From e96ff8b41e411ffdbf31d279411f4384c850bc6b Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Tue, 1 Sep 2020 18:15:27 +0100
Subject: [PATCH] staging/fbtft: Add support for display variants

Display variants are intended as a replacement for the now-deleted
fbtft_device drivers. Drivers can register additional compatible
strings with a custom callback that can make the required changes
to the fbtft_display structure.

Start the ball rolling by adding adafruit18, adafruit18_green and
sainsmart18 displays.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
 drivers/staging/fbtft/fb_st7735r.c |  38 +++++++++-
 drivers/staging/fbtft/fbtft-core.c |  16 ++++-
 drivers/staging/fbtft/fbtft.h      | 112 +++++++++++++++++++----------
 3 files changed, 126 insertions(+), 40 deletions(-)

--- a/drivers/staging/fbtft/fb_st7735r.c
+++ b/drivers/staging/fbtft/fb_st7735r.c
@@ -16,6 +16,10 @@
 #define DEFAULT_GAMMA   "0F 1A 0F 18 2F 28 20 22 1F 1B 23 37 00 07 02 10\n" \
 			"0F 1B 0F 17 33 2C 29 2E 30 30 39 3F 00 07 03 10"
 
+#define ADAFRUIT18_GAMMA \
+			"02 1c 07 12 37 32 29 2d 29 25 2B 39 00 01 03 10\n" \
+			"03 1d 07 06 2E 2C 29 2D 2E 2E 37 3F 00 00 02 10"
+
 static const s16 default_init_sequence[] = {
 	-1, MIPI_DCS_SOFT_RESET,
 	-2, 150,                               /* delay */
@@ -94,6 +98,14 @@ static void set_addr_win(struct fbtft_pa
 	write_reg(par, MIPI_DCS_WRITE_MEMORY_START);
 }
 
+static void adafruit18_green_tab_set_addr_win(struct fbtft_par *par,
+					      int xs, int ys, int xe, int ye)
+{
+	write_reg(par, 0x2A, 0, xs + 2, 0, xe + 2);
+	write_reg(par, 0x2B, 0, ys + 1, 0, ye + 1);
+	write_reg(par, 0x2C);
+}
+
 #define MY BIT(7)
 #define MX BIT(6)
 #define MV BIT(5)
@@ -174,12 +186,36 @@ static struct fbtft_display display = {
 	},
 };
 
-FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7735r", &display);
+static int variant_adafruit18(struct fbtft_display *display)
+{
+	display->gamma = ADAFRUIT18_GAMMA;
+	return 0;
+}
+
+static int variant_adafruit18_green(struct fbtft_display *display)
+{
+	display->gamma = ADAFRUIT18_GAMMA;
+	display->fbtftops.set_addr_win = adafruit18_green_tab_set_addr_win;
+	return 0;
+}
+
+FBTFT_REGISTER_DRIVER_START(&display)
+FBTFT_COMPATIBLE("sitronix,st7735r")
+FBTFT_COMPATIBLE("fbtft,sainsmart18")
+FBTFT_VARIANT_COMPATIBLE("fbtft,adafruit18", variant_adafruit18)
+FBTFT_VARIANT_COMPATIBLE("fbtft,adafruit18_green", variant_adafruit18_green)
+FBTFT_REGISTER_DRIVER_END(DRVNAME, &display);
 
 MODULE_ALIAS("spi:" DRVNAME);
 MODULE_ALIAS("platform:" DRVNAME);
 MODULE_ALIAS("spi:st7735r");
 MODULE_ALIAS("platform:st7735r");
+MODULE_ALIAS("spi:sainsmart18");
+MODULE_ALIAS("platform:sainsmart");
+MODULE_ALIAS("spi:adafruit18");
+MODULE_ALIAS("platform:adafruit18");
+MODULE_ALIAS("spi:adafruit18_green");
+MODULE_ALIAS("platform:adafruit18_green");
 
