drivers/staging/fbtft/fbtft.h - kernel/bruno - Git at Google

 /*
  * Copyright (C) 2013 Noralf Tronnes
  *
  * 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.
  *
  * 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.
  */

 #ifndef __LINUX_FBTFT_H
 #define __LINUX_FBTFT_H

 #include <linux/fb.h>
 #include <linux/spinlock.h>
 #include <linux/spi/spi.h>
 #include <linux/platform_device.h>

 #define FBTFT_NOP		0x00
 #define FBTFT_SWRESET	0x01
 #define FBTFT_RDDID		0x04
 #define FBTFT_RDDST		0x09
 #define FBTFT_CASET		0x2A
 #define FBTFT_RASET		0x2B
 #define FBTFT_RAMWR		0x2C

 #define FBTFT_ONBOARD_BACKLIGHT 2

 #define FBTFT_GPIO_NO_MATCH		0xFFFF
 #define FBTFT_GPIO_NAME_SIZE	32
 #define FBTFT_MAX_INIT_SEQUENCE      512
 #define FBTFT_GAMMA_MAX_VALUES_TOTAL 128

 #define FBTFT_OF_INIT_CMD	BIT(24)
 #define FBTFT_OF_INIT_DELAY	BIT(25)

 /**
  * struct fbtft_gpio - Structure that holds one pinname to gpio mapping
  * @name: pinname (reset, dc, etc.)
  * @gpio: GPIO number
  *
  */
 struct fbtft_gpio {
 	char name[FBTFT_GPIO_NAME_SIZE];
 	unsigned gpio;
 };

 struct fbtft_par;

 /**
  * struct fbtft_ops - FBTFT operations structure
  * @write: Writes to interface bus
  * @read: Reads from interface bus
  * @write_vmem: Writes video memory to display
  * @write_reg: Writes to controller register
  * @set_addr_win: Set the GRAM update window
  * @reset: Reset the LCD controller
  * @mkdirty: Marks display lines for update
  * @update_display: Updates the display
  * @init_display: Initializes the display
  * @blank: Blank the display (optional)
  * @request_gpios_match: Do pinname to gpio matching
  * @request_gpios: Request gpios from the kernel
  * @free_gpios: Free previously requested gpios
  * @verify_gpios: Verify that necessary gpios is present (optional)
  * @register_backlight: Used to register backlight device (optional)
  * @unregister_backlight: Unregister backlight device (optional)
  * @set_var: Configure LCD with values from variables like @rotate and @bgr
  *           (optional)
  * @set_gamma: Set Gamma curve (optional)
  *
  * Most of these operations have default functions assigned to them in
  *     fbtft_framebuffer_alloc()
  */
 struct fbtft_ops {
 	int (*write)(struct fbtft_par *par, void *buf, size_t len);
 	int (*read)(struct fbtft_par *par, void *buf, size_t len);
 	int (*write_vmem)(struct fbtft_par *par, size_t offset, size_t len);
 	void (*write_register)(struct fbtft_par *par, int len, ...);

 	void (*set_addr_win)(struct fbtft_par *par,
 		int xs, int ys, int xe, int ye);
 	void (*reset)(struct fbtft_par *par);
 	void (*mkdirty)(struct fb_info *info, int from, int to);
 	void (*update_display)(struct fbtft_par *par,
 				unsigned start_line, unsigned end_line);
 	int (*init_display)(struct fbtft_par *par);
 	int (*blank)(struct fbtft_par *par, bool on);

 	unsigned long (*request_gpios_match)(struct fbtft_par *par,
 		const struct fbtft_gpio *gpio);
 	int (*request_gpios)(struct fbtft_par *par);
 	int (*verify_gpios)(struct fbtft_par *par);

 	void (*register_backlight)(struct fbtft_par *par);
 	void (*unregister_backlight)(struct fbtft_par *par);

 	int (*set_var)(struct fbtft_par *par);
 	int (*set_gamma)(struct fbtft_par *par, unsigned long *curves);
 };

