OPP: Allow multiple clocks for a device

This patch adds support to allow multiple clocks for a device.

The design is pretty much similar to how this is done for regulators,
and platforms can supply their own version of the config_clks() callback
if they have multiple clocks for their device. The core manages the
calls via opp_table->config_clks() eventually.

We have kept both "clk" and "clks" fields in the OPP table structure and
the reason is provided as a comment in _opp_set_clknames(). The same
isn't done for "rates" though and we use rates[0] at most of the places
now.
Co-developed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/debugfs.c

@@ -74,6 +74,24 @@ static void opp_debug_create_bw(struct dev_pm_opp *opp,
 	}
 }
 
+static void opp_debug_create_clks(struct dev_pm_opp *opp,
+				  struct opp_table *opp_table,
+				  struct dentry *pdentry)
+{
+	char name[12];
+	int i;
+
+	if (opp_table->clk_count == 1) {
+		debugfs_create_ulong("rate_hz", S_IRUGO, pdentry, &opp->rates[0]);
+		return;
+	}
+
+	for (i = 0; i < opp_table->clk_count; i++) {
+		snprintf(name, sizeof(name), "rate_hz_%d", i);
+		debugfs_create_ulong(name, S_IRUGO, pdentry, &opp->rates[i]);
+	}
+}
+
 static void opp_debug_create_supplies(struct dev_pm_opp *opp,
 				      struct opp_table *opp_table,
 				      struct dentry *pdentry)
@@ -117,10 +135,11 @@ void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 	 * Get directory name for OPP.
 	 *
 	 * - Normally rate is unique to each OPP, use it to get unique opp-name.
-	 * - For some devices rate isn't available, use index instead.
+	 * - For some devices rate isn't available or there are multiple, use
+	 *   index instead for them.
 	 */
-	if (likely(opp->rate))
-		id = opp->rate;
+	if (likely(opp_table->clk_count == 1 && opp->rates[0]))
+		id = opp->rates[0];
 	else
 		id = _get_opp_count(opp_table);
 
@@ -134,7 +153,6 @@ void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 	debugfs_create_bool("turbo", S_IRUGO, d, &opp->turbo);
 	debugfs_create_bool("suspend", S_IRUGO, d, &opp->suspend);
 	debugfs_create_u32("performance_state", S_IRUGO, d, &opp->pstate);
-	debugfs_create_ulong("rate_hz", S_IRUGO, d, &opp->rate);
 	debugfs_create_u32("level", S_IRUGO, d, &opp->level);
 	debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
 			     &opp->clock_latency_ns);
@@ -142,6 +160,7 @@ void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 	opp->of_name = of_node_full_name(opp->np);
 	debugfs_create_str("of_name", S_IRUGO, d, (char **)&opp->of_name);
 
+	opp_debug_create_clks(opp, opp_table, d);
 	opp_debug_create_supplies(opp, opp_table, d);
 	opp_debug_create_bw(opp, opp_table, d);
 

drivers/opp/of.c

@@ -767,6 +767,50 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
+static int _read_rate(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
+		      struct device_node *np)
+{
+	struct property *prop;
+	int i, count, ret;
+	u64 *rates;
+
+	prop = of_find_property(np, "opp-hz", NULL);
+	if (!prop)
+		return -ENODEV;
+
+	count = prop->length / sizeof(u64);
+	if (opp_table->clk_count != count) {
+		pr_err("%s: Count mismatch between opp-hz and clk_count (%d %d)\n",
+		       __func__, count, opp_table->clk_count);
+		return -EINVAL;
+	}
+
+	rates = kmalloc_array(count, sizeof(*rates), GFP_KERNEL);
+	if (!rates)
+		return -ENOMEM;
+
+	ret = of_property_read_u64_array(np, "opp-hz", rates, count);
+	if (ret) {
+		pr_err("%s: Error parsing opp-hz: %d\n", __func__, ret);
+	} else {
+		/*
+		 * Rate is defined as an unsigned long in clk API, and so
+		 * casting explicitly to its type. Must be fixed once rate is 64
+		 * bit guaranteed in clk API.
+		 */
+		for (i = 0; i < count; i++) {
+			new_opp->rates[i] = (unsigned long)rates[i];
+
+			/* This will happen for frequencies > 4.29 GHz */
+			WARN_ON(new_opp->rates[i] != rates[i]);
+		}
+	}
+
+	kfree(rates);
+
+	return ret;
+}
+
 static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
 		    struct device_node *np, bool peak)
 {
@@ -812,19 +856,13 @@ static int _read_opp_key(struct dev_pm_opp *new_opp,
 			 struct opp_table *opp_table, struct device_node *np)
 {
 	bool found = false;
-	u64 rate;
 	int ret;
 
-	ret = of_property_read_u64(np, "opp-hz", &rate);
-	if (!ret) {
-		/*
-		 * Rate is defined as an unsigned long in clk API, and so
-		 * casting explicitly to its type. Must be fixed once rate is 64
-		 * bit guaranteed in clk API.
-		 */
-		new_opp->rate = (unsigned long)rate;
+	ret = _read_rate(new_opp, opp_table, np);
+	if (!ret)
 		found = true;
-	}
+	else if (ret != -ENODEV)
+		return ret;
 