 MODULE_DESCRIPTION("FB driver for the ST7735R LCD Controller");
 MODULE_AUTHOR("Noralf Tronnes");
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -24,6 +24,8 @@
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/spinlock.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #include <video/mipi_display.h>
 
@@ -1132,6 +1134,7 @@ static struct fbtft_platform_data *fbtft
  * @display: Display properties
  * @sdev: SPI device
  * @pdev: Platform device
+ * @dt_ids: Compatible string table
  *
  * Allocates, initializes and registers a framebuffer
  *
@@ -1141,12 +1144,15 @@ static struct fbtft_platform_data *fbtft
  */
 int fbtft_probe_common(struct fbtft_display *display,
 		       struct spi_device *sdev,
-		       struct platform_device *pdev)
+		       struct platform_device *pdev,
+		       const struct of_device_id *dt_ids)
 {
 	struct device *dev;
 	struct fb_info *info;
 	struct fbtft_par *par;
 	struct fbtft_platform_data *pdata;
+	const struct of_device_id *match;
+	int (*variant)(struct fbtft_display *);
 	int ret;
 
 	if (sdev)
@@ -1159,6 +1165,14 @@ int fbtft_probe_common(struct fbtft_disp
 		pdata = fbtft_properties_read(dev);
 		if (IS_ERR(pdata))
 			return PTR_ERR(pdata);
+		match = of_match_device(dt_ids, dev);
+		if (match && match->data) {
+			/* apply the variant */
+			variant = match->data;
+			ret = (*variant)(display);
+			if (ret)
+				return ret;
+		}
 	}
 
 	info = fbtft_framebuffer_alloc(display, dev, pdata);
--- a/drivers/staging/fbtft/fbtft.h
+++ b/drivers/staging/fbtft/fbtft.h
@@ -253,7 +253,8 @@ void fbtft_register_backlight(struct fbt
 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);
+		       struct platform_device *pdev,
+		       const struct of_device_id *dt_ids);
 void fbtft_remove_common(struct device *dev, struct fb_info *info);
 
 /* fbtft-io.c */
@@ -274,42 +275,25 @@ void fbtft_write_reg8_bus9(struct fbtft_
 void fbtft_write_reg16_bus8(struct fbtft_par *par, int len, ...);
 void fbtft_write_reg16_bus16(struct fbtft_par *par, int len, ...);
 