 /**
  * struct fbtft_display - Describes the display properties
  * @width: Width of display in pixels
  * @height: Height of display in pixels
  * @regwidth: LCD Controller Register width in bits
  * @buswidth: Display interface bus width in bits
  * @backlight: Backlight type.
  * @fbtftops: FBTFT operations provided by driver or device (platform_data)
  * @bpp: Bits per pixel
  * @fps: Frames per second
  * @txbuflen: Size of transmit buffer
  * @init_sequence: Pointer to LCD initialization array
  * @gamma: String representation of Gamma curve(s)
  * @gamma_num: Number of Gamma curves
  * @gamma_len: Number of values per Gamma curve
  * @debug: Initial debug value
  *
  * This structure is not stored by FBTFT except for init_sequence.
  */
 struct fbtft_display {
 	unsigned width;
 	unsigned height;
 	unsigned regwidth;
 	unsigned buswidth;
 	unsigned backlight;
 	struct fbtft_ops fbtftops;
 	unsigned bpp;
 	unsigned fps;
 	int txbuflen;
 	int *init_sequence;
 	char *gamma;
 	int gamma_num;
 	int gamma_len;
 	unsigned long debug;
 };

 /**
  * struct fbtft_platform_data - Passes display specific data to the driver
  * @display: Display properties
  * @gpios: Pointer to an array of pinname to gpio mappings
  * @rotate: Display rotation angle
  * @bgr: LCD Controller BGR bit
  * @fps: Frames per second (this will go away, use @fps in @fbtft_display)
  * @txbuflen: Size of transmit buffer
  * @startbyte: When set, enables use of Startbyte in transfers
  * @gamma: String representation of Gamma curve(s)
  * @extra: A way to pass extra info
  */
 struct fbtft_platform_data {
 	struct fbtft_display display;
 	const struct fbtft_gpio *gpios;
 	unsigned rotate;
 	bool bgr;
 	unsigned fps;
 	int txbuflen;
 	u8 startbyte;
 	char *gamma;
 	void *extra;
 };

 /**
  * struct fbtft_par - Main FBTFT data structure
  *
  * This structure holds all relevant data to operate the display
  *
  * See sourcefile for documentation since nested structs is not
  * supported by kernel-doc.
  *
  */
 /* @spi: Set if it is a SPI device
  * @pdev: Set if it is a platform device
  * @info: Pointer to framebuffer fb_info structure
  * @pdata: Pointer to platform data
  * @ssbuf: Not used
  * @pseudo_palette: Used by fb_set_colreg()
  * @txbuf.buf: Transmit buffer
  * @txbuf.len: Transmit buffer length
  * @buf: Small buffer used when writing init data over SPI
  * @startbyte: Used by some controllers when in SPI mode.
  *             Format: 6 bit Device id + RS bit + RW bit
  * @fbtftops: FBTFT operations provided by driver or device (platform_data)
  * @dirty_lock: Protects dirty_lines_start and dirty_lines_end
  * @dirty_lines_start: Where to begin updating display
  * @dirty_lines_end: Where to end updating display
  * @gpio.reset: GPIO used to reset display
  * @gpio.dc: Data/Command signal, also known as RS
  * @gpio.rd: Read latching signal
  * @gpio.wr: Write latching signal
  * @gpio.latch: Bus latch signal, eg. 16->8 bit bus latch
  * @gpio.cs: LCD Chip Select with parallel interface bus
  * @gpio.db[16]: Parallel databus
  * @gpio.led[16]: Led control signals
  * @gpio.aux[16]: Auxiliary signals, not used by core
  * @init_sequence: Pointer to LCD initialization array
  * @gamma.lock: Mutex for Gamma curve locking
  * @gamma.curves: Pointer to Gamma curve array
  * @gamma.num_values: Number of values per Gamma curve
  * @gamma.num_curves: Number of Gamma curves
  * @debug: Pointer to debug value
  * @current_debug:
  * @first_update_done: Used to only time the first display update
  * @update_time: Used to calculate 'fps' in debug output
  * @bgr: BGR mode/\n
  * @extra: Extra info needed by driver
  */
 struct fbtft_par {
 	struct spi_device *spi;
 	struct platform_device *pdev;
 	struct fb_info *info;
 	struct fbtft_platform_data *pdata;
 	u16 *ssbuf;
 	u32 pseudo_palette[16];
 	struct {
 		void *buf;
 		dma_addr_t dma;
 		size_t len;
 	} txbuf;
 	u8 *buf;
 	u8 startbyte;
 	struct fbtft_ops fbtftops;
 	spinlock_t dirty_lock;
 	unsigned dirty_lines_start;
 	unsigned dirty_lines_end;
 	struct {
 		int reset;
 		int dc;
 		int rd;
 		int wr;
 		int latch;
 		int cs;
 		int db[16];
 		int led[16];
 		int aux[16];
 	} gpio;
 	int *init_sequence;
 	struct {
 		struct mutex lock;
 		unsigned long *curves;
 		int num_values;
 		int num_curves;
 	} gamma;
 	unsigned long debug;
 	bool first_update_done;
 	ktime_t update_time;
 	bool bgr;
 	void *extra;
 };

