[TEST PATCH] WIP: Test OPP multi regulator support with ti-opp-domain driver

[Dave Gerlach]

NOT FOR MERGE!

Introduce a test version of a 'ti-opp-domain' driver that will use new
multiple regulator support introduced to the OPP core by Viresh [1].
Tested on v4.9-rc1 with that series applied.  This is needed on TI
platforms like DRA7/AM57 in order to control both CPU regulator and
Adaptive Body Bias (ABB) regulator as described by Nishanth Menon here
[2]. These regulators must be scaled in sequence during an OPP
transition depending on whether or not the frequency is being scaled up
or down. Based on the new functionality provided by Viresh this driver
does the following:

* Call dev_pm_opp_set_regulators with the names of the two regulators
  that feed the CPU:
	* vdd is the 'cpu-supply' commonly used for cpufreq-dt but
	  renamed so the cpufreq-dt driver doesn't use it directly.
	  Note that this is supplied in board dts as it's external to
	  SoC.
	* vbb for the ABB regulator. This is provided in SoC dtsi as it
	  is internal to the SoC.
* Provide a platform set_opp function using
  dev_pm_opp_register_set_opp_helper that is called when an OPP
  transition is requested.
* Allow cpufreq-dt to probe which will work because no cpu-supply
  regulator is found so the driver proceeds and calls
  dev_pm_opp_set_rate which through the OPP core invokes the platform
  set_opp call we provided
* Platform set_opp call provided by this driver checks to see if we are
  scaling frequency up or down and based on this, scales vbb before vdd
  for up or the other way around for down.

In addition to that, this driver implements AVS Class 0 as described in
section 18.4.6.12 of AM572x TRM [3] using the same platform set_rate
hook added to the OPP core. There are registers that define the optimal
voltage for that specific piece of silicon for an OPP so this driver
simply looks up this optimal value and programs that for an OPP instead
of the nominal value.

Missing from this is a good way to ensure that cpufreq-dt does not just
proceed if no cpu-supply regulator is found but we were intending to
rely on a platform set_opp and multiple regulators.

[1] https://marc.info/?l=linux-pm&m=147746362402994&w=2
[2] https://marc.info/?l=linux-pm&m=145684495832764&w=2
[3] http://www.ti.com/lit/ug/spruhz6g/spruhz6g.pdf

Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx>
---
 arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi |   2 +-
 arch/arm/boot/dts/dra7.dtsi                     |  46 ++-
 drivers/soc/ti/Makefile                         |   2 +
 drivers/soc/ti/ti-opp-domain.c                  | 427 ++++++++++++++++++++++++
 4 files changed, 471 insertions(+), 6 deletions(-)
 create mode 100644 drivers/soc/ti/ti-opp-domain.c

diff --git a/arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi b/arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi
index 6df7829a2c15..d92551c15780 100644
--- a/arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi
+++ b/arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi
@@ -410,7 +410,7 @@
 };
 
 &cpu0 {
-	cpu0-supply = <&smps12_reg>;
+	vdd-supply = <&smps12_reg>;
 	voltage-tolerance = <1>;
 };
 
diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
index d4fcd68f6349..311166b9e8c4 100644
--- a/arch/arm/boot/dts/dra7.dtsi
+++ b/arch/arm/boot/dts/dra7.dtsi
@@ -80,11 +80,7 @@
 			compatible = "arm,cortex-a15";
 			reg = <0>;
 
-			operating-points = <
-				/* kHz    uV */
-				1000000	1060000
-				1176000	1160000
-				>;
+			operating-points-v2 = <&cpu0_opp_table>;
 
 			clocks = <&dpll_mpu_ck>;
 			clock-names = "cpu";
@@ -95,6 +91,32 @@
 			cooling-min-level = <0>;
 			cooling-max-level = <2>;
 			#cooling-cells = <2>; /* min followed by max */
+
+			vbb-supply = <&abb_mpu>;
+		};
+	};
+
+	cpu0_opp_table: opp_table0 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp_nom@1000000000 {
+			opp-hz = /bits/ 64 <1000000000>;
+			opp-microvolt = <1060000 850000 1150000>,
+					<1060000 850000 1150000>;
+			opp-suspend;
+		};
+
+		opp_od@1176000000 {
+			opp-hz = /bits/ 64 <1176000000>;
+			opp-microvolt = <1160000 885000 1160000>,
+					<1160000 885000 1160000>;
+		};
+
+		opp_high@1500000000 {
+			opp-hz = /bits/ 64 <1500000000>;
+			opp-microvolt = <1210000 950000 1250000>,
+					< 1210000 950000 1250000>;
 		};
 	};
 