-#define FBTFT_DT_TABLE(_compatible)						\
-static const struct of_device_id dt_ids[] = {					\
-	{ .compatible = _compatible },						\
-	{},									\
-};										\
-MODULE_DEVICE_TABLE(of, dt_ids);
-
-#define FBTFT_SPI_DRIVER(_name, _compatible, _display, _spi_ids)		\
-										\
-static int fbtft_driver_probe_spi(struct spi_device *spi)			\
-{										\
-	return fbtft_probe_common(_display, spi, NULL);				\
-}										\
-										\
-static void fbtft_driver_remove_spi(struct spi_device *spi)			\
-{										\
-	struct fb_info *info = spi_get_drvdata(spi);				\
-										\
-	fbtft_remove_common(&spi->dev, info);					\
-}										\
-										\
-static struct spi_driver fbtft_driver_spi_driver = {				\
-	.driver = {								\
-		.name = _name,							\
-		.of_match_table = dt_ids,					\
-	},									\
-	.id_table = _spi_ids,							\
-	.probe = fbtft_driver_probe_spi,					\
-	.remove = fbtft_driver_remove_spi,					\
-};
-
-#define FBTFT_REGISTER_DRIVER(_name, _compatible, _display)                \
+#define FBTFT_REGISTER_DRIVER_START(_display)                              \
+									   \
+static const struct of_device_id dt_ids[];                                 \
+									   \
+static int fbtft_driver_probe_spi(struct spi_device *spi)                  \
+{                                                                          \
+	return fbtft_probe_common(_display, spi, NULL, dt_ids);	           \
+}                                                                          \
+									   \
+static void fbtft_driver_remove_spi(struct spi_device *spi)                 \
+{                                                                          \
+	struct fb_info *info = spi_get_drvdata(spi);                       \
+									   \
+	fbtft_remove_common(&spi->dev, info);                              \
+}                                                                          \
 									   \
 static int fbtft_driver_probe_pdev(struct platform_device *pdev)           \
 {                                                                          \
-	return fbtft_probe_common(_display, NULL, pdev);                   \
+	return fbtft_probe_common(_display, NULL, pdev, dt_ids);           \
 }                                                                          \
 									   \
 static void fbtft_driver_remove_pdev(struct platform_device *pdev)	   \
@@ -319,9 +303,30 @@ static void fbtft_driver_remove_pdev(str
 	fbtft_remove_common(&pdev->dev, info);                             \
 }                                                                          \
 									   \
-FBTFT_DT_TABLE(_compatible)						   \
+static const struct of_device_id dt_ids[] = {
+
+#define FBTFT_COMPATIBLE(_compatible)                                      \
+	{ .compatible = _compatible },
+
+#define FBTFT_VARIANT_COMPATIBLE(_compatible, _variant)                    \
+	{ .compatible = _compatible, .data = _variant },
+
+#define FBTFT_REGISTER_DRIVER_END(_name, _display)                         \
 									   \
-FBTFT_SPI_DRIVER(_name, _compatible, _display, NULL)			   \
+	{},                                                                \
+};                                                                         \
+									   \
+MODULE_DEVICE_TABLE(of, dt_ids);                                           \
+									   \
+									   \
+static struct spi_driver fbtft_driver_spi_driver = {                       \
+	.driver = {                                                        \
+		.name   = _name,                                           \
+		.of_match_table = dt_ids,                                  \
+	},                                                                 \
+	.probe  = fbtft_driver_probe_spi,                                  \
+	.remove = fbtft_driver_remove_spi,                                 \
+};                                                                         \
 									   \
 static struct platform_driver fbtft_driver_platform_driver = {             \
 	.driver = {                                                        \
@@ -357,18 +362,49 @@ module_exit(fbtft_driver_module_exit);
 
 #define FBTFT_REGISTER_SPI_DRIVER(_name, _comp_vend, _comp_dev, _display)	\
 										\
-FBTFT_DT_TABLE(_comp_vend "," _comp_dev)					\
+static const struct of_device_id dt_ids[] = {					\
+	{ .compatible = _comp_vend "," _comp_dev },				\
+	{},									\
+};										\
+										\
+static int fbtft_driver_probe_spi(struct spi_device *spi)			\
+{										\
+	return fbtft_probe_common(_display, spi, NULL, dt_ids);			\
+}										\
+										\
+static void fbtft_driver_remove_spi(struct spi_device *spi)			\
+{										\
+	struct fb_info *info = spi_get_drvdata(spi);				\
+										\
+	fbtft_remove_common(&spi->dev, info);					\
+}										\
+										\
+MODULE_DEVICE_TABLE(of, dt_ids);						\
 										\
 static const struct spi_device_id spi_ids[] = {					\
 	{ .name = _comp_dev },							\
 	{},									\
 };										\
+										\
 MODULE_DEVICE_TABLE(spi, spi_ids);						\
 										\
-FBTFT_SPI_DRIVER(_name, _comp_vend "," _comp_dev, _display, spi_ids)		\
+static struct spi_driver fbtft_driver_spi_driver = {				\
+	.driver = {								\
+		.name  = _name,							\
+		.of_match_table = dt_ids,					\
+	},									\
+	.id_table = spi_ids,							\
+	.probe  = fbtft_driver_probe_spi,					\
+	.remove = fbtft_driver_remove_spi,					\
+};										\
 										\
 module_spi_driver(fbtft_driver_spi_driver);
 
+#define FBTFT_REGISTER_DRIVER(_name, _compatible, _display)                \
+	FBTFT_REGISTER_DRIVER_START(_display)                              \
+	FBTFT_COMPATIBLE(_compatible)                                      \
+	FBTFT_REGISTER_DRIVER_END(_name, _display)
+
 /* Debug macros */
 
 /* shorthand debug levels */
