root/drivers/clk/sunxi/clk-sun4i-display.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2015 Maxime Ripard
 *
 * Maxime Ripard <maxime.ripard@free-electrons.com>
 */

#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

struct sun4i_a10_display_clk_data {
        bool    has_div;
        u8      num_rst;
        u8      parents;

        u8      offset_en;
        u8      offset_div;
        u8      offset_mux;
        u8      offset_rst;

        u8      width_div;
        u8      width_mux;

        u32     flags;
};

struct reset_data {
        void __iomem                    *reg;
        spinlock_t                      *lock;
        struct reset_controller_dev     rcdev;
        u8                              offset;
};

static DEFINE_SPINLOCK(sun4i_a10_display_lock);

static inline struct reset_data *rcdev_to_reset_data(struct reset_controller_dev *rcdev)
{
        return container_of(rcdev, struct reset_data, rcdev);
};

static int sun4i_a10_display_assert(struct reset_controller_dev *rcdev,
                                    unsigned long id)
{
        struct reset_data *data = rcdev_to_reset_data(rcdev);
        unsigned long flags;
        u32 reg;

        spin_lock_irqsave(data->lock, flags);

        reg = readl(data->reg);
        writel(reg & ~BIT(data->offset + id), data->reg);

        spin_unlock_irqrestore(data->lock, flags);

        return 0;
}

static int sun4i_a10_display_deassert(struct reset_controller_dev *rcdev,
                                      unsigned long id)
{
        struct reset_data *data = rcdev_to_reset_data(rcdev);
        unsigned long flags;
        u32 reg;

        spin_lock_irqsave(data->lock, flags);

        reg = readl(data->reg);
        writel(reg | BIT(data->offset + id), data->reg);

        spin_unlock_irqrestore(data->lock, flags);

        return 0;
}

static int sun4i_a10_display_status(struct reset_controller_dev *rcdev,
                                    unsigned long id)
{
        struct reset_data *data = rcdev_to_reset_data(rcdev);

        return !(readl(data->reg) & BIT(data->offset + id));
}

static const struct reset_control_ops sun4i_a10_display_reset_ops = {
        .assert         = sun4i_a10_display_assert,
        .deassert       = sun4i_a10_display_deassert,
        .status         = sun4i_a10_display_status,
};

static int sun4i_a10_display_reset_xlate(struct reset_controller_dev *rcdev,
                                         const struct of_phandle_args *spec)
{
        /* We only have a single reset signal */
        return 0;
}

static void __init sun4i_a10_display_init(struct device_node *node,
                                          const struct sun4i_a10_display_clk_data *data)
{
        const char *parents[4];
        const char *clk_name = node->name;
        struct reset_data *reset_data;
        struct clk_divider *div = NULL;
        struct clk_gate *gate;
        struct resource res;
        struct clk_mux *mux;
        void __iomem *reg;
        struct clk *clk;
        int ret;

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

        reg = of_io_request_and_map(node, 0, of_node_full_name(node));
        if (IS_ERR(reg)) {
                pr_err("%s: Could not map the clock registers\n", clk_name);
                return;
        }

        ret = of_clk_parent_fill(node, parents, data->parents);
        if (ret != data->parents) {
                pr_err("%s: Could not retrieve the parents\n", clk_name);
                goto unmap;
        }

        mux = kzalloc_obj(*mux);
        if (!mux)
                goto unmap;

        mux->reg = reg;
        mux->shift = data->offset_mux;
        mux->mask = (1 << data->width_mux) - 1;
        mux->lock = &sun4i_a10_display_lock;

        gate = kzalloc_obj(*gate);
        if (!gate)
                goto free_mux;

        gate->reg = reg;
        gate->bit_idx = data->offset_en;
        gate->lock = &sun4i_a10_display_lock;

        if (data->has_div) {
                div = kzalloc_obj(*div);
                if (!div)
                        goto free_gate;

                div->reg = reg;
                div->shift = data->offset_div;
                div->width = data->width_div;
                div->lock = &sun4i_a10_display_lock;
        }

        clk = clk_register_composite(NULL, clk_name,
                                     parents, data->parents,
                                     &mux->hw, &clk_mux_ops,
                                     data->has_div ? &div->hw : NULL,
                                     data->has_div ? &clk_divider_ops : NULL,
                                     &gate->hw, &clk_gate_ops,
                                     data->flags);
        if (IS_ERR(clk)) {
                pr_err("%s: Couldn't register the clock\n", clk_name);
                goto free_div;
        }

        ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
        if (ret) {
                pr_err("%s: Couldn't register DT provider\n", clk_name);
                goto free_clk;
        }

        if (!data->num_rst)
                return;

        reset_data = kzalloc_obj(*reset_data);
        if (!reset_data)
                goto free_of_clk;

        reset_data->reg = reg;
        reset_data->offset = data->offset_rst;
        reset_data->lock = &sun4i_a10_display_lock;
        reset_data->rcdev.nr_resets = data->num_rst;
        reset_data->rcdev.ops = &sun4i_a10_display_reset_ops;
        reset_data->rcdev.of_node = node;

        if (data->num_rst == 1) {
                reset_data->rcdev.of_reset_n_cells = 0;
                reset_data->rcdev.of_xlate = &sun4i_a10_display_reset_xlate;
        } else {
                reset_data->rcdev.of_reset_n_cells = 1;
        }

        if (reset_controller_register(&reset_data->rcdev)) {
                pr_err("%s: Couldn't register the reset controller\n",
                       clk_name);
                goto free_reset;
        }

        return;

free_reset:
        kfree(reset_data);
free_of_clk:
        of_clk_del_provider(node);
free_clk:
        clk_unregister_composite(clk);
free_div:
        kfree(div);
free_gate:
        kfree(gate);
free_mux:
        kfree(mux);
unmap:
        iounmap(reg);
        of_address_to_resource(node, 0, &res);
        release_mem_region(res.start, resource_size(&res));
}

static const struct sun4i_a10_display_clk_data sun4i_a10_tcon_ch0_data __initconst = {
        .num_rst        = 2,
        .parents        = 4,
        .offset_en      = 31,
        .offset_rst     = 29,
        .offset_mux     = 24,
        .width_mux      = 2,
        .flags          = CLK_SET_RATE_PARENT,
};

static void __init sun4i_a10_tcon_ch0_setup(struct device_node *node)
{
        sun4i_a10_display_init(node, &sun4i_a10_tcon_ch0_data);
}
CLK_OF_DECLARE(sun4i_a10_tcon_ch0, "allwinner,sun4i-a10-tcon-ch0-clk",
               sun4i_a10_tcon_ch0_setup);

static const struct sun4i_a10_display_clk_data sun4i_a10_display_data __initconst = {
        .has_div        = true,
        .num_rst        = 1,
        .parents        = 3,
        .offset_en      = 31,
        .offset_rst     = 30,
        .offset_mux     = 24,
        .offset_div     = 0,
        .width_mux      = 2,
        .width_div      = 4,
};

static void __init sun4i_a10_display_setup(struct device_node *node)
{
        sun4i_a10_display_init(node, &sun4i_a10_display_data);
}
CLK_OF_DECLARE(sun4i_a10_display, "allwinner,sun4i-a10-display-clk",
               sun4i_a10_display_setup);