 	/*
 	 * Bandwidth consists of peak and average (optional) values:
@@ -893,8 +931,8 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 
 	/* Check if the OPP supports hardware's hierarchy of versions or not */
 	if (!_opp_is_supported(dev, opp_table, np)) {
-		dev_dbg(dev, "OPP not supported by hardware: %lu\n",
-			new_opp->rate);
+		dev_dbg(dev, "OPP not supported by hardware: %s\n",
+			of_node_full_name(np));
 		goto free_opp;
 	}
 
@@ -930,7 +968,7 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	if (of_property_read_bool(np, "opp-suspend")) {
 		if (opp_table->suspend_opp) {
 			/* Pick the OPP with higher rate/bw/level as suspend OPP */
-			if (_opp_compare_key(new_opp, opp_table->suspend_opp) == 1) {
+			if (_opp_compare_key(opp_table, new_opp, opp_table->suspend_opp) == 1) {
 				opp_table->suspend_opp->suspend = false;
 				new_opp->suspend = true;
 				opp_table->suspend_opp = new_opp;
@@ -945,7 +983,7 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
 
 	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu level:%u\n",
-		 __func__, new_opp->turbo, new_opp->rate,
+		 __func__, new_opp->turbo, new_opp->rates[0],
 		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
 		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns,
 		 new_opp->level);

drivers/opp/opp.h

@@ -79,7 +79,7 @@ struct opp_config_data {
  * @suspend:	true if suspend OPP
  * @removed:	flag indicating that OPP's reference is dropped by OPP core.
  * @pstate: Device's power domain's performance state.
- * @rate:	Frequency in hertz
+ * @rates:	Frequencies in hertz
  * @level:	Performance level
  * @supplies:	Power supplies voltage/current values
  * @bandwidth:	Interconnect bandwidth values
@@ -102,7 +102,7 @@ struct dev_pm_opp {
 	bool suspend;
 	bool removed;
 	unsigned int pstate;
-	unsigned long rate;
+	unsigned long *rates;
 	unsigned int level;
 
 	struct dev_pm_opp_supply *supplies;
@@ -170,8 +170,10 @@ enum opp_table_access {
  * @supported_hw: Array of version number to support.
  * @supported_hw_count: Number of elements in supported_hw array.
  * @prop_name: A name to postfix to many DT properties, while parsing them.
- * @clk_configured: Clock name is configured by the platform.
- * @clk: Device's clock handle
+ * @config_clks: Platform specific config_clks() callback.
+ * @clks: Device's clock handles, for multiple clocks.
+ * @clk: Device's clock handle, for single clock.
+ * @clk_count: Number of clocks.
  * @config_regulators: Platform specific config_regulators() callback.
  * @regulators: Supply regulators
  * @regulator_count: Number of power supply regulators. Its value can be -1
@@ -220,8 +222,10 @@ struct opp_table {
 	unsigned int *supported_hw;
 	unsigned int supported_hw_count;
 	const char *prop_name;
-	bool clk_configured;
+	config_clks_t config_clks;
+	struct clk **clks;
 	struct clk *clk;
+	int clk_count;
 	config_regulators_t config_regulators;
 	struct regulator **regulators;
 	int regulator_count;
@@ -246,7 +250,7 @@ struct opp_table *_find_opp_table(struct device *dev);
 struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
 struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
 void _opp_free(struct dev_pm_opp *opp);
-int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2);
+int _opp_compare_key(struct opp_table *opp_table, struct dev_pm_opp *opp1, struct dev_pm_opp *opp2);
 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table);
 int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, int last_cpu);

include/linux/pm_opp.h

@@ -61,9 +61,13 @@ typedef int (*config_regulators_t)(struct device *dev,
 			struct dev_pm_opp *old_opp, struct dev_pm_opp *new_opp,
 			struct regulator **regulators, unsigned int count);
 
+typedef int (*config_clks_t)(struct device *dev, struct opp_table *opp_table,
+			struct dev_pm_opp *opp, void *data, bool scaling_down);
+
 /**
  * struct dev_pm_opp_config - Device OPP configuration values
- * @clk_names: Clk names, NULL terminated array, max 1 clock for now.
+ * @clk_names: Clk names, NULL terminated array.
+ * @config_clks: Custom set clk helper.
  * @prop_name: Name to postfix to properties.
  * @config_regulators: Custom set regulator helper.
  * @supported_hw: Array of hierarchy of versions to match.
@@ -78,6 +82,7 @@ typedef int (*config_regulators_t)(struct device *dev,
 struct dev_pm_opp_config {
 	/* NULL terminated */
 	const char * const *clk_names;
+	config_clks_t config_clks;
 	const char *prop_name;
 	config_regulators_t config_regulators;
 	const unsigned int *supported_hw;