// SPDX-License-Identifier: GPL-2.0
/*
 * Clock driver for TI Davinci PSC controllers
 *
 * Copyright (C) 2017 David Lechner <david@lechnology.com>
 *
 * Based on: drivers/clk/keystone/gate.c
 * Copyright (C) 2013 Texas Instruments.
 *      Murali Karicheri <m-karicheri2@ti.com>
 *      Santosh Shilimkar <santosh.shilimkar@ti.com>
 *
 * And: arch/arm/mach-davinci/psc.c
 * Copyright (C) 2006 Texas Instruments.
 */

#include <linux/clk-provider.h>
#include <linux/clk.h>
#include <linux/clk/davinci.h>
#include <linux/clkdev.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/pm_clock.h>
#include <linux/pm_domain.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/types.h>

#include "psc.h"

/* PSC register offsets */
#define EPCPR                   0x070
#define PTCMD                   0x120
#define PTSTAT                  0x128
#define PDSTAT(n)               (0x200 + 4 * (n))
#define PDCTL(n)                (0x300 + 4 * (n))
#define MDSTAT(n)               (0x800 + 4 * (n))
#define MDCTL(n)                (0xa00 + 4 * (n))

/* PSC module states */
enum davinci_lpsc_state {
        LPSC_STATE_SWRSTDISABLE = 0,
        LPSC_STATE_SYNCRST      = 1,
        LPSC_STATE_DISABLE      = 2,
        LPSC_STATE_ENABLE       = 3,
};

#define MDSTAT_STATE_MASK       GENMASK(5, 0)
#define MDSTAT_MCKOUT           BIT(12)
#define PDSTAT_STATE_MASK       GENMASK(4, 0)
#define MDCTL_FORCE             BIT(31)
#define MDCTL_LRESET            BIT(8)
#define PDCTL_EPCGOOD           BIT(8)
#define PDCTL_NEXT              BIT(0)

struct davinci_psc_data {
        struct clk_onecell_data clk_data;
        struct genpd_onecell_data pm_data;
        struct reset_controller_dev rcdev;
};

/**
 * struct davinci_lpsc_clk - LPSC clock structure
 * @dev: the device that provides this LPSC or NULL
 * @hw: clk_hw for the LPSC
 * @pm_domain: power domain for the LPSC
 * @genpd_clk: clock reference owned by @pm_domain
 * @regmap: PSC MMIO region
 * @md: Module domain (LPSC module id)
 * @pd: Power domain
 * @flags: LPSC_* quirk flags
 */
struct davinci_lpsc_clk {
        struct device *dev;
        struct clk_hw hw;
        struct generic_pm_domain pm_domain;
        struct clk *genpd_clk;
        struct regmap *regmap;
        u32 md;
        u32 pd;
        u32 flags;
};

#define to_davinci_psc_data(x) container_of(x, struct davinci_psc_data, x)
#define to_davinci_lpsc_clk(x) container_of(x, struct davinci_lpsc_clk, x)

/**
 * best_dev_name - get the "best" device name.
 * @dev: the device
 *
 * Returns the device tree compatible name if the device has a DT node,
 * otherwise return the device name. This is mainly needed because clkdev
 * lookups are limited to 20 chars for dev_id and when using device tree,
 * dev_name(dev) is much longer than that.
 */
static inline const char *best_dev_name(struct device *dev)
{
        const char *compatible;

        if (!of_property_read_string(dev->of_node, "compatible", &compatible))
                return compatible;

        return dev_name(dev);
}

static void davinci_lpsc_config(struct davinci_lpsc_clk *lpsc,
                                enum davinci_lpsc_state next_state)
{
        u32 epcpr, pdstat, mdstat, ptstat;

        regmap_write_bits(lpsc->regmap, MDCTL(lpsc->md), MDSTAT_STATE_MASK,
                          next_state);

        if (lpsc->flags & LPSC_FORCE)
                regmap_write_bits(lpsc->regmap, MDCTL(lpsc->md), MDCTL_FORCE,
                                  MDCTL_FORCE);

        regmap_read(lpsc->regmap, PDSTAT(lpsc->pd), &pdstat);
        if ((pdstat & PDSTAT_STATE_MASK) == 0) {
                regmap_write_bits(lpsc->regmap, PDCTL(lpsc->pd), PDCTL_NEXT,
                                  PDCTL_NEXT);

                regmap_write(lpsc->regmap, PTCMD, BIT(lpsc->pd));

                regmap_read_poll_timeout(lpsc->regmap, EPCPR, epcpr,
                                         epcpr & BIT(lpsc->pd), 0, 0);

