drm/tilcdc: add support for LCD panels (v5)

Add an output panel driver for LCD panels.  Tested with LCD3 cape on
beaglebone.

v1: original
v2: s/of_find_node_by_name()/of_get_child_by_name()/ from Pantelis
    Antoniou
v3: add backlight support
v4: rebase to latest of video timing helpers
v5: remove some unneeded fields from panel-info struct, add DT bindings
    docs
Signed-off-by: Rob Clark <robdclark@gmail.com>
Tested-by: Koen Kooi <koen@dominion.thruhere.net>

Documentation/devicetree/bindings/drm/tilcdc/panel.txt

+Device-Tree bindings for tilcdc DRM generic panel output driver
+
+Required properties:
+ - compatible: value should be "ti,tilcdc,panel".
+ - panel-info: configuration info to configure LCDC correctly for the panel
+   - ac-bias: AC Bias Pin Frequency
+   - ac-bias-intrpt: AC Bias Pin Transitions per Interrupt
+   - dma-burst-sz: DMA burst size
+   - bpp: Bits per pixel
+   - fdd: FIFO DMA Request Delay
+   - sync-edge: Horizontal and Vertical Sync Edge: 0=rising 1=falling
+   - sync-ctrl: Horizontal and Vertical Sync: Control: 0=ignore
+   - raster-order: Raster Data Order Select: 1=Most-to-least 0=Least-to-most
+   - fifo-th: DMA FIFO threshold
+ - display-timings: typical videomode of lcd panel.  Multiple video modes
+   can be listed if the panel supports multiple timings, but the 'native-mode'
+   should be the preferred/default resolution.  Refer to
+   Documentation/devicetree/bindings/video/display-timing.txt for display
+   timing binding details.
+
+Recommended properties:
+ - pinctrl-names, pinctrl-0: the pincontrol settings to configure
+   muxing properly for pins that connect to TFP410 device
+
+Example:
+
+	/* Settings for CDTech_S035Q01 / LCD3 cape: */
+	lcd3 {
+		compatible = "ti,tilcdc,panel";
+		pinctrl-names = "default";
+		pinctrl-0 = <&bone_lcd3_cape_lcd_pins>;
+		panel-info {
+			ac-bias           = <255>;
+			ac-bias-intrpt    = <0>;
+			dma-burst-sz      = <16>;
+			bpp               = <16>;
+			fdd               = <0x80>;
+			sync-edge         = <0>;
+			sync-ctrl         = <1>;
+			raster-order      = <0>;
+			fifo-th           = <0>;
+		};
+		display-timings {
+			native-mode = <&timing0>;
+			timing0: 320x240 {
+				hactive         = <320>;
+				vactive         = <240>;
+				hback-porch     = <21>;
+				hfront-porch    = <58>;
+				hsync-len       = <47>;
+				vback-porch     = <11>;
+				vfront-porch    = <23>;
+				vsync-len       = <2>;
+				clock-frequency = <8000000>;
+				hsync-active    = <0>;
+				vsync-active    = <0>;
+			};
+		};
+	};

drivers/gpu/drm/tilcdc/Kconfig

@@ -4,6 +4,9 @@ config DRM_TILCDC
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_GEM_CMA_HELPER
+	select OF_VIDEOMODE
+	select OF_DISPLAY_TIMING
+	select BACKLIGHT_CLASS_DEVICE
 	help
 	  Choose this option if you have an TI SoC with LCDC display
 	  controller, for example AM33xx in beagle-bone, DA8xx, or

drivers/gpu/drm/tilcdc/Makefile

@@ -4,6 +4,7 @@ tilcdc-y := \
 	tilcdc_crtc.o \
 	tilcdc_tfp410.o \
 	tilcdc_slave.o \
+	tilcdc_panel.o \
 	tilcdc_drv.o
 
 obj-$(CONFIG_DRM_TILCDC)	+= tilcdc.o

drivers/gpu/drm/tilcdc/tilcdc_drv.c

@@ -21,6 +21,7 @@
 #include "tilcdc_regs.h"
 #include "tilcdc_tfp410.h"
 #include "tilcdc_slave.h"
+#include "tilcdc_panel.h"
 
 #include "drm_fb_helper.h"
 
@@ -589,6 +590,7 @@ static int __init tilcdc_drm_init(void)
 	DBG("init");
 	tilcdc_tfp410_init();
 	tilcdc_slave_init();
+	tilcdc_panel_init();
 	return platform_driver_register(&tilcdc_platform_driver);
 }
 
