Merge tag 'auxdisplay-for-linus-v5.11' of git://github.com/ojeda/linux

Pull auxdisplay updates from Miguel Ojeda:
 "A bigger set of changes than usual for auxdisplay. There have been
  quite a few changes in auxdisplay thanks to a refactor by Lars
  Poeschel to share code in order to introduce a new driver.

  Summary:

   - Significant refactor work to make charlcd independent of device,
     i.e. hd44780 (Lars Poeschel)

   - New driver: lcd2s (Lars Poeschel)

   - Fixes on top of the rework while being tested in -next (Lars
     Poeschel, Dan Carpenter and kernel test robot)"

* tag 'auxdisplay-for-linus-v5.11' of git://github.com/ojeda/linux: (30 commits)
  auxdisplay: panel: Remove redundant charlcd_ops structures
  auxdisplay: panel: Fix missing print function pointer
  auxdisplay: fix platform_no_drv_owner.cocci warnings
  auxdisplay: fix use after free in lcd2s_i2c_remove()
  auxdisplay: hd44780_common: Fix build error
  auxdisplay: add a driver for lcd2s character display
  auxdisplay: lcd2s DT binding doc
  auxdisplay: charlcd: Do not print chars at end of line
  auxdisplay: Change gotoxy calling interface
  auxdisplay: charlcd: replace last device specific stuff
  auxdisplay: hd44780: Remove clear_fast
  auxdisplay: hd44780_common: Reduce clear_display timeout
  auxdisplay: Call charlcd_backlight in place
  auxdisplay: Move char redefine code to hd44780_common
  auxdisplay: cleanup unnecessary hd44780 code in charlcd
  auxdisplay: implement various hd44780_common_ functions
  auxdisplay: Move init_display to hd44780_common
  auxdisplay: Make use of enum for backlight on / off
  auxdisplay: make charlcd_backlight visible to hd44780_common
  auxdisplay: Move clear_display to hd44780_common
  ...

Documentation/devicetree/bindings/auxdisplay/modtronix,lcd2s.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/auxdisplay/modtronix,lcd2s.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Modtronix engineering LCD2S Character LCD Display
+
+maintainers:
+  - Lars Poeschel <poeschel@lemonage.de>
+
+description:
+  The LCD2S is a Character LCD Display manufactured by Modtronix Engineering.
+  The display supports a serial I2C and SPI interface. The driver currently
+  only supports the I2C interface.
+
+properties:
+  compatible:
+    const: modtronix,lcd2s
+
+  reg:
+    maxItems: 1
+    description:
+      I2C bus address of the display.
+
+  display-height-chars:
+    description: Height of the display, in character cells.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 4
+
+  display-width-chars:
+    description: Width of the display, in character cells.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 16
+    maximum: 20
+
+required:
+  - compatible
+  - reg
+  - display-height-chars
+  - display-width-chars
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      lcd2s: auxdisplay@28 {
+        compatible = "modtronix,lcd2s";
+        reg = <0x28>;
+        display-height-chars = <4>;
+        display-width-chars = <20>;
+      };
+    };

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -683,6 +683,8 @@ patternProperties:
     description: MiraMEMS Sensing Technology Co., Ltd.
   "^mitsubishi,.*":
     description: Mitsubishi Electric Corporation
+  "^modtronix,.*":
+    description: Modtronix Engineering
   "^mosaixtech,.*":
     description: Mosaix Technologies, Inc.
   "^motorola,.*":

drivers/auxdisplay/Kconfig

@@ -16,10 +16,29 @@ menuconfig AUXDISPLAY
 
 if AUXDISPLAY
 
+config CHARLCD
+	tristate "Character LCD core support" if COMPILE_TEST
+	help
+	  This is the base system for character-based LCD displays.
+	  It makes no sense to have this alone, you select your display driver
+	  and if it needs the charlcd core, it will select it automatically.
+	  This is some character LCD core interface that multiple drivers can
+	  use.
+
+config HD44780_COMMON
+	tristate "Common functions for HD44780 (and compatibles) LCD displays" if COMPILE_TEST
+	select CHARLCD
+	help
+	  This is a module with the common symbols for HD44780 (and compatibles)
+	  displays. This is the code that multiple other modules use. It is not
+	  useful alone. If you have some sort of HD44780 compatible display,
+	  you very likely use this. It is selected automatically by selecting
+	  your concrete display.
+
 config HD44780
 	tristate "HD44780 Character LCD support"
 	depends on GPIOLIB || COMPILE_TEST
-	select CHARLCD
+	select HD44780_COMMON
 	help
 	  Enable support for Character LCDs using a HD44780 controller.
 	  The LCD is accessible through the /dev/lcd char device (10, 156).
@@ -154,6 +173,16 @@ config HT16K33
 	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8
 	  LED controller driver with keyscan.
 
