PM / OPP: Add ti-opp-supply driver

Introduce a ti-opp-supply driver that will use new multiple regulator
support that is part of the OPP core This is needed on TI platforms like
DRA7/AM57 in order to control both CPU regulator and Adaptive Body Bias
(ABB) regulator. These regulators must be scaled in sequence during an
OPP transition depending on whether or not the frequency is being scaled
up or down.

This driver also implements AVS Class0 for these parts by looking up the
required values from registers in the SoC and programming adjusted
optimal voltage values for each OPP.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 426 insertions, 0 deletions

diff --git a/drivers/opp/Makefile b/drivers/opp/Makefile
index e70ceb406fe9..6ce6aefacc81 100644
--- a/drivers/opp/Makefile
+++ b/drivers/opp/Makefile
@@ -2,3 +2,4 @@ ccflags-$(CONFIG_DEBUG_DRIVER)	:= -DDEBUG
 obj-y                           += core.o cpu.o
 obj-$(CONFIG_OF)                += of.o
 obj-$(CONFIG_DEBUG_FS)          += debugfs.o
+obj-$(CONFIG_ARM_TI_CPUFREQ)    += ti-opp-supply.o
diff --git a/drivers/opp/ti-opp-supply.c b/drivers/opp/ti-opp-supply.c
new file mode 100644
index 000000000000..44dae3e51aac
--- /dev/null
+++ b/drivers/opp/ti-opp-supply.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
+ *      Nishanth Menon <nm@ti.com>
+ *      Dave Gerlach <d-gerlach@ti.com>
+ *
+ * TI OPP supply driver that provides override into the regulator control
+ * for generic opp core 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_opp_supply_optimum_voltage_table - optimized voltage table
+ * @reference_uv:       reference voltage (usually Nominal voltage)
+ * @optimized_uv:       Optimized voltage from efuse
+ */
+struct ti_opp_supply_optimum_voltage_table {
+        unsigned int reference_uv;
+        unsigned int optimized_uv;
+};
+
+/**
+ * struct ti_opp_supply_data - OMAP specific opp supply data
+ * @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 supply
+ */
+struct ti_opp_supply_data {
+        struct ti_opp_supply_optimum_voltage_table *vdd_table;
+        u32 num_vdd_table;
+        u32 vdd_absolute_max_voltage_uv;
+};
+
+static struct ti_opp_supply_data opp_data;
+
+/**
+ * struct ti_opp_supply_of_data - device tree match data
+ * @flags:      specific type of opp supply
+ * @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_opp_supply_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;
+};
+
+/**
+ * _store_optimized_voltages() - store optimized voltages
+ * @dev:        ti opp supply 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 _store_optimized_voltages(struct device *dev,
+                                     struct ti_opp_supply_data *data)
+{
+        void __iomem *base;
+        struct property *prop;
+        struct resource *res;
+        const __be32 *val;
+        int proplen, i;
+        int ret = 0;
+        struct ti_opp_supply_optimum_voltage_table *table;
+        const struct ti_opp_supply_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;
+}
+
+/**
+ * _free_optimized_voltages() - free resources for optvoltages
+ * @dev:        device for which we need to free info
+ * @data:       data specific to the device
+ */
+static void _free_optimized_voltages(struct device *dev,
+                                     struct ti_opp_supply_data *data)
+{
+        kfree(data->vdd_table);
+        data->vdd_table = NULL;
+        data->num_vdd_table = 0;
+}
+
+/**
+ * _get_optimal_vdd_voltage() - Finds optimal voltage for the supply
+ * @dev:        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 _get_optimal_vdd_voltage(struct device *dev,
+                                    struct ti_opp_supply_data *data,
+                                    int reference_uv)
+{
+        int i;
+        struct ti_opp_supply_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;
+}
+
+static int _opp_set_voltage(struct device *dev,
+                            struct dev_pm_opp_supply *supply,
+                            int new_target_uv, struct regulator *reg,
+                            char *reg_name)
+{
+        int ret;
+        unsigned long vdd_uv, uv_max;
+
+        if (new_target_uv)
+                vdd_uv = new_target_uv;
+        else
+                vdd_uv = supply->u_volt;
+
+        /*
+         * If we do have an absolute max voltage specified, then we should
+         * use that voltage instead to allow for cases where the voltage rails
+         * are ganged (example if we set the max for an opp as 1.12v, and
+         * the absolute max is 1.5v, for another rail to get 1.25v, it cannot
+         * be achieved if the regulator is constrainted to max of 1.12v, even
+         * if it can function at 1.25v
+         */
+        if (opp_data.vdd_absolute_max_voltage_uv)
+                uv_max = opp_data.vdd_absolute_max_voltage_uv;