@@ -597,6 +599,7 @@ static void __exit tilcdc_drm_fini(void)
 	DBG("fini");
 	tilcdc_tfp410_fini();
 	tilcdc_slave_fini();
+	tilcdc_panel_fini();
 	platform_driver_unregister(&tilcdc_platform_driver);
 }
 

drivers/gpu/drm/tilcdc/tilcdc_panel.c

+/*
+ * Copyright (C) 2012 Texas Instruments
+ * Author: Rob Clark <robdclark@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/backlight.h>
+#include <video/display_timing.h>
+#include <video/of_display_timing.h>
+#include <video/videomode.h>
+
+#include "tilcdc_drv.h"
+
+struct panel_module {
+	struct tilcdc_module base;
+	struct tilcdc_panel_info *info;
+	struct display_timings *timings;
+	struct backlight_device *backlight;
+};
+#define to_panel_module(x) container_of(x, struct panel_module, base)
+
+
+/*
+ * Encoder:
+ */
+
+struct panel_encoder {
+	struct drm_encoder base;
+	struct panel_module *mod;
+};
+#define to_panel_encoder(x) container_of(x, struct panel_encoder, base)
+
+
+static void panel_encoder_destroy(struct drm_encoder *encoder)
+{
+	struct panel_encoder *panel_encoder = to_panel_encoder(encoder);
+	drm_encoder_cleanup(encoder);
+	kfree(panel_encoder);
+}
+
+static void panel_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+	struct panel_encoder *panel_encoder = to_panel_encoder(encoder);
+	struct backlight_device *backlight = panel_encoder->mod->backlight;
+
+	if (!backlight)
+		return;
+
+	backlight->props.power = mode == DRM_MODE_DPMS_ON
+				     ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
+	backlight_update_status(backlight);
+}
+
+static bool panel_encoder_mode_fixup(struct drm_encoder *encoder,
+		const struct drm_display_mode *mode,
+		struct drm_display_mode *adjusted_mode)
+{
+	/* nothing needed */
+	return true;
+}
+
+static void panel_encoder_prepare(struct drm_encoder *encoder)
+{
+	struct panel_encoder *panel_encoder = to_panel_encoder(encoder);
+	panel_encoder_dpms(encoder, DRM_MODE_DPMS_OFF);
+	tilcdc_crtc_set_panel_info(encoder->crtc, panel_encoder->mod->info);
+}
+
+static void panel_encoder_commit(struct drm_encoder *encoder)
+{
+	panel_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
+}
+
+static void panel_encoder_mode_set(struct drm_encoder *encoder,
+		struct drm_display_mode *mode,
+		struct drm_display_mode *adjusted_mode)
+{
+	/* nothing needed */
+}
+
+static const struct drm_encoder_funcs panel_encoder_funcs = {
+		.destroy        = panel_encoder_destroy,
+};
+
+static const struct drm_encoder_helper_funcs panel_encoder_helper_funcs = {
+		.dpms           = panel_encoder_dpms,
+		.mode_fixup     = panel_encoder_mode_fixup,
+		.prepare        = panel_encoder_prepare,
+		.commit         = panel_encoder_commit,
+		.mode_set       = panel_encoder_mode_set,
+};
+
+static struct drm_encoder *panel_encoder_create(struct drm_device *dev,
+		struct panel_module *mod)
+{
+	struct panel_encoder *panel_encoder;
+	struct drm_encoder *encoder;
+	int ret;
+
+	panel_encoder = kzalloc(sizeof(*panel_encoder), GFP_KERNEL);
+	if (!panel_encoder) {
+		dev_err(dev->dev, "allocation failed\n");
+		return NULL;
+	}
+
+	panel_encoder->mod = mod;
+
+	encoder = &panel_encoder->base;
+	encoder->possible_crtcs = 1;
+
+	ret = drm_encoder_init(dev, encoder, &panel_encoder_funcs,
+			DRM_MODE_ENCODER_LVDS);
+	if (ret < 0)
+		goto fail;
+
+	drm_encoder_helper_add(encoder, &panel_encoder_helper_funcs);
+
+	return encoder;
+
+fail:
+	panel_encoder_destroy(encoder);
+	return NULL;
+}
+
+/*
+ * Connector:
+ */
+
+struct panel_connector {
+	struct drm_connector base;
+
+	struct drm_encoder *encoder;  /* our connected encoder */
+	struct panel_module *mod;
+};
+#define to_panel_connector(x) container_of(x, struct panel_connector, base)
+
+
+static void panel_connector_destroy(struct drm_connector *connector)
+{
+	struct panel_connector *panel_connector = to_panel_connector(connector);