+config LCD2S
+	tristate "lcd2s 20x4 character display over I2C console"
+	depends on I2C
+	select CHARLCD
+	help
+	  This is a driver that lets you use the lcd2s 20x4 character display
+	  from Modtronix engineering as a console output device. The display
+	  is a simple single color character display. You have to connect it
+	  to an I2C bus.
+
 config ARM_CHARLCD
 	bool "ARM Ltd. Character LCD Driver"
 	depends on PLAT_VERSATILE
@@ -167,7 +196,7 @@ config ARM_CHARLCD
 menuconfig PARPORT_PANEL
 	tristate "Parallel port LCD/Keypad Panel support"
 	depends on PARPORT
-	select CHARLCD
+	select HD44780_COMMON
 	help
 	  Say Y here if you have an HD44780 or KS-0074 LCD connected to your
 	  parallel port. This driver also features 4 and 6-key keypads. The LCD

drivers/auxdisplay/Makefile

@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_CHARLCD)		+= charlcd.o
+obj-$(CONFIG_HD44780_COMMON)	+= hd44780_common.o
 obj-$(CONFIG_ARM_CHARLCD)	+= arm-charlcd.o
 obj-$(CONFIG_KS0108)		+= ks0108.o
 obj-$(CONFIG_CFAG12864B)	+= cfag12864b.o cfag12864bfb.o
@@ -11,3 +12,4 @@ obj-$(CONFIG_IMG_ASCII_LCD)	+= img-ascii-lcd.o
 obj-$(CONFIG_HD44780)		+= hd44780.o
 obj-$(CONFIG_HT16K33)		+= ht16k33.o
 obj-$(CONFIG_PARPORT_PANEL)	+= panel.o
+obj-$(CONFIG_LCD2S)		+= lcd2s.o

drivers/auxdisplay/charlcd.h

@@ -9,31 +9,91 @@
 #ifndef _CHARLCD_H
 #define _CHARLCD_H
 
+#define LCD_FLAG_B		0x0004	/* Blink on */
+#define LCD_FLAG_C		0x0008	/* Cursor on */
+#define LCD_FLAG_D		0x0010	/* Display on */
+#define LCD_FLAG_F		0x0020	/* Large font mode */
+#define LCD_FLAG_N		0x0040	/* 2-rows mode */
+#define LCD_FLAG_L		0x0080	/* Backlight enabled */
+
+enum charlcd_onoff {
+	CHARLCD_OFF = 0,
+	CHARLCD_ON,
+};
+
+enum charlcd_shift_dir {
+	CHARLCD_SHIFT_LEFT,
+	CHARLCD_SHIFT_RIGHT,
+};
+
+enum charlcd_fontsize {
+	CHARLCD_FONTSIZE_SMALL,
+	CHARLCD_FONTSIZE_LARGE,
+};
+
+enum charlcd_lines {
+	CHARLCD_LINES_1,
+	CHARLCD_LINES_2,
+};
+
 struct charlcd {
 	const struct charlcd_ops *ops;
 	const unsigned char *char_conv;	/* Optional */
 
-	int ifwidth;			/* 4-bit or 8-bit (default) */
 	int height;
 	int width;
-	int bwidth;			/* Default set by charlcd_alloc() */
-	int hwidth;			/* Default set by charlcd_alloc() */
 
-	void *drvdata;			/* Set by charlcd_alloc() */
+	/* Contains the LCD X and Y offset */
+	struct {
+		unsigned long x;
+		unsigned long y;
+	} addr;
+
+	void *drvdata;
 };
 
+/**
+ * struct charlcd_ops - Functions used by charlcd. Drivers have to implement
+ * these.
+ * @backlight: Turn backlight on or off. Optional.
+ * @print: Print one character to the display at current cursor position.
+ * The buffered cursor position is advanced by charlcd. The cursor should not
+ * wrap to the next line at the end of a line.
+ * @gotoxy: Set cursor to x, y. The x and y values to set the cursor to are
+ * previously set in addr.x and addr.y by charlcd.
+ * @home: Set cursor to 0, 0. The values in addr.x and addr.y are set to 0, 0 by
+ * charlcd prior to calling this function.
+ * @clear_display: Clear the whole display and set the cursor to 0, 0. The
+ * values in addr.x and addr.y are set to 0, 0 by charlcd after to calling this
+ * function.
+ * @init_display: Initialize the display.
+ * @shift_cursor: Shift cursor left or right one position.
+ * @shift_display: Shift whole display content left or right.
+ * @display: Turn display on or off.
+ * @cursor: Turn cursor on or off.
+ * @blink: Turn cursor blink on or off.
+ * @lines: One or two lines.
+ * @redefine_char: Redefine the actual pixel matrix of character.
+ */
 struct charlcd_ops {
-	/* Required */
-	void (*write_cmd)(struct charlcd *lcd, int cmd);
-	void (*write_data)(struct charlcd *lcd, int data);
-
-	/* Optional */
-	void (*write_cmd_raw4)(struct charlcd *lcd, int cmd);	/* 4-bit only */
-	void (*clear_fast)(struct charlcd *lcd);
-	void (*backlight)(struct charlcd *lcd, int on);
+	void (*backlight)(struct charlcd *lcd, enum charlcd_onoff on);
+	int (*print)(struct charlcd *lcd, int c);
+	int (*gotoxy)(struct charlcd *lcd, unsigned int x, unsigned int y);
+	int (*home)(struct charlcd *lcd);
+	int (*clear_display)(struct charlcd *lcd);
+	int (*init_display)(struct charlcd *lcd);
+	int (*shift_cursor)(struct charlcd *lcd, enum charlcd_shift_dir dir);
+	int (*shift_display)(struct charlcd *lcd, enum charlcd_shift_dir dir);
+	int (*display)(struct charlcd *lcd, enum charlcd_onoff on);
+	int (*cursor)(struct charlcd *lcd, enum charlcd_onoff on);
+	int (*blink)(struct charlcd *lcd, enum charlcd_onoff on);
+	int (*fontsize)(struct charlcd *lcd, enum charlcd_fontsize size);
+	int (*lines)(struct charlcd *lcd, enum charlcd_lines lines);
+	int (*redefine_char)(struct charlcd *lcd, char *esc);
 };
 
