[linux-2.6-block.git] / drivers / gpu / drm / i915 / intel_dp_aux_backlight.c

/*
 * Copyright © 2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "intel_drv.h"

static void set_aux_backlight_enable(struct intel_dp *intel_dp, bool enable)
{
	uint8_t reg_val = 0;

	/* Early return when display use other mechanism to enable backlight. */
	if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
		return;

	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
			      &reg_val) < 0) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_DISPLAY_CONTROL_REGISTER);
		return;
	}
	if (enable)
		reg_val |= DP_EDP_BACKLIGHT_ENABLE;
	else
		reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);

	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
			       reg_val) != 1) {
		DRM_DEBUG_KMS("Failed to %s aux backlight\n",
			      enable ? "enable" : "disable");
	}
}

/*
 * Read the current backlight value from DPCD register(s) based
 * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported
 */
static uint32_t intel_dp_aux_get_backlight(struct intel_connector *connector)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	uint8_t read_val[2] = { 0x0 };
	uint16_t level = 0;

	if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
			     &read_val, sizeof(read_val)) < 0) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
		return 0;
	}
	level = read_val[0];
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
		level = (read_val[0] << 8 | read_val[1]);

	return level;
}

/*
 * Sends the current backlight level over the aux channel, checking if its using
 * 8-bit or 16 bit value (MSB and LSB)
 */
static void
intel_dp_aux_set_backlight(const struct drm_connector_state *conn_state, u32 level)
{
	struct intel_connector *connector = to_intel_connector(conn_state->connector);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	uint8_t vals[2] = { 0x0 };

	vals[0] = level;

	/* Write the MSB and/or LSB */
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) {
		vals[0] = (level & 0xFF00) >> 8;
		vals[1] = (level & 0xFF);
	}
	if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
			      vals, sizeof(vals)) < 0) {
		DRM_DEBUG_KMS("Failed to write aux backlight level\n");
		return;
	}
}

/*
 * Set PWM Frequency divider to match desired frequency in vbt.
 * The PWM Frequency is calculated as 27Mhz / (F x P).
 * - Where F = PWM Frequency Pre-Divider value programmed by field 7:0 of the
 *             EDP_BACKLIGHT_FREQ_SET register (DPCD Address 00728h)
 * - Where P = 2^Pn, where Pn is the value programmed by field 4:0 of the
 *             EDP_PWMGEN_BIT_COUNT register (DPCD Address 00724h)
 */
static bool intel_dp_aux_set_pwm_freq(struct intel_connector *connector)
{
	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
	u8 pn, pn_min, pn_max;

	/* Find desired value of (F x P)
	 * Note that, if F x P is out of supported range, the maximum value or
	 * minimum value will applied automatically. So no need to check that.
	 */
	freq = dev_priv->vbt.backlight.pwm_freq_hz;
	DRM_DEBUG_KMS("VBT defined backlight frequency %u Hz\n", freq);
	if (!freq) {
		DRM_DEBUG_KMS("Use panel default backlight frequency\n");
		return false;
	}

	fxp = DIV_ROUND_CLOSEST(KHz(DP_EDP_BACKLIGHT_FREQ_BASE_KHZ), freq);

	/* Use highest possible value of Pn for more granularity of brightness
	 * adjustment while satifying the conditions below.
	 * - Pn is in the range of Pn_min and Pn_max
	 * - F is in the range of 1 and 255
	 * - FxP is within 25% of desired value.
	 *   Note: 25% is arbitrary value and may need some tweak.
	 */
	if (drm_dp_dpcd_readb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min) != 1) {
		DRM_DEBUG_KMS("Failed to read pwmgen bit count cap min\n");
		return false;
	}
	if (drm_dp_dpcd_readb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max) != 1) {
		DRM_DEBUG_KMS("Failed to read pwmgen bit count cap max\n");
		return false;
	}
	pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
	pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK;

	fxp_min = DIV_ROUND_CLOSEST(fxp * 3, 4);
	fxp_max = DIV_ROUND_CLOSEST(fxp * 5, 4);
	if (fxp_min < (1 << pn_min) || (255 << pn_max) < fxp_max) {
		DRM_DEBUG_KMS("VBT defined backlight frequency out of range\n");
		return false;
	}

