drm/i915: Dual link needs Shutdown and Turn on packet for both ports

For dual link MIPI panels, SHUTDOWN packet needs to send to both Ports
A & C during MIPI encoder disabling sequence. Similarly, TURN ON packet
to be sent to both Ports during MIPI encoder enabling sequence.

v2: Address review comments by Jani
    - Used a for loop instead of do-while loop.

v3: Used for_each_dsi_port macro instead of for loop
Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dsi_cmd.c

@@ -385,8 +385,7 @@ int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs)
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
-	enum port port = intel_dsi_pipe_to_port(intel_crtc->pipe);
+	enum port port;
 	u32 mask;
 
 	/* XXX: pipe, hs */
@@ -395,18 +394,23 @@ int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs)
 	else
 		cmd |= DPI_LP_MODE;
 
-	/* clear bit */
-	I915_WRITE(MIPI_INTR_STAT(port), SPL_PKT_SENT_INTERRUPT);
+	for_each_dsi_port(port, intel_dsi->ports) {
+		/* clear bit */
+		I915_WRITE(MIPI_INTR_STAT(port), SPL_PKT_SENT_INTERRUPT);
 
-	/* XXX: old code skips write if control unchanged */
-	if (cmd == I915_READ(MIPI_DPI_CONTROL(port)))
-		DRM_ERROR("Same special packet %02x twice in a row.\n", cmd);
+		/* XXX: old code skips write if control unchanged */
+		if (cmd == I915_READ(MIPI_DPI_CONTROL(port)))
+			DRM_ERROR("Same special packet %02x twice in a row.\n",
+									cmd);
 
-	I915_WRITE(MIPI_DPI_CONTROL(port), cmd);
+		I915_WRITE(MIPI_DPI_CONTROL(port), cmd);
 
-	mask = SPL_PKT_SENT_INTERRUPT;
-	if (wait_for((I915_READ(MIPI_INTR_STAT(port)) & mask) == mask, 100))
-		DRM_ERROR("Video mode command 0x%08x send failed.\n", cmd);
+		mask = SPL_PKT_SENT_INTERRUPT;
+		if (wait_for((I915_READ(MIPI_INTR_STAT(port)) & mask) == mask,
+									100))
+			DRM_ERROR("Video mode command 0x%08x send failed.\n",
+									cmd);
+	}
 
 	return 0;
 }