drivers/gpu/drm/i915/intel_dp_aux_backlight.c

   1 /*
   2  * Copyright © 2015 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24
  25 #include "intel_drv.h"
  26
  27 static void set_aux_backlight_enable(struct intel_dp *intel_dp, bool enable)
  28 {
  29         uint8_t reg_val = 0;
  30
  31         /* Early return when display use other mechanism to enable backlight. */
  32         if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
  33                 return;
  34
  35         if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
  36                               &reg_val) < 0) {
  37                 DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
  38                               DP_EDP_DISPLAY_CONTROL_REGISTER);
  39                 return;
  40         }
  41         if (enable)
  42                 reg_val |= DP_EDP_BACKLIGHT_ENABLE;
  43         else
  44                 reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);
  45
  46         if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
  47                                reg_val) != 1) {
  48                 DRM_DEBUG_KMS("Failed to %s aux backlight\n",
  49                               enable ? "enable" : "disable");
  50         }
  51 }
  52
  53 /*
  54  * Read the current backlight value from DPCD register(s) based
  55  * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported
  56  */
  57 static uint32_t intel_dp_aux_get_backlight(struct intel_connector *connector)
  58 {
  59         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
  60         uint8_t read_val[2] = { 0x0 };
  61         uint16_t level = 0;
  62
  63         if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
  64                              &read_val, sizeof(read_val)) < 0) {
  65                 DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
  66                               DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
  67                 return 0;
  68         }
  69         level = read_val[0];
  70         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
  71                 level = (read_val[0] << 8 | read_val[1]);
  72
  73         return level;
  74 }
  75
  76 /*
  77  * Sends the current backlight level over the aux channel, checking if its using
  78  * 8-bit or 16 bit value (MSB and LSB)
  79  */
  80 static void
  81 intel_dp_aux_set_backlight(const struct drm_connector_state *conn_state, u32 level)
  82 {
  83         struct intel_connector *connector = to_intel_connector(conn_state->connector);
  84         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
  85         uint8_t vals[2] = { 0x0 };
  86
  87         vals[0] = level;
  88
  89         /* Write the MSB and/or LSB */
  90         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) {
  91                 vals[0] = (level & 0xFF00) >> 8;
  92                 vals[1] = (level & 0xFF);
  93         }
  94         if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
  95                               vals, sizeof(vals)) < 0) {
  96                 DRM_DEBUG_KMS("Failed to write aux backlight level\n");
  97                 return;
  98         }
  99 }
 100
 101 static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_state,
 102                                           const struct drm_connector_state *conn_state)
 103 {
 104         struct intel_connector *connector = to_intel_connector(conn_state->connector);
 105         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 106         uint8_t dpcd_buf = 0;
 107         uint8_t edp_backlight_mode = 0;
 108
 109         if (drm_dp_dpcd_readb(&intel_dp->aux,
 110                         DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
 111                 DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
 112                               DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
 113                 return;
 114         }
 115
 116         edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
 117
 118         switch (edp_backlight_mode) {
 119         case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
 120         case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
 121         case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
 122                 dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
 123                 dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
 124                 if (drm_dp_dpcd_writeb(&intel_dp->aux,
 125                         DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf) < 0) {
 126                         DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
 127                 }
 128                 break;
 129
 130         /* Do nothing when it is already DPCD mode */
 131         case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
 132         default:
 133                 break;
 134         }
 135
 136         set_aux_backlight_enable(intel_dp, true);
 137         intel_dp_aux_set_backlight(conn_state, connector->panel.backlight.level);
 138 }
 139
 140 static void intel_dp_aux_disable_backlight(const struct drm_connector_state *old_conn_state)
 141 {
 142         set_aux_backlight_enable(enc_to_intel_dp(old_conn_state->best_encoder), false);
 143 }
 144
 145 static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
 146                                         enum pipe pipe)
 147 {
 148         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 149         struct intel_panel *panel = &connector->panel;
 150
 151         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
 152                 panel->backlight.max = 0xFFFF;
 153         else
 154                 panel->backlight.max = 0xFF;
 155
 156         panel->backlight.min = 0;
 157         panel->backlight.level = intel_dp_aux_get_backlight(connector);
 158
 159         panel->backlight.enabled = panel->backlight.level != 0;
 160
 161         return 0;
 162 }
 163
 164 static bool
 165 intel_dp_aux_display_control_capable(struct intel_connector *connector)
 166 {
 167         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 168
 169         /* Check the eDP Display control capabilities registers to determine if
 170          * the panel can support backlight control over the aux channel
 171          */
 172         if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
 173             (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
 174             !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) {
 175                 DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
 176                 return true;
 177         }
 178         return false;
 179 }
 180
 181 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
 182 {
 183         struct intel_panel *panel = &intel_connector->panel;
 184
 185         if (!i915.enable_dpcd_backlight)
 186                 return -ENODEV;
 187
 188         if (!intel_dp_aux_display_control_capable(intel_connector))
 189                 return -ENODEV;
 190
 191         panel->backlight.setup = intel_dp_aux_setup_backlight;
 192         panel->backlight.enable = intel_dp_aux_enable_backlight;
 193         panel->backlight.disable = intel_dp_aux_disable_backlight;
 194         panel->backlight.set = intel_dp_aux_set_backlight;
 195         panel->backlight.get = intel_dp_aux_get_backlight;
 196
 197         return 0;
 198 }