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         if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
  32                               &reg_val) < 0) {
  33                 DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
  34                               DP_EDP_DISPLAY_CONTROL_REGISTER);
  35                 return;
  36         }
  37         if (enable)
  38                 reg_val |= DP_EDP_BACKLIGHT_ENABLE;
  39         else
  40                 reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);
  41
  42         if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
  43                                reg_val) != 1) {
  44                 DRM_DEBUG_KMS("Failed to %s aux backlight\n",
  45                               enable ? "enable" : "disable");
  46         }
  47 }
  48
  49 /*
  50  * Read the current backlight value from DPCD register(s) based
  51  * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported
  52  */
  53 static uint32_t intel_dp_aux_get_backlight(struct intel_connector *connector)
  54 {
  55         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
  56         uint8_t read_val[2] = { 0x0 };
  57         uint16_t level = 0;
  58
  59         if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
  60                              &read_val, sizeof(read_val)) < 0) {
  61                 DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
  62                               DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
  63                 return 0;
  64         }
  65         level = read_val[0];
  66         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
  67                 level = (read_val[0] << 8 | read_val[1]);
  68
  69         return level;
  70 }
  71
  72 /*
  73  * Sends the current backlight level over the aux channel, checking if its using
  74  * 8-bit or 16 bit value (MSB and LSB)
  75  */
  76 static void
  77 intel_dp_aux_set_backlight(struct intel_connector *connector, u32 level)
  78 {
  79         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
  80         uint8_t vals[2] = { 0x0 };
  81
  82         vals[0] = level;
  83
  84         /* Write the MSB and/or LSB */
  85         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) {
  86                 vals[0] = (level & 0xFF00) >> 8;
  87                 vals[1] = (level & 0xFF);
  88         }
  89         if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
  90                               vals, sizeof(vals)) < 0) {
  91                 DRM_DEBUG_KMS("Failed to write aux backlight level\n");
  92                 return;
  93         }
  94 }
  95
  96 static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
  97 {
  98         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
  99         uint8_t dpcd_buf = 0;
 100
 101         set_aux_backlight_enable(intel_dp, true);
 102
 103         if ((drm_dp_dpcd_readb(&intel_dp->aux,
 104                                DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&
 105             ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==
 106              DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))
 107                 drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
 108                                    (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));
 109 }
 110
 111 static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
 112 {
 113         set_aux_backlight_enable(enc_to_intel_dp(&connector->encoder->base), false);
 114 }
 115
 116 static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
 117                                         enum pipe pipe)
 118 {
 119         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 120         struct intel_panel *panel = &connector->panel;
 121
 122         intel_dp_aux_enable_backlight(connector);
 123
 124         if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
 125                 panel->backlight.max = 0xFFFF;
 126         else
 127                 panel->backlight.max = 0xFF;
 128
 129         panel->backlight.min = 0;
 130         panel->backlight.level = intel_dp_aux_get_backlight(connector);
 131
 132         panel->backlight.enabled = panel->backlight.level != 0;
 133
 134         return 0;
 135 }
 136
 137 static bool
 138 intel_dp_aux_display_control_capable(struct intel_connector *connector)
 139 {
 140         struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 141
 142         /* Check the  eDP Display control capabilities registers to determine if
 143          * the panel can support backlight control over the aux channel
 144          */
 145         if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
 146             (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
 147             !((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
 148               (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
 149                 DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
 150                 return true;
 151         }
 152         return false;
 153 }
 154
 155 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
 156 {
 157         struct intel_panel *panel = &intel_connector->panel;
 158
 159         if (!i915.enable_dpcd_backlight)
 160                 return -ENODEV;
 161
 162         if (!intel_dp_aux_display_control_capable(intel_connector))
 163                 return -ENODEV;
 164
 165         panel->backlight.setup = intel_dp_aux_setup_backlight;
 166         panel->backlight.enable = intel_dp_aux_enable_backlight;
 167         panel->backlight.disable = intel_dp_aux_disable_backlight;
 168         panel->backlight.set = intel_dp_aux_set_backlight;
 169         panel->backlight.get = intel_dp_aux_get_backlight;
 170
 171         return 0;
 172 }