	for (pn = pn_max; pn >= pn_min; pn--) {
		f = clamp(DIV_ROUND_CLOSEST(fxp, 1 << pn), 1, 255);
		fxp_actual = f << pn;
		if (fxp_min <= fxp_actual && fxp_actual <= fxp_max)
			break;
	}

	if (drm_dp_dpcd_writeb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT, pn) < 0) {
		DRM_DEBUG_KMS("Failed to write aux pwmgen bit count\n");
		return false;
	}
	if (drm_dp_dpcd_writeb(&intel_dp->aux,
			       DP_EDP_BACKLIGHT_FREQ_SET, (u8) f) < 0) {
		DRM_DEBUG_KMS("Failed to write aux backlight freq\n");
		return false;
	}
	return true;
}

/*
* Set minimum / maximum dynamic brightness percentage. This value is expressed
* as the percentage of normal brightness in 5% increments.
*/
static bool
intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp,
					   u32 min, u32 max)
{
	u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5) };

	if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
			  dbc, sizeof(dbc)) < 0) {
		DRM_DEBUG_KMS("Failed to write aux DBC brightness level\n");
		return false;
	}
	return true;
}

static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_state,
					  const struct drm_connector_state *conn_state)
{
	struct intel_connector *connector = to_intel_connector(conn_state->connector);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	uint8_t dpcd_buf, new_dpcd_buf, edp_backlight_mode;

	if (drm_dp_dpcd_readb(&intel_dp->aux,
			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
		return;
	}

	new_dpcd_buf = dpcd_buf;
	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

	switch (edp_backlight_mode) {
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
		new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
		new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
		break;

	/* Do nothing when it is already DPCD mode */
	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
	default:
		break;
	}

	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP)
		if (intel_dp_aux_set_pwm_freq(connector))
			new_dpcd_buf |= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE;

	if (i915.enable_dbc &&
	    (intel_dp->edp_dpcd[2] & DP_EDP_DYNAMIC_BACKLIGHT_CAP)) {
		if(intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0, 100)) {
			new_dpcd_buf |= DP_EDP_DYNAMIC_BACKLIGHT_ENABLE;
			DRM_DEBUG_KMS("Enable dynamic brightness.\n");
		}
	}

	if (new_dpcd_buf != dpcd_buf) {
		if (drm_dp_dpcd_writeb(&intel_dp->aux,
			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) {
			DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
		}
	}

	set_aux_backlight_enable(intel_dp, true);
	intel_dp_aux_set_backlight(conn_state, connector->panel.backlight.level);
}

static void intel_dp_aux_disable_backlight(const struct drm_connector_state *old_conn_state)
{
	set_aux_backlight_enable(enc_to_intel_dp(old_conn_state->best_encoder), false);
}

static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
					enum pipe pipe)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	struct intel_panel *panel = &connector->panel;

	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
		panel->backlight.max = 0xFFFF;
	else
		panel->backlight.max = 0xFF;

	panel->backlight.min = 0;
	panel->backlight.level = intel_dp_aux_get_backlight(connector);

	panel->backlight.enabled = panel->backlight.level != 0;

	return 0;
}

static bool
intel_dp_aux_display_control_capable(struct intel_connector *connector)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);

	/* Check the eDP Display control capabilities registers to determine if
	 * the panel can support backlight control over the aux channel
	 */
	if ((intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP) &&
	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
		DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
		return true;
	}
	return false;
}

/*
 * Heuristic function whether we should use AUX for backlight adjustment or not.
 *
 * We should use AUX for backlight brightness adjustment if panel doesn't this
 * via PWM pin or using AUX is better than using PWM pin.
 *
 * The heuristic to determine that using AUX pin is better than using PWM pin is
 * that the panel support any of the feature list here.
 * - Regional backlight brightness adjustment
 * - Backlight PWM frequency set
 * - More than 8 bits resolution of brightness level
 * - Backlight enablement via AUX and not by BL_ENABLE pin
 *
 * If all above are not true, assume that using PWM pin is better.
 */
static bool
intel_dp_aux_display_control_heuristic(struct intel_connector *connector)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	uint8_t reg_val;

