root/drivers/clk/clk-max77686.c
// SPDX-License-Identifier: GPL-2.0+
//
// clk-max77686.c - Clock driver for Maxim 77686/MAX77802
//
// Copyright (C) 2012 Samsung Electornics
// Jonghwa Lee <jonghwa3.lee@samsung.com>

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mfd/max77620.h>
#include <linux/mfd/max77686.h>
#include <linux/mfd/max77686-private.h>
#include <linux/clk-provider.h>
#include <linux/mutex.h>
#include <linux/clkdev.h>
#include <linux/of.h>
#include <linux/regmap.h>

#include <dt-bindings/clock/maxim,max77686.h>
#include <dt-bindings/clock/maxim,max77802.h>
#include <dt-bindings/clock/maxim,max77620.h>

#define MAX77802_CLOCK_LOW_JITTER_SHIFT 0x3

enum max77686_chip_name {
        CHIP_MAX77686,
        CHIP_MAX77802,
        CHIP_MAX77620,
};

struct max77686_hw_clk_info {
        const char *name;
        u32 clk_reg;
        u32 clk_enable_mask;
        u32 flags;
};

struct max77686_clk_init_data {
        struct regmap *regmap;
        struct clk_hw hw;
        struct clk_init_data clk_idata;
        const struct max77686_hw_clk_info *clk_info;
};

struct max77686_clk_driver_data {
        enum max77686_chip_name chip;
        struct max77686_clk_init_data *max_clk_data;
        size_t num_clks;
};

static const struct
max77686_hw_clk_info max77686_hw_clks_info[MAX77686_CLKS_NUM] = {
        [MAX77686_CLK_AP] = {
                .name = "32khz_ap",
                .clk_reg = MAX77686_REG_32KHZ,
                .clk_enable_mask = BIT(MAX77686_CLK_AP),
        },
        [MAX77686_CLK_CP] = {
                .name = "32khz_cp",
                .clk_reg = MAX77686_REG_32KHZ,
                .clk_enable_mask = BIT(MAX77686_CLK_CP),
        },
        [MAX77686_CLK_PMIC] = {
                .name = "32khz_pmic",
                .clk_reg = MAX77686_REG_32KHZ,
                .clk_enable_mask = BIT(MAX77686_CLK_PMIC),
        },
};

static const struct
max77686_hw_clk_info max77802_hw_clks_info[MAX77802_CLKS_NUM] = {
        [MAX77802_CLK_32K_AP] = {
                .name = "32khz_ap",
                .clk_reg = MAX77802_REG_32KHZ,
                .clk_enable_mask = BIT(MAX77802_CLK_32K_AP),
        },
        [MAX77802_CLK_32K_CP] = {
                .name = "32khz_cp",
                .clk_reg = MAX77802_REG_32KHZ,
                .clk_enable_mask = BIT(MAX77802_CLK_32K_CP),
        },
};

static const struct
max77686_hw_clk_info max77620_hw_clks_info[MAX77620_CLKS_NUM] = {
        [MAX77620_CLK_32K_OUT0] = {
                .name = "32khz_out0",
                .clk_reg = MAX77620_REG_CNFG1_32K,
                .clk_enable_mask = MAX77620_CNFG1_32K_OUT0_EN,
        },
};

static struct max77686_clk_init_data *to_max77686_clk_init_data(
                                struct clk_hw *hw)
{
        return container_of(hw, struct max77686_clk_init_data, hw);
}

static int max77686_clk_prepare(struct clk_hw *hw)
{
        struct max77686_clk_init_data *max77686 = to_max77686_clk_init_data(hw);

        return regmap_update_bits(max77686->regmap, max77686->clk_info->clk_reg,
                                  max77686->clk_info->clk_enable_mask,
                                  max77686->clk_info->clk_enable_mask);
}

static void max77686_clk_unprepare(struct clk_hw *hw)
{
        struct max77686_clk_init_data *max77686 = to_max77686_clk_init_data(hw);

        regmap_update_bits(max77686->regmap, max77686->clk_info->clk_reg,
                           max77686->clk_info->clk_enable_mask,
                           ~max77686->clk_info->clk_enable_mask);
}

static int max77686_clk_is_prepared(struct clk_hw *hw)
{
        struct max77686_clk_init_data *max77686 = to_max77686_clk_init_data(hw);
        int ret;
        u32 val;

        ret = regmap_read(max77686->regmap, max77686->clk_info->clk_reg, &val);

        if (ret < 0)
                return -EINVAL;

        return val & max77686->clk_info->clk_enable_mask;
}

static unsigned long max77686_recalc_rate(struct clk_hw *hw,
                                          unsigned long parent_rate)
{
        return 32768;
}

static const struct clk_ops max77686_clk_ops = {
        .prepare        = max77686_clk_prepare,
        .unprepare      = max77686_clk_unprepare,
        .is_prepared    = max77686_clk_is_prepared,
        .recalc_rate    = max77686_recalc_rate,
};