+	drm_connector_cleanup(connector);
+	kfree(panel_connector);
+}
+
+static enum drm_connector_status panel_connector_detect(
+		struct drm_connector *connector,
+		bool force)
+{
+	return connector_status_connected;
+}
+
+static int panel_connector_get_modes(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct panel_connector *panel_connector = to_panel_connector(connector);
+	struct display_timings *timings = panel_connector->mod->timings;
+	int i;
+
+	for (i = 0; i < timings->num_timings; i++) {
+		struct drm_display_mode *mode = drm_mode_create(dev);
+		struct videomode vm;
+
+		if (videomode_from_timing(timings, &vm, i))
+			break;
+
+		drm_display_mode_from_videomode(&vm, mode);
+
+		mode->type = DRM_MODE_TYPE_DRIVER;
+
+		if (timings->native_mode == i)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+		drm_mode_set_name(mode);
+		drm_mode_probed_add(connector, mode);
+	}
+
+	return i;
+}
+
+static int panel_connector_mode_valid(struct drm_connector *connector,
+		  struct drm_display_mode *mode)
+{
+	struct tilcdc_drm_private *priv = connector->dev->dev_private;
+	/* our only constraints are what the crtc can generate: */
+	return tilcdc_crtc_mode_valid(priv->crtc, mode);
+}
+
+static struct drm_encoder *panel_connector_best_encoder(
+		struct drm_connector *connector)
+{
+	struct panel_connector *panel_connector = to_panel_connector(connector);
+	return panel_connector->encoder;
+}
+
+static const struct drm_connector_funcs panel_connector_funcs = {
+	.destroy            = panel_connector_destroy,
+	.dpms               = drm_helper_connector_dpms,
+	.detect             = panel_connector_detect,
+	.fill_modes         = drm_helper_probe_single_connector_modes,
+};
+
+static const struct drm_connector_helper_funcs panel_connector_helper_funcs = {
+	.get_modes          = panel_connector_get_modes,
+	.mode_valid         = panel_connector_mode_valid,
+	.best_encoder       = panel_connector_best_encoder,
+};
+
+static struct drm_connector *panel_connector_create(struct drm_device *dev,
+		struct panel_module *mod, struct drm_encoder *encoder)
+{
+	struct panel_connector *panel_connector;
+	struct drm_connector *connector;
+	int ret;
+
+	panel_connector = kzalloc(sizeof(*panel_connector), GFP_KERNEL);
+	if (!panel_connector) {
+		dev_err(dev->dev, "allocation failed\n");
+		return NULL;
+	}
+
+	panel_connector->encoder = encoder;
+	panel_connector->mod = mod;
+
+	connector = &panel_connector->base;
+
+	drm_connector_init(dev, connector, &panel_connector_funcs,
+			DRM_MODE_CONNECTOR_LVDS);
+	drm_connector_helper_add(connector, &panel_connector_helper_funcs);
+
+	connector->interlace_allowed = 0;
+	connector->doublescan_allowed = 0;
+
+	ret = drm_mode_connector_attach_encoder(connector, encoder);
+	if (ret)
+		goto fail;
+
+	drm_sysfs_connector_add(connector);
+
+	return connector;
+
+fail:
+	panel_connector_destroy(connector);
+	return NULL;
+}
+
+/*
+ * Module:
+ */
+
+static int panel_modeset_init(struct tilcdc_module *mod, struct drm_device *dev)
+{
+	struct panel_module *panel_mod = to_panel_module(mod);
+	struct tilcdc_drm_private *priv = dev->dev_private;
+	struct drm_encoder *encoder;
+	struct drm_connector *connector;
+
+	encoder = panel_encoder_create(dev, panel_mod);
+	if (!encoder)
+		return -ENOMEM;
+
+	connector = panel_connector_create(dev, panel_mod, encoder);
+	if (!connector)
+		return -ENOMEM;
+
+	priv->encoders[priv->num_encoders++] = encoder;
+	priv->connectors[priv->num_connectors++] = connector;
+
+	return 0;
+}
+
+static void panel_destroy(struct tilcdc_module *mod)
+{
+	struct panel_module *panel_mod = to_panel_module(mod);
+
+	if (panel_mod->timings) {
+		display_timings_release(panel_mod->timings);
+		kfree(panel_mod->timings);
+	}
+
+	tilcdc_module_cleanup(mod);
+	kfree(panel_mod->info);
+	kfree(panel_mod);
+}
+