 #define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__})/sizeof(int))

 #define write_reg(par, ...)                                              \
 	par->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__)

 /* fbtft-core.c */
 void fbtft_dbg_hex(const struct device *dev, int groupsize,
 		   void *buf, size_t len, const char *fmt, ...);
 struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 					struct device *dev,
 					struct fbtft_platform_data *pdata);
 void fbtft_framebuffer_release(struct fb_info *info);
 int fbtft_register_framebuffer(struct fb_info *fb_info);
 int fbtft_unregister_framebuffer(struct fb_info *fb_info);
 void fbtft_register_backlight(struct fbtft_par *par);
 void fbtft_unregister_backlight(struct fbtft_par *par);
 int fbtft_init_display(struct fbtft_par *par);
 int fbtft_probe_common(struct fbtft_display *display, struct spi_device *sdev,
 		       struct platform_device *pdev);
 int fbtft_remove_common(struct device *dev, struct fb_info *info);

 /* fbtft-io.c */
 int fbtft_write_spi(struct fbtft_par *par, void *buf, size_t len);
 int fbtft_write_spi_emulate_9(struct fbtft_par *par, void *buf, size_t len);
 int fbtft_read_spi(struct fbtft_par *par, void *buf, size_t len);
 int fbtft_write_gpio8_wr(struct fbtft_par *par, void *buf, size_t len);
 int fbtft_write_gpio16_wr(struct fbtft_par *par, void *buf, size_t len);
 int fbtft_write_gpio16_wr_latched(struct fbtft_par *par, void *buf, size_t len);

 /* fbtft-bus.c */
 int fbtft_write_vmem8_bus8(struct fbtft_par *par, size_t offset, size_t len);
 int fbtft_write_vmem16_bus16(struct fbtft_par *par, size_t offset, size_t len);
 int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len);
 int fbtft_write_vmem16_bus9(struct fbtft_par *par, size_t offset, size_t len);
 void fbtft_write_reg8_bus8(struct fbtft_par *par, int len, ...);
 void fbtft_write_reg8_bus9(struct fbtft_par *par, int len, ...);
 void fbtft_write_reg16_bus8(struct fbtft_par *par, int len, ...);
 void fbtft_write_reg16_bus16(struct fbtft_par *par, int len, ...);

 #define FBTFT_REGISTER_DRIVER(_name, _compatible, _display)                \
 									   \
 static int fbtft_driver_probe_spi(struct spi_device *spi)                  \
 {                                                                          \
 	return fbtft_probe_common(_display, spi, NULL);                    \
 }                                                                          \
 									   \
 static int fbtft_driver_remove_spi(struct spi_device *spi)                 \
 {                                                                          \
 	struct fb_info *info = spi_get_drvdata(spi);                       \
 									   \
 	return fbtft_remove_common(&spi->dev, info);                       \
 }                                                                          \
 									   \
 static int fbtft_driver_probe_pdev(struct platform_device *pdev)           \
 {                                                                          \
 	return fbtft_probe_common(_display, NULL, pdev);                   \
 }                                                                          \
 									   \
 static int fbtft_driver_remove_pdev(struct platform_device *pdev)          \
 {                                                                          \
 	struct fb_info *info = platform_get_drvdata(pdev);                 \
 									   \
 	return fbtft_remove_common(&pdev->dev, info);                      \
 }                                                                          \
 									   \
 static const struct of_device_id dt_ids[] = {                              \
 	{ .compatible = _compatible },                                     \
 	{},                                                                \
 };                                                                         \
 									   \
 MODULE_DEVICE_TABLE(of, dt_ids);                                           \
 									   \
 									   \
 static struct spi_driver fbtft_driver_spi_driver = {                       \
 	.driver = {                                                        \
 		.name   = _name,                                           \
 		.of_match_table = of_match_ptr(dt_ids),                    \
 	},                                                                 \
 	.probe  = fbtft_driver_probe_spi,                                  \
 	.remove = fbtft_driver_remove_spi,                                 \
 };                                                                         \
 									   \
 static struct platform_driver fbtft_driver_platform_driver = {             \
 	.driver = {                                                        \
 		.name   = _name,                                           \
 		.owner  = THIS_MODULE,                                     \
 		.of_match_table = of_match_ptr(dt_ids),                    \
 	},                                                                 \
 	.probe  = fbtft_driver_probe_pdev,                                 \
 	.remove = fbtft_driver_remove_pdev,                                \
 };                                                                         \
 									   \
 static int __init fbtft_driver_module_init(void)                           \
 {                                                                          \
 	int ret;                                                           \
 									   \
 	ret = spi_register_driver(&fbtft_driver_spi_driver);               \
 	if (ret < 0)                                                       \
 		return ret;                                                \
 	return platform_driver_register(&fbtft_driver_platform_driver);    \
 }                                                                          \
 									   \
 static void __exit fbtft_driver_module_exit(void)                          \
 {                                                                          \
 	spi_unregister_driver(&fbtft_driver_spi_driver);                   \
 	platform_driver_unregister(&fbtft_driver_platform_driver);         \
 }                                                                          \
 									   \
 module_init(fbtft_driver_module_init);                                     \
 module_exit(fbtft_driver_module_exit);