-struct charlcd *charlcd_alloc(unsigned int drvdata_size);
+void charlcd_backlight(struct charlcd *lcd, enum charlcd_onoff on);
+struct charlcd *charlcd_alloc(void);
 void charlcd_free(struct charlcd *lcd);
 
 int charlcd_register(struct charlcd *lcd);

drivers/auxdisplay/hd44780.c

@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 
 #include "charlcd.h"
+#include "hd44780_common.h"
 
 enum hd44780_pin {
 	/* Order does matter due to writing to GPIO array subsets! */
@@ -37,9 +38,10 @@ struct hd44780 {
 	struct gpio_desc *pins[PIN_NUM];
 };
 
-static void hd44780_backlight(struct charlcd *lcd, int on)
+static void hd44780_backlight(struct charlcd *lcd, enum charlcd_onoff on)
 {
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780_common *hdc = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 
 	if (hd->pins[PIN_CTRL_BL])
 		gpiod_set_value_cansleep(hd->pins[PIN_CTRL_BL], on);
@@ -101,9 +103,9 @@ static void hd44780_write_gpio4(struct hd44780 *hd, u8 val, unsigned int rs)
 }
 
 /* Send a command to the LCD panel in 8 bit GPIO mode */
-static void hd44780_write_cmd_gpio8(struct charlcd *lcd, int cmd)
+static void hd44780_write_cmd_gpio8(struct hd44780_common *hdc, int cmd)
 {
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 
 	hd44780_write_gpio8(hd, cmd, 0);
 
@@ -112,9 +114,9 @@ static void hd44780_write_cmd_gpio8(struct charlcd *lcd, int cmd)
 }
 
 /* Send data to the LCD panel in 8 bit GPIO mode */
-static void hd44780_write_data_gpio8(struct charlcd *lcd, int data)
+static void hd44780_write_data_gpio8(struct hd44780_common *hdc, int data)
 {
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 
 	hd44780_write_gpio8(hd, data, 1);
 
@@ -123,15 +125,26 @@ static void hd44780_write_data_gpio8(struct charlcd *lcd, int data)
 }
 
 static const struct charlcd_ops hd44780_ops_gpio8 = {
-	.write_cmd	= hd44780_write_cmd_gpio8,
-	.write_data	= hd44780_write_data_gpio8,
 	.backlight	= hd44780_backlight,
+	.print		= hd44780_common_print,
+	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
+	.clear_display	= hd44780_common_clear_display,
+	.init_display	= hd44780_common_init_display,
+	.shift_cursor	= hd44780_common_shift_cursor,
+	.shift_display	= hd44780_common_shift_display,
+	.display	= hd44780_common_display,
+	.cursor		= hd44780_common_cursor,
+	.blink		= hd44780_common_blink,
+	.fontsize	= hd44780_common_fontsize,
+	.lines		= hd44780_common_lines,
+	.redefine_char	= hd44780_common_redefine_char,
 };
 
 /* Send a command to the LCD panel in 4 bit GPIO mode */
-static void hd44780_write_cmd_gpio4(struct charlcd *lcd, int cmd)
+static void hd44780_write_cmd_gpio4(struct hd44780_common *hdc, int cmd)
 {
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 
 	hd44780_write_gpio4(hd, cmd, 0);
 
@@ -140,10 +153,10 @@ static void hd44780_write_cmd_gpio4(struct charlcd *lcd, int cmd)
 }
 
 /* Send 4-bits of a command to the LCD panel in raw 4 bit GPIO mode */
-static void hd44780_write_cmd_raw_gpio4(struct charlcd *lcd, int cmd)
+static void hd44780_write_cmd_raw_gpio4(struct hd44780_common *hdc, int cmd)
 {
 	DECLARE_BITMAP(values, 6); /* for DATA[4-7], RS, RW */
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 	unsigned int n;
 
 	/* Command nibble + RS, RW */
@@ -157,9 +170,9 @@ static void hd44780_write_cmd_raw_gpio4(struct charlcd *lcd, int cmd)
 }
 
 /* Send data to the LCD panel in 4 bit GPIO mode */
-static void hd44780_write_data_gpio4(struct charlcd *lcd, int data)
+static void hd44780_write_data_gpio4(struct hd44780_common *hdc, int data)
 {
-	struct hd44780 *hd = lcd->drvdata;
+	struct hd44780 *hd = hdc->hd44780;
 
 	hd44780_write_gpio4(hd, data, 1);
 
@@ -168,10 +181,20 @@ static void hd44780_write_data_gpio4(struct charlcd *lcd, int data)
 }
 
 static const struct charlcd_ops hd44780_ops_gpio4 = {
-	.write_cmd	= hd44780_write_cmd_gpio4,
-	.write_cmd_raw4	= hd44780_write_cmd_raw_gpio4,
-	.write_data	= hd44780_write_data_gpio4,
 	.backlight	= hd44780_backlight,
+	.print		= hd44780_common_print,
+	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
+	.clear_display	= hd44780_common_clear_display,
+	.init_display	= hd44780_common_init_display,
+	.shift_cursor	= hd44780_common_shift_cursor,
+	.shift_display	= hd44780_common_shift_display,
+	.display	= hd44780_common_display,
+	.cursor		= hd44780_common_cursor,
+	.blink		= hd44780_common_blink,
+	.fontsize	= hd44780_common_fontsize,
+	.lines		= hd44780_common_lines,
+	.redefine_char	= hd44780_common_redefine_char,
 };
 
 static int hd44780_probe(struct platform_device *pdev)
@@ -179,8 +202,9 @@ static int hd44780_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	unsigned int i, base;
 	struct charlcd *lcd;
+	struct hd44780_common *hdc;
 	struct hd44780 *hd;
-	int ifwidth, ret;
+	int ifwidth, ret = -ENOMEM;
 
