root/drivers/video/fbdev/omap2/omapfb/displays/connector-dvi.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic DVI Connector driver
 *
 * Copyright (C) 2013 Texas Instruments
 * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
 */

#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <drm/drm_edid.h>

#include <video/omapfb_dss.h>

static const struct omap_video_timings dvic_default_timings = {
        .x_res          = 640,
        .y_res          = 480,

        .pixelclock     = 23500000,

        .hfp            = 48,
        .hsw            = 32,
        .hbp            = 80,

        .vfp            = 3,
        .vsw            = 4,
        .vbp            = 7,

        .vsync_level    = OMAPDSS_SIG_ACTIVE_HIGH,
        .hsync_level    = OMAPDSS_SIG_ACTIVE_HIGH,
        .data_pclk_edge = OMAPDSS_DRIVE_SIG_RISING_EDGE,
        .de_level       = OMAPDSS_SIG_ACTIVE_HIGH,
        .sync_pclk_edge = OMAPDSS_DRIVE_SIG_FALLING_EDGE,
};

struct panel_drv_data {
        struct omap_dss_device dssdev;
        struct omap_dss_device *in;

        struct omap_video_timings timings;

        struct i2c_adapter *i2c_adapter;
};

#define to_panel_data(x) container_of(x, struct panel_drv_data, dssdev)

static int dvic_connect(struct omap_dss_device *dssdev)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;

        if (omapdss_device_is_connected(dssdev))
                return 0;

        return in->ops.dvi->connect(in, dssdev);
}

static void dvic_disconnect(struct omap_dss_device *dssdev)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;

        if (!omapdss_device_is_connected(dssdev))
                return;

        in->ops.dvi->disconnect(in, dssdev);
}

static int dvic_enable(struct omap_dss_device *dssdev)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;
        int r;

        if (!omapdss_device_is_connected(dssdev))
                return -ENODEV;

        if (omapdss_device_is_enabled(dssdev))
                return 0;

        in->ops.dvi->set_timings(in, &ddata->timings);

        r = in->ops.dvi->enable(in);
        if (r)
                return r;

        dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;

        return 0;
}

static void dvic_disable(struct omap_dss_device *dssdev)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;

        if (!omapdss_device_is_enabled(dssdev))
                return;

        in->ops.dvi->disable(in);

        dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
}

static void dvic_set_timings(struct omap_dss_device *dssdev,
                struct omap_video_timings *timings)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;

        ddata->timings = *timings;
        dssdev->panel.timings = *timings;

        in->ops.dvi->set_timings(in, timings);
}

static void dvic_get_timings(struct omap_dss_device *dssdev,
                struct omap_video_timings *timings)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);

        *timings = ddata->timings;
}

static int dvic_check_timings(struct omap_dss_device *dssdev,
                struct omap_video_timings *timings)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        struct omap_dss_device *in = ddata->in;

        return in->ops.dvi->check_timings(in, timings);
}

static int dvic_ddc_read(struct i2c_adapter *adapter,
                unsigned char *buf, u16 count, u8 offset)
{
        int r, retries;

        for (retries = 3; retries > 0; retries--) {
                struct i2c_msg msgs[] = {
                        {
                                .addr   = DDC_ADDR,
                                .flags  = 0,
                                .len    = 1,
                                .buf    = &offset,
                        }, {
                                .addr   = DDC_ADDR,
                                .flags  = I2C_M_RD,
                                .len    = count,
                                .buf    = buf,
                        }
                };

                r = i2c_transfer(adapter, msgs, 2);
                if (r == 2)
                        return 0;

                if (r != -EAGAIN)
                        break;
        }

        return r < 0 ? r : -EIO;
}

static int dvic_read_edid(struct omap_dss_device *dssdev,
                u8 *edid, int len)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        int r, l, bytes_read;

        if (!ddata->i2c_adapter)
                return -ENODEV;

        l = min(EDID_LENGTH, len);
        r = dvic_ddc_read(ddata->i2c_adapter, edid, l, 0);
        if (r)
                return r;

        bytes_read = l;