	/* Panel doesn't support adjusting backlight brightness via PWN pin */
	if (!(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))
		return true;

	/* Panel supports regional backlight brightness adjustment */
	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_GENERAL_CAP_3,
			      &reg_val) != 1) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			       DP_EDP_GENERAL_CAP_3);
		return false;
	}
	if (reg_val > 0)
		return true;

	/* Panel supports backlight PWM frequency set */
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP)
		return true;

	/* Panel supports more than 8 bits resolution of brightness level */
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
		return true;

	/* Panel supports enabling backlight via AUX but not by BL_ENABLE pin */
	if ((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
	    !(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP))
		return true;

	return false;

}

int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
{
	struct intel_panel *panel = &intel_connector->panel;

	if (!i915.enable_dpcd_backlight)
		return -ENODEV;

	if (!intel_dp_aux_display_control_capable(intel_connector))
		return -ENODEV;

	if (i915.enable_dpcd_backlight == -1 &&
	    !intel_dp_aux_display_control_heuristic(intel_connector))
		return -ENODEV;

	panel->backlight.setup = intel_dp_aux_setup_backlight;
	panel->backlight.enable = intel_dp_aux_enable_backlight;
	panel->backlight.disable = intel_dp_aux_disable_backlight;
	panel->backlight.set = intel_dp_aux_set_backlight;
	panel->backlight.get = intel_dp_aux_get_backlight;