 	/* Required pins */
 	ifwidth = gpiod_count(dev, "data");
@@ -198,31 +222,39 @@ static int hd44780_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	lcd = charlcd_alloc(sizeof(struct hd44780));
-	if (!lcd)
+	hdc = hd44780_common_alloc();
+	if (!hdc)
 		return -ENOMEM;
 
-	hd = lcd->drvdata;
+	lcd = charlcd_alloc();
+	if (!lcd)
+		goto fail1;
+
+	hd = kzalloc(sizeof(struct hd44780), GFP_KERNEL);
+	if (!hd)
+		goto fail2;
 
+	hdc->hd44780 = hd;
+	lcd->drvdata = hdc;
 	for (i = 0; i < ifwidth; i++) {
 		hd->pins[base + i] = devm_gpiod_get_index(dev, "data", i,
 							  GPIOD_OUT_LOW);
 		if (IS_ERR(hd->pins[base + i])) {
 			ret = PTR_ERR(hd->pins[base + i]);
-			goto fail;
+			goto fail3;
 		}
 	}
 
 	hd->pins[PIN_CTRL_E] = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
 	if (IS_ERR(hd->pins[PIN_CTRL_E])) {
 		ret = PTR_ERR(hd->pins[PIN_CTRL_E]);
-		goto fail;
+		goto fail3;
 	}
 
 	hd->pins[PIN_CTRL_RS] = devm_gpiod_get(dev, "rs", GPIOD_OUT_HIGH);
 	if (IS_ERR(hd->pins[PIN_CTRL_RS])) {
 		ret = PTR_ERR(hd->pins[PIN_CTRL_RS]);
-		goto fail;
+		goto fail3;
 	}
 
 	/* Optional pins */
@@ -230,47 +262,60 @@ static int hd44780_probe(struct platform_device *pdev)
 							GPIOD_OUT_LOW);
 	if (IS_ERR(hd->pins[PIN_CTRL_RW])) {
 		ret = PTR_ERR(hd->pins[PIN_CTRL_RW]);
-		goto fail;
+		goto fail3;
 	}
 
 	hd->pins[PIN_CTRL_BL] = devm_gpiod_get_optional(dev, "backlight",
 							GPIOD_OUT_LOW);
 	if (IS_ERR(hd->pins[PIN_CTRL_BL])) {
 		ret = PTR_ERR(hd->pins[PIN_CTRL_BL]);
-		goto fail;
+		goto fail3;
 	}
 
 	/* Required properties */
 	ret = device_property_read_u32(dev, "display-height-chars",
 				       &lcd->height);
 	if (ret)
-		goto fail;
+		goto fail3;
 	ret = device_property_read_u32(dev, "display-width-chars", &lcd->width);
 	if (ret)
-		goto fail;
+		goto fail3;
 
 	/*
 	 * On displays with more than two rows, the internal buffer width is
 	 * usually equal to the display width
 	 */
 	if (lcd->height > 2)
-		lcd->bwidth = lcd->width;
+		hdc->bwidth = lcd->width;
 
 	/* Optional properties */
-	device_property_read_u32(dev, "internal-buffer-width", &lcd->bwidth);
-
-	lcd->ifwidth = ifwidth;
-	lcd->ops = ifwidth == 8 ? &hd44780_ops_gpio8 : &hd44780_ops_gpio4;
+	device_property_read_u32(dev, "internal-buffer-width", &hdc->bwidth);
+
+	hdc->ifwidth = ifwidth;
+	if (ifwidth == 8) {
+		lcd->ops = &hd44780_ops_gpio8;
+		hdc->write_data = hd44780_write_data_gpio8;
+		hdc->write_cmd = hd44780_write_cmd_gpio8;
+	} else {
+		lcd->ops = &hd44780_ops_gpio4;
+		hdc->write_data = hd44780_write_data_gpio4;
+		hdc->write_cmd = hd44780_write_cmd_gpio4;
+		hdc->write_cmd_raw4 = hd44780_write_cmd_raw_gpio4;
+	}
 
 	ret = charlcd_register(lcd);
 	if (ret)
-		goto fail;
+		goto fail3;
 
 	platform_set_drvdata(pdev, lcd);
 	return 0;
 
-fail:
-	charlcd_free(lcd);
+fail3:
+	kfree(hd);
+fail2:
+	kfree(lcd);
+fail1:
+	kfree(hdc);
 	return ret;
 }
 
@@ -278,9 +323,10 @@ static int hd44780_remove(struct platform_device *pdev)
 {
 	struct charlcd *lcd = platform_get_drvdata(pdev);
 
+	kfree(lcd->drvdata);
 	charlcd_unregister(lcd);
 