 /* Debug macros */

 /* shorthand debug levels */
 #define DEBUG_LEVEL_1	DEBUG_REQUEST_GPIOS
 #define DEBUG_LEVEL_2	(DEBUG_LEVEL_1 | DEBUG_DRIVER_INIT_FUNCTIONS | DEBUG_TIME_FIRST_UPDATE)
 #define DEBUG_LEVEL_3	(DEBUG_LEVEL_2 | DEBUG_RESET | DEBUG_INIT_DISPLAY | DEBUG_BLANK | DEBUG_REQUEST_GPIOS | DEBUG_FREE_GPIOS | DEBUG_VERIFY_GPIOS | DEBUG_BACKLIGHT | DEBUG_SYSFS)
 #define DEBUG_LEVEL_4	(DEBUG_LEVEL_2 | DEBUG_FB_READ | DEBUG_FB_WRITE | DEBUG_FB_FILLRECT | DEBUG_FB_COPYAREA | DEBUG_FB_IMAGEBLIT | DEBUG_FB_BLANK)
 #define DEBUG_LEVEL_5	(DEBUG_LEVEL_3 | DEBUG_UPDATE_DISPLAY)
 #define DEBUG_LEVEL_6	(DEBUG_LEVEL_4 | DEBUG_LEVEL_5)
 #define DEBUG_LEVEL_7	0xFFFFFFFF

 #define DEBUG_DRIVER_INIT_FUNCTIONS (1<<3)
 #define DEBUG_TIME_FIRST_UPDATE     (1<<4)
 #define DEBUG_TIME_EACH_UPDATE      (1<<5)
 #define DEBUG_DEFERRED_IO           (1<<6)
 #define DEBUG_FBTFT_INIT_FUNCTIONS  (1<<7)

 /* fbops */
 #define DEBUG_FB_READ               (1<<8)
 #define DEBUG_FB_WRITE              (1<<9)
 #define DEBUG_FB_FILLRECT           (1<<10)
 #define DEBUG_FB_COPYAREA           (1<<11)
 #define DEBUG_FB_IMAGEBLIT          (1<<12)
 #define DEBUG_FB_SETCOLREG          (1<<13)
 #define DEBUG_FB_BLANK              (1<<14)

 #define DEBUG_SYSFS                 (1<<16)

 /* fbtftops */
 #define DEBUG_BACKLIGHT             (1<<17)
 #define DEBUG_READ                  (1<<18)
 #define DEBUG_WRITE                 (1<<19)
 #define DEBUG_WRITE_VMEM            (1<<20)
 #define DEBUG_WRITE_REGISTER        (1<<21)
 #define DEBUG_SET_ADDR_WIN          (1<<22)
 #define DEBUG_RESET                 (1<<23)
 #define DEBUG_MKDIRTY               (1<<24)
 #define DEBUG_UPDATE_DISPLAY        (1<<25)
 #define DEBUG_INIT_DISPLAY          (1<<26)
 #define DEBUG_BLANK                 (1<<27)
 #define DEBUG_REQUEST_GPIOS         (1<<28)
 #define DEBUG_FREE_GPIOS            (1<<29)
 #define DEBUG_REQUEST_GPIOS_MATCH   (1<<30)
 #define DEBUG_VERIFY_GPIOS          (1<<31)

 #define fbtft_init_dbg(dev, format, arg...)                  \
 do {                                                         \
 	if (unlikely((dev)->platform_data &&                 \
 	    (((struct fbtft_platform_data *)(dev)->platform_data)->display.debug & DEBUG_DRIVER_INIT_FUNCTIONS))) \
 		dev_info(dev, format, ##arg);                \
 } while (0)