                regmap_write_bits(lpsc->regmap, PDCTL(lpsc->pd), PDCTL_EPCGOOD,
                                  PDCTL_EPCGOOD);
        } else {
                regmap_write(lpsc->regmap, PTCMD, BIT(lpsc->pd));
        }

        regmap_read_poll_timeout(lpsc->regmap, PTSTAT, ptstat,
                                 !(ptstat & BIT(lpsc->pd)), 0, 0);

        regmap_read_poll_timeout(lpsc->regmap, MDSTAT(lpsc->md), mdstat,
                                 (mdstat & MDSTAT_STATE_MASK) == next_state,
                                 0, 0);
}

static int davinci_lpsc_clk_enable(struct clk_hw *hw)
{
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(hw);

        davinci_lpsc_config(lpsc, LPSC_STATE_ENABLE);

        return 0;
}

static void davinci_lpsc_clk_disable(struct clk_hw *hw)
{
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(hw);

        davinci_lpsc_config(lpsc, LPSC_STATE_DISABLE);
}

static int davinci_lpsc_clk_is_enabled(struct clk_hw *hw)
{
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(hw);
        u32 mdstat;

        regmap_read(lpsc->regmap, MDSTAT(lpsc->md), &mdstat);

        return (mdstat & MDSTAT_MCKOUT) ? 1 : 0;
}

static const struct clk_ops davinci_lpsc_clk_ops = {
        .enable         = davinci_lpsc_clk_enable,
        .disable        = davinci_lpsc_clk_disable,
        .is_enabled     = davinci_lpsc_clk_is_enabled,
};

static int davinci_psc_genpd_attach_dev(struct generic_pm_domain *pm_domain,
                                        struct device *dev)
{
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(pm_domain);
        struct clk *clk;
        int ret;

        /*
         * pm_clk_remove_clk() will call clk_put(), so we have to use clk_get()
         * to get the clock instead of using lpsc->hw.clk directly.
         */
        clk = clk_get_sys(best_dev_name(lpsc->dev), clk_hw_get_name(&lpsc->hw));
        if (IS_ERR(clk))
                return (PTR_ERR(clk));

        ret = pm_clk_create(dev);
        if (ret < 0)
                goto fail_clk_put;

        ret = pm_clk_add_clk(dev, clk);
        if (ret < 0)
                goto fail_pm_clk_destroy;

        lpsc->genpd_clk = clk;

        return 0;

fail_pm_clk_destroy:
        pm_clk_destroy(dev);
fail_clk_put:
        clk_put(clk);

        return ret;
}

static void davinci_psc_genpd_detach_dev(struct generic_pm_domain *pm_domain,
                                         struct device *dev)
{
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(pm_domain);

        pm_clk_remove_clk(dev, lpsc->genpd_clk);
        pm_clk_destroy(dev);

        lpsc->genpd_clk = NULL;
}

/**
 * davinci_lpsc_clk_register - register LPSC clock
 * @dev: the clocks's device or NULL
 * @name: name of this clock
 * @parent_name: name of clock's parent
 * @regmap: PSC MMIO region
 * @md: local PSC number
 * @pd: power domain
 * @flags: LPSC_* flags
 */
static struct davinci_lpsc_clk *
davinci_lpsc_clk_register(struct device *dev, const char *name,
                          const char *parent_name, struct regmap *regmap,
                          u32 md, u32 pd, u32 flags)
{
        struct clk_init_data init;
        struct davinci_lpsc_clk *lpsc;
        int ret;
        bool is_on;

        lpsc = kzalloc_obj(*lpsc);
        if (!lpsc)
                return ERR_PTR(-ENOMEM);

        init.name = name;
        init.ops = &davinci_lpsc_clk_ops;
        init.parent_names = (parent_name ? &parent_name : NULL);
        init.num_parents = (parent_name ? 1 : 0);
        init.flags = 0;

        if (flags & LPSC_ALWAYS_ENABLED)
                init.flags |= CLK_IS_CRITICAL;

        if (flags & LPSC_SET_RATE_PARENT)
                init.flags |= CLK_SET_RATE_PARENT;

        lpsc->dev = dev;
        lpsc->regmap = regmap;
        lpsc->hw.init = &init;
        lpsc->md = md;
        lpsc->pd = pd;
        lpsc->flags = flags;

        ret = clk_hw_register(dev, &lpsc->hw);
        if (ret < 0) {
                kfree(lpsc);
                return ERR_PTR(ret);
        }

        /* for now, genpd is only registered when using device-tree */
        if (!dev || !dev->of_node)
                return lpsc;

