Quelle  display-connector.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 */

#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_edid.h>

struct display_connector {
 struct drm_bridge bridge;

 struct gpio_desc *hpd_gpio;
 int   hpd_irq;

 struct regulator *supply;
 struct gpio_desc *ddc_en;
};

static inline struct display_connector *
to_display_connector(struct drm_bridge *bridge)
{
 return container_of(bridge, struct display_connector, bridge);
}

static int display_connector_attach(struct drm_bridge *bridge,
        struct drm_encoder *encoder,
        enum drm_bridge_attach_flags flags)
{
 return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;
}

static enum drm_connector_status display_connector_detect(struct drm_bridge *bridge)
{
 struct display_connector *conn = to_display_connector(bridge);

 if (conn->hpd_gpio) {
  if (gpiod_get_value_cansleep(conn->hpd_gpio))
   return connector_status_connected;
  else
   return connector_status_disconnected;
 }

 if (conn->bridge.ddc && drm_probe_ddc(conn->bridge.ddc))
  return connector_status_connected;

 switch (conn->bridge.type) {
 case DRM_MODE_CONNECTOR_DVIA:
 case DRM_MODE_CONNECTOR_DVID:
 case DRM_MODE_CONNECTOR_DVII:
 case DRM_MODE_CONNECTOR_HDMIA:
 case DRM_MODE_CONNECTOR_HDMIB:
  /*
 * For DVI and HDMI connectors a DDC probe failure indicates
 * that no cable is connected.
 */
  return connector_status_disconnected;

 case DRM_MODE_CONNECTOR_Composite:
 case DRM_MODE_CONNECTOR_SVIDEO:
 case DRM_MODE_CONNECTOR_VGA:
 default:
  /*
 * Composite and S-Video connectors have no other detection
 * mean than the HPD GPIO. For VGA connectors, even if we have
 * an I2C bus, we can't assume that the cable is disconnected
 * if drm_probe_ddc fails, as some cables don't wire the DDC
 * pins.
 */
  return connector_status_unknown;
 }
}

static enum drm_connector_status
display_connector_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
{
 return display_connector_detect(bridge);
}

static const struct drm_edid *display_connector_edid_read(struct drm_bridge *bridge,
         struct drm_connector *connector)
{
 struct display_connector *conn = to_display_connector(bridge);

 return drm_edid_read_ddc(connector, conn->bridge.ddc);
}

/*
 * Since this bridge is tied to the connector, it acts like a passthrough,
 * so concerning the output bus formats, either pass the bus formats from the
 * previous bridge or return fallback data like done in the bridge function:
 * drm_atomic_bridge_chain_select_bus_fmts().
 * This supports negotiation if the bridge chain has all bits in place.
 */
static u32 *display_connector_get_output_bus_fmts(struct drm_bridge *bridge,
     struct drm_bridge_state *bridge_state,
     struct drm_crtc_state *crtc_state,
     struct drm_connector_state *conn_state,
     unsigned int *num_output_fmts)
{
 struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
 struct drm_bridge_state *prev_bridge_state;

 if (!prev_bridge || !prev_bridge->funcs->atomic_get_output_bus_fmts) {
  struct drm_connector *conn = conn_state->connector;
  u32 *out_bus_fmts;

  *num_output_fmts = 1;
  out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
  if (!out_bus_fmts)
   return NULL;

  if (conn->display_info.num_bus_formats &&
      conn->display_info.bus_formats)
   out_bus_fmts[0] = conn->display_info.bus_formats[0];
  else
   out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;

  return out_bus_fmts;
 }

 prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
           prev_bridge);

 return prev_bridge->funcs->atomic_get_output_bus_fmts(prev_bridge, prev_bridge_state,
             crtc_state, conn_state,
             num_output_fmts);
}

/*
 * Since this bridge is tied to the connector, it acts like a passthrough,
 * so concerning the input bus formats, either pass the bus formats from the
 * previous bridge or MEDIA_BUS_FMT_FIXED (like select_bus_fmt_recursive())
 * when atomic_get_input_bus_fmts is not supported.
 * This supports negotiation if the bridge chain has all bits in place.
 */
static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge,
     struct drm_bridge_state *bridge_state,
     struct drm_crtc_state *crtc_state,
     struct drm_connector_state *conn_state,
     u32 output_fmt,
     unsigned int *num_input_fmts)
{
 struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
 struct drm_bridge_state *prev_bridge_state;

 if (!prev_bridge || !prev_bridge->funcs->atomic_get_input_bus_fmts) {
  u32 *in_bus_fmts;