 #define fbtft_par_dbg(level, par, format, arg...)            \
 do {                                                         \
 	if (unlikely(par->debug & level))                    \
 		dev_info(par->info->device, format, ##arg);  \
 } while (0)

 #define fbtft_par_dbg_hex(level, par, dev, type, buf, num, format, arg...) \
 do {                                                                       \
 	if (unlikely(par->debug & level))                                  \
 		fbtft_dbg_hex(dev, sizeof(type), buf, num * sizeof(type), format, ##arg); \
 } while (0)

 #endif /* __LINUX_FBTFT_H */
	/*
	* Copyright (C) 2013 Noralf Tronnes
	*
	* 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.
	*
	* 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.
	*/

	#ifndef __LINUX_FBTFT_H
	#define __LINUX_FBTFT_H

	#include <linux/fb.h>
	#include <linux/spinlock.h>
	#include <linux/spi/spi.h>
	#include <linux/platform_device.h>

	#define FBTFT_NOP 0x00
	#define FBTFT_SWRESET 0x01
	#define FBTFT_RDDID 0x04
	#define FBTFT_RDDST 0x09
	#define FBTFT_CASET 0x2A
	#define FBTFT_RASET 0x2B
	#define FBTFT_RAMWR 0x2C

	#define FBTFT_ONBOARD_BACKLIGHT 2

	#define FBTFT_GPIO_NO_MATCH 0xFFFF
	#define FBTFT_GPIO_NAME_SIZE 32
	#define FBTFT_MAX_INIT_SEQUENCE 512
	#define FBTFT_GAMMA_MAX_VALUES_TOTAL 128

	#define FBTFT_OF_INIT_CMD BIT(24)
	#define FBTFT_OF_INIT_DELAY BIT(25)

	/**
	* struct fbtft_gpio - Structure that holds one pinname to gpio mapping
	* @name: pinname (reset, dc, etc.)
	* @gpio: GPIO number
	*
	*/
	struct fbtft_gpio {
	char name[FBTFT_GPIO_NAME_SIZE];
	unsigned gpio;
	};

	struct fbtft_par;

	/**
	* struct fbtft_ops - FBTFT operations structure
	* @write: Writes to interface bus
	* @read: Reads from interface bus
	* @write_vmem: Writes video memory to display
	* @write_reg: Writes to controller register
	* @set_addr_win: Set the GRAM update window
	* @reset: Reset the LCD controller
	* @mkdirty: Marks display lines for update
	* @update_display: Updates the display
	* @init_display: Initializes the display
	* @blank: Blank the display (optional)
	* @request_gpios_match: Do pinname to gpio matching
	* @request_gpios: Request gpios from the kernel
	* @free_gpios: Free previously requested gpios
	* @verify_gpios: Verify that necessary gpios is present (optional)
	* @register_backlight: Used to register backlight device (optional)
	* @unregister_backlight: Unregister backlight device (optional)
	* @set_var: Configure LCD with values from variables like @rotate and @bgr
	* (optional)
	* @set_gamma: Set Gamma curve (optional)
	*
	* Most of these operations have default functions assigned to them in
	* fbtft_framebuffer_alloc()
	*/
	struct fbtft_ops {
	int (write)(struct fbtft_par par, void *buf, size_t len);
	int (read)(struct fbtft_par par, void *buf, size_t len);
	int (write_vmem)(struct fbtft_par par, size_t offset, size_t len);
	void (write_register)(struct fbtft_par par, int len, ...);

	void (set_addr_win)(struct fbtft_par par,
	int xs, int ys, int xe, int ye);
	void (reset)(struct fbtft_par par);
	void (mkdirty)(struct fb_info info, int from, int to);
	void (update_display)(struct fbtft_par par,
	unsigned start_line, unsigned end_line);
	int (init_display)(struct fbtft_par par);
	int (blank)(struct fbtft_par par, bool on);

	unsigned long (request_gpios_match)(struct fbtft_par par,
	const struct fbtft_gpio *gpio);
	int (request_gpios)(struct fbtft_par par);
	int (verify_gpios)(struct fbtft_par par);

	void (register_backlight)(struct fbtft_par par);
	void (unregister_backlight)(struct fbtft_par par);

	int (set_var)(struct fbtft_par par);
	int (set_gamma)(struct fbtft_par par, unsigned long *curves);
	};