        /* genpd attach needs a way to look up this clock */
        ret = clk_hw_register_clkdev(&lpsc->hw, name, best_dev_name(dev));

        lpsc->pm_domain.name = devm_kasprintf(dev, GFP_KERNEL, "%s: %s",
                                              best_dev_name(dev), name);
        if (!lpsc->pm_domain.name) {
                clk_hw_unregister(&lpsc->hw);
                kfree(lpsc);
                return ERR_PTR(-ENOMEM);
        }
        lpsc->pm_domain.attach_dev = davinci_psc_genpd_attach_dev;
        lpsc->pm_domain.detach_dev = davinci_psc_genpd_detach_dev;
        lpsc->pm_domain.flags = GENPD_FLAG_PM_CLK;

        is_on = davinci_lpsc_clk_is_enabled(&lpsc->hw);
        pm_genpd_init(&lpsc->pm_domain, NULL, is_on);

        return lpsc;
}

static int davinci_lpsc_clk_reset(struct clk *clk, bool reset)
{
        struct clk_hw *hw = __clk_get_hw(clk);
        struct davinci_lpsc_clk *lpsc = to_davinci_lpsc_clk(hw);
        u32 mdctl;

        if (IS_ERR_OR_NULL(lpsc))
                return -EINVAL;

        mdctl = reset ? 0 : MDCTL_LRESET;
        regmap_write_bits(lpsc->regmap, MDCTL(lpsc->md), MDCTL_LRESET, mdctl);

        return 0;
}

static int davinci_psc_reset_assert(struct reset_controller_dev *rcdev,
                                    unsigned long id)
{
        struct davinci_psc_data *psc = to_davinci_psc_data(rcdev);
        struct clk *clk = psc->clk_data.clks[id];

        return davinci_lpsc_clk_reset(clk, true);
}

static int davinci_psc_reset_deassert(struct reset_controller_dev *rcdev,
                                      unsigned long id)
{
        struct davinci_psc_data *psc = to_davinci_psc_data(rcdev);
        struct clk *clk = psc->clk_data.clks[id];

        return davinci_lpsc_clk_reset(clk, false);
}

static const struct reset_control_ops davinci_psc_reset_ops = {
        .assert         = davinci_psc_reset_assert,
        .deassert       = davinci_psc_reset_deassert,
};

static int davinci_psc_reset_of_xlate(struct reset_controller_dev *rcdev,
                                      const struct of_phandle_args *reset_spec)
{
        struct of_phandle_args clkspec = *reset_spec; /* discard const qualifier */
        struct clk *clk;
        struct clk_hw *hw;
        struct davinci_lpsc_clk *lpsc;

        /* the clock node is the same as the reset node */
        clk = of_clk_get_from_provider(&clkspec);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        hw = __clk_get_hw(clk);
        lpsc = to_davinci_lpsc_clk(hw);
        clk_put(clk);

        /* not all modules support local reset */
        if (!(lpsc->flags & LPSC_LOCAL_RESET))
                return -EINVAL;

        return lpsc->md;
}

static const struct regmap_config davinci_psc_regmap_config = {
        .reg_bits       = 32,
        .reg_stride     = 4,
        .val_bits       = 32,
};

static struct davinci_psc_data *
__davinci_psc_register_clocks(struct device *dev,
                              const struct davinci_lpsc_clk_info *info,
                              int num_clks,
                              void __iomem *base)
{
        struct davinci_psc_data *psc;
        struct clk **clks;
        struct generic_pm_domain **pm_domains;
        struct regmap *regmap;
        int i, ret;

        psc = kzalloc_obj(*psc);
        if (!psc)
                return ERR_PTR(-ENOMEM);

        clks = kmalloc_objs(*clks, num_clks);
        if (!clks) {
                ret = -ENOMEM;
                goto err_free_psc;
        }

        psc->clk_data.clks = clks;
        psc->clk_data.clk_num = num_clks;

        /*
         * init array with error so that of_clk_src_onecell_get() doesn't
         * return NULL for gaps in the sparse array
         */
        for (i = 0; i < num_clks; i++)
                clks[i] = ERR_PTR(-ENOENT);

        pm_domains = kzalloc_objs(*pm_domains, num_clks);
        if (!pm_domains) {
                ret = -ENOMEM;
                goto err_free_clks;
        }

        psc->pm_data.domains = pm_domains;
        psc->pm_data.num_domains = num_clks;

        regmap = regmap_init_mmio(dev, base, &davinci_psc_regmap_config);
        if (IS_ERR(regmap)) {
                ret = PTR_ERR(regmap);
                goto err_free_pm_domains;
        }

        for (; info->name; info++) {
                struct davinci_lpsc_clk *lpsc;

                lpsc = davinci_lpsc_clk_register(dev, info->name, info->parent,
                                                 regmap, info->md, info->pd,
                                                 info->flags);
                if (IS_ERR(lpsc)) {
                        dev_warn(dev, "Failed to register %s (%ld)\n",
                                 info->name, PTR_ERR(lpsc));
                        continue;
                }

                clks[info->md] = lpsc->hw.clk;
                pm_domains[info->md] = &lpsc->pm_domain;
        }