static struct clk_hw *
of_clk_max77686_get(struct of_phandle_args *clkspec, void *data)
{
        struct max77686_clk_driver_data *drv_data = data;
        unsigned int idx = clkspec->args[0];

        if (idx >= drv_data->num_clks) {
                pr_err("%s: invalid index %u\n", __func__, idx);
                return ERR_PTR(-EINVAL);
        }

        return &drv_data->max_clk_data[idx].hw;
}

static int max77686_clk_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device *parent = dev->parent;
        const struct platform_device_id *id = platform_get_device_id(pdev);
        struct max77686_clk_driver_data *drv_data;
        const struct max77686_hw_clk_info *hw_clks;
        struct regmap *regmap;
        int i, ret, num_clks;

        drv_data = devm_kzalloc(dev, sizeof(*drv_data), GFP_KERNEL);
        if (!drv_data)
                return -ENOMEM;

        regmap = dev_get_regmap(parent, NULL);
        if (!regmap) {
                dev_err(dev, "Failed to get rtc regmap\n");
                return -ENODEV;
        }

        drv_data->chip = id->driver_data;

        switch (drv_data->chip) {
        case CHIP_MAX77686:
                num_clks = MAX77686_CLKS_NUM;
                hw_clks = max77686_hw_clks_info;
                break;

        case CHIP_MAX77802:
                num_clks = MAX77802_CLKS_NUM;
                hw_clks = max77802_hw_clks_info;
                break;

        case CHIP_MAX77620:
                num_clks = MAX77620_CLKS_NUM;
                hw_clks = max77620_hw_clks_info;
                break;

        default:
                dev_err(dev, "Unknown Chip ID\n");
                return -EINVAL;
        }

        drv_data->num_clks = num_clks;
        drv_data->max_clk_data = devm_kcalloc(dev, num_clks,
                                              sizeof(*drv_data->max_clk_data),
                                              GFP_KERNEL);
        if (!drv_data->max_clk_data)
                return -ENOMEM;

        for (i = 0; i < num_clks; i++) {
                struct max77686_clk_init_data *max_clk_data;
                const char *clk_name;

                max_clk_data = &drv_data->max_clk_data[i];

                max_clk_data->regmap = regmap;
                max_clk_data->clk_info = &hw_clks[i];
                max_clk_data->clk_idata.flags = hw_clks[i].flags;
                max_clk_data->clk_idata.ops = &max77686_clk_ops;

                if (parent->of_node &&
                    !of_property_read_string_index(parent->of_node,
                                                   "clock-output-names",
                                                   i, &clk_name))
                        max_clk_data->clk_idata.name = clk_name;
                else
                        max_clk_data->clk_idata.name = hw_clks[i].name;

                max_clk_data->hw.init = &max_clk_data->clk_idata;

                ret = devm_clk_hw_register(dev, &max_clk_data->hw);
                if (ret) {
                        dev_err(dev, "Failed to clock register: %d\n", ret);
                        return ret;
                }

                ret = devm_clk_hw_register_clkdev(dev, &max_clk_data->hw,
                                                  max_clk_data->clk_idata.name,
                                                  NULL);
                if (ret < 0) {
                        dev_err(dev, "Failed to clkdev register: %d\n", ret);
                        return ret;
                }
        }

        if (parent->of_node) {
                ret = devm_of_clk_add_hw_provider(dev, of_clk_max77686_get,
                                                  drv_data);

                if (ret < 0) {
                        dev_err(dev, "Failed to register OF clock provider: %d\n",
                                ret);
                        return ret;
                }
        }

        /* MAX77802: Enable low-jitter mode on the 32khz clocks. */
        if (drv_data->chip == CHIP_MAX77802) {
                ret = regmap_update_bits(regmap, MAX77802_REG_32KHZ,
                                         1 << MAX77802_CLOCK_LOW_JITTER_SHIFT,
                                         1 << MAX77802_CLOCK_LOW_JITTER_SHIFT);
                if (ret < 0) {
                        dev_err(dev, "Failed to config low-jitter: %d\n", ret);
                        return ret;
                }
        }

        return 0;
}

static const struct platform_device_id max77686_clk_id[] = {
        { "max77686-clk", .driver_data = CHIP_MAX77686, },
        { "max77802-clk", .driver_data = CHIP_MAX77802, },
        { "max77620-clock", .driver_data = CHIP_MAX77620, },
        {},
};
MODULE_DEVICE_TABLE(platform, max77686_clk_id);

static struct platform_driver max77686_clk_driver = {
        .driver = {
                .name  = "max77686-clk",
        },
        .probe = max77686_clk_probe,
        .id_table = max77686_clk_id,
};

module_platform_driver(max77686_clk_driver);

MODULE_DESCRIPTION("MAXIM 77686 Clock Driver");
MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
MODULE_LICENSE("GPL");