/* $NetBSD: ti_mux_clock.c,v 1.4 2025/12/16 12:20:22 skrll Exp $ */

/*-
 * Copyright (c) 2019 Jared McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ti_mux_clock.c,v 1.4 2025/12/16 12:20:22 skrll Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/bus.h>

#include <dev/clk/clk_backend.h>

#include <dev/fdt/fdtvar.h>

static int      ti_mux_clock_match(device_t, cfdata_t, void *);
static void     ti_mux_clock_attach(device_t, device_t, void *);

static struct clk *ti_mux_clock_decode(device_t, int, const void *, size_t);

static const struct fdtbus_clock_controller_func ti_mux_clock_fdt_funcs = {
        .decode = ti_mux_clock_decode
};

static struct clk *ti_mux_clock_get(void *, const char *);
static void     ti_mux_clock_put(void *, struct clk *);
static u_int    ti_mux_clock_get_rate(void *, struct clk *);
static struct clk *ti_mux_clock_get_parent(void *, struct clk *);
static int      ti_mux_clock_set_parent(void *, struct clk *, struct clk *);

static const struct clk_funcs ti_mux_clock_clk_funcs = {
        .get = ti_mux_clock_get,
        .put = ti_mux_clock_put,
        .get_rate = ti_mux_clock_get_rate,
        .get_parent = ti_mux_clock_get_parent,
        .set_parent = ti_mux_clock_set_parent,
};

struct ti_mux_clock_softc {
        device_t                sc_dev;
        int                     sc_phandle;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;

        struct clk_domain       sc_clkdom;
        struct clk              sc_clk;
        u_int                   sc_nparent;

        uint32_t                sc_mask;
        u_int                   sc_start_index;
};

#define RD4(sc, reg)                    \
        bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define WR4(sc, reg, val)               \
        bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))

CFATTACH_DECL_NEW(ti_mux_clock, sizeof(struct ti_mux_clock_softc),
    ti_mux_clock_match, ti_mux_clock_attach, NULL, NULL);

static const struct device_compatible_entry compat_data[] = {
        { .compat = "ti,composite-mux-clock" },
        { .compat = "ti,mux-clock" },
        DEVICE_COMPAT_EOL
};

static int
ti_mux_clock_match(device_t parent, cfdata_t cf, void *aux)
{
        const struct fdt_attach_args *faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
ti_mux_clock_attach(device_t parent, device_t self, void *aux)
{
        struct ti_mux_clock_softc * const sc = device_private(self);
        const struct fdt_attach_args *faa = aux;
        const int phandle = faa->faa_phandle;
        bus_addr_t addr, base_addr;
        u_int shift;

        const int prcm_phandle = OF_parent(OF_parent(phandle));
        if (fdtbus_get_reg(phandle, 0, &addr, NULL) != 0 ||
            fdtbus_get_reg(prcm_phandle, 0, &base_addr, NULL) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_phandle = phandle;
        sc->sc_bst = faa->faa_bst;
        if (bus_space_map(sc->sc_bst, base_addr + addr, 4, 0, &sc->sc_bsh) != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }

        sc->sc_nparent = fdtbus_clock_count(phandle, "clocks");
        sc->sc_start_index = of_hasprop(phandle, "ti,index-starts-at-one") ? 1 : 0;
        sc->sc_nparent += sc->sc_start_index;
        while (!powerof2(sc->sc_nparent))
                sc->sc_nparent++;

        if (of_getprop_uint32(phandle, "ti,bit-shift", &shift) != 0)
                shift = 0;

        sc->sc_mask = (sc->sc_nparent - 1) << shift;

        sc->sc_clkdom.name = device_xname(self);
        sc->sc_clkdom.funcs = &ti_mux_clock_clk_funcs;
        sc->sc_clkdom.priv = sc;

        sc->sc_clk.domain = &sc->sc_clkdom;
        sc->sc_clk.name = kmem_asprintf("%s", faa->faa_name);
        clk_attach(&sc->sc_clk);

        aprint_naive("\n");
        aprint_normal(": TI mux clock (%s)\n", sc->sc_clk.name);

        fdtbus_register_clock_controller(self, phandle, &ti_mux_clock_fdt_funcs);
}

static struct clk *
ti_mux_clock_decode(device_t dev, int cc_phandle, const void *data,
                    size_t len)
{
        struct ti_mux_clock_softc * const sc = device_private(dev);

        return &sc->sc_clk;
}

static struct clk *
ti_mux_clock_get(void *priv, const char *name)
{
        struct ti_mux_clock_softc * const sc = priv;

        return &sc->sc_clk;
}

static void
ti_mux_clock_put(void *priv, struct clk *clk)
{
}

static u_int
ti_mux_clock_get_rate(void *priv, struct clk *clk)
{
        struct clk *clk_parent = clk_get_parent(clk);

        if (clk_parent == NULL)
                return 0;

        return clk_get_rate(clk_parent);
}

static struct clk *
ti_mux_clock_get_parent(void *priv, struct clk *clk)
{
        struct ti_mux_clock_softc * const sc = priv;
        uint32_t val;
        u_int sel;

        val = RD4(sc, 0);
        sel = __SHIFTOUT(val, sc->sc_mask);

        return fdtbus_clock_get_index(sc->sc_phandle, sel - sc->sc_start_index);
}

static int
ti_mux_clock_set_parent(void *priv, struct clk *clk, struct clk *parent_clk)
{
        struct ti_mux_clock_softc * const sc = priv;
        uint32_t val;
        u_int sel;

        for (sel = sc->sc_start_index; sel < sc->sc_nparent; sel++) {
                if (fdtbus_clock_get_index(sc->sc_phandle, sel - sc->sc_start_index) == parent_clk)
                        break;
        }
        if (sel == sc->sc_nparent)
                return EINVAL;

        val = RD4(sc, 0);
        val &= ~sc->sc_mask;
        val |= __SHIFTIN(sel, sc->sc_mask);
        WR4(sc, 0, val);

        return 0;
}