drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2014 Traphandler
   4  * Copyright (C) 2014 Free Electrons
   5  * Copyright (C) 2014 Atmel
   6  *
   7  * Author: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
   8  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
   9  */
  10
  11 #include <linux/of_graph.h>
  12
  13 #include <drm/drmP.h>
  14 #include <drm/drm_of.h>
  15 #include <drm/drm_bridge.h>
  16
  17 #include "atmel_hlcdc_dc.h"
  18
  19 struct atmel_hlcdc_rgb_output {
  20         struct drm_encoder encoder;
  21         int bus_fmt;
  22 };
  23
  24 static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
  25         .destroy = drm_encoder_cleanup,
  26 };
  27
  28 static struct atmel_hlcdc_rgb_output *
  29 atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
  30 {
  31         return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
  32 }
  33
  34 int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder)
  35 {
  36         struct atmel_hlcdc_rgb_output *output;
  37
  38         output = atmel_hlcdc_encoder_to_rgb_output(encoder);
  39
  40         return output->bus_fmt;
  41 }
  42
  43 static int atmel_hlcdc_of_bus_fmt(const struct device_node *ep)
  44 {
  45         u32 bus_width;
  46         int ret;
  47
  48         ret = of_property_read_u32(ep, "bus-width", &bus_width);
  49         if (ret == -EINVAL)
  50                 return 0;
  51         if (ret)
  52                 return ret;
  53
  54         switch (bus_width) {
  55         case 12:
  56                 return MEDIA_BUS_FMT_RGB444_1X12;
  57         case 16:
  58                 return MEDIA_BUS_FMT_RGB565_1X16;
  59         case 18:
  60                 return MEDIA_BUS_FMT_RGB666_1X18;
  61         case 24:
  62                 return MEDIA_BUS_FMT_RGB888_1X24;
  63         default:
  64                 return -EINVAL;
  65         }
  66 }
  67
  68 static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
  69 {
  70         struct atmel_hlcdc_rgb_output *output;
  71         struct device_node *ep;
  72         struct drm_panel *panel;
  73         struct drm_bridge *bridge;
  74         int ret;
  75
  76         ep = of_graph_get_endpoint_by_regs(dev->dev->of_node, 0, endpoint);
  77         if (!ep)
  78                 return -ENODEV;
  79
  80         ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
  81                                           &panel, &bridge);
  82         if (ret) {
  83                 of_node_put(ep);
  84                 return ret;
  85         }
  86
  87         output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
  88         if (!output) {
  89                 of_node_put(ep);
  90                 return -ENOMEM;
  91         }
  92
  93         output->bus_fmt = atmel_hlcdc_of_bus_fmt(ep);
  94         of_node_put(ep);
  95         if (output->bus_fmt < 0) {
  96                 dev_err(dev->dev, "endpoint %d: invalid bus width\n", endpoint);
  97                 return -EINVAL;
  98         }
  99
 100         ret = drm_encoder_init(dev, &output->encoder,
 101                                &atmel_hlcdc_panel_encoder_funcs,
 102                                DRM_MODE_ENCODER_NONE, NULL);
 103         if (ret)
 104                 return ret;
 105
 106         output->encoder.possible_crtcs = 0x1;
 107
 108         if (panel) {
 109                 bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_Unknown);
 110                 if (IS_ERR(bridge))
 111                         return PTR_ERR(bridge);
 112         }
 113
 114         if (bridge) {
 115                 ret = drm_bridge_attach(&output->encoder, bridge, NULL);
 116                 if (!ret)
 117                         return 0;
 118
 119                 if (panel)
 120                         drm_panel_bridge_remove(bridge);
 121         }
 122
 123         drm_encoder_cleanup(&output->encoder);
 124
 125         return ret;
 126 }
 127
 128 int atmel_hlcdc_create_outputs(struct drm_device *dev)
 129 {
 130         int endpoint, ret = 0;
 131         int attached = 0;
 132
 133         /*
 134          * Always scan the first few endpoints even if we get -ENODEV,
 135          * but keep going after that as long as we keep getting hits.
 136          */
 137         for (endpoint = 0; !ret || endpoint < 4; endpoint++) {
 138                 ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
 139                 if (ret == -ENODEV)
 140                         continue;
 141                 if (ret)
 142                         break;
 143                 attached++;
 144         }
 145
 146         /* At least one device was successfully attached.*/
 147         if (ret == -ENODEV && attached)
 148                 return 0;
 149
 150         return ret;
 151 }