+static const struct tilcdc_module_ops panel_module_ops = {
+		.modeset_init = panel_modeset_init,
+		.destroy = panel_destroy,
+};
+
+/*
+ * Device:
+ */
+
+/* maybe move this somewhere common if it is needed by other outputs? */
+static struct tilcdc_panel_info * of_get_panel_info(struct device_node *np)
+{
+	struct device_node *info_np;
+	struct tilcdc_panel_info *info;
+	int ret = 0;
+
+	if (!np) {
+		pr_err("%s: no devicenode given\n", __func__);
+		return NULL;
+	}
+
+	info_np = of_get_child_by_name(np, "panel-info");
+	if (!info_np) {
+		pr_err("%s: could not find panel-info node\n", __func__);
+		return NULL;
+	}
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		pr_err("%s: allocation failed\n", __func__);
+		return NULL;
+	}
+
+	ret |= of_property_read_u32(info_np, "ac-bias", &info->ac_bias);
+	ret |= of_property_read_u32(info_np, "ac-bias-intrpt", &info->ac_bias_intrpt);
+	ret |= of_property_read_u32(info_np, "dma-burst-sz", &info->dma_burst_sz);
+	ret |= of_property_read_u32(info_np, "bpp", &info->bpp);
+	ret |= of_property_read_u32(info_np, "fdd", &info->fdd);
+	ret |= of_property_read_u32(info_np, "sync-edge", &info->sync_edge);
+	ret |= of_property_read_u32(info_np, "sync-ctrl", &info->sync_ctrl);
+	ret |= of_property_read_u32(info_np, "raster-order", &info->raster_order);
+	ret |= of_property_read_u32(info_np, "fifo-th", &info->fifo_th);
+
+	/* optional: */
+	info->tft_alt_mode      = of_property_read_bool(info_np, "tft-alt-mode");
+	info->invert_pxl_clk    = of_property_read_bool(info_np, "invert-pxl-clk");
+
+	if (ret) {
+		pr_err("%s: error reading panel-info properties\n", __func__);
+		kfree(info);
+		return NULL;
+	}
+
+	return info;
+}
+
+static struct of_device_id panel_of_match[];
+
+static int panel_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct panel_module *panel_mod;
+	struct tilcdc_module *mod;
+	struct pinctrl *pinctrl;
+	int ret = -EINVAL;
+
+
+	/* bail out early if no DT data: */
+	if (!node) {
+		dev_err(&pdev->dev, "device-tree data is missing\n");
+		return -ENXIO;
+	}
+
+	panel_mod = kzalloc(sizeof(*panel_mod), GFP_KERNEL);
+	if (!panel_mod)
+		return -ENOMEM;
+
+	mod = &panel_mod->base;
+
+	tilcdc_module_init(mod, "panel", &panel_module_ops);
+
+	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
+	if (IS_ERR(pinctrl))
+		dev_warn(&pdev->dev, "pins are not configured\n");
+
+
+	panel_mod->timings = of_get_display_timings(node);
+	if (!panel_mod->timings) {
+		dev_err(&pdev->dev, "could not get panel timings\n");
+		goto fail;
+	}
+
+	panel_mod->info = of_get_panel_info(node);
+	if (!panel_mod->info) {
+		dev_err(&pdev->dev, "could not get panel info\n");
+		goto fail;
+	}
+
+	panel_mod->backlight = of_find_backlight_by_node(node);
+	if (panel_mod->backlight)
+		dev_info(&pdev->dev, "found backlight\n");
+
+	return 0;
+
+fail:
+	panel_destroy(mod);
+	return ret;
+}
+
+static int panel_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static struct of_device_id panel_of_match[] = {
+		{ .compatible = "ti,tilcdc,panel", },
+		{ },
+};
+MODULE_DEVICE_TABLE(of, panel_of_match);
+
+struct platform_driver panel_driver = {
+	.probe = panel_probe,
+	.remove = panel_remove,
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "panel",
+		.of_match_table = panel_of_match,
+	},
+};
+
+int __init tilcdc_panel_init(void)
+{
+	return platform_driver_register(&panel_driver);
+}
+
+void __exit tilcdc_panel_fini(void)
+{
+	platform_driver_unregister(&panel_driver);
+}

drivers/gpu/drm/tilcdc/tilcdc_panel.h

+/*
+ * Copyright (C) 2012 Texas Instruments
+ * Author: Rob Clark <robdclark@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TILCDC_PANEL_H__
+#define __TILCDC_PANEL_H__
+
+/* sub-module for generic lcd panel output */
+
+int tilcdc_panel_init(void);
+void tilcdc_panel_fini(void);
+
+#endif /* __TILCDC_PANEL_H__ */