  *num_input_fmts = 1;
  in_bus_fmts = kmalloc(sizeof(*in_bus_fmts), GFP_KERNEL);
  if (!in_bus_fmts)
   return NULL;

  in_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;

  return in_bus_fmts;
 }

 prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
           prev_bridge);

 return prev_bridge->funcs->atomic_get_input_bus_fmts(prev_bridge, prev_bridge_state,
            crtc_state, conn_state, output_fmt,
            num_input_fmts);
}

static const struct drm_bridge_funcs display_connector_bridge_funcs = {
 .attach = display_connector_attach,
 .detect = display_connector_bridge_detect,
 .edid_read = display_connector_edid_read,
 .atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts,
 .atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts,
 .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 .atomic_reset = drm_atomic_helper_bridge_reset,
};

static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
{
 struct display_connector *conn = arg;
 struct drm_bridge *bridge = &conn->bridge;

 drm_bridge_hpd_notify(bridge, display_connector_detect(bridge));

 return IRQ_HANDLED;
}

static int display_connector_get_supply(struct platform_device *pdev,
     struct display_connector *conn,
     const char *name)
{
 conn->supply = devm_regulator_get_optional(&pdev->dev, name);

 if (conn->supply == ERR_PTR(-ENODEV))
  conn->supply = NULL;

 return PTR_ERR_OR_ZERO(conn->supply);
}

static int display_connector_probe(struct platform_device *pdev)
{
 struct display_connector *conn;
 unsigned int type;
 const char *label = NULL;
 int ret;

 conn = devm_drm_bridge_alloc(&pdev->dev, struct display_connector, bridge,
         &display_connector_bridge_funcs);
 if (IS_ERR(conn))
  return PTR_ERR(conn);

 platform_set_drvdata(pdev, conn);

 type = (uintptr_t)of_device_get_match_data(&pdev->dev);

 /* Get the exact connector type. */
 switch (type) {
 case DRM_MODE_CONNECTOR_DVII: {
  bool analog, digital;

  analog = of_property_read_bool(pdev->dev.of_node, "analog");
  digital = of_property_read_bool(pdev->dev.of_node, "digital");
  if (analog && !digital) {
   conn->bridge.type = DRM_MODE_CONNECTOR_DVIA;
  } else if (!analog && digital) {
   conn->bridge.type = DRM_MODE_CONNECTOR_DVID;
  } else if (analog && digital) {
   conn->bridge.type = DRM_MODE_CONNECTOR_DVII;
  } else {
   dev_err(&pdev->dev, "DVI connector with no type\n");
   return -EINVAL;
  }
  break;
 }

 case DRM_MODE_CONNECTOR_HDMIA: {
  const char *hdmi_type;

  ret = of_property_read_string(pdev->dev.of_node, "type",
           &hdmi_type);
  if (ret < 0) {
   dev_err(&pdev->dev, "HDMI connector with no type\n");
   return -EINVAL;
  }

  if (!strcmp(hdmi_type, "a") || !strcmp(hdmi_type, "c") ||
      !strcmp(hdmi_type, "d") || !strcmp(hdmi_type, "e")) {
   conn->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
  } else if (!strcmp(hdmi_type, "b")) {
   conn->bridge.type = DRM_MODE_CONNECTOR_HDMIB;
  } else {
   dev_err(&pdev->dev,
    "Unsupported HDMI connector type '%s'\n",
    hdmi_type);
   return -EINVAL;
  }

  break;
 }

 default:
  conn->bridge.type = type;
  break;
 }

 /* All the supported connector types support interlaced modes. */
 conn->bridge.interlace_allowed = true;

 if (type == DRM_MODE_CONNECTOR_HDMIA ||
     type == DRM_MODE_CONNECTOR_DisplayPort)
  conn->bridge.ycbcr_420_allowed = true;

 /* Get the optional connector label. */
 of_property_read_string(pdev->dev.of_node, "label", &label);

 /*
 * Get the HPD GPIO for DVI, HDMI and DP connectors. If the GPIO can provide
 * edge interrupts, register an interrupt handler.
 */
 if (type == DRM_MODE_CONNECTOR_DVII ||
     type == DRM_MODE_CONNECTOR_HDMIA ||
     type == DRM_MODE_CONNECTOR_DisplayPort) {
  conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
        GPIOD_IN);
  if (IS_ERR(conn->hpd_gpio))
   return dev_err_probe(&pdev->dev, PTR_ERR(conn->hpd_gpio),
          "Unable to retrieve HPD GPIO\n");

  conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
 } else {
  conn->hpd_irq = -EINVAL;
 }

 if (conn->hpd_irq >= 0) {
  ret = devm_request_threaded_irq(&pdev->dev, conn->hpd_irq,
      NULL, display_connector_hpd_irq,
      IRQF_TRIGGER_RISING |
      IRQF_TRIGGER_FALLING |
      IRQF_ONESHOT,
      "HPD", conn);
  if (ret) {
   dev_info(&pdev->dev,
     "Failed to request HPD edge interrupt, falling back to polling\n");
   conn->hpd_irq = -EINVAL;
  }
 }

