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 /*
26  * Laptops with Intel GPUs which have panels that support controlling the
27  * backlight through DP AUX can actually use two different interfaces: Intel's
28  * proprietary DP AUX backlight interface, and the standard VESA backlight
29  * interface. Unfortunately, at the time of writing this a lot of laptops will
30  * advertise support for the standard VESA backlight interface when they
31  * don't properly support it. However, on these systems the Intel backlight
32  * interface generally does work properly. Additionally, these systems will
33  * usually just indicate that they use PWM backlight controls in their VBIOS
34  * for some reason.
35  */
36 
37 #include "intel_display_types.h"
38 #include "intel_dp_aux_backlight.h"
39 #include "intel_panel.h"
40 
41 /* TODO:
42  * Implement HDR, right now we just implement the bare minimum to bring us back into SDR mode so we
43  * can make people's backlights work in the mean time
44  */
45 
46 /*
47  * DP AUX registers for Intel's proprietary HDR backlight interface. We define
48  * them here since we'll likely be the only driver to ever use these.
49  */
50 #define INTEL_EDP_HDR_TCON_CAP0                                        0x340
51 
52 #define INTEL_EDP_HDR_TCON_CAP1                                        0x341
53 # define INTEL_EDP_HDR_TCON_2084_DECODE_CAP                           BIT(0)
54 # define INTEL_EDP_HDR_TCON_2020_GAMUT_CAP                            BIT(1)
55 # define INTEL_EDP_HDR_TCON_TONE_MAPPING_CAP                          BIT(2)
56 # define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_CAP                   BIT(3)
57 # define INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP                       BIT(4)
58 # define INTEL_EDP_HDR_TCON_OPTIMIZATION_CAP                          BIT(5)
59 # define INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_CAP                       BIT(6)
60 # define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_CONVERSION_CAP        BIT(7)
61 
62 #define INTEL_EDP_HDR_TCON_CAP2                                        0x342
63 # define INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP                        BIT(0)
64 
65 #define INTEL_EDP_HDR_TCON_CAP3                                        0x343
66 
67 #define INTEL_EDP_HDR_GETSET_CTRL_PARAMS                               0x344
68 # define INTEL_EDP_HDR_TCON_2084_DECODE_ENABLE                        BIT(0)
69 # define INTEL_EDP_HDR_TCON_2020_GAMUT_ENABLE                         BIT(1)
70 # define INTEL_EDP_HDR_TCON_TONE_MAPPING_ENABLE                       BIT(2) /* Pre-TGL+ */
71 # define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_ENABLE                BIT(3)
72 # define INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE                     BIT(4)
73 # define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_ENABLE                BIT(5)
74 /* Bit 6 is reserved */
75 # define INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_ENABLE                    BIT(7)
76 
77 #define INTEL_EDP_HDR_CONTENT_LUMINANCE                                0x346 /* Pre-TGL+ */
78 #define INTEL_EDP_HDR_PANEL_LUMINANCE_OVERRIDE                         0x34A
79 #define INTEL_EDP_SDR_LUMINANCE_LEVEL                                  0x352
80 #define INTEL_EDP_BRIGHTNESS_NITS_LSB                                  0x354
81 #define INTEL_EDP_BRIGHTNESS_NITS_MSB                                  0x355
82 #define INTEL_EDP_BRIGHTNESS_DELAY_FRAMES                              0x356
83 #define INTEL_EDP_BRIGHTNESS_PER_FRAME_STEPS                           0x357
84 
85 #define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_0                            0x358
86 # define INTEL_EDP_TCON_USAGE_MASK                             GENMASK(0, 3)
87 # define INTEL_EDP_TCON_USAGE_UNKNOWN                                    0x0
88 # define INTEL_EDP_TCON_USAGE_DESKTOP                                    0x1
89 # define INTEL_EDP_TCON_USAGE_FULL_SCREEN_MEDIA                          0x2
90 # define INTEL_EDP_TCON_USAGE_FULL_SCREEN_GAMING                         0x3
91 # define INTEL_EDP_TCON_POWER_MASK                                    BIT(4)
92 # define INTEL_EDP_TCON_POWER_DC                                    (0 << 4)
93 # define INTEL_EDP_TCON_POWER_AC                                    (1 << 4)
94 # define INTEL_EDP_TCON_OPTIMIZATION_STRENGTH_MASK             GENMASK(5, 7)