	/**
	* struct fbtft_display - Describes the display properties
	* @width: Width of display in pixels
	* @height: Height of display in pixels
	* @regwidth: LCD Controller Register width in bits
	* @buswidth: Display interface bus width in bits
	* @backlight: Backlight type.
	* @fbtftops: FBTFT operations provided by driver or device (platform_data)
	* @bpp: Bits per pixel
	* @fps: Frames per second
	* @txbuflen: Size of transmit buffer
	* @init_sequence: Pointer to LCD initialization array
	* @gamma: String representation of Gamma curve(s)
	* @gamma_num: Number of Gamma curves
	* @gamma_len: Number of values per Gamma curve
	* @debug: Initial debug value
	*
	* This structure is not stored by FBTFT except for init_sequence.
	*/
	struct fbtft_display {
	unsigned width;
	unsigned height;
	unsigned regwidth;
	unsigned buswidth;
	unsigned backlight;
	struct fbtft_ops fbtftops;
	unsigned bpp;
	unsigned fps;
	int txbuflen;
	int *init_sequence;
	char *gamma;
	int gamma_num;
	int gamma_len;
	unsigned long debug;
	};

	/**
	* struct fbtft_platform_data - Passes display specific data to the driver
	* @display: Display properties
	* @gpios: Pointer to an array of pinname to gpio mappings
	* @rotate: Display rotation angle
	* @bgr: LCD Controller BGR bit
	* @fps: Frames per second (this will go away, use @fps in @fbtft_display)
	* @txbuflen: Size of transmit buffer
	* @startbyte: When set, enables use of Startbyte in transfers
	* @gamma: String representation of Gamma curve(s)
	* @extra: A way to pass extra info
	*/
	struct fbtft_platform_data {
	struct fbtft_display display;
	const struct fbtft_gpio *gpios;
	unsigned rotate;
	bool bgr;
	unsigned fps;
	int txbuflen;
	u8 startbyte;
	char *gamma;
	void *extra;
	};

	/**
	* struct fbtft_par - Main FBTFT data structure
	*
	* This structure holds all relevant data to operate the display
	*
	* See sourcefile for documentation since nested structs is not
	* supported by kernel-doc.
	*
	*/
	/* @spi: Set if it is a SPI device
	* @pdev: Set if it is a platform device
	* @info: Pointer to framebuffer fb_info structure
	* @pdata: Pointer to platform data
	* @ssbuf: Not used
	* @pseudo_palette: Used by fb_set_colreg()
	* @txbuf.buf: Transmit buffer
	* @txbuf.len: Transmit buffer length
	* @buf: Small buffer used when writing init data over SPI
	* @startbyte: Used by some controllers when in SPI mode.
	* Format: 6 bit Device id + RS bit + RW bit
	* @fbtftops: FBTFT operations provided by driver or device (platform_data)
	* @dirty_lock: Protects dirty_lines_start and dirty_lines_end
	* @dirty_lines_start: Where to begin updating display
	* @dirty_lines_end: Where to end updating display
	* @gpio.reset: GPIO used to reset display
	* @gpio.dc: Data/Command signal, also known as RS
	* @gpio.rd: Read latching signal
	* @gpio.wr: Write latching signal
	* @gpio.latch: Bus latch signal, eg. 16->8 bit bus latch
	* @gpio.cs: LCD Chip Select with parallel interface bus
	* @gpio.db[16]: Parallel databus
	* @gpio.led[16]: Led control signals
	* @gpio.aux[16]: Auxiliary signals, not used by core
	* @init_sequence: Pointer to LCD initialization array
	* @gamma.lock: Mutex for Gamma curve locking
	* @gamma.curves: Pointer to Gamma curve array
	* @gamma.num_values: Number of values per Gamma curve
	* @gamma.num_curves: Number of Gamma curves
	* @debug: Pointer to debug value
	* @current_debug:
	* @first_update_done: Used to only time the first display update
	* @update_time: Used to calculate 'fps' in debug output
	* @bgr: BGR mode/\n
	* @extra: Extra info needed by driver
	*/
	struct fbtft_par {
	struct spi_device *spi;
	struct platform_device *pdev;
	struct fb_info *info;
	struct fbtft_platform_data *pdata;
	u16 *ssbuf;
	u32 pseudo_palette[16];
	struct {
	void *buf;
	dma_addr_t dma;
	size_t len;
	} txbuf;
	u8 *buf;
	u8 startbyte;
	struct fbtft_ops fbtftops;
	spinlock_t dirty_lock;
	unsigned dirty_lines_start;
	unsigned dirty_lines_end;
	struct {
	int reset;
	int dc;
	int rd;
	int wr;
	int latch;
	int cs;
	int db[16];
	int led[16];
	int aux[16];
	} gpio;
	int *init_sequence;
	struct {
	struct mutex lock;
	unsigned long *curves;
	int num_values;
	int num_curves;
	} gamma;
	unsigned long debug;
	bool first_update_done;
	ktime_t update_time;
	bool bgr;
	void *extra;
	};

