// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2016-2017 Texas Instruments Incorporated - https://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(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 = kcalloc(data->num_vdd_table, sizeof(*data->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.
 */
static 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_vdd->u_volt);

        if (new_supply_vdd->u_volt_min < vdd_uv)
                new_supply_vdd->u_volt_min = vdd_uv;

        /* 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",
                   .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");