-	charlcd_free(lcd);
+	kfree(lcd);
 	return 0;
 }
 

drivers/auxdisplay/hd44780_common.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "charlcd.h"
+#include "hd44780_common.h"
+
+/* LCD commands */
+#define LCD_CMD_DISPLAY_CLEAR	0x01	/* Clear entire display */
+
+#define LCD_CMD_ENTRY_MODE	0x04	/* Set entry mode */
+#define LCD_CMD_CURSOR_INC	0x02	/* Increment cursor */
+
+#define LCD_CMD_DISPLAY_CTRL	0x08	/* Display control */
+#define LCD_CMD_DISPLAY_ON	0x04	/* Set display on */
+#define LCD_CMD_CURSOR_ON	0x02	/* Set cursor on */
+#define LCD_CMD_BLINK_ON	0x01	/* Set blink on */
+
+#define LCD_CMD_SHIFT		0x10	/* Shift cursor/display */
+#define LCD_CMD_DISPLAY_SHIFT	0x08	/* Shift display instead of cursor */
+#define LCD_CMD_SHIFT_RIGHT	0x04	/* Shift display/cursor to the right */
+
+#define LCD_CMD_FUNCTION_SET	0x20	/* Set function */
+#define LCD_CMD_DATA_LEN_8BITS	0x10	/* Set data length to 8 bits */
+#define LCD_CMD_TWO_LINES	0x08	/* Set to two display lines */
+#define LCD_CMD_FONT_5X10_DOTS	0x04	/* Set char font to 5x10 dots */
+
+#define LCD_CMD_SET_CGRAM_ADDR	0x40	/* Set char generator RAM address */
+
+#define LCD_CMD_SET_DDRAM_ADDR	0x80	/* Set display data RAM address */
+
+/* sleeps that many milliseconds with a reschedule */
+static void long_sleep(int ms)
+{
+	schedule_timeout_interruptible(msecs_to_jiffies(ms));
+}
+
+int hd44780_common_print(struct charlcd *lcd, int c)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (lcd->addr.x < hdc->bwidth) {
+		hdc->write_data(hdc, c);
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_print);
+
+int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+	unsigned int addr;
+
+	/*
+	 * we force the cursor to stay at the end of the
+	 * line if it wants to go farther
+	 */
+	addr = x < hdc->bwidth ? x & (hdc->hwidth - 1) : hdc->bwidth - 1;
+	if (y & 1)
+		addr += hdc->hwidth;
+	if (y & 2)
+		addr += hdc->bwidth;
+	hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_gotoxy);
+
+int hd44780_common_home(struct charlcd *lcd)
+{
+	return hd44780_common_gotoxy(lcd, 0, 0);
+}
+EXPORT_SYMBOL_GPL(hd44780_common_home);
+
+/* clears the display and resets X/Y */
+int hd44780_common_clear_display(struct charlcd *lcd)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR);
+	/* datasheet says to wait 1,64 milliseconds */
+	long_sleep(2);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_clear_display);
+
+int hd44780_common_init_display(struct charlcd *lcd)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd);
+	u8 init;
+
+	if (hdc->ifwidth != 4 && hdc->ifwidth != 8)
+		return -EINVAL;
+
+	hdc->hd44780_common_flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) |
+		LCD_FLAG_D | LCD_FLAG_C | LCD_FLAG_B;
+
+	long_sleep(20);		/* wait 20 ms after power-up for the paranoid */
+
+	/*
+	 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure
+	 * the LCD is in 8-bit mode afterwards
+	 */
+	init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;
+	if (hdc->ifwidth == 4) {
+		init >>= 4;
+		write_cmd_raw = hdc->write_cmd_raw4;
+	} else {
+		write_cmd_raw = hdc->write_cmd;
+	}
+	write_cmd_raw(hdc, init);
+	long_sleep(10);
+	write_cmd_raw(hdc, init);
+	long_sleep(10);
+	write_cmd_raw(hdc, init);
+	long_sleep(10);
+
+	if (hdc->ifwidth == 4) {
+		/* Switch to 4-bit mode, 1 line, small fonts */
+		hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4);
+		long_sleep(10);
+	}
+
+	/* set font height and lines number */
+	hdc->write_cmd(hdc,
+		LCD_CMD_FUNCTION_SET |
+		((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_F) ?
+			LCD_CMD_FONT_5X10_DOTS : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_N) ?
+			LCD_CMD_TWO_LINES : 0));
+	long_sleep(10);
+
+	/* display off, cursor off, blink off */
+	hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL);
+	long_sleep(10);
+
+	hdc->write_cmd(hdc,
+		LCD_CMD_DISPLAY_CTRL |	/* set display mode */
+		((hdc->hd44780_common_flags & LCD_FLAG_D) ?
+			LCD_CMD_DISPLAY_ON : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_C) ?
+			LCD_CMD_CURSOR_ON : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_B) ?
+			LCD_CMD_BLINK_ON : 0));
+
+	charlcd_backlight(lcd,
+			(hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0);
+
+	long_sleep(10);
+
+	/* entry mode set : increment, cursor shifting */
+	hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
+
+	hd44780_common_clear_display(lcd);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_init_display);
+