	#define NUMARGS(...) (sizeof((int[]){__VA_ARGS__})/sizeof(int))

	#define write_reg(par, ...) \
	par->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__)

	/* fbtft-core.c */
	void fbtft_dbg_hex(const struct device *dev, int groupsize,
	void buf, size_t len, const char fmt, ...);
	struct fb_info fbtft_framebuffer_alloc(struct fbtft_display display,
	struct device *dev,
	struct fbtft_platform_data *pdata);
	void fbtft_framebuffer_release(struct fb_info *info);
	int fbtft_register_framebuffer(struct fb_info *fb_info);
	int fbtft_unregister_framebuffer(struct fb_info *fb_info);
	void fbtft_register_backlight(struct fbtft_par *par);
	void fbtft_unregister_backlight(struct fbtft_par *par);
	int fbtft_init_display(struct fbtft_par *par);
	int fbtft_probe_common(struct fbtft_display display, struct spi_device sdev,
	struct platform_device *pdev);
	int fbtft_remove_common(struct device dev, struct fb_info info);

	/* fbtft-io.c */
	int fbtft_write_spi(struct fbtft_par par, void buf, size_t len);
	int fbtft_write_spi_emulate_9(struct fbtft_par par, void buf, size_t len);
	int fbtft_read_spi(struct fbtft_par par, void buf, size_t len);
	int fbtft_write_gpio8_wr(struct fbtft_par par, void buf, size_t len);
	int fbtft_write_gpio16_wr(struct fbtft_par par, void buf, size_t len);
	int fbtft_write_gpio16_wr_latched(struct fbtft_par par, void buf, size_t len);

	/* fbtft-bus.c */
	int fbtft_write_vmem8_bus8(struct fbtft_par *par, size_t offset, size_t len);
	int fbtft_write_vmem16_bus16(struct fbtft_par *par, size_t offset, size_t len);
	int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len);
	int fbtft_write_vmem16_bus9(struct fbtft_par *par, size_t offset, size_t len);
	void fbtft_write_reg8_bus8(struct fbtft_par *par, int len, ...);
	void fbtft_write_reg8_bus9(struct fbtft_par *par, int len, ...);
	void fbtft_write_reg16_bus8(struct fbtft_par *par, int len, ...);
	void fbtft_write_reg16_bus16(struct fbtft_par *par, int len, ...);

	#define FBTFT_REGISTER_DRIVER(_name, _compatible, _display) \
	\
	static int fbtft_driver_probe_spi(struct spi_device *spi) \
	{ \
	return fbtft_probe_common(_display, spi, NULL); \
	} \
	\
	static int fbtft_driver_remove_spi(struct spi_device *spi) \
	{ \
	struct fb_info *info = spi_get_drvdata(spi); \
	\
	return fbtft_remove_common(&spi->dev, info); \
	} \
	\
	static int fbtft_driver_probe_pdev(struct platform_device *pdev) \
	{ \
	return fbtft_probe_common(_display, NULL, pdev); \
	} \
	\
	static int fbtft_driver_remove_pdev(struct platform_device *pdev) \
	{ \
	struct fb_info *info = platform_get_drvdata(pdev); \
	\
	return fbtft_remove_common(&pdev->dev, info); \
	} \
	\
	static const struct of_device_id dt_ids[] = { \
	{ .compatible = _compatible }, \
	{}, \
	}; \
	\
	MODULE_DEVICE_TABLE(of, dt_ids); \
	\
	\
	static struct spi_driver fbtft_driver_spi_driver = { \
	.driver = { \
	.name = _name, \
	.of_match_table = of_match_ptr(dt_ids), \
	}, \
	.probe = fbtft_driver_probe_spi, \
	.remove = fbtft_driver_remove_spi, \
	}; \
	\
	static struct platform_driver fbtft_driver_platform_driver = { \
	.driver = { \
	.name = _name, \
	.owner = THIS_MODULE, \
	.of_match_table = of_match_ptr(dt_ids), \
	}, \
	.probe = fbtft_driver_probe_pdev, \
	.remove = fbtft_driver_remove_pdev, \
	}; \
	\
	static int __init fbtft_driver_module_init(void) \
	{ \
	int ret; \
	\
	ret = spi_register_driver(&fbtft_driver_spi_driver); \
	if (ret < 0) \
	return ret; \
	return platform_driver_register(&fbtft_driver_platform_driver); \
	} \
	\
	static void __exit fbtft_driver_module_exit(void) \
	{ \
	spi_unregister_driver(&fbtft_driver_spi_driver); \
	platform_driver_unregister(&fbtft_driver_platform_driver); \
	} \
	\
	module_init(fbtft_driver_module_init); \
	module_exit(fbtft_driver_module_exit);