        /* if there are extensions, read second block */
        if (len > EDID_LENGTH && edid[0x7e] > 0) {
                l = min(EDID_LENGTH, len - EDID_LENGTH);

                r = dvic_ddc_read(ddata->i2c_adapter, edid + EDID_LENGTH,
                                l, EDID_LENGTH);
                if (r)
                        return r;

                bytes_read += l;
        }

        return bytes_read;
}

static bool dvic_detect(struct omap_dss_device *dssdev)
{
        struct panel_drv_data *ddata = to_panel_data(dssdev);
        unsigned char out;
        int r;

        if (!ddata->i2c_adapter)
                return true;

        r = dvic_ddc_read(ddata->i2c_adapter, &out, 1, 0);

        return r == 0;
}

static struct omap_dss_driver dvic_driver = {
        .connect        = dvic_connect,
        .disconnect     = dvic_disconnect,

        .enable         = dvic_enable,
        .disable        = dvic_disable,

        .set_timings    = dvic_set_timings,
        .get_timings    = dvic_get_timings,
        .check_timings  = dvic_check_timings,

        .get_resolution = omapdss_default_get_resolution,

        .read_edid      = dvic_read_edid,
        .detect         = dvic_detect,
};

static int dvic_probe_of(struct platform_device *pdev)
{
        struct panel_drv_data *ddata = platform_get_drvdata(pdev);
        struct device_node *node = pdev->dev.of_node;
        struct omap_dss_device *in;
        struct device_node *adapter_node;
        struct i2c_adapter *adapter;

        in = omapdss_of_find_source_for_first_ep(node);
        if (IS_ERR(in)) {
                dev_err(&pdev->dev, "failed to find video source\n");
                return PTR_ERR(in);
        }

        ddata->in = in;

        adapter_node = of_parse_phandle(node, "ddc-i2c-bus", 0);
        if (adapter_node) {
                adapter = of_get_i2c_adapter_by_node(adapter_node);
                of_node_put(adapter_node);
                if (adapter == NULL) {
                        dev_err(&pdev->dev, "failed to parse ddc-i2c-bus\n");
                        omap_dss_put_device(ddata->in);
                        return -EPROBE_DEFER;
                }

                ddata->i2c_adapter = adapter;
        }

        return 0;
}

static int dvic_probe(struct platform_device *pdev)
{
        struct panel_drv_data *ddata;
        struct omap_dss_device *dssdev;
        int r;

        if (!pdev->dev.of_node)
                return -ENODEV;

        ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
        if (!ddata)
                return -ENOMEM;

        platform_set_drvdata(pdev, ddata);

        r = dvic_probe_of(pdev);
        if (r)
                return r;

        ddata->timings = dvic_default_timings;

        dssdev = &ddata->dssdev;
        dssdev->driver = &dvic_driver;
        dssdev->dev = &pdev->dev;
        dssdev->type = OMAP_DISPLAY_TYPE_DVI;
        dssdev->owner = THIS_MODULE;
        dssdev->panel.timings = dvic_default_timings;

        r = omapdss_register_display(dssdev);
        if (r) {
                dev_err(&pdev->dev, "Failed to register panel\n");
                goto err_reg;
        }

        return 0;

err_reg:
        omap_dss_put_device(ddata->in);

        i2c_put_adapter(ddata->i2c_adapter);

        return r;
}

static void dvic_remove(struct platform_device *pdev)
{
        struct panel_drv_data *ddata = platform_get_drvdata(pdev);
        struct omap_dss_device *dssdev = &ddata->dssdev;
        struct omap_dss_device *in = ddata->in;

        omapdss_unregister_display(&ddata->dssdev);

        dvic_disable(dssdev);
        dvic_disconnect(dssdev);

        omap_dss_put_device(in);

        i2c_put_adapter(ddata->i2c_adapter);
}

static const struct of_device_id dvic_of_match[] = {
        { .compatible = "omapdss,dvi-connector", },
        {},
};

MODULE_DEVICE_TABLE(of, dvic_of_match);

static struct platform_driver dvi_connector_driver = {
        .probe  = dvic_probe,
        .remove = dvic_remove,
        .driver = {
                .name   = "connector-dvi",
                .of_match_table = dvic_of_match,
        },
};

module_platform_driver(dvi_connector_driver);

MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
MODULE_DESCRIPTION("Generic DVI Connector driver");
MODULE_LICENSE("GPL");