 /* Retrieve the DDC I2C adapter for DVI, HDMI and VGA connectors. */
 if (type == DRM_MODE_CONNECTOR_DVII ||
     type == DRM_MODE_CONNECTOR_HDMIA ||
     type == DRM_MODE_CONNECTOR_VGA) {
  struct device_node *phandle;

  phandle = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0);
  if (phandle) {
   conn->bridge.ddc = of_get_i2c_adapter_by_node(phandle);
   of_node_put(phandle);
   if (!conn->bridge.ddc)
    return -EPROBE_DEFER;
  } else {
   dev_dbg(&pdev->dev,
    "No I2C bus specified, disabling EDID readout\n");
  }
 }

 /* Get the DP PWR for DP connector. */
 if (type == DRM_MODE_CONNECTOR_DisplayPort) {
  int ret;

  ret = display_connector_get_supply(pdev, conn, "dp-pwr");
  if (ret < 0)
   return dev_err_probe(&pdev->dev, ret, "failed to get DP PWR regulator\n");
 }

 /* enable DDC */
 if (type == DRM_MODE_CONNECTOR_HDMIA) {
  int ret;

  conn->ddc_en = devm_gpiod_get_optional(&pdev->dev, "ddc-en",
             GPIOD_OUT_HIGH);

  if (IS_ERR(conn->ddc_en)) {
   dev_err(&pdev->dev, "Couldn't get ddc-en gpio\n");
   return PTR_ERR(conn->ddc_en);
  }

  ret = display_connector_get_supply(pdev, conn, "hdmi-pwr");
  if (ret < 0)
   return dev_err_probe(&pdev->dev, ret, "failed to get HDMI +5V Power regulator\n");
 }

 if (conn->supply) {
  ret = regulator_enable(conn->supply);
  if (ret) {
   dev_err(&pdev->dev, "failed to enable PWR regulator: %d\n", ret);
   return ret;
  }
 }

 conn->bridge.of_node = pdev->dev.of_node;

 if (conn->bridge.ddc)
  conn->bridge.ops |= DRM_BRIDGE_OP_EDID
     |  DRM_BRIDGE_OP_DETECT;
 /* Detecting the monitor requires reading DPCD */
 if (conn->hpd_gpio && type != DRM_MODE_CONNECTOR_DisplayPort)
  conn->bridge.ops |= DRM_BRIDGE_OP_DETECT;
 if (conn->hpd_irq >= 0)
  conn->bridge.ops |= DRM_BRIDGE_OP_HPD;

 dev_dbg(&pdev->dev,
  "Found %s display connector '%s' %s DDC bus and %s HPD GPIO (ops 0x%x)\n",
  drm_get_connector_type_name(conn->bridge.type),
  label ? label : "",
  conn->bridge.ddc ? "with" : "without",
  conn->hpd_gpio ? "with" : "without",
  conn->bridge.ops);

 drm_bridge_add(&conn->bridge);

 return 0;
}

static void display_connector_remove(struct platform_device *pdev)
{
 struct display_connector *conn = platform_get_drvdata(pdev);

 if (conn->ddc_en)
  gpiod_set_value(conn->ddc_en, 0);

 if (conn->supply)
  regulator_disable(conn->supply);

 drm_bridge_remove(&conn->bridge);

 if (!IS_ERR(conn->bridge.ddc))
  i2c_put_adapter(conn->bridge.ddc);
}

static const struct of_device_id display_connector_match[] = {
 {
  .compatible = "composite-video-connector",
  .data = (void *)DRM_MODE_CONNECTOR_Composite,
 }, {
  .compatible = "dvi-connector",
  .data = (void *)DRM_MODE_CONNECTOR_DVII,
 }, {
  .compatible = "hdmi-connector",
  .data = (void *)DRM_MODE_CONNECTOR_HDMIA,
 }, {
  .compatible = "svideo-connector",
  .data = (void *)DRM_MODE_CONNECTOR_SVIDEO,
 }, {
  .compatible = "vga-connector",
  .data = (void *)DRM_MODE_CONNECTOR_VGA,
 }, {
  .compatible = "dp-connector",
  .data = (void *)DRM_MODE_CONNECTOR_DisplayPort,
 },
 {},
};
MODULE_DEVICE_TABLE(of, display_connector_match);

static struct platform_driver display_connector_driver = {
 .probe = display_connector_probe,
 .remove = display_connector_remove,
 .driver  = {
  .name  = "display-connector",
  .of_match_table = display_connector_match,
 },
};
module_platform_driver(display_connector_driver);

MODULE_AUTHOR("Laurent Pinchart ");
MODULE_DESCRIPTION("Display connector driver");
MODULE_LICENSE("GPL");