@@ -1966,6 +1988,20 @@
 			clocks = <&l3_iclk_div>;
 			clock-names = "fck";
 		};
+
+		oppdm_mpu: oppdm@4a003b20 {
+			compatible = "ti,omap5-oppdm";
+			#oppdm-cells = <0>;
+			reg = <0x4a003b20 0xc>;
+			ti,efuse-settings = <
+			/* uV   offset */
+			1060000 0x0
+			1160000 0x4
+			1210000 0x8
+			>;
+			ti,absolute-max-voltage-uv = <1500000>;
+		};
+
 	};
 
 	thermal_zones: thermal-zones {
diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index 48ff3a79634f..e3595e3f1d6a 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile
@@ -5,3 +5,5 @@ obj-$(CONFIG_KEYSTONE_NAVIGATOR_QMSS)	+= knav_qmss.o
 knav_qmss-y := knav_qmss_queue.o knav_qmss_acc.o
 obj-$(CONFIG_KEYSTONE_NAVIGATOR_DMA)	+= knav_dma.o
 obj-$(CONFIG_WKUP_M3_IPC)		+= wkup_m3_ipc.o
+obj-y             += ti-opp-domain.o
+#obj-$(CONFIG_OPP_DOMAIN_TI)             += ti-opp-domain.o
diff --git a/drivers/soc/ti/ti-opp-domain.c b/drivers/soc/ti/ti-opp-domain.c
new file mode 100644
index 000000000000..33683548b326
--- /dev/null
+++ b/drivers/soc/ti/ti-opp-domain.c
@@ -0,0 +1,427 @@
+/*
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
+ *	Nishanth Menon <nm@xxxxxx>
+ *	Dave Gerlach <d-gerlach@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * TI OPP Domain driver that provides overrides into the regulator control
+ * for generic opp domains to handle devices with ABB regulator and/or
+ * SmartReflex Class0.
+ */
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+/**
+ * struct ti_oppdm_optimum_voltage_table - optimized voltage table
+ * @reference_uv:	reference voltage (usually Nominal voltage)
+ * @optimized_uv:	Optimized voltage from efuse
+ */
+struct ti_oppdm_optimum_voltage_table {
+	unsigned int reference_uv;
+	unsigned int optimized_uv;
+};
+
+/**
+ * struct ti_oppdm_data - OMAP specific opp domain data
+ * @vdd_reg:	VDD regulator
+ * @vbb_reg:	Body Bias regulator
+ * @vdd_table:	Optimized voltage mapping table
+ * @num_vdd_table: number of entries in vdd_table
+ * @vdd_absolute_max_voltage_uv: absolute maximum voltage in UV for the domain
+ */
+struct ti_oppdm_data {
+	struct regulator *vdd_reg;
+	struct regulator *vbb_reg;
+	struct ti_oppdm_optimum_voltage_table *vdd_table;
+	u32 num_vdd_table;
+	u32 vdd_absolute_max_voltage_uv;
+};
+
+static struct ti_oppdm_data opp_data;
+/**
+ * struct ti_oppdm_of_data - device tree match data
+ * @desc:	opp domain descriptor for opp domain core
+ * @flags:	specific type of opp domain
+ * @efuse_voltage_mask: mask required for efuse register representing voltage
+ * @efuse_voltage_uv: Are the efuse entries in micro-volts? if not, assume
+ *		milli-volts.
+ */
+struct ti_oppdm_of_data {
+#define OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE	BIT(1)
+#define OPPDM_HAS_NO_ABB			BIT(2)
+	const u8 flags;
+	const u32 efuse_voltage_mask;
+	const bool efuse_voltage_uv;
+};
+
+/**
+ * oppdm_store_optimized_voltages() - store optimized voltages
+ * @dev:	opp domain device for which we need to store info
+ * @data:	data specific to the device
+ *
+ * Picks up efuse based optimized voltages for VDD unique per device and
+ * stores it in internal data structure for use during transition requests.
+ *
+ * Return: If successful, 0, else appropriate error value.
+ */
+static int oppdm_store_optimized_voltages(struct device *dev,
+					  struct ti_oppdm_data *data)
+{
+	void __iomem *base;
+	struct property *prop;
+	struct resource *res;
+	const __be32 *val;
+	int proplen, i;