+        else
+                uv_max = supply->u_volt_max;
+
+        if (vdd_uv > uv_max ||
+            vdd_uv < supply->u_volt_min ||
+            supply->u_volt_min > uv_max) {
+                dev_warn(dev,
+                         "Invalid range voltages [Min:%lu target:%lu Max:%lu]\n",
+                         supply->u_volt_min, vdd_uv, uv_max);
+                return -EINVAL;
+        }
+
+        dev_dbg(dev, "%s scaling to %luuV[min %luuV max %luuV]\n", reg_name,
+                vdd_uv, supply->u_volt_min,
+                uv_max);
+
+        ret = regulator_set_voltage_triplet(reg,
+                                            supply->u_volt_min,
+                                            vdd_uv,
+                                            uv_max);
+        if (ret) {
+                dev_err(dev, "%s failed for %luuV[min %luuV max %luuV]\n",
+                        reg_name, vdd_uv, supply->u_volt_min,
+                        uv_max);
+                return ret;
+        }
+
+        return 0;
+}
+
+/**
+ * ti_opp_supply_set_opp() - do the opp supply 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_opp_supply_set_opp(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];
+        struct device *dev = data->dev;
+        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 = _get_optimal_vdd_voltage(dev, &opp_data,
+                                          new_supply_vbb->u_volt);
+
+        /* Scaling up? Scale voltage before frequency */
+        if (freq > old_freq) {
+                ret = _opp_set_voltage(dev, new_supply_vdd, vdd_uv, vdd_reg,
+                                       "vdd");
+                if (ret)
+                        goto restore_voltage;
+
+                ret = _opp_set_voltage(dev, new_supply_vbb, 0, vbb_reg, "vbb");
+                if (ret)
+                        goto restore_voltage;
+        }
+
+        /* 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);
+                goto restore_voltage;
+        }
+
+        /* Scaling down? Scale voltage after frequency */
+        if (freq < old_freq) {
+                ret = _opp_set_voltage(dev, new_supply_vbb, 0, vbb_reg, "vbb");
+                if (ret)
+                        goto restore_freq;
+
+                ret = _opp_set_voltage(dev, new_supply_vdd, vdd_uv, vdd_reg,
+                                       "vdd");
+                if (ret)
+                        goto restore_freq;
+        }
+
+        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) {
+                ret = _opp_set_voltage(dev, old_supply_vbb, 0, vbb_reg, "vbb");
+                if (ret)
+                        return ret;
+
+                ret = _opp_set_voltage(dev, old_supply_vdd, 0, vdd_reg,
+                                       "vdd");
+                if (ret)
+                        return ret;
+        }
+
+        return ret;
+}
+
+static const struct ti_opp_supply_of_data omap_generic_of_data = {
+};
+
+static const struct ti_opp_supply_of_data omap_omap5_of_data = {
+        .flags = OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE,
+        .efuse_voltage_mask = 0xFFF,
+        .efuse_voltage_uv = false,
+};
+
+static const struct ti_opp_supply_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_opp_supply_of_match[] = {
+        {.compatible = "ti,omap-opp-supply", .data = &omap_generic_of_data},
+        {.compatible = "ti,omap5-opp-supply", .data = &omap_omap5_of_data},
+        {.compatible = "ti,omap5-core-opp-supply",
+         .data = &omap_omap5core_of_data},
+        {},
+};
+MODULE_DEVICE_TABLE(of, ti_opp_supply_of_match);
+
+static int ti_opp_supply_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct device *cpu_dev = get_cpu_device(0);
+        const struct of_device_id *match;
+        const struct ti_opp_supply_of_data *of_data;
+        int ret = 0;
+
+        match = of_match_device(ti_opp_supply_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 = _store_optimized_voltages(dev, &opp_data);
+                if (ret)
+                        return ret;
+        }
+
+        ret = PTR_ERR_OR_ZERO(dev_pm_opp_register_set_opp_helper(cpu_dev,
+                                                                 ti_opp_supply_set_opp));
+        if (ret)
+                _free_optimized_voltages(dev, &opp_data);
+
+        return ret;
+}
+
+static struct platform_driver ti_opp_supply_driver = {
+        .probe = ti_opp_supply_probe,
+        .driver = {
+                   .name = "ti_opp_supply",
+                   .owner = THIS_MODULE,
+                   .of_match_table = of_match_ptr(ti_opp_supply_of_match),
+                   },
+};
+module_platform_driver(ti_opp_supply_driver);
+
+MODULE_DESCRIPTION("Texas Instruments OMAP OPP Supply driver");
+MODULE_AUTHOR("Texas Instruments Inc.");
+MODULE_LICENSE("GPL v2");