95 
96 #define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_1                            0x359
97 
98 /* Intel EDP backlight callbacks */
99 static bool
100 intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
101 {
102 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
103 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
104 	struct drm_dp_aux *aux = &intel_dp->aux;
105 	struct intel_panel *panel = &connector->panel;
106 	int ret;
107 	u8 tcon_cap[4];
108 
109 	ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap));
110 	if (ret != sizeof(tcon_cap))
111 		return false;
112 
113 	if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP))
114 		return false;
115 
116 	if (tcon_cap[0] >= 1) {
117 		drm_dbg_kms(&i915->drm, "Detected Intel HDR backlight interface version %d\n",
118 			    tcon_cap[0]);
119 	} else {
120 		drm_dbg_kms(&i915->drm, "Detected unsupported HDR backlight interface version %d\n",
121 			    tcon_cap[0]);
122 		return false;
123 	}
124 
125 	panel->backlight.edp.intel.sdr_uses_aux =
126 		tcon_cap[2] & INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP;
127 
128 	return true;
129 }
130 
131 static u32
132 intel_dp_aux_hdr_get_backlight(struct intel_connector *connector, enum pipe pipe)
133 {
134 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
135 	struct intel_panel *panel = &connector->panel;
136 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
137 	u8 tmp;
138 	u8 buf[2] = { 0 };
139 
140 	if (drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &tmp) != 1) {
141 		drm_err(&i915->drm, "Failed to read current backlight mode from DPCD\n");
142 		return 0;
143 	}
144 
145 	if (!(tmp & INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE)) {
146 		if (!panel->backlight.edp.intel.sdr_uses_aux) {
147 			u32 pwm_level = panel->backlight.pwm_funcs->get(connector, pipe);
148 
149 			return intel_panel_backlight_level_from_pwm(connector, pwm_level);
150 		}
151 
152 		/* Assume 100% brightness if backlight controls aren't enabled yet */
153 		return panel->backlight.max;
154 	}
155 
156 	if (drm_dp_dpcd_read(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
157 			     sizeof(buf)) != sizeof(buf)) {
158 		drm_err(&i915->drm, "Failed to read brightness from DPCD\n");
159 		return 0;
160 	}
161 
162 	return (buf[1] << 8 | buf[0]);
163 }
164 
165 static void
166 intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state, u32 level)
167 {
168 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
169 	struct drm_device *dev = connector->base.dev;
170 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
171 	u8 buf[4] = { 0 };
172 
173 	buf[0] = level & 0xFF;
174 	buf[1] = (level & 0xFF00) >> 8;
175 
176 	if (drm_dp_dpcd_write(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
177 			      sizeof(buf)) != sizeof(buf))
178 		drm_err(dev, "Failed to write brightness level to DPCD\n");
179 }
180 
181 static void
182 intel_dp_aux_hdr_set_backlight(const struct drm_connector_state *conn_state, u32 level)
183 {
184 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
185 	struct intel_panel *panel = &connector->panel;
186 
187 	if (panel->backlight.edp.intel.sdr_uses_aux) {
188 		intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
189 	} else {
190 		const u32 pwm_level = intel_panel_backlight_level_to_pwm(connector, level);
191 
192 		intel_panel_set_pwm_level(conn_state, pwm_level);
193 	}
194 }
195 
196 static void
197 intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
198 				  const struct drm_connector_state *conn_state, u32 level)
199 {
200 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
201 	struct intel_panel *panel = &connector->panel;
202 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
203 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
204 	int ret;
205 	u8 old_ctrl, ctrl;
206 
207 	ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl);
208 	if (ret != 1) {
209 		drm_err(&i915->drm, "Failed to read current backlight control mode: %d\n", ret);
210 		return;
211 	}
212 
213 	ctrl = old_ctrl;
214 	if (panel->backlight.edp.intel.sdr_uses_aux) {
215 		ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;
216 		intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
217 	} else {
218 		u32 pwm_level = intel_panel_backlight_level_to_pwm(connector, level);
219 
220 		panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level);
221 
222 		ctrl &= ~INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;
