
 {
 	struct clk *clk = hw->clk, *parent, *best_parent = NULL;
 	int i, num_parents;
@@ -747,7 +753,7 @@ long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
 			parent_rate = __clk_round_rate(parent, rate);
 		else
 			parent_rate = __clk_get_rate(parent);
-		if (parent_rate <= rate && parent_rate > best) {
+		if (mux_is_better_rate(rate, parent_rate, best, flags)) {
 			best_parent = parent;
 			best = parent_rate;
 		}
@@ -760,8 +766,31 @@ out:
 
 	return best;
 }
+
+/*
+ * Helper for finding best parent to provide a given frequency. This can be used
+ * directly as a determine_rate callback (e.g. for a mux), or from a more
+ * complex clock that may combine a mux with other operations.
+ */
+long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long *best_parent_rate,
+			      struct clk **best_parent_p)
+{
+	return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
+					    best_parent_p, 0);
+}
 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
 
+long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
+			      unsigned long *best_parent_rate,
+			      struct clk **best_parent_p)
+{
+	return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
+					    best_parent_p,
+					    CLK_MUX_ROUND_CLOSEST);
+}
+EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
+
 /***        clk api        ***/
 
 void __clk_unprepare(struct clk *clk)
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 48a92e318542..ba97e25c1115 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -372,6 +372,8 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name,
  *	register, and mask of mux bits are in higher 16-bit of this register.
  *	While setting the mux bits, higher 16-bit should also be updated to
  *	indicate changing mux bits.
+ * CLK_MUX_ROUND_CLOSEST - Use the parent rate that is closest to the desired
+ *	frequency.
  */
 struct clk_mux {
 	struct clk_hw	hw;
@@ -386,7 +388,8 @@ struct clk_mux {
 #define CLK_MUX_INDEX_ONE		BIT(0)
 #define CLK_MUX_INDEX_BIT		BIT(1)
 #define CLK_MUX_HIWORD_MASK		BIT(2)
-#define CLK_MUX_READ_ONLY	BIT(3) /* mux setting cannot be changed */
+#define CLK_MUX_READ_ONLY		BIT(3) /* mux can't be changed */
+#define CLK_MUX_ROUND_CLOSEST		BIT(4)
 
 extern const struct clk_ops clk_mux_ops;
 extern const struct clk_ops clk_mux_ro_ops;
@@ -529,7 +532,9 @@ struct clk *__clk_lookup(const char *name);
 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
 			      unsigned long *best_parent_rate,
 			      struct clk **best_parent_p);
-
+long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
+			      unsigned long *best_parent_rate,
+			      struct clk **best_parent_p);
 /*
  * FIXME clock api without lock protection
  */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

  parent reply	other threads:[~2014-09-05 22:47 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-05 22:47 [PATCH v2 00/15] Krait clocks + Krait CPUfreq Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 01/15] clk: mux: Add unregistration API Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 02/15] clk: mux: Split out register accessors for reuse Stephen Boyd
2014-09-05 22:47 ` Stephen Boyd [this message]
2014-09-05 22:47 ` [PATCH v2 04/15] clk: divider: Make generic for usage elsewhere Stephen Boyd
2014-10-03 18:07   ` Stephen Boyd
2014-10-07 17:27     ` Srinivas Kandagatla
2014-10-07 18:26       ` Stephen Boyd
2014-10-07 19:28         ` Srinivas Kandagatla
2014-10-08 15:04         ` Srinivas Kandagatla
2014-09-05 22:47 ` Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 05/15] clk: Add safe switch hook Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 06/15] clk: Avoid sending high rates to downstream clocks during set_rate Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 07/15] clk: qcom: Add support for High-Frequency PLLs (HFPLLs) Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 08/15] clk: qcom: Add HFPLL driver Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 09/15] clk: qcom: Add MSM8960/APQ8064's HFPLLs Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 10/15] clk: qcom: Add IPQ806X's HFPLLs Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 11/15] clk: qcom: Add support for Krait clocks Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 12/15] clk: qcom: Add KPSS ACC/GCC driver Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 13/15] clk: qcom: Add Krait clock controller driver Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 14/15] cpufreq: Add module to register cpufreq on Krait CPUs Stephen Boyd
2014-09-08  4:46   ` Viresh Kumar
2014-09-08 17:15     ` Christopher Covington
2014-09-09  0:37     ` Stephen Boyd
2014-09-09  4:53       ` Viresh Kumar
2014-09-05 22:47 ` Stephen Boyd
2014-09-05 22:47 ` [PATCH v2 15/15] ARM: dts: qcom: Add necessary DT data for Krait cpufreq Stephen Boyd
2014-09-08  9:42 ` [PATCH v2 00/15] Krait clocks + Krait CPUfreq Pramod Gurav
2014-09-08 11:59   ` Pramod Gurav

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