+	int ret = 0;
+	struct ti_oppdm_optimum_voltage_table *table;
+	const struct ti_oppdm_of_data *of_data = dev_get_drvdata(dev);
+
+	/* pick up Efuse based voltages */
+	res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Unable to get IO resource\n");
+		ret = -ENODEV;
+		goto out_map;
+	}
+
+	base = ioremap_nocache(res->start, resource_size(res));
+	if (!base) {
+		dev_err(dev, "Unable to map Efuse registers\n");
+		ret = -ENOMEM;
+		goto out_map;
+	}
+
+	/* Fetch efuse-settings. */
+	prop = of_find_property(dev->of_node, "ti,efuse-settings", NULL);
+	if (!prop) {
+		dev_err(dev, "No 'ti,efuse-settings' property found\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	proplen = prop->length / sizeof(int);
+	data->num_vdd_table = proplen / 2;
+	/* Verify for corrupted OPP entries in dt */
+	if (data->num_vdd_table * 2 * sizeof(int) != prop->length) {
+		dev_err(dev, "Invalid 'ti,efuse-settings'\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = of_property_read_u32(dev->of_node, "ti,absolute-max-voltage-uv",
+				   &data->vdd_absolute_max_voltage_uv);
+	if (ret) {
+		dev_err(dev, "ti,absolute-max-voltage-uv is missing\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	table = kzalloc(sizeof(*data->vdd_table) *
+				  data->num_vdd_table, GFP_KERNEL);
+	if (!table) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	data->vdd_table = table;
+
+	val = prop->value;
+	for (i = 0; i < data->num_vdd_table; i++, table++) {
+		u32 efuse_offset;
+		u32 tmp;
+
+		table->reference_uv = be32_to_cpup(val++);
+		efuse_offset = be32_to_cpup(val++);
+
+		tmp = readl(base + efuse_offset);
+		tmp &= of_data->efuse_voltage_mask;
+		tmp >>= __ffs(of_data->efuse_voltage_mask);
+
+		table->optimized_uv = of_data->efuse_voltage_uv ? tmp :
+					tmp * 1000;
+
+		dev_dbg(dev, "[%d] efuse=0x%08x volt_table=%d vset=%d\n",
+			i, efuse_offset, table->reference_uv,
+			table->optimized_uv);
+
+		/*
+		 * Some older samples might not have optimized efuse
+		 * Use reference voltage for those - just add debug message
+		 * for them.
+		 */
+		if (!table->optimized_uv) {
+			dev_dbg(dev, "[%d] efuse=0x%08x volt_table=%d:vset0\n",
+				i, efuse_offset, table->reference_uv);
+			table->optimized_uv = table->reference_uv;
+		}
+	}
+out:
+	iounmap(base);
+out_map:
+	return ret;
+}
+
+/**
+ * oppdm_free_optimized_voltages() - free resources for optimized voltages
+ * @dev:	opp domain device for which we need to free info
+ * @data:	data specific to the device
+ */
+static void oppdm_free_optimized_voltages(struct device *dev,
+					  struct ti_oppdm_data *data)
+{
+	kfree(data->vdd_table);
+	data->vdd_table = NULL;
+	data->num_vdd_table = 0;
+}
+
+/**
+ * oppdm_get_optimal_vdd_voltage() - Finds optimal voltage for the domain
+ * @dev:	opp domain device for which we need to find info
+ * @data:	data specific to the device
+ * @reference_uv:	reference voltage (OPP voltage) for which we need value
+ *
+ * Return: if a match is found, return optimized voltage, else return
+ * reference_uv, also return reference_uv if no optimization is needed.
+ */
+static int oppdm_get_optimal_vdd_voltage(struct device *dev,
+					 struct ti_oppdm_data *data,
+					 int reference_uv)
+{
+	int i;
+	struct ti_oppdm_optimum_voltage_table *table;
+
+	if (!data->num_vdd_table)
+		return reference_uv;
+
+	table = data->vdd_table;
+	if (!table)
+		return -EINVAL;
+
+	/* Find a exact match - this list is usually very small */