223 	}
224 
225 	if (ctrl != old_ctrl)
226 		if (drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) != 1)
227 			drm_err(&i915->drm, "Failed to configure DPCD brightness controls\n");
228 }
229 
230 static void
231 intel_dp_aux_hdr_disable_backlight(const struct drm_connector_state *conn_state, u32 level)
232 {
233 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
234 	struct intel_panel *panel = &connector->panel;
235 
236 	/* Nothing to do for AUX based backlight controls */
237 	if (panel->backlight.edp.intel.sdr_uses_aux)
238 		return;
239 
240 	/* Note we want the actual pwm_level to be 0, regardless of pwm_min */
241 	panel->backlight.pwm_funcs->disable(conn_state, intel_panel_invert_pwm_level(connector, 0));
242 }
243 
244 static int
245 intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pipe)
246 {
247 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
248 	struct intel_panel *panel = &connector->panel;
249 	int ret;
250 
251 	if (panel->backlight.edp.intel.sdr_uses_aux) {
252 		drm_dbg_kms(&i915->drm, "SDR backlight is controlled through DPCD\n");
253 	} else {
254 		drm_dbg_kms(&i915->drm, "SDR backlight is controlled through PWM\n");
255 
256 		ret = panel->backlight.pwm_funcs->setup(connector, pipe);
257 		if (ret < 0) {
258 			drm_err(&i915->drm,
259 				"Failed to setup SDR backlight controls through PWM: %d\n", ret);
260 			return ret;
261 		}
262 	}
263 
264 	panel->backlight.max = 512;
265 	panel->backlight.min = 0;
266 	panel->backlight.level = intel_dp_aux_hdr_get_backlight(connector, pipe);
267 	panel->backlight.enabled = panel->backlight.level != 0;
268 
269 	return 0;
270 }
271 
272 /* VESA backlight callbacks */
273 static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, enum pipe unused)
274 {
275 	return connector->panel.backlight.level;
276 }
277 
278 static void
279 intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state, u32 level)
280 {
281 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
282 	struct intel_panel *panel = &connector->panel;
283 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
284 
285 	drm_edp_backlight_set_level(&intel_dp->aux, &panel->backlight.edp.vesa.info, level);
286 }
287 
288 static void
289 intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
290 				   const struct drm_connector_state *conn_state, u32 level)
291 {
292 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
293 	struct intel_panel *panel = &connector->panel;
294 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
295 
296 	drm_edp_backlight_enable(&intel_dp->aux, &panel->backlight.edp.vesa.info, level);
297 }
298 
299 static void intel_dp_aux_vesa_disable_backlight(const struct drm_connector_state *old_conn_state,
300 						u32 level)
301 {
302 	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
303 	struct intel_panel *panel = &connector->panel;
304 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
305 
306 	drm_edp_backlight_disable(&intel_dp->aux, &panel->backlight.edp.vesa.info);
307 }
308 
309 static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, enum pipe pipe)
310 {
311 	struct intel_dp *intel_dp = intel_attached_dp(connector);
312 	struct intel_panel *panel = &connector->panel;
313 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
314 	u16 current_level;
315 	u8 current_mode;
316 	int ret;
317 
318 	ret = drm_edp_backlight_init(&intel_dp->aux, &panel->backlight.edp.vesa.info,
319 				     i915->vbt.backlight.pwm_freq_hz, intel_dp->edp_dpcd,
320 				     &current_level, &current_mode);
321 	if (ret < 0)
322 		return ret;
323 
324 	panel->backlight.max = panel->backlight.edp.vesa.info.max;
325 	panel->backlight.min = 0;
326 	if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
327 		panel->backlight.level = current_level;
328 		panel->backlight.enabled = panel->backlight.level != 0;
329 	} else {
330 		panel->backlight.level = panel->backlight.max;
331 		panel->backlight.enabled = false;
332 	}
333 
334 	return 0;
335 }
336 
337 static bool
338 intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
339 {
340 	struct intel_dp *intel_dp = intel_attached_dp(connector);
341 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
342 
343 	/* TODO: We currently only support AUX only backlight configurations, not backlights which
344 	 * require a mix of PWM and AUX controls to work. In the mean time, these machines typically
345 	 * work just fine using normal PWM controls anyway.
