[RFC 14/21] DRM: Add VIA DRM driver

[James Simmons]

commit 9549976c231b676c2c8e70fd6979115c1c8ed747
Author: James Simmons <jsimmons at infradead.org>
Date:   Sat Jun 8 12:02:59 2013 -0400

    via: VGA analog support
    
    Implement the encoder and connector for VGA analog displays.
    
    Signed-Off-by: James Simmons <jsimmons at infradead.org>

diff --git a/drivers/gpu/drm/via/via_analog.c b/drivers/gpu/drm/via/via_analog.c
new file mode 100644
index 0000000..8fabeac
--- /dev/null
+++ b/drivers/gpu/drm/via/via_analog.c
@@ -0,0 +1,146 @@
+/*
+ * Copyright © 2012 James Simmons
+ *
+ * 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.
+ *
+ * Authors:
+ *	James Simmons <jsimmons at infradead.org>
+ */
+#include "via_drv.h"
+
+/*
+ * Routines for controlling stuff on the analog port
+ */
+static const struct drm_encoder_funcs via_dac_enc_funcs = {
+	.destroy = via_encoder_cleanup,
+};
+
+/* Manage the power state of the DAC */
+static void
+via_dac_dpms(struct drm_encoder *encoder, int mode)
+{
+	struct drm_via_private *dev_priv = encoder->dev->dev_private;
+	u8 mask = 0;
+
+	switch (mode) {
+	case DRM_MODE_DPMS_SUSPEND:
+		mask = BIT(5);		// VSync off
+		break;
+	case DRM_MODE_DPMS_STANDBY:
+		mask = BIT(4);		// HSync off
+		break;
+	case DRM_MODE_DPMS_OFF:
+		mask = (BIT(5) | BIT(4));// HSync and VSync off
+		break;
+	case DRM_MODE_DPMS_ON:
+	default:
+		break;
+	}
+	svga_wcrt_mask(VGABASE, 0x36, mask, BIT(5) | BIT(4));
+}
+
+/* Pass our mode to the connectors and the CRTC to give them a chance to
+ * adjust it according to limitations or connector properties, and also
+ * a chance to reject the mode entirely. Usefule for things like scaling.
+ */
+static bool
+via_dac_mode_fixup(struct drm_encoder *encoder,
+		 const struct drm_display_mode *mode,
+		 struct drm_display_mode *adjusted_mode)
+{
+	drm_mode_set_crtcinfo(adjusted_mode, 0);
+	return true;
+}
+
+static const struct drm_encoder_helper_funcs via_dac_enc_helper_funcs = {
+	.dpms = via_dac_dpms,
+	.mode_fixup = via_dac_mode_fixup,
+	.mode_set = via_set_sync_polarity,
+	.prepare = via_encoder_prepare,
+	.commit = via_encoder_commit,
+	.disable = via_encoder_disable,
+};
+
+static enum drm_connector_status
+via_analog_detect(struct drm_connector *connector, bool force)
+{
+	struct via_connector *con = container_of(connector, struct via_connector, base);
+	enum drm_connector_status ret = connector_status_disconnected;
+	struct edid *edid = NULL;
+
+	drm_mode_connector_update_edid_property(connector, edid);
+	if (con->ddc_bus) {
+		edid = drm_get_edid(connector, con->ddc_bus);
+		if (edid) {
+			drm_mode_connector_update_edid_property(connector, edid);
+			kfree(edid);
+			ret = connector_status_connected;
+		}
+	}
+	return ret;
+}
+
+static const struct drm_connector_funcs via_analog_connector_funcs = {
+	.dpms = drm_helper_connector_dpms,
+	.detect = via_analog_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.set_property = via_connector_set_property,
+	.destroy = via_connector_destroy,
+};
+
+static const struct drm_connector_helper_funcs via_analog_connector_helper_funcs = {
+	.mode_valid = via_connector_mode_valid,
+	.get_modes = via_get_edid_modes,
+	.best_encoder = via_best_encoder,
+};
+
+void
+via_analog_init(struct drm_device *dev)
+{
+	struct via_connector *con;
+	struct via_encoder *enc;
+
+	enc = kzalloc(sizeof(*enc) + sizeof(*con), GFP_KERNEL);
+	if (!enc) {
+		DRM_ERROR("Failed to allocate connector and encoder\n");
+		return;
+	}
+	con = &enc->cons[0];
+
+	/* Piece together our connector */
+	drm_connector_init(dev, &con->base, &via_analog_connector_funcs,
+				DRM_MODE_CONNECTOR_VGA);
+	drm_connector_helper_add(&con->base, &via_analog_connector_helper_funcs);
+	drm_sysfs_connector_add(&con->base);
+
+	con->ddc_bus = via_find_ddc_bus(0x26);
+	con->base.doublescan_allowed = false;
+	con->base.interlace_allowed = true;
+
+	/* Setup the encoders and attach them */
+	drm_encoder_init(dev, &enc->base, &via_dac_enc_funcs, DRM_MODE_ENCODER_DAC);
+	drm_encoder_helper_add(&enc->base, &via_dac_enc_helper_funcs);
+
+	enc->base.possible_crtcs = BIT(1) | BIT(0);
+	enc->base.possible_clones = 0;
+	enc->diPort = DISP_DI_DAC;
+
+	drm_mode_connector_attach_encoder(&con->base, &enc->base);
+}