drm/tinydrm: Add helper functions

Add common functionality needed by many tinydrm drivers.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Thierry Reding <treding@nvidia.com>

Documentation/gpu/tinydrm.rst

@@ -19,3 +19,12 @@ Core functionality
 
 .. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
    :export:
+
+Additional helpers
+==================
+
+.. kernel-doc:: include/drm/tinydrm/tinydrm-helpers.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
+   :export:

drivers/gpu/drm/tinydrm/Kconfig

@@ -3,6 +3,8 @@ menuconfig DRM_TINYDRM
 	depends on DRM
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
+	select BACKLIGHT_LCD_SUPPORT
+	select BACKLIGHT_CLASS_DEVICE
 	help
 	  Choose this option if you have a tinydrm supported display.
 	  If M is selected the module will be called tinydrm.

drivers/gpu/drm/tinydrm/core/Makefile

-tinydrm-y := tinydrm-core.o tinydrm-pipe.o
+tinydrm-y := tinydrm-core.o tinydrm-pipe.o tinydrm-helpers.o
 
 obj-$(CONFIG_DRM_TINYDRM) += tinydrm.o

include/drm/tinydrm/tinydrm-helpers.h

+/*
+ * Copyright (C) 2016 Noralf Trønnes
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __LINUX_TINYDRM_HELPERS_H
+#define __LINUX_TINYDRM_HELPERS_H
+
+struct backlight_device;
+struct tinydrm_device;
+struct drm_clip_rect;
+struct spi_transfer;
+struct spi_message;
+struct spi_device;
+struct device;
+
+/**
+ * tinydrm_machine_little_endian - Machine is little endian
+ *
+ * Returns:
+ * true if *defined(__LITTLE_ENDIAN)*, false otherwise
+ */
+static inline bool tinydrm_machine_little_endian(void)
+{
+#if defined(__LITTLE_ENDIAN)
+	return true;
+#else
+	return false;
+#endif
+}
+
+bool tinydrm_merge_clips(struct drm_clip_rect *dst,
+			 struct drm_clip_rect *src, unsigned int num_clips,
+			 unsigned int flags, u32 max_width, u32 max_height);
+void tinydrm_memcpy(void *dst, void *vaddr, struct drm_framebuffer *fb,
+		    struct drm_clip_rect *clip);
+void tinydrm_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
+		    struct drm_clip_rect *clip);
+void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
+				struct drm_framebuffer *fb,
+				struct drm_clip_rect *clip, bool swap);
+
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
+struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
+int tinydrm_enable_backlight(struct backlight_device *backlight);
+int tinydrm_disable_backlight(struct backlight_device *backlight);
+#else
+static inline struct backlight_device *
+tinydrm_of_find_backlight(struct device *dev)
+{
+	return NULL;
+}
+
+static inline int tinydrm_enable_backlight(struct backlight_device *backlight)
+{
+	return 0;
+}
+
+static inline int
+tinydrm_disable_backlight(struct backlight_device *backlight)
+{
+	return 0;
+}
+#endif
+
+size_t tinydrm_spi_max_transfer_size(struct spi_device *spi, size_t max_len);
+bool tinydrm_spi_bpw_supported(struct spi_device *spi, u8 bpw);
+int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz,
+			 struct spi_transfer *header, u8 bpw, const void *buf,
+			 size_t len);
+void _tinydrm_dbg_spi_message(struct spi_device *spi, struct spi_message *m);
+
+#ifdef DEBUG
+/**
+ * tinydrm_dbg_spi_message - Dump SPI message
+ * @spi: SPI device
+ * @m: SPI message
+ *
+ * Dumps info about the transfers in a SPI message including buffer content.
+ * DEBUG has to be defined for this function to be enabled alongside setting
+ * the DRM_UT_DRIVER bit of &drm_debug.
+ */
+static inline void tinydrm_dbg_spi_message(struct spi_device *spi,
+					   struct spi_message *m)
+{
+	if (drm_debug & DRM_UT_DRIVER)
+		_tinydrm_dbg_spi_message(spi, m);
+}
+#else
+static inline void tinydrm_dbg_spi_message(struct spi_device *spi,
+					   struct spi_message *m)
+{
+}
+#endif /* DEBUG */
+
+#endif /* __LINUX_TINYDRM_HELPERS_H */