346 	 */
347 	if ((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
348 	    drm_edp_backlight_supported(intel_dp->edp_dpcd)) {
349 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
350 		return true;
351 	}
352 	return false;
353 }
354 
355 static const struct intel_panel_bl_funcs intel_dp_hdr_bl_funcs = {
356 	.setup = intel_dp_aux_hdr_setup_backlight,
357 	.enable = intel_dp_aux_hdr_enable_backlight,
358 	.disable = intel_dp_aux_hdr_disable_backlight,
359 	.set = intel_dp_aux_hdr_set_backlight,
360 	.get = intel_dp_aux_hdr_get_backlight,
361 };
362 
363 static const struct intel_panel_bl_funcs intel_dp_vesa_bl_funcs = {
364 	.setup = intel_dp_aux_vesa_setup_backlight,
365 	.enable = intel_dp_aux_vesa_enable_backlight,
366 	.disable = intel_dp_aux_vesa_disable_backlight,
367 	.set = intel_dp_aux_vesa_set_backlight,
368 	.get = intel_dp_aux_vesa_get_backlight,
369 };
370 
371 enum intel_dp_aux_backlight_modparam {
372 	INTEL_DP_AUX_BACKLIGHT_AUTO = -1,
373 	INTEL_DP_AUX_BACKLIGHT_OFF = 0,
374 	INTEL_DP_AUX_BACKLIGHT_ON = 1,
375 	INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2,
376 	INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3,
377 };
378 
379 int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
380 {
381 	struct drm_device *dev = connector->base.dev;
382 	struct intel_panel *panel = &connector->panel;
383 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
384 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
385 	bool try_intel_interface = false, try_vesa_interface = false;
386 
387 	/* Check the VBT and user's module parameters to figure out which
388 	 * interfaces to probe
389 	 */
390 	switch (i915->params.enable_dpcd_backlight) {
391 	case INTEL_DP_AUX_BACKLIGHT_OFF:
392 		return -ENODEV;
393 	case INTEL_DP_AUX_BACKLIGHT_AUTO:
394 		switch (i915->vbt.backlight.type) {
395 		case INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE:
396 			try_vesa_interface = true;
397 			break;
398 		case INTEL_BACKLIGHT_DISPLAY_DDI:
399 			try_intel_interface = true;
400 			break;
401 		default:
402 			return -ENODEV;
403 		}
404 		break;
405 	case INTEL_DP_AUX_BACKLIGHT_ON:
406 		if (i915->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE)
407 			try_intel_interface = true;
408 
409 		try_vesa_interface = true;
410 		break;
411 	case INTEL_DP_AUX_BACKLIGHT_FORCE_VESA:
412 		try_vesa_interface = true;
413 		break;
414 	case INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL:
415 		try_intel_interface = true;
416 		break;
417 	}
418 
419 	/*
420 	 * A lot of eDP panels in the wild will report supporting both the
421 	 * Intel proprietary backlight control interface, and the VESA
422 	 * backlight control interface. Many of these panels are liars though,
423 	 * and will only work with the Intel interface. So, always probe for
424 	 * that first.
425 	 */
426 	if (try_intel_interface && intel_dp_aux_supports_hdr_backlight(connector)) {
427 		drm_dbg_kms(dev, "Using Intel proprietary eDP backlight controls\n");
428 		panel->backlight.funcs = &intel_dp_hdr_bl_funcs;
429 		return 0;
430 	}
431 
432 	if (try_vesa_interface && intel_dp_aux_supports_vesa_backlight(connector)) {
433 		drm_dbg_kms(dev, "Using VESA eDP backlight controls\n");
434 		panel->backlight.funcs = &intel_dp_vesa_bl_funcs;
435 		return 0;
436 	}
437 
438 	return -ENODEV;
439 }
440