drm/i915: Add lspcon support for I915 driver

This patch adds a new file, to accommodate lspcon support
for I915 driver. These functions probe, detect, initialize
and configure an on-board lspcon device during the driver
init time.

Also, this patch adds a small structure for lspcon device,
which will provide the runtime status of the device.

V2: addressed ville's review comments
- Clean the leftover macros from previous patch set

V3: Rebase
V4: addressed ville's review comments
- make internal functions static
- remove lspcon_detect_identifier, make it inline with lspcon_probe
- remove is_lspcon_active function
- remove force check while setting a lspcon mode

V5: Rebase
V6: Pass dev_priv to IS_GEN9 check

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Akashdeep Sharma <akashdeep.sharma@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476455212-27893-3-git-send-email-shashank.sharma@intel.com

drivers/gpu/drm/i915/Makefile

@@ -101,6 +101,7 @@ i915-y += dvo_ch7017.o \
 	  intel_dvo.o \
 	  intel_hdmi.o \
 	  intel_i2c.o \
+	  intel_lspcon.o \
 	  intel_lvds.o \
 	  intel_panel.o \
 	  intel_sdvo.o \

drivers/gpu/drm/i915/intel_drv.h

@@ -961,12 +961,19 @@ struct intel_dp {
 	bool compliance_test_active;
 };
 
+struct intel_lspcon {
+	bool active;
+	enum drm_lspcon_mode mode;
+	struct drm_dp_aux *aux;
+};
+
 struct intel_digital_port {
 	struct intel_encoder base;
 	enum port port;
 	u32 saved_port_bits;
 	struct intel_dp dp;
 	struct intel_hdmi hdmi;
+	struct intel_lspcon lspcon;
 	enum irqreturn (*hpd_pulse)(struct intel_digital_port *, bool);
 	bool release_cl2_override;
 	uint8_t max_lanes;
@@ -1848,4 +1855,6 @@ int intel_color_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
 void intel_color_set_csc(struct drm_crtc_state *crtc_state);
 void intel_color_load_luts(struct drm_crtc_state *crtc_state);
 
+/* intel_lspcon.c */
+bool lspcon_init(struct intel_digital_port *intel_dig_port);
 #endif /* __INTEL_DRV_H__ */

drivers/gpu/drm/i915/intel_lspcon.c

@@ -0,0 +1,128 @@
+/*
+ * Copyright © 2016 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 <drm/drm_edid.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_dp_dual_mode_helper.h>
+#include "intel_drv.h"
+
+enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
+{
+	enum drm_lspcon_mode current_mode = DRM_LSPCON_MODE_INVALID;
+	struct i2c_adapter *adapter = &lspcon->aux->ddc;
+
+	if (drm_lspcon_get_mode(adapter, &current_mode))
+		DRM_ERROR("Error reading LSPCON mode\n");
+	else
+		DRM_DEBUG_KMS("Current LSPCON mode %s\n",
+			current_mode == DRM_LSPCON_MODE_PCON ? "PCON" : "LS");
+	return current_mode;
+}
+
+static int lspcon_change_mode(struct intel_lspcon *lspcon,
+	enum drm_lspcon_mode mode, bool force)
+{
+	int err;
+	enum drm_lspcon_mode current_mode;
+	struct i2c_adapter *adapter = &lspcon->aux->ddc;
+
+	err = drm_lspcon_get_mode(adapter, &current_mode);
+	if (err) {
+		DRM_ERROR("Error reading LSPCON mode\n");
+		return err;
+	}
+
+	if (current_mode == mode) {
+		DRM_DEBUG_KMS("Current mode = desired LSPCON mode\n");
+		return 0;
+	}
+
+	err = drm_lspcon_set_mode(adapter, mode);
+	if (err < 0) {
+		DRM_ERROR("LSPCON mode change failed\n");
+		return err;
+	}
+
+	lspcon->mode = mode;
+	DRM_DEBUG_KMS("LSPCON mode changed done\n");
+	return 0;
+}
+
+static bool lspcon_probe(struct intel_lspcon *lspcon)
+{
+	enum drm_dp_dual_mode_type adaptor_type;
+	struct i2c_adapter *adapter = &lspcon->aux->ddc;
+
+	/* Lets probe the adaptor and check its type */
+	adaptor_type = drm_dp_dual_mode_detect(adapter);
+	if (adaptor_type != DRM_DP_DUAL_MODE_LSPCON) {
+		DRM_DEBUG_KMS("No LSPCON detected, found %s\n",
+			drm_dp_get_dual_mode_type_name(adaptor_type));
+		return false;
+	}
+
+	/* Yay ... got a LSPCON device */
+	DRM_DEBUG_KMS("LSPCON detected\n");
+	lspcon->mode = lspcon_get_current_mode(lspcon);
+	lspcon->active = true;
+	return true;
+}
+
+bool lspcon_init(struct intel_digital_port *intel_dig_port)
+{
+	struct intel_dp *dp = &intel_dig_port->dp;
+	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+
+	if (!IS_GEN9(dev_priv)) {
+		DRM_ERROR("LSPCON is supported on GEN9 only\n");
+		return false;
+	}
+
+	lspcon->active = false;
+	lspcon->mode = DRM_LSPCON_MODE_INVALID;
+	lspcon->aux = &dp->aux;
+
+	if (!lspcon_probe(lspcon)) {
+		DRM_ERROR("Failed to probe lspcon\n");
+		return false;
+	}
+
+	/*
+	* In the SW state machine, lets Put LSPCON in PCON mode only.
+	* In this way, it will work with both HDMI 1.4 sinks as well as HDMI
+	* 2.0 sinks.
+	*/
+	if (lspcon->active && lspcon->mode != DRM_LSPCON_MODE_PCON) {
+		if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON,
+			true) < 0) {
+			DRM_ERROR("LSPCON mode change to PCON failed\n");
+			return false;
+		}
+	}
+
+	DRM_DEBUG_KMS("Success: LSPCON init\n");
+	return true;
+}