        /*
         * for now, a reset controller is only registered when there is a device
         * to associate it with.
         */
        if (!dev)
                return psc;

        psc->rcdev.ops = &davinci_psc_reset_ops;
        psc->rcdev.owner = THIS_MODULE;
        psc->rcdev.dev = dev;
        psc->rcdev.of_node = dev->of_node;
        psc->rcdev.of_reset_n_cells = 1;
        psc->rcdev.of_xlate = davinci_psc_reset_of_xlate;
        psc->rcdev.nr_resets = num_clks;

        ret = devm_reset_controller_register(dev, &psc->rcdev);
        if (ret < 0)
                dev_warn(dev, "Failed to register reset controller (%d)\n", ret);

        return psc;

err_free_pm_domains:
        kfree(pm_domains);
err_free_clks:
        kfree(clks);
err_free_psc:
        kfree(psc);

        return ERR_PTR(ret);
}

int davinci_psc_register_clocks(struct device *dev,
                                const struct davinci_lpsc_clk_info *info,
                                u8 num_clks,
                                void __iomem *base)
{
        struct davinci_psc_data *psc;

        psc = __davinci_psc_register_clocks(dev, info, num_clks, base);
        if (IS_ERR(psc))
                return PTR_ERR(psc);

        for (; info->name; info++) {
                const struct davinci_lpsc_clkdev_info *cdevs = info->cdevs;
                struct clk *clk = psc->clk_data.clks[info->md];

                if (!cdevs || IS_ERR_OR_NULL(clk))
                        continue;

                for (; cdevs->con_id || cdevs->dev_id; cdevs++)
                        clk_register_clkdev(clk, cdevs->con_id, cdevs->dev_id);
        }

        return 0;
}

int of_davinci_psc_clk_init(struct device *dev,
                            const struct davinci_lpsc_clk_info *info,
                            u8 num_clks,
                            void __iomem *base)
{
        struct device_node *node = dev->of_node;
        struct davinci_psc_data *psc;

        psc = __davinci_psc_register_clocks(dev, info, num_clks, base);
        if (IS_ERR(psc))
                return PTR_ERR(psc);

        of_genpd_add_provider_onecell(node, &psc->pm_data);

        of_clk_add_provider(node, of_clk_src_onecell_get, &psc->clk_data);

        return 0;
}

static const struct of_device_id davinci_psc_of_match[] = {
        { .compatible = "ti,da850-psc0", .data = &of_da850_psc0_init_data },
        { .compatible = "ti,da850-psc1", .data = &of_da850_psc1_init_data },
        { }
};

static const struct platform_device_id davinci_psc_id_table[] = {
        { .name = "da850-psc0", .driver_data = (kernel_ulong_t)&da850_psc0_init_data },
        { .name = "da850-psc1", .driver_data = (kernel_ulong_t)&da850_psc1_init_data },
        { }
};

static int davinci_psc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct davinci_psc_init_data *init_data = NULL;
        void __iomem *base;
        int ret;

        init_data = device_get_match_data(dev);
        if (!init_data && pdev->id_entry)
                init_data = (void *)pdev->id_entry->driver_data;

        if (!init_data) {
                dev_err(dev, "unable to find driver init data\n");
                return -EINVAL;
        }

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        ret = devm_clk_bulk_get(dev, init_data->num_parent_clks,
                                init_data->parent_clks);
        if (ret < 0)
                return ret;

        return init_data->psc_init(dev, base);
}

static struct platform_driver davinci_psc_driver = {
        .probe          = davinci_psc_probe,
        .driver         = {
                .name           = "davinci-psc-clk",
                .of_match_table = davinci_psc_of_match,
        },
        .id_table       = davinci_psc_id_table,
};

static int __init davinci_psc_driver_init(void)
{
        return platform_driver_register(&davinci_psc_driver);
}

/* has to be postcore_initcall because davinci_gpio depend on PSC clocks */
postcore_initcall(davinci_psc_driver_init);