+int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (dir == CHARLCD_SHIFT_LEFT) {
+		/* back one char if not at end of line */
+		if (lcd->addr.x < hdc->bwidth)
+			hdc->write_cmd(hdc, LCD_CMD_SHIFT);
+	} else if (dir == CHARLCD_SHIFT_RIGHT) {
+		/* allow the cursor to pass the end of the line */
+		if (lcd->addr.x < (hdc->bwidth - 1))
+			hdc->write_cmd(hdc,
+					LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor);
+
+int hd44780_common_shift_display(struct charlcd *lcd,
+		enum charlcd_shift_dir dir)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (dir == CHARLCD_SHIFT_LEFT)
+		hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
+	else if (dir == CHARLCD_SHIFT_RIGHT)
+		hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
+			LCD_CMD_SHIFT_RIGHT);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_shift_display);
+
+static void hd44780_common_set_mode(struct hd44780_common *hdc)
+{
+	hdc->write_cmd(hdc,
+		LCD_CMD_DISPLAY_CTRL |
+		((hdc->hd44780_common_flags & LCD_FLAG_D) ?
+			LCD_CMD_DISPLAY_ON : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_C) ?
+			LCD_CMD_CURSOR_ON : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_B) ?
+			LCD_CMD_BLINK_ON : 0));
+}
+
+int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (on == CHARLCD_ON)
+		hdc->hd44780_common_flags |= LCD_FLAG_D;
+	else
+		hdc->hd44780_common_flags &= ~LCD_FLAG_D;
+
+	hd44780_common_set_mode(hdc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_display);
+
+int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (on == CHARLCD_ON)
+		hdc->hd44780_common_flags |= LCD_FLAG_C;
+	else
+		hdc->hd44780_common_flags &= ~LCD_FLAG_C;
+
+	hd44780_common_set_mode(hdc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_cursor);
+
+int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (on == CHARLCD_ON)
+		hdc->hd44780_common_flags |= LCD_FLAG_B;
+	else
+		hdc->hd44780_common_flags &= ~LCD_FLAG_B;
+
+	hd44780_common_set_mode(hdc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_blink);
+
+static void hd44780_common_set_function(struct hd44780_common *hdc)
+{
+	hdc->write_cmd(hdc,
+		LCD_CMD_FUNCTION_SET |
+		((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_F) ?
+			LCD_CMD_FONT_5X10_DOTS : 0) |
+		((hdc->hd44780_common_flags & LCD_FLAG_N) ?
+			LCD_CMD_TWO_LINES : 0));
+}
+
+int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (size == CHARLCD_FONTSIZE_LARGE)
+		hdc->hd44780_common_flags |= LCD_FLAG_F;
+	else
+		hdc->hd44780_common_flags &= ~LCD_FLAG_F;
+
+	hd44780_common_set_function(hdc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_fontsize);
+
+int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines)
+{
+	struct hd44780_common *hdc = lcd->drvdata;
+
+	if (lines == CHARLCD_LINES_2)
+		hdc->hd44780_common_flags |= LCD_FLAG_N;
+	else
+		hdc->hd44780_common_flags &= ~LCD_FLAG_N;
+
+	hd44780_common_set_function(hdc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_lines);
+
+int hd44780_common_redefine_char(struct charlcd *lcd, char *esc)
+{
+	/* Generator : LGcxxxxx...xx; must have <c> between '0'
+	 * and '7', representing the numerical ASCII code of the
+	 * redefined character, and <xx...xx> a sequence of 16
+	 * hex digits representing 8 bytes for each character.
+	 * Most LCDs will only use 5 lower bits of the 7 first
+	 * bytes.
+	 */
+
+	struct hd44780_common *hdc = lcd->drvdata;
+	unsigned char cgbytes[8];
+	unsigned char cgaddr;
+	int cgoffset;
+	int shift;
+	char value;
+	int addr;
+
+	if (!strchr(esc, ';'))
+		return 0;
+
+	esc++;
+
+	cgaddr = *(esc++) - '0';
+	if (cgaddr > 7)
+		return 1;
+
+	cgoffset = 0;
+	shift = 0;
+	value = 0;
+	while (*esc && cgoffset < 8) {
+		int half;
+
+		shift ^= 4;
+		half = hex_to_bin(*esc++);
+		if (half < 0)
+			continue;
+
+		value |= half << shift;
+		if (shift == 0) {
+			cgbytes[cgoffset++] = value;
+			value = 0;
+		}
+	}
+
+	hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));
+	for (addr = 0; addr < cgoffset; addr++)
+		hdc->write_data(hdc, cgbytes[addr]);
+
+	/* ensures that we stop writing to CGRAM */
+	lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_redefine_char);
+
+struct hd44780_common *hd44780_common_alloc(void)
+{
+	struct hd44780_common *hd;
+
+	hd = kzalloc(sizeof(*hd), GFP_KERNEL);
+	if (!hd)
+		return NULL;
+
+	hd->ifwidth = 8;
+	hd->bwidth = DEFAULT_LCD_BWIDTH;
+	hd->hwidth = DEFAULT_LCD_HWIDTH;
+	return hd;
+}
+EXPORT_SYMBOL_GPL(hd44780_common_alloc);
+
+MODULE_LICENSE("GPL");

