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
 27static 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 */
 53static 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 */
 76static void
 77intel_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
 96static 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
111static 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
116static 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
137static bool
138intel_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
155int 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}