// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Free Electrons
 *
 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
 *
 * Allwinner A31 APB0 clock driver
 */

#include <linux/clk-provider.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>

/*
 * The APB0 clk has a configurable divisor.
 *
 * We must use a clk_div_table and not a regular power of 2
 * divisor here, because the first 2 values divide the clock
 * by 2.
 */
static const struct clk_div_table sun6i_a31_apb0_divs[] = {
        { .val = 0, .div = 2, },
        { .val = 1, .div = 2, },
        { .val = 2, .div = 4, },
        { .val = 3, .div = 8, },
        { /* sentinel */ },
};

static int sun6i_a31_apb0_clk_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        const char *clk_name = np->name;
        const char *clk_parent;
        void __iomem *reg;
        struct clk *clk;

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

        clk_parent = of_clk_get_parent_name(np, 0);
        if (!clk_parent)
                return -EINVAL;

        of_property_read_string(np, "clock-output-names", &clk_name);

        clk = clk_register_divider_table(&pdev->dev, clk_name, clk_parent,
                                         0, reg, 0, 2, 0, sun6i_a31_apb0_divs,
                                         NULL);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        return of_clk_add_provider(np, of_clk_src_simple_get, clk);
}

static const struct of_device_id sun6i_a31_apb0_clk_dt_ids[] = {
        { .compatible = "allwinner,sun6i-a31-apb0-clk" },
        { /* sentinel */ }
};

static struct platform_driver sun6i_a31_apb0_clk_driver = {
        .driver = {
                .name = "sun6i-a31-apb0-clk",
                .of_match_table = sun6i_a31_apb0_clk_dt_ids,
        },
        .probe = sun6i_a31_apb0_clk_probe,
};
builtin_platform_driver(sun6i_a31_apb0_clk_driver);