diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dp_aux_backlight.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c new file mode 100644 index 000000000..357136f17 --- /dev/null +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c @@ -0,0 +1,280 @@ +/* + * 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) +{ + u8 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, + ®_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 u32 intel_dp_aux_get_backlight(struct intel_connector *connector) +{ + struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); + u8 read_val[2] = { 0x0 }; + u16 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); + u8 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; +} + +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); + u8 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 (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) && + !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) { + DRM_DEBUG_KMS("AUX Backlight Control Supported!\n"); + 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_modparams.enable_dpcd_backlight) + return -ENODEV; + + if (!intel_dp_aux_display_control_capable(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; +} |