Quelle  nxp-ptn3460.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * NXP PTN3460 DP/LVDS bridge driver
 *
 * Copyright (C) 2013 Google, Inc.
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_of.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

#define PTN3460_EDID_ADDR   0x0
#define PTN3460_EDID_EMULATION_ADDR  0x84
#define PTN3460_EDID_ENABLE_EMULATION  0
#define PTN3460_EDID_EMULATION_SELECTION 1
#define PTN3460_EDID_SRAM_LOAD_ADDR  0x85

struct ptn3460_bridge {
 struct drm_connector connector;
 struct i2c_client *client;
 struct drm_bridge bridge;
 struct drm_bridge *panel_bridge;
 struct gpio_desc *gpio_pd_n;
 struct gpio_desc *gpio_rst_n;
 u32 edid_emulation;
 bool enabled;
};

static inline struct ptn3460_bridge *
  bridge_to_ptn3460(struct drm_bridge *bridge)
{
 return container_of(bridge, struct ptn3460_bridge, bridge);
}

static inline struct ptn3460_bridge *
  connector_to_ptn3460(struct drm_connector *connector)
{
 return container_of(connector, struct ptn3460_bridge, connector);
}

static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
  u8 *buf, int len)
{
 int ret;

 ret = i2c_master_send(ptn_bridge->client, &addr, 1);
 if (ret < 0) {
  DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  return ret;
 }

 ret = i2c_master_recv(ptn_bridge->client, buf, len);
 if (ret < 0) {
  DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
  return ret;
 }

 return 0;
}

static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
  char val)
{
 int ret;
 char buf[2];

 buf[0] = addr;
 buf[1] = val;

 ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
 if (ret < 0) {
  DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  return ret;
 }

 return 0;
}

static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
{
 int ret;
 char val;

 /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
   ptn_bridge->edid_emulation);
 if (ret) {
  DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
  return ret;
 }

 /* Enable EDID emulation and select the desired EDID */
 val = 1 << PTN3460_EDID_ENABLE_EMULATION |
  ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;

 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
 if (ret) {
  DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
  return ret;
 }

 return 0;
}

static void ptn3460_pre_enable(struct drm_bridge *bridge)
{
 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 int ret;

 if (ptn_bridge->enabled)
  return;

 gpiod_set_value(ptn_bridge->gpio_pd_n, 1);

 gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
 usleep_range(10, 20);
 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);

 /*
 * There's a bug in the PTN chip where it falsely asserts hotplug before
 * it is fully functional. We're forced to wait for the maximum start up
 * time specified in the chip's datasheet to make sure we're really up.
 */
 msleep(90);

 ret = ptn3460_select_edid(ptn_bridge);
 if (ret)
  DRM_ERROR("Select EDID failed ret=%d\n", ret);

 ptn_bridge->enabled = true;
}

static void ptn3460_disable(struct drm_bridge *bridge)
{
 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);

 if (!ptn_bridge->enabled)
  return;

 ptn_bridge->enabled = false;

 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
 gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
}


static const struct drm_edid *ptn3460_edid_read(struct drm_bridge *bridge,
      struct drm_connector *connector)
{
 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 const struct drm_edid *drm_edid = NULL;
 bool power_off;
 u8 *edid;
 int ret;

 power_off = !ptn_bridge->enabled;
 ptn3460_pre_enable(&ptn_bridge->bridge);

 edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
 if (!edid) {
  DRM_ERROR("Failed to allocate EDID\n");
  goto out;
 }

 ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
     EDID_LENGTH);
 if (ret) {
  kfree(edid);
  goto out;
 }

 drm_edid = drm_edid_alloc(edid, EDID_LENGTH);

out:
 if (power_off)
  ptn3460_disable(&ptn_bridge->bridge);

 return drm_edid;
}

static int ptn3460_connector_get_modes(struct drm_connector *connector)
{
 struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
 const struct drm_edid *drm_edid;
 int num_modes;

 drm_edid = ptn3460_edid_read(&ptn_bridge->bridge, connector);
 drm_edid_connector_update(connector, drm_edid);
 num_modes = drm_edid_connector_add_modes(connector);
 drm_edid_free(drm_edid);

 return num_modes;
}

static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
 .get_modes = ptn3460_connector_get_modes,
};

static const struct drm_connector_funcs ptn3460_connector_funcs = {
 .fill_modes = drm_helper_probe_single_connector_modes,
 .destroy = drm_connector_cleanup,
 .reset = drm_atomic_helper_connector_reset,
 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};

static int ptn3460_bridge_attach(struct drm_bridge *bridge,
     struct drm_encoder *encoder,
     enum drm_bridge_attach_flags flags)
{
 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 int ret;

 /* Let this driver create connector if requested */
 ret = drm_bridge_attach(encoder, ptn_bridge->panel_bridge,
    bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 if (ret < 0)
  return ret;

 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
  return 0;

 ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
 ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
   &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
 if (ret) {
  DRM_ERROR("Failed to initialize connector with drm\n");
  return ret;
 }
 drm_connector_helper_add(&ptn_bridge->connector,
     &ptn3460_connector_helper_funcs);
 drm_connector_register(&ptn_bridge->connector);
 drm_connector_attach_encoder(&ptn_bridge->connector,
       encoder);

 drm_helper_hpd_irq_event(ptn_bridge->connector.dev);

 return ret;
}

static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
 .pre_enable = ptn3460_pre_enable,
 .disable = ptn3460_disable,
 .attach = ptn3460_bridge_attach,
 .edid_read = ptn3460_edid_read,
};

static int ptn3460_probe(struct i2c_client *client)
{
 struct device *dev = &client->dev;
 struct ptn3460_bridge *ptn_bridge;
 struct drm_bridge *panel_bridge;
 int ret;

 ptn_bridge = devm_drm_bridge_alloc(dev, struct ptn3460_bridge, bridge,
        &ptn3460_bridge_funcs);
 if (IS_ERR(ptn_bridge))
  return PTR_ERR(ptn_bridge);

 panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
 if (IS_ERR(panel_bridge))
  return PTR_ERR(panel_bridge);

 ptn_bridge->panel_bridge = panel_bridge;
 ptn_bridge->client = client;

 ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
            GPIOD_OUT_HIGH);
 if (IS_ERR(ptn_bridge->gpio_pd_n)) {
  ret = PTR_ERR(ptn_bridge->gpio_pd_n);
  dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
  return ret;
 }

 /*
 * Request the reset pin low to avoid the bridge being
 * initialized prematurely
 */
 ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
      GPIOD_OUT_LOW);
 if (IS_ERR(ptn_bridge->gpio_rst_n)) {
  ret = PTR_ERR(ptn_bridge->gpio_rst_n);
  DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
  return ret;
 }

 ret = of_property_read_u32(dev->of_node, "edid-emulation",
   &ptn_bridge->edid_emulation);
 if (ret) {
  dev_err(dev, "Can't read EDID emulation value\n");
  return ret;
 }

 ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
 ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
 ptn_bridge->bridge.of_node = dev->of_node;
 drm_bridge_add(&ptn_bridge->bridge);

 i2c_set_clientdata(client, ptn_bridge);

 return 0;
}

static void ptn3460_remove(struct i2c_client *client)
{
 struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);

 drm_bridge_remove(&ptn_bridge->bridge);
}

static const struct i2c_device_id ptn3460_i2c_table[] = {
 { "ptn3460" },
 {}
};
MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);

static const struct of_device_id ptn3460_match[] = {
 { .compatible = "nxp,ptn3460" },
 {},
};
MODULE_DEVICE_TABLE(of, ptn3460_match);

static struct i2c_driver ptn3460_driver = {
 .id_table = ptn3460_i2c_table,
 .probe  = ptn3460_probe,
 .remove  = ptn3460_remove,
 .driver  = {
  .name = "nxp,ptn3460",
  .of_match_table = ptn3460_match,
 },
};
module_i2c_driver(ptn3460_driver);

MODULE_AUTHOR("Sean Paul ");
MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
MODULE_LICENSE("GPL v2");