drivers/auxdisplay/hd44780_common.h

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#define DEFAULT_LCD_BWIDTH      40
+#define DEFAULT_LCD_HWIDTH      64
+
+struct hd44780_common {
+	int ifwidth;			/* 4-bit or 8-bit (default) */
+	int bwidth;			/* Default set by hd44780_alloc() */
+	int hwidth;			/* Default set by hd44780_alloc() */
+	unsigned long hd44780_common_flags;
+	void (*write_data)(struct hd44780_common *hdc, int data);
+	void (*write_cmd)(struct hd44780_common *hdc, int cmd);
+	/* write_cmd_raw4 is for 4-bit connected displays only */
+	void (*write_cmd_raw4)(struct hd44780_common *hdc, int cmd);
+	void *hd44780;
+};
+
+int hd44780_common_print(struct charlcd *lcd, int c);
+int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y);
+int hd44780_common_home(struct charlcd *lcd);
+int hd44780_common_clear_display(struct charlcd *lcd);
+int hd44780_common_init_display(struct charlcd *lcd);
+int hd44780_common_shift_cursor(struct charlcd *lcd,
+		enum charlcd_shift_dir dir);
+int hd44780_common_shift_display(struct charlcd *lcd,
+		enum charlcd_shift_dir dir);
+int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on);
+int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on);
+int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on);
+int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size);
+int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines);
+int hd44780_common_redefine_char(struct charlcd *lcd, char *esc);
+struct hd44780_common *hd44780_common_alloc(void);