+	for (i = 0; i < data->num_vdd_table; i++, table++)
+		if (table->reference_uv == reference_uv)
+			return table->optimized_uv;
+
+	/* IF things are screwed up, we'd make a mess on console.. ratelimit */
+	dev_err_ratelimited(dev, "%s: Failed optimized voltage match for %d\n",
+			    __func__, reference_uv);
+	return reference_uv;
+}
+
+/**
+ * ti_oppdm_set_opp() - do the opp domain transition
+ * @dev:	opp domain device for which we are doing the transition
+ * @data:	information on regulators and new and old opps provided by
+ *		opp core to use in transition
+ *
+ * Return: If successful, 0, else appropriate error value.
+ */
+int ti_oppdm_set_opp(struct device *dev, struct dev_pm_set_opp_data *data)
+{
+	struct dev_pm_opp_supply *old_supply_vdd = &data->old_opp.supplies[0];
+	struct dev_pm_opp_supply *old_supply_vbb = &data->old_opp.supplies[1];
+	struct dev_pm_opp_supply *new_supply_vdd = &data->new_opp.supplies[0];
+	struct dev_pm_opp_supply *new_supply_vbb = &data->new_opp.supplies[1];
+	unsigned long old_freq = data->old_opp.rate, freq = data->new_opp.rate;
+	struct clk *clk = data->clk;
+	struct regulator *vdd_reg = data->regulators[0];
+	struct regulator *vbb_reg = data->regulators[1];
+	int vdd_uv;
+	int ret;
+
+	vdd_uv = oppdm_get_optimal_vdd_voltage(dev, &opp_data, new_supply_vbb->u_volt);
+
+	/* Scaling up? Scale voltage before frequency */
+	if (freq > old_freq) {
+		/* Regulator not available for device */
+
+		dev_dbg(dev, "vbb pre %luuV[min %luuV max %luuV]\n",
+			new_supply_vbb->u_volt, new_supply_vbb->u_volt_min,
+			new_supply_vbb->u_volt_max);
+
+		ret = regulator_set_voltage_triplet(vbb_reg,
+						    new_supply_vbb->u_volt_min,
+						    new_supply_vbb->u_volt,
+						    new_supply_vbb->u_volt_max);
+		if (ret) {
+			dev_err(dev, "vbb failed for %luuV[min %luuV max %luuV]\n",
+				new_supply_vbb->u_volt, new_supply_vbb->u_volt_min,
+				new_supply_vbb->u_volt_max);
+			return ret;
+		}
+
+		dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__,
+			new_supply_vdd->u_volt_min, new_supply_vdd->u_volt,
+			new_supply_vdd->u_volt_max);
+
+		ret = regulator_set_voltage_triplet(vdd_reg,
+						    new_supply_vdd->u_volt_min,
+						    new_supply_vdd->u_volt,
+						    new_supply_vdd->u_volt_max);
+		if (ret)
+			dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+				__func__, new_supply_vdd->u_volt_min,
+				new_supply_vdd->u_volt,
+				new_supply_vdd->u_volt_max, ret);
+	}
+
+	/* Change frequency */
+	dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n",
+		__func__, old_freq, freq);
+
+	ret = clk_set_rate(clk, freq);
+	if (ret) {
+		dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
+			ret);
+	}
+
+	/* Scaling down? Scale voltage after frequency */
+	if (freq < old_freq) {
+		dev_dbg(dev, "vbb post %luuV[min %luuV max %luuV]\n",
+			 new_supply_vbb->u_volt, new_supply_vbb->u_volt_min,
+			 new_supply_vbb->u_volt_max);
+
+		ret = regulator_set_voltage_triplet(vbb_reg,
+						    new_supply_vbb->u_volt_min,
+						    new_supply_vbb->u_volt,
+						    new_supply_vbb->u_volt_max);
+		if (ret) {
+			dev_err(dev, "vbb failed for %luuV[min %luuV max %luuV]\n",
+				new_supply_vbb->u_volt,
+				new_supply_vbb->u_volt_min,
+				new_supply_vbb->u_volt_max);
+			return ret;
+		}
+
+		dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__,
+			new_supply_vdd->u_volt_min, new_supply_vdd->u_volt,
+			new_supply_vdd->u_volt_max);
+