	/* Debug macros */

	/* shorthand debug levels */
	#define DEBUG_LEVEL_1 DEBUG_REQUEST_GPIOS
	#define DEBUG_LEVEL_2 (DEBUG_LEVEL_1 \| DEBUG_DRIVER_INIT_FUNCTIONS \| DEBUG_TIME_FIRST_UPDATE)
	#define DEBUG_LEVEL_3 (DEBUG_LEVEL_2 \| DEBUG_RESET \| DEBUG_INIT_DISPLAY \| DEBUG_BLANK \| DEBUG_REQUEST_GPIOS \| DEBUG_FREE_GPIOS \| DEBUG_VERIFY_GPIOS \| DEBUG_BACKLIGHT \| DEBUG_SYSFS)
	#define DEBUG_LEVEL_4 (DEBUG_LEVEL_2 \| DEBUG_FB_READ \| DEBUG_FB_WRITE \| DEBUG_FB_FILLRECT \| DEBUG_FB_COPYAREA \| DEBUG_FB_IMAGEBLIT \| DEBUG_FB_BLANK)
	#define DEBUG_LEVEL_5 (DEBUG_LEVEL_3 \| DEBUG_UPDATE_DISPLAY)
	#define DEBUG_LEVEL_6 (DEBUG_LEVEL_4 \| DEBUG_LEVEL_5)
	#define DEBUG_LEVEL_7 0xFFFFFFFF

	#define DEBUG_DRIVER_INIT_FUNCTIONS (1<<3)
	#define DEBUG_TIME_FIRST_UPDATE (1<<4)
	#define DEBUG_TIME_EACH_UPDATE (1<<5)
	#define DEBUG_DEFERRED_IO (1<<6)
	#define DEBUG_FBTFT_INIT_FUNCTIONS (1<<7)

	/* fbops */
	#define DEBUG_FB_READ (1<<8)
	#define DEBUG_FB_WRITE (1<<9)
	#define DEBUG_FB_FILLRECT (1<<10)
	#define DEBUG_FB_COPYAREA (1<<11)
	#define DEBUG_FB_IMAGEBLIT (1<<12)
	#define DEBUG_FB_SETCOLREG (1<<13)
	#define DEBUG_FB_BLANK (1<<14)

	#define DEBUG_SYSFS (1<<16)

	/* fbtftops */
	#define DEBUG_BACKLIGHT (1<<17)
	#define DEBUG_READ (1<<18)
	#define DEBUG_WRITE (1<<19)
	#define DEBUG_WRITE_VMEM (1<<20)
	#define DEBUG_WRITE_REGISTER (1<<21)
	#define DEBUG_SET_ADDR_WIN (1<<22)
	#define DEBUG_RESET (1<<23)
	#define DEBUG_MKDIRTY (1<<24)
	#define DEBUG_UPDATE_DISPLAY (1<<25)
	#define DEBUG_INIT_DISPLAY (1<<26)
	#define DEBUG_BLANK (1<<27)
	#define DEBUG_REQUEST_GPIOS (1<<28)
	#define DEBUG_FREE_GPIOS (1<<29)
	#define DEBUG_REQUEST_GPIOS_MATCH (1<<30)
	#define DEBUG_VERIFY_GPIOS (1<<31)

	#define fbtft_init_dbg(dev, format, arg...) \
	do { \
	if (unlikely((dev)->platform_data && \
	(((struct fbtft_platform_data *)(dev)->platform_data)->display.debug & DEBUG_DRIVER_INIT_FUNCTIONS))) \
	dev_info(dev, format, ##arg); \
	} while (0)

	#define fbtft_par_dbg(level, par, format, arg...) \
	do { \
	if (unlikely(par->debug & level)) \
	dev_info(par->info->device, format, ##arg); \
	} while (0)

	#define fbtft_par_dbg_hex(level, par, dev, type, buf, num, format, arg...) \
	do { \
	if (unlikely(par->debug & level)) \
	fbtft_dbg_hex(dev, sizeof(type), buf, num * sizeof(type), format, ##arg); \
	} while (0)

	#endif /* __LINUX_FBTFT_H */