cpufreq: dt: Allow platforms to provide suspend/resume hooks

index 72a2975499db..9dafb3bbc334 100644
@@ -166,6 +166,7 @@ static int __init armada37xx_cpufreq_driver_init(void)
 {
 	struct armada_37xx_dvfs *dvfs;
 	struct platform_device *pdev;
+	unsigned long freq;
 	unsigned int cur_frequency;
 	struct regmap *nb_pm_base;
 	struct device *cpu_dev;

@@ -202,38 +203,49 @@ static int __init armada37xx_cpufreq_driver_init(void)
 	cur_frequency = clk_get_rate(clk);
 	if (!cur_frequency) {
 		dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
-		clk_put(clk);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto put_clk;
 	}
 
 	dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
-	if (!dvfs)
-		return -EINVAL;
+	if (!dvfs) {
+		ret = -EINVAL;
+		goto put_clk;
+	}
 
 	armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider);
 	clk_put(clk);
 
 	for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
 	     load_lvl++) {
-		unsigned long freq = cur_frequency / dvfs->divider[load_lvl];
+		freq = cur_frequency / dvfs->divider[load_lvl];
 
 		ret = dev_pm_opp_add(cpu_dev, freq, 0);
-		if (ret) {
-			/* clean-up the already added opp before leaving */
-			while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
-				freq = cur_frequency / dvfs->divider[load_lvl];
-				dev_pm_opp_remove(cpu_dev, freq);
-			}
-			return ret;
-		}
+		if (ret)
+			goto remove_opp;
 	}
 
 	/* Now that everything is setup, enable the DVFS at hardware level */
 	armada37xx_cpufreq_enable_dvfs(nb_pm_base);
 
 	pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
+	ret = PTR_ERR_OR_ZERO(pdev);
+	if (ret)
+		goto disable_dvfs;
+
+	return 0;
 
-	return PTR_ERR_OR_ZERO(pdev);
+disable_dvfs:
+	armada37xx_cpufreq_disable_dvfs(nb_pm_base);
+remove_opp:
+	/* clean-up the already added opp before leaving */
+	while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
+		freq = cur_frequency / dvfs->divider[load_lvl];
+		dev_pm_opp_remove(cpu_dev, freq);
+	}
+put_clk:
+	clk_put(clk);
+	return ret;
 }
 /* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
 late_initcall(armada37xx_cpufreq_driver_init);

index 9dafb3bbc334..c827d2437246 100644
@@ -23,6 +23,8 @@
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
+#include "cpufreq-dt.h"
+
 /* Power management in North Bridge register set */
 #define ARMADA_37XX_NB_L0L1	0x18
 #define ARMADA_37XX_NB_L2L3	0x1C

@@ -56,6 +58,16 @@
  */
 #define LOAD_LEVEL_NR	4
 
+struct armada37xx_cpufreq_state {
+	struct regmap *regmap;
+	u32 nb_l0l1;
+	u32 nb_l2l3;
+	u32 nb_dyn_mod;
+	u32 nb_cpu_load;
+};
+
+static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state;
+
 struct armada_37xx_dvfs {
 	u32 cpu_freq_max;
 	u8 divider[LOAD_LEVEL_NR];

@@ -136,7 +148,7 @@ static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
 	clk_set_parent(clk, parent);
 }
 
-static void __init armada37xx_cpufreq_disable_dvfs(struct regmap *base)
+static void armada37xx_cpufreq_disable_dvfs(struct regmap *base)
 {
 	unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
 		mask = ARMADA_37XX_NB_DFS_EN;

@@ -162,8 +174,44 @@ static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
 	regmap_update_bits(base, reg, mask, mask);
 }
 
+static int armada37xx_cpufreq_suspend(struct cpufreq_policy *policy)
+{
+	struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
+
+	regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1);
+	regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3);
+	regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
+		    &state->nb_cpu_load);
+	regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod);
+
+	return 0;
+}
+
+static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy)
+{
+	struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
+
+	/* Ensure DVFS is disabled otherwise the following registers are RO */
+	armada37xx_cpufreq_disable_dvfs(state->regmap);
+
+	regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1);
+	regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3);
+	regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
+		     state->nb_cpu_load);
+
+	/*
+	 * NB_DYN_MOD register is the one that actually enable back DVFS if it
+	 * was enabled before the suspend operation. This must be done last
+	 * otherwise other registers are not writable.
+	 */
+	regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod);
+
+	return 0;
+}
+
 static int __init armada37xx_cpufreq_driver_init(void)
 {
+	struct cpufreq_dt_platform_data pdata;
 	struct armada_37xx_dvfs *dvfs;
 	struct platform_device *pdev;
 	unsigned long freq;

@@ -213,6 +261,15 @@ static int __init armada37xx_cpufreq_driver_init(void)
 		goto put_clk;
 	}
 
+	armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state),
+					   GFP_KERNEL);
+	if (!armada37xx_cpufreq_state) {
+		ret = -ENOMEM;
+		goto put_clk;
+	}
+
+	armada37xx_cpufreq_state->regmap = nb_pm_base;
+
 	armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider);
 	clk_put(clk);
 

@@ -228,7 +285,11 @@ static int __init armada37xx_cpufreq_driver_init(void)
 	/* Now that everything is setup, enable the DVFS at hardware level */
 	armada37xx_cpufreq_enable_dvfs(nb_pm_base);
 
-	pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
+	pdata.suspend = armada37xx_cpufreq_suspend;
+	pdata.resume = armada37xx_cpufreq_resume;
+
+	pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata,
+					     sizeof(pdata));
 	ret = PTR_ERR_OR_ZERO(pdev);
 	if (ret)
 		goto disable_dvfs;

@@ -243,6 +304,8 @@ static int __init armada37xx_cpufreq_driver_init(void)
 		freq = cur_frequency / dvfs->divider[load_lvl];
 		dev_pm_opp_remove(cpu_dev, freq);
 	}
+
+	kfree(armada37xx_cpufreq_state);
 put_clk:
 	clk_put(clk);
 	return ret;