+		ret = regulator_set_voltage_triplet(vdd_reg,
+						    new_supply_vdd->u_volt_min,
+						    new_supply_vdd->u_volt,
+						    new_supply_vdd->u_volt_max);
+		if (ret)
+			dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+				__func__, new_supply_vdd->u_volt_min,
+				new_supply_vdd->u_volt,
+				new_supply_vdd->u_volt_max, ret);
+	}
+
+	return 0;
+
+restore_freq:
+	ret = clk_set_rate(clk, old_freq);
+	if (ret)
+		dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
+			__func__, old_freq);
+restore_voltage:
+	/* This shouldn't harm even if the voltages weren't updated earlier */
+	if (old_supply_vdd->u_volt) {
+		dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__,
+			old_supply_vdd->u_volt_min, old_supply_vdd->u_volt,
+			old_supply_vdd->u_volt_max);
+
+		ret = regulator_set_voltage_triplet(vdd_reg,
+						    old_supply_vdd->u_volt_min,
+						    old_supply_vdd->u_volt,
+						    old_supply_vdd->u_volt_max);
+		if (ret)
+			dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+				__func__, old_supply_vdd->u_volt_min,
+				old_supply_vdd->u_volt,
+				old_supply_vdd->u_volt_max, ret);
+	}
+
+	return ret;
+}
+
+static const struct ti_oppdm_of_data omap_generic_of_data = {
+};
+
+static const struct ti_oppdm_of_data omap_omap5_of_data = {
+	.flags = OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE,
+	.efuse_voltage_mask = 0xFFF,
+	.efuse_voltage_uv = false,
+};
+
+static const struct ti_oppdm_of_data omap_omap5core_of_data = {
+	.flags = OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE | OPPDM_HAS_NO_ABB,
+	.efuse_voltage_mask = 0xFFF,
+	.efuse_voltage_uv = false,
+};
+
+static const struct of_device_id ti_oppdm_of_match[] = {
+	{.compatible = "ti,omap-oppdm", .data = &omap_generic_of_data},
+	{.compatible = "ti,omap5-oppdm", .data = &omap_omap5_of_data},
+	{.compatible = "ti,omap5-core-oppdm", .data = &omap_omap5core_of_data},
+	{},
+};
+
+static int ti_oppdm_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device *cpu_dev = get_cpu_device(0); /* Gross hack */
+	const struct of_device_id *match;
+	struct pm_opp_domain_dev *oppdm_dev;
+	int ret = 0;
+	const struct ti_oppdm_of_data *of_data;
+	const char *names[] = {"vdd", "vbb"};
+
+	ret = dev_pm_opp_set_regulators(cpu_dev, names,
+					ARRAY_SIZE(names));
+
+	if (ret)
+		return ret;
+
+	match = of_match_device(ti_oppdm_of_match, dev);
+	if (!match) {
+		/* We do not expect this to happen */
+		dev_err(dev, "%s: Unable to match device\n", __func__);
+		return -ENODEV;
+	}
+	if (!match->data) {
+		/* Again, unlikely.. but mistakes do happen */
+		dev_err(dev, "%s: Bad data in match\n", __func__);
+		return -EINVAL;
+	}
+	of_data = match->data;
+
+	dev_set_drvdata(dev, (void *)of_data);
+	/* If we need optimized voltage */
+	if (of_data->flags & OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE) {
+		ret = oppdm_store_optimized_voltages(dev, &opp_data);
+	}
+
+	dev_pm_opp_register_set_opp_helper(cpu_dev, ti_oppdm_set_opp);
+
+	return ret;
+}
+
+MODULE_DEVICE_TABLE(of, ti_oppdm_of_match);
+
+static struct platform_driver ti_oppdm_driver = {
+	.probe = ti_oppdm_probe,
+	.driver = {
+		   .name = "ti_oppdm",
+		   .owner = THIS_MODULE,
+		   .of_match_table = of_match_ptr(ti_oppdm_of_match),
+		   },
+};
+module_platform_driver(ti_oppdm_driver);
+
+MODULE_DESCRIPTION("Texas Instruments OMAP OPP Domain driver");
+MODULE_AUTHOR("Texas Instruments Inc.");
+MODULE_LICENSE("GPL v2");
-- 
2.9.3