drm/tinydrm: Add MIPI DBI support

Add support for MIPI DBI compatible controllers.
Interface type C option 1 and 3 are supported (SPI).
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Thierry Reding <treding@nvidia.com>

Documentation/gpu/tinydrm.rst

@@ -28,3 +28,15 @@ Additional helpers
 
 .. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
    :export:
+
+MIPI DBI Compatible Controllers
+===============================
+
+.. kernel-doc:: drivers/gpu/drm/tinydrm/mipi-dbi.c
+   :doc: overview
+
+.. kernel-doc:: include/drm/tinydrm/mipi-dbi.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/tinydrm/mipi-dbi.c
+   :export:

drivers/gpu/drm/tinydrm/Kconfig

@@ -8,3 +8,6 @@ menuconfig DRM_TINYDRM
 	help
 	  Choose this option if you have a tinydrm supported display.
 	  If M is selected the module will be called tinydrm.
+
+config TINYDRM_MIPI_DBI
+	tristate

drivers/gpu/drm/tinydrm/Makefile

 obj-$(CONFIG_DRM_TINYDRM)		+= core/
+
+# Controllers
+obj-$(CONFIG_TINYDRM_MIPI_DBI)		+= mipi-dbi.o

include/drm/tinydrm/mipi-dbi.h

+/*
+ * MIPI Display Bus Interface (DBI) LCD controller support
+ *
+ * Copyright 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_MIPI_DBI_H
+#define __LINUX_MIPI_DBI_H
+
+#include <drm/tinydrm/tinydrm.h>
+
+struct spi_device;
+struct gpio_desc;
+struct regulator;
+
+/**
+ * struct mipi_dbi - MIPI DBI controller
+ * @tinydrm: tinydrm base
+ * @spi: SPI device
+ * @enabled: Pipeline is enabled
+ * @cmdlock: Command lock
+ * @command: Bus specific callback executing commands.
+ * @read_commands: Array of read commands terminated by a zero entry.
+ *                 Reading is disabled if this is NULL.
+ * @dc: Optional D/C gpio.
+ * @tx_buf: Buffer used for transfer (copy clip rect area)
+ * @tx_buf9: Buffer used for Option 1 9-bit conversion
+ * @tx_buf9_len: Size of tx_buf9.
+ * @swap_bytes: Swap bytes in buffer before transfer
+ * @reset: Optional reset gpio
+ * @rotation: initial rotation in degrees Counter Clock Wise
+ * @backlight: backlight device (optional)
+ * @regulator: power regulator (optional)
+ */
+struct mipi_dbi {
+	struct tinydrm_device tinydrm;
+	struct spi_device *spi;
+	bool enabled;
+	struct mutex cmdlock;
+	int (*command)(struct mipi_dbi *mipi, u8 cmd, u8 *param, size_t num);
+	const u8 *read_commands;
+	struct gpio_desc *dc;
+	u16 *tx_buf;
+	void *tx_buf9;
+	size_t tx_buf9_len;
+	bool swap_bytes;
+	struct gpio_desc *reset;
+	unsigned int rotation;
+	struct backlight_device *backlight;
+	struct regulator *regulator;
+};
+
+static inline struct mipi_dbi *
+mipi_dbi_from_tinydrm(struct tinydrm_device *tdev)
+{
+	return container_of(tdev, struct mipi_dbi, tinydrm);
+}
+
+int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi,
+		      struct gpio_desc *dc,
+		      const struct drm_simple_display_pipe_funcs *pipe_funcs,
+		      struct drm_driver *driver,
+		      const struct drm_display_mode *mode,
+		      unsigned int rotation);
+int mipi_dbi_init(struct device *dev, struct mipi_dbi *mipi,
+		  const struct drm_simple_display_pipe_funcs *pipe_funcs,
+		  struct drm_driver *driver,
+		  const struct drm_display_mode *mode, unsigned int rotation);
+void mipi_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
+			  struct drm_crtc_state *crtc_state);
+void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe);
+void mipi_dbi_hw_reset(struct mipi_dbi *mipi);
+bool mipi_dbi_display_is_on(struct mipi_dbi *mipi);
+
+int mipi_dbi_command_read(struct mipi_dbi *mipi, u8 cmd, u8 *val);
+int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len);
+
+/**
+ * mipi_dbi_command - MIPI DCS command with optional parameter(s)
+ * @mipi: MIPI structure
+ * @cmd: Command
+ * @seq...: Optional parameter(s)
+ *
+ * Send MIPI DCS command to the controller. Use mipi_dbi_command_read() for
+ * get/read.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+#define mipi_dbi_command(mipi, cmd, seq...) \
+({ \
+	u8 d[] = { seq }; \
+	mipi_dbi_command_buf(mipi, cmd, d, ARRAY_SIZE(d)); \
+})
+
+#ifdef CONFIG_DEBUG_FS
+int mipi_dbi_debugfs_init(struct drm_minor *minor);
+#else
+#define mipi_dbi_debugfs_init		NULL
+#endif
+
+#endif /* __LINUX_MIPI_DBI_H */