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Message-Id: <20250124-clk-ssc-v1-1-2d39f6baf2af@nxp.com>
Date: Fri, 24 Jan 2025 22:25:17 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>, Russell King <linux@...linux.org.uk>,
Sudeep Holla <sudeep.holla@....com>,
Cristian Marussi <cristian.marussi@....com>
Cc: linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
arm-scmi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk@...nel.org>,
Dario Binacchi <dario.binacchi@...rulasolutions.com>,
Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>, imx@...ts.linux.dev,
Peng Fan <peng.fan@....com>
Subject: [PATCH 1/3] clk: Introduce clk_set_spread_spectrum
From: Peng Fan <peng.fan@....com>
Add clk_set_spread_spectrum to configure a clock to enable spread spectrum
feature. set_spread_spectrum ops is added for clk drivers to have their
own hardware specific implementation.
Signed-off-by: Peng Fan <peng.fan@....com>
---
drivers/clk/clk.c | 39 +++++++++++++++++++++++++++++++++++++++
include/linux/clk-provider.h | 22 ++++++++++++++++++++++
include/linux/clk.h | 22 ++++++++++++++++++++++
3 files changed, 83 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index cf7720b9172ff223d86227aad144e15375ddfd86..a4fe4a60f839244b736e3c2751eeb38dc4577b1f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2790,6 +2790,45 @@ int clk_set_max_rate(struct clk *clk, unsigned long rate)
}
EXPORT_SYMBOL_GPL(clk_set_max_rate);
+int clk_set_spread_spectrum(struct clk *clk, unsigned int modfreq,
+ unsigned int spreadpercent, unsigned int method,
+ bool enable)
+{
+ struct clk_spread_spectrum clk_ss;
+ struct clk_core *core;
+ int ret = 0;
+
+ if (!clk || !clk->core)
+ return 0;
+
+ clk_ss.modfreq = modfreq;
+ clk_ss.spreadpercent = spreadpercent;
+ clk_ss.method = method;
+ clk_ss.enable = enable;
+
+ clk_prepare_lock();
+
+ core = clk->core;
+
+ if (core->prepare_count) {
+ ret = -EBUSY;
+ goto fail;
+ }
+
+ ret = clk_pm_runtime_get(core);
+ if (ret)
+ goto fail;
+
+ if (core->ops->set_spread_spectrum)
+ ret = core->ops->set_spread_spectrum(core->hw, &clk_ss);
+
+ clk_pm_runtime_put(core);
+ clk_prepare_unlock();
+fail:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(clk_set_spread_spectrum);
+
/**
* clk_get_parent - return the parent of a clk
* @clk: the clk whose parent gets returned
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 2e6e603b749342931c0d0693c3e72b62c000791b..478005f4d53ed0698ea17331730c755e08ea7984 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -84,6 +84,21 @@ struct clk_duty {
unsigned int den;
};
+/**
+ * struct clk_spread_spectrum - Structure encoding spread spectrum of a clock
+ *
+ * @modfreq: Modulation frequency
+ * @spreadpercent: Modulation percent
+ * @method: Modulation method
+ * @enable: enable or disable modulation
+ */
+struct clk_spread_spectrum {
+ unsigned int modfreq;
+ unsigned int spreadpercent;
+ unsigned int method;
+ bool enable;
+};
+
/**
* struct clk_ops - Callback operations for hardware clocks; these are to
* be provided by the clock implementation, and will be called by drivers
@@ -178,6 +193,11 @@ struct clk_duty {
* separately via calls to .set_parent and .set_rate.
* Returns 0 on success, -EERROR otherwise.
*
+ * @set_spread_spectrum: Configure the modulation frequency, modulation percentage
+ * and method. This callback is optional for clocks that does not
+ * support spread spectrum feature or no need to enable this feature.
+ * Returns 0 on success, -EERROR otherwise.
+ *
* @recalc_accuracy: Recalculate the accuracy of this clock. The clock accuracy
* is expressed in ppb (parts per billion). The parent accuracy is
* an input parameter.
@@ -255,6 +275,8 @@ struct clk_ops {
int (*set_rate_and_parent)(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate, u8 index);
+ int (*set_spread_spectrum)(struct clk_hw *hw,
+ struct clk_spread_spectrum *clk_ss);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
int (*get_phase)(struct clk_hw *hw);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index b607482ca77e987b9344c38f25ebb5c8d35c1d39..49a7f7eb8b03233e11cd3b92768896c4e45c4e7c 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -858,6 +858,21 @@ int clk_set_rate(struct clk *clk, unsigned long rate);
*/
int clk_set_rate_exclusive(struct clk *clk, unsigned long rate);
+/**
+ * clk_set_spread_spectrum - set the spread spectrum for a clock
+ * @clk: clock source
+ * @modfreq: modulation freq
+ * @spreadpercent: modulation percentage
+ * @method: down spread, up spread, center spread or else
+ * @enable: enable or disable
+ *
+ * Configure the spread spectrum parameters for a clock.
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_spread_spectrum(struct clk *clk, unsigned int modfreq,
+ unsigned int spreadpercent, unsigned int method,
+ bool enable);
/**
* clk_has_parent - check if a clock is a possible parent for another
* @clk: clock source
@@ -1088,6 +1103,13 @@ static inline int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
return 0;
}
+static inline int clk_set_spread_spectrum(struct clk *clk, unsigned int modfreq,
+ unsigned int spreadpercent,
+ unsigned int method, bool enable)
+{
+ return 0;
+}
+
static inline long clk_round_rate(struct clk *clk, unsigned long rate)
{
return 0;
--
2.35.3
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