drm/stm: Add STM32 LTDC driver

This controller provides output signals to interface directly a variety
of LCD and TFT panels. These output signals are: RGB signals
(up to 24bpp), vertical & horizontal synchronisations, data enable and
the pixel clock.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/1492164819-10513-5-git-send-email-yannick.fertre@st.com
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/stm/ltdc.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2017
+ *
+ * Authors: Philippe Cornu <philippe.cornu@st.com>
+ *          Yannick Fertre <yannick.fertre@st.com>
+ *          Fabien Dessenne <fabien.dessenne@st.com>
+ *          Mickael Reulier <mickael.reulier@st.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _LTDC_H_
+#define _LTDC_H_
+
+struct ltdc_caps {
+	u32 hw_version;		/* hardware version */
+	u32 nb_layers;		/* number of supported layers */
+	u32 reg_ofs;		/* register offset for applicable regs */
+	u32 bus_width;		/* bus width (32 or 64 bits) */
+	const u32 *pix_fmt_hw;	/* supported pixel formats */
+};
+
+struct ltdc_device {
+	struct drm_fbdev_cma *fbdev;
+	void __iomem *regs;
+	struct clk *pixel_clk;	/* lcd pixel clock */
+	struct drm_panel *panel;
+	struct mutex err_lock;	/* protecting error_status */
+	struct ltdc_caps caps;
+	u32 clut[256];		/* color look up table */
+	u32 error_status;
+	u32 irq_status;
+};
+
+int ltdc_crtc_enable_vblank(struct drm_device *dev, unsigned int pipe);
+void ltdc_crtc_disable_vblank(struct drm_device *dev, unsigned int pipe);
+int ltdc_load(struct drm_device *ddev);
+void ltdc_unload(struct drm_device *ddev);
+
+#endif