/*
 * Copyright (C) 2009 Nokia Corporation
 * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define DSS_SUBSYS_NAME "SDI"

#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/regulator/consumer.h>
#include <linux/export.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/of.h>

#include "omapdss.h"
#include "dss.h"

struct sdi_device {
        struct platform_device *pdev;
        struct dss_device *dss;

        bool update_enabled;
        struct regulator *vdds_sdi_reg;

        struct dss_lcd_mgr_config mgr_config;
        struct videomode vm;
        int datapairs;

        struct omap_dss_device output;
};

#define dssdev_to_sdi(dssdev) container_of(dssdev, struct sdi_device, output)

struct sdi_clk_calc_ctx {
        struct sdi_device *sdi;
        unsigned long pck_min, pck_max;

        unsigned long fck;
        struct dispc_clock_info dispc_cinfo;
};

static bool dpi_calc_dispc_cb(int lckd, int pckd, unsigned long lck,
                unsigned long pck, void *data)
{
        struct sdi_clk_calc_ctx *ctx = data;

        ctx->dispc_cinfo.lck_div = lckd;
        ctx->dispc_cinfo.pck_div = pckd;
        ctx->dispc_cinfo.lck = lck;
        ctx->dispc_cinfo.pck = pck;

        return true;
}

static bool dpi_calc_dss_cb(unsigned long fck, void *data)
{
        struct sdi_clk_calc_ctx *ctx = data;

        ctx->fck = fck;

        return dispc_div_calc(ctx->sdi->dss->dispc, fck,
                              ctx->pck_min, ctx->pck_max,
                              dpi_calc_dispc_cb, ctx);
}

static int sdi_calc_clock_div(struct sdi_device *sdi, unsigned long pclk,
                              unsigned long *fck,
                              struct dispc_clock_info *dispc_cinfo)
{
        int i;
        struct sdi_clk_calc_ctx ctx;

        /*
         * DSS fclk gives us very few possibilities, so finding a good pixel
         * clock may not be possible. We try multiple times to find the clock,
         * each time widening the pixel clock range we look for, up to
         * +/- 1MHz.
         */

        for (i = 0; i < 10; ++i) {
                bool ok;

                memset(&ctx, 0, sizeof(ctx));

                ctx.sdi = sdi;

                if (pclk > 1000 * i * i * i)
                        ctx.pck_min = max(pclk - 1000 * i * i * i, 0lu);
                else
                        ctx.pck_min = 0;
                ctx.pck_max = pclk + 1000 * i * i * i;

                ok = dss_div_calc(sdi->dss, pclk, ctx.pck_min,
                                  dpi_calc_dss_cb, &ctx);
                if (ok) {
                        *fck = ctx.fck;
                        *dispc_cinfo = ctx.dispc_cinfo;
                        return 0;
                }
        }

        return -EINVAL;
}

static void sdi_config_lcd_manager(struct sdi_device *sdi)
{
        sdi->mgr_config.io_pad_mode = DSS_IO_PAD_MODE_BYPASS;

        sdi->mgr_config.stallmode = false;
        sdi->mgr_config.fifohandcheck = false;

        sdi->mgr_config.video_port_width = 24;
        sdi->mgr_config.lcden_sig_polarity = 1;

        dss_mgr_set_lcd_config(&sdi->output, &sdi->mgr_config);
}

static int sdi_display_enable(struct omap_dss_device *dssdev)
{
        struct sdi_device *sdi = dssdev_to_sdi(dssdev);
        struct dispc_clock_info dispc_cinfo;
        unsigned long fck;
        int r;

        if (!sdi->output.dispc_channel_connected) {
                DSSERR("failed to enable display: no output/manager\n");
                return -ENODEV;
        }

        r = regulator_enable(sdi->vdds_sdi_reg);
        if (r)
                goto err_reg_enable;

        r = dispc_runtime_get(sdi->dss->dispc);
        if (r)
                goto err_get_dispc;

        r = sdi_calc_clock_div(sdi, sdi->vm.pixelclock, &fck, &dispc_cinfo);
        if (r)
                goto err_calc_clock_div;

        sdi->mgr_config.clock_info = dispc_cinfo;

        r = dss_set_fck_rate(sdi->dss, fck);
        if (r)
                goto err_set_dss_clock_div;

        sdi_config_lcd_manager(sdi);

        /*
         * LCLK and PCLK divisors are located in shadow registers, and we
         * normally write them to DISPC registers when enabling the output.
         * However, SDI uses pck-free as source clock for its PLL, and pck-free
         * is affected by the divisors. And as we need the PLL before enabling
         * the output, we need to write the divisors early.
         *
         * It seems just writing to the DISPC register is enough, and we don't
         * need to care about the shadow register mechanism for pck-free. The
         * exact reason for this is unknown.
         */
        dispc_mgr_set_clock_div(sdi->dss->dispc, sdi->output.dispc_channel,
                                &sdi->mgr_config.clock_info);

        dss_sdi_init(sdi->dss, sdi->datapairs);
        r = dss_sdi_enable(sdi->dss);
        if (r)
                goto err_sdi_enable;
        mdelay(2);

        r = dss_mgr_enable(&sdi->output);
        if (r)
                goto err_mgr_enable;

        return 0;