	return 0;
}
Commit	Line	Data
e7156c83 YA	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
49d191dd PV	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
e7156c83 YA	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
7d025e08	81	intel_dp_aux_set_backlight(const struct drm_connector_state *conn_state, u32 level)
e7156c83	82	{
7d025e08	83	struct intel_connector *connector = to_intel_connector(conn_state->connector);
e7156c83 YA	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
c03e53b0 PV	101	/*
	102	* Set PWM Frequency divider to match desired frequency in vbt.
	103	* The PWM Frequency is calculated as 27Mhz / (F x P).
	104	* - Where F = PWM Frequency Pre-Divider value programmed by field 7:0 of the
	105	* EDP_BACKLIGHT_FREQ_SET register (DPCD Address 00728h)
	106	* - Where P = 2^Pn, where Pn is the value programmed by field 4:0 of the
	107	* EDP_PWMGEN_BIT_COUNT register (DPCD Address 00724h)
	108	*/
	109	static bool intel_dp_aux_set_pwm_freq(struct intel_connector *connector)
	110	{
	111	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
	112	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	113	int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
	114	u8 pn, pn_min, pn_max;
	115
	116	/* Find desired value of (F x P)
	117	* Note that, if F x P is out of supported range, the maximum value or
	118	* minimum value will applied automatically. So no need to check that.
	119	*/
	120	freq = dev_priv->vbt.backlight.pwm_freq_hz;
	121	DRM_DEBUG_KMS("VBT defined backlight frequency %u Hz\n", freq);
	122	if (!freq) {
	123	DRM_DEBUG_KMS("Use panel default backlight frequency\n");
	124	return false;
	125	}
	126
	127	fxp = DIV_ROUND_CLOSEST(KHz(DP_EDP_BACKLIGHT_FREQ_BASE_KHZ), freq);
	128
	129	/* Use highest possible value of Pn for more granularity of brightness
	130	* adjustment while satifying the conditions below.
	131	* - Pn is in the range of Pn_min and Pn_max
	132	* - F is in the range of 1 and 255
	133	* - FxP is within 25% of desired value.
	134	* Note: 25% is arbitrary value and may need some tweak.
	135	*/
	136	if (drm_dp_dpcd_readb(&intel_dp->aux,
	137	DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min) != 1) {
	138	DRM_DEBUG_KMS("Failed to read pwmgen bit count cap min\n");
	139	return false;
	140	}
	141	if (drm_dp_dpcd_readb(&intel_dp->aux,
	142	DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max) != 1) {
	143	DRM_DEBUG_KMS("Failed to read pwmgen bit count cap max\n");
	144	return false;
	145	}
	146	pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
	147	pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
	148
	149	fxp_min = DIV_ROUND_CLOSEST(fxp * 3, 4);
	150	fxp_max = DIV_ROUND_CLOSEST(fxp * 5, 4);
	151	if (fxp_min < (1 << pn_min) \|\| (255 << pn_max) < fxp_max) {
	152	DRM_DEBUG_KMS("VBT defined backlight frequency out of range\n");
	153	return false;
	154	}
	155
	156	for (pn = pn_max; pn >= pn_min; pn--) {
	157	f = clamp(DIV_ROUND_CLOSEST(fxp, 1 << pn), 1, 255);
	158	fxp_actual = f << pn;
	159	if (fxp_min <= fxp_actual && fxp_actual <= fxp_max)
	160	break;
	161	}
	162
	163	if (drm_dp_dpcd_writeb(&intel_dp->aux,
	164	DP_EDP_PWMGEN_BIT_COUNT, pn) < 0) {
165	DRM_DEBUG_KMS("Failed to write aux pwmgen bit count\n");
166	return false;
167	}
168	if (drm_dp_dpcd_writeb(&intel_dp->aux,
169	DP_EDP_BACKLIGHT_FREQ_SET, (u8) f) < 0) {
170	DRM_DEBUG_KMS("Failed to write aux backlight freq\n");
171	return false;
172	}
173	return true;
174	}
175
ae25ecea PV	176	/*
	177	* Set minimum / maximum dynamic brightness percentage. This value is expressed
	178	* as the percentage of normal brightness in 5% increments.
	179	*/
	180	static bool
	181	intel_dp_aux_set_dynamic_backlight_percent(struct intel_dp *intel_dp,
	182	u32 min, u32 max)
	183	{
	184	u8 dbc[] = { DIV_ROUND_CLOSEST(min, 5), DIV_ROUND_CLOSEST(max, 5) };
	185
	186	if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET,
	187	dbc, sizeof(dbc)) < 0) {
	188	DRM_DEBUG_KMS("Failed to write aux DBC brightness level\n");
	189	return false;
	190	}
	191	return true;
	192	}
	193
7d025e08 ML	194	static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_state,
7d025e08 ML	195	const struct drm_connector_state *conn_state)
e7156c83	196	{
7d025e08	197	struct intel_connector *connector = to_intel_connector(conn_state->connector);
e7156c83	198	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
c03e53b0	199	uint8_t dpcd_buf, new_dpcd_buf, edp_backlight_mode;
e7156c83	200
73ab484c PV	201	if (drm_dp_dpcd_readb(&intel_dp->aux,
	202	DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
	203	DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
	204	DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
	205	return;
	206	}
	207
c03e53b0	208	new_dpcd_buf = dpcd_buf;
73ab484c PV	209	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
	210
	211	switch (edp_backlight_mode) {
	212	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
	213	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
	214	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
c03e53b0 PV	215	new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
c03e53b0 PV	216	new_dpcd_buf \|= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
73ab484c PV	217	break;
	218