drivers/auxdisplay/lcd2s.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  console driver for LCD2S 4x20 character displays connected through i2c.
+ *  The display also has a spi interface, but the driver does not support
+ *  this yet.
+ *
+ *  This is a driver allowing you to use a LCD2S 4x20 from modtronix
+ *  engineering as auxdisplay character device.
+ *
+ *  (C) 2019 by Lemonage Software GmbH
+ *  Author: Lars Pöschel <poeschel@lemonage.de>
+ *  All rights reserved.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+
+#include "charlcd.h"
+
+#define LCD2S_CMD_CUR_MOVES_FWD		0x09
+#define LCD2S_CMD_CUR_BLINK_OFF		0x10
+#define LCD2S_CMD_CUR_UL_OFF		0x11
+#define LCD2S_CMD_DISPLAY_OFF		0x12
+#define LCD2S_CMD_CUR_BLINK_ON		0x18
+#define LCD2S_CMD_CUR_UL_ON		0x19
+#define LCD2S_CMD_DISPLAY_ON		0x1a
+#define LCD2S_CMD_BACKLIGHT_OFF		0x20
+#define LCD2S_CMD_BACKLIGHT_ON		0x28
+#define LCD2S_CMD_WRITE			0x80
+#define LCD2S_CMD_MOV_CUR_RIGHT		0x83
+#define LCD2S_CMD_MOV_CUR_LEFT		0x84
+#define LCD2S_CMD_SHIFT_RIGHT		0x85
+#define LCD2S_CMD_SHIFT_LEFT		0x86
+#define LCD2S_CMD_SHIFT_UP		0x87
+#define LCD2S_CMD_SHIFT_DOWN		0x88
+#define LCD2S_CMD_CUR_ADDR		0x89
+#define LCD2S_CMD_CUR_POS		0x8a
+#define LCD2S_CMD_CUR_RESET		0x8b
+#define LCD2S_CMD_CLEAR			0x8c
+#define LCD2S_CMD_DEF_CUSTOM_CHAR	0x92
+#define LCD2S_CMD_READ_STATUS		0xd0
+
+#define LCD2S_CHARACTER_SIZE		8
+
+#define LCD2S_STATUS_BUF_MASK		0x7f
+
+struct lcd2s_data {
+	struct i2c_client *i2c;
+	struct charlcd *charlcd;
+};
+
+static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
+{
+	s32 status;
+
+	status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
+	if (status < 0)
+		return status;
+
+	while ((status & LCD2S_STATUS_BUF_MASK) < count) {
+		mdelay(1);
+		status = i2c_smbus_read_byte_data(client,
+						  LCD2S_CMD_READ_STATUS);
+		if (status < 0)
+			return status;
+	}
+	return 0;
+}
+
+static int lcd2s_i2c_master_send(const struct i2c_client *client,
+				 const char *buf, int count)
+{
+	s32 status;
+
+	status = lcd2s_wait_buf_free(client, count);
+	if (status < 0)
+		return status;
+
+	return i2c_master_send(client, buf, count);
+}
+
+static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
+{
+	s32 status;
+
+	status = lcd2s_wait_buf_free(client, 1);
+	if (status < 0)
+		return status;
+
+	return i2c_smbus_write_byte(client, value);
+}
+
+static int lcd2s_print(struct charlcd *lcd, int c)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+	u8 buf[2] = { LCD2S_CMD_WRITE, c };
+
+	lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
+	return 0;
+}
+
+static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+	u8 buf[] = { LCD2S_CMD_CUR_POS, y + 1, x + 1};
+
+	lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
+
+	return 0;
+}
+
+static int lcd2s_home(struct charlcd *lcd)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
+	return 0;
+}
+
+static int lcd2s_init_display(struct charlcd *lcd)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	/* turn everything off, but display on */
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
+
+	return 0;
+}
+
+static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (dir == CHARLCD_SHIFT_LEFT)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
+
+	return 0;
+}
+
+static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (dir == CHARLCD_SHIFT_LEFT)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
+
+	return 0;
+}
+
+static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (on)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
+}
+
+static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (on)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
+
+	return 0;
+}
+
+static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (on)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
+
+	return 0;
+}
+
+static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	if (on)
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
+	else
+		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
+
+	return 0;
+}
+
+static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
+{
+	return 0;
+}
+
+static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines)
+{
+	return 0;
+}
+
+static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
+{
+	/* Generator : LGcxxxxx...xx; must have <c> between '0'
+	 * and '7', representing the numerical ASCII code of the
+	 * redefined character, and <xx...xx> a sequence of 16
+	 * hex digits representing 8 bytes for each character.
+	 * Most LCDs will only use 5 lower bits of the 7 first
+	 * bytes.
+	 */
+
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+	u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR };
+	u8 value;
+	int shift, i;
+
+	if (!strchr(esc, ';'))
+		return 0;
+
+	esc++;
+
+	buf[1] = *(esc++) - '0';
+	if (buf[1] > 7)
+		return 1;
+
+	i = 0;
+	shift = 0;
+	value = 0;
+	while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
+		int half;
+
+		shift ^= 4;
+		half = hex_to_bin(*esc++);
+		if (half < 0)
+			continue;
+
+		value |= half << shift;
+		if (shift == 0) {
+			buf[i++] = value;
+			value = 0;
+		}
+	}
+
+	lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
+	return 1;
+}
+
+static int lcd2s_clear_display(struct charlcd *lcd)
+{
+	struct lcd2s_data *lcd2s = lcd->drvdata;
+
+	/* This implicitly sets cursor to first row and column */
+	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
+	return 0;
+}
+
+static const struct charlcd_ops lcd2s_ops = {
+	.print		= lcd2s_print,
+	.backlight	= lcd2s_backlight,
+	.gotoxy		= lcd2s_gotoxy,
+	.home		= lcd2s_home,
+	.clear_display	= lcd2s_clear_display,
+	.init_display	= lcd2s_init_display,
+	.shift_cursor	= lcd2s_shift_cursor,
+	.shift_display	= lcd2s_shift_display,
+	.display	= lcd2s_display,
+	.cursor		= lcd2s_cursor,
+	.blink		= lcd2s_blink,
+	.fontsize	= lcd2s_fontsize,
+	.lines		= lcd2s_lines,
+	.redefine_char	= lcd2s_redefine_char,
+};
+
+static int lcd2s_i2c_probe(struct i2c_client *i2c,
+				const struct i2c_device_id *id)
+{
+	struct charlcd *lcd;
+	struct lcd2s_data *lcd2s;
+	int err;
+
+	if (!i2c_check_functionality(i2c->adapter,
+			I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+			I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
+		return -EIO;
+
+	/* Test, if the display is responding */
+	err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
+	if (err < 0)
+		return err;
+
+	lcd = charlcd_alloc();
+	if (!lcd)
+		return -ENOMEM;
+
+	lcd2s = kzalloc(sizeof(struct lcd2s_data), GFP_KERNEL);
+	if (!lcd2s) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	lcd->drvdata = lcd2s;
+	lcd2s->i2c = i2c;
+	lcd2s->charlcd = lcd;
+
+	/* Required properties */
+	err = device_property_read_u32(&i2c->dev, "display-height-chars",
+			&lcd->height);
+	if (err)
+		goto fail2;
+
+	err = device_property_read_u32(&i2c->dev, "display-width-chars",
+			&lcd->width);
+	if (err)
+		goto fail2;
+
+	lcd->ops = &lcd2s_ops;
+
+	err = charlcd_register(lcd2s->charlcd);
+	if (err)
+		goto fail2;
+
+	i2c_set_clientdata(i2c, lcd2s);
+	return 0;
+
+fail2:
+	kfree(lcd2s);
+fail1:
+	kfree(lcd);
+	return err;
+}
+
+static int lcd2s_i2c_remove(struct i2c_client *i2c)
+{
+	struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
+
+	charlcd_unregister(lcd2s->charlcd);
+	kfree(lcd2s->charlcd);
+	return 0;
+}
+
+static const struct i2c_device_id lcd2s_i2c_id[] = {
+	{ "lcd2s", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id lcd2s_of_table[] = {
+	{ .compatible = "modtronix,lcd2s" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lcd2s_of_table);
+#endif
+
+static struct i2c_driver lcd2s_i2c_driver = {
+	.driver = {
+		.name = "lcd2s",
+#ifdef CONFIG_OF
+		.of_match_table = of_match_ptr(lcd2s_of_table),
+#endif
+	},
+	.probe = lcd2s_i2c_probe,
+	.remove = lcd2s_i2c_remove,
+	.id_table = lcd2s_i2c_id,
+};
+
+static int __init lcd2s_modinit(void)
+{
+	int ret = 0;
+
+	ret = i2c_add_driver(&lcd2s_i2c_driver);
+	if (ret != 0)
+		pr_err("Failed to register lcd2s driver\n");
+
+	return ret;
+}
+module_init(lcd2s_modinit)
+
+static void __exit lcd2s_exit(void)
+{
+	i2c_del_driver(&lcd2s_i2c_driver);
+}
+module_exit(lcd2s_exit)
+
+MODULE_DESCRIPTION("LCD2S character display driver");
+MODULE_AUTHOR("Lars Poeschel");
+MODULE_LICENSE("GPL");

drivers/auxdisplay/panel.c

@@ -56,6 +56,7 @@
 #include <linux/uaccess.h>
 
 #include "charlcd.h"
+#include "hd44780_common.h"
 
 #define LCD_MAXBYTES		256	/* max burst write */
 
@@ -298,8 +299,6 @@ static unsigned char lcd_bits[LCD_PORTS][LCD_BITS][BIT_STATES];
 #define DEFAULT_LCD_TYPE        LCD_TYPE_OLD
 #define DEFAULT_LCD_HEIGHT      2
 #define DEFAULT_LCD_WIDTH       40
-#define DEFAULT