err_mgr_enable:
        dss_sdi_disable(sdi->dss);
err_sdi_enable:
err_set_dss_clock_div:
err_calc_clock_div:
        dispc_runtime_put(sdi->dss->dispc);
err_get_dispc:
        regulator_disable(sdi->vdds_sdi_reg);
err_reg_enable:
        return r;
}

static void sdi_display_disable(struct omap_dss_device *dssdev)
{
        struct sdi_device *sdi = dssdev_to_sdi(dssdev);

        dss_mgr_disable(&sdi->output);

        dss_sdi_disable(sdi->dss);

        dispc_runtime_put(sdi->dss->dispc);

        regulator_disable(sdi->vdds_sdi_reg);
}

static void sdi_set_timings(struct omap_dss_device *dssdev,
                            const struct videomode *vm)
{
        struct sdi_device *sdi = dssdev_to_sdi(dssdev);

        sdi->vm = *vm;
}

static int sdi_check_timings(struct omap_dss_device *dssdev,
                             struct videomode *vm)
{
        struct sdi_device *sdi = dssdev_to_sdi(dssdev);
        struct dispc_clock_info dispc_cinfo;
        unsigned long fck;
        unsigned long pck;
        int r;

        if (vm->pixelclock == 0)
                return -EINVAL;

        r = sdi_calc_clock_div(sdi, vm->pixelclock, &fck, &dispc_cinfo);
        if (r)
                return r;

        pck = fck / dispc_cinfo.lck_div / dispc_cinfo.pck_div;

        if (pck != vm->pixelclock) {
                DSSWARN("Pixel clock adjusted from %lu Hz to %lu Hz\n",
                        vm->pixelclock, pck);

                vm->pixelclock = pck;
        }

        return 0;
}

static int sdi_connect(struct omap_dss_device *src,
                       struct omap_dss_device *dst)
{
        int r;

        r = omapdss_device_connect(dst->dss, dst, dst->next);
        if (r)
                return r;

        dst->dispc_channel_connected = true;
        return 0;
}

static void sdi_disconnect(struct omap_dss_device *src,
                           struct omap_dss_device *dst)
{
        dst->dispc_channel_connected = false;

        omapdss_device_disconnect(dst, dst->next);
}

static const struct omap_dss_device_ops sdi_ops = {
        .connect = sdi_connect,
        .disconnect = sdi_disconnect,

        .enable = sdi_display_enable,
        .disable = sdi_display_disable,

        .check_timings = sdi_check_timings,
        .set_timings = sdi_set_timings,
};

static int sdi_init_output(struct sdi_device *sdi)
{
        struct omap_dss_device *out = &sdi->output;
        int r;

        out->dev = &sdi->pdev->dev;
        out->id = OMAP_DSS_OUTPUT_SDI;
        out->output_type = OMAP_DISPLAY_TYPE_SDI;
        out->name = "sdi.0";
        out->dispc_channel = OMAP_DSS_CHANNEL_LCD;
        /* We have SDI only on OMAP3, where it's on port 1 */
        out->of_ports = BIT(1);
        out->ops = &sdi_ops;
        out->owner = THIS_MODULE;
        out->bus_flags = DRM_BUS_FLAG_PIXDATA_POSEDGE   /* 15.5.9.1.2 */
                       | DRM_BUS_FLAG_SYNC_POSEDGE;

        out->next = omapdss_of_find_connected_device(out->dev->of_node, 1);
        if (IS_ERR(out->next)) {
                if (PTR_ERR(out->next) != -EPROBE_DEFER)
                        dev_err(out->dev, "failed to find video sink\n");
                return PTR_ERR(out->next);
        }

        r = omapdss_output_validate(out);
        if (r) {
                omapdss_device_put(out->next);
                out->next = NULL;
                return r;
        }

        omapdss_device_register(out);

        return 0;
}

static void sdi_uninit_output(struct sdi_device *sdi)
{
        if (sdi->output.next)
                omapdss_device_put(sdi->output.next);
        omapdss_device_unregister(&sdi->output);
}

int sdi_init_port(struct dss_device *dss, struct platform_device *pdev,
                  struct device_node *port)
{
        struct sdi_device *sdi;
        struct device_node *ep;
        u32 datapairs;
        int r;

        sdi = kzalloc(sizeof(*sdi), GFP_KERNEL);
        if (!sdi)
                return -ENOMEM;

        ep = of_get_next_child(port, NULL);
        if (!ep) {
                r = 0;
                goto err_free;
        }

        r = of_property_read_u32(ep, "datapairs", &datapairs);
        of_node_put(ep);
        if (r) {
                DSSERR("failed to parse datapairs\n");
                goto err_free;
        }

        sdi->datapairs = datapairs;
        sdi->dss = dss;

        sdi->pdev = pdev;
        port->data = sdi;

        sdi->vdds_sdi_reg = devm_regulator_get(&pdev->dev, "vdds_sdi");
        if (IS_ERR(sdi->vdds_sdi_reg)) {
                r = PTR_ERR(sdi->vdds_sdi_reg);
                if (r != -EPROBE_DEFER)
                        DSSERR("can't get VDDS_SDI regulator\n");
                goto err_free;
        }

        r = sdi_init_output(sdi);
        if (r)
                goto err_free;

        return 0;

err_free:
        kfree(sdi);

        return r;
}

void sdi_uninit_port(struct device_node *port)
{
        struct sdi_device *sdi = port->data;

        if (!sdi)
                return;

        sdi_uninit_output(sdi);
        kfree(sdi);
}