	219	/* Do nothing when it is already DPCD mode */
	220	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
	221	default:
	222	break;
	223	}
e9c9e5ae	224
c03e53b0 PV	225	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP)
	226	if (intel_dp_aux_set_pwm_freq(connector))
	227	new_dpcd_buf \|= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE;
	228
ae25ecea PV	229	if (i915.enable_dbc &&
	230	(intel_dp->edp_dpcd[2] & DP_EDP_DYNAMIC_BACKLIGHT_CAP)) {
	231	if(intel_dp_aux_set_dynamic_backlight_percent(intel_dp, 0, 100)) {
	232	new_dpcd_buf \|= DP_EDP_DYNAMIC_BACKLIGHT_ENABLE;
	233	DRM_DEBUG_KMS("Enable dynamic brightness.\n");
	234	}
	235	}
	236
c03e53b0 PV	237	if (new_dpcd_buf != dpcd_buf) {
	238	if (drm_dp_dpcd_writeb(&intel_dp->aux,
	239	DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) {
	240	DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
	241	}
	242	}
	243
e9c9e5ae	244	set_aux_backlight_enable(intel_dp, true);
7d025e08	245	intel_dp_aux_set_backlight(conn_state, connector->panel.backlight.level);
e7156c83 YA	246	}
e7156c83 YA	247
7d025e08	248	static void intel_dp_aux_disable_backlight(const struct drm_connector_state *old_conn_state)
e7156c83	249	{
7d025e08	250	set_aux_backlight_enable(enc_to_intel_dp(old_conn_state->best_encoder), false);
e7156c83 YA	251	}
	252
	253	static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
	254	enum pipe pipe)
	255	{
	256	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	257	struct intel_panel *panel = &connector->panel;
	258
e7156c83 YA	259	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
	260	panel->backlight.max = 0xFFFF;
	261	else
	262	panel->backlight.max = 0xFF;
	263
	264	panel->backlight.min = 0;
	265	panel->backlight.level = intel_dp_aux_get_backlight(connector);
	266
	267	panel->backlight.enabled = panel->backlight.level != 0;
	268
	269	return 0;
	270	}
	271
	272	static bool
	273	intel_dp_aux_display_control_capable(struct intel_connector *connector)
	274	{
	275	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	276
7d025e08	277	/* Check the eDP Display control capabilities registers to determine if
e7156c83 YA	278	* the panel can support backlight control over the aux channel
e7156c83 YA	279	*/
560a758d PV	280	if ((intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP) &&
560a758d PV	281	(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
e7156c83 YA	282	DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
	283	return true;
	284	}
	285	return false;
	286	}
	287
560a758d PV	288	/*
	289	* Heuristic function whether we should use AUX for backlight adjustment or not.
	290	*
	291	* We should use AUX for backlight brightness adjustment if panel doesn't this
	292	* via PWM pin or using AUX is better than using PWM pin.
	293	*
	294	* The heuristic to determine that using AUX pin is better than using PWM pin is
	295	* that the panel support any of the feature list here.
	296	* - Regional backlight brightness adjustment
	297	* - Backlight PWM frequency set
	298	* - More than 8 bits resolution of brightness level
	299	* - Backlight enablement via AUX and not by BL_ENABLE pin
	300	*
	301	* If all above are not true, assume that using PWM pin is better.
	302	*/
	303	static bool
	304	intel_dp_aux_display_control_heuristic(struct intel_connector *connector)
	305	{
	306	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	307	uint8_t reg_val;
	308
	309	/* Panel doesn't support adjusting backlight brightness via PWN pin */
	310	if (!(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))
	311	return true;
	312
	313	/* Panel supports regional backlight brightness adjustment */
	314	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_GENERAL_CAP_3,
	315	&reg_val) != 1) {
	316	DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
	317	DP_EDP_GENERAL_CAP_3);
	318	return false;
	319	}
	320	if (reg_val > 0)
	321	return true;
	322
	323	/* Panel supports backlight PWM frequency set */
	324	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP)
	325	return true;
	326
	327	/* Panel supports more than 8 bits resolution of brightness level */
	328	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
	329	return true;
	330
	331	/* Panel supports enabling backlight via AUX but not by BL_ENABLE pin */
	332	if ((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
	333	!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP))
	334	return true;
	335
	336	return false;
	337
	338	}
	339
e7156c83 YA	340	int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
	341	{
	342	struct intel_panel *panel = &intel_connector->panel;
	343
	344	if (!i915.enable_dpcd_backlight)
	345	return -ENODEV;
	346
	347	if (!intel_dp_aux_display_control_capable(intel_connector))
	348	return -ENODEV;
	349
560a758d PV	350	if (i915.enable_dpcd_backlight == -1 &&
	351	!intel_dp_aux_display_control_heuristic(intel_connector))
	352	return -ENODEV;
	353
e7156c83 YA	354	panel->backlight.setup = intel_dp_aux_setup_backlight;
	355	panel->backlight.enable = intel_dp_aux_enable_backlight;
	356	panel->backlight.disable = intel_dp_aux_disable_backlight;
	357	panel->backlight.set = intel_dp_aux_set_backlight;
	358	panel->backlight.get = intel_dp_aux_get_backlight;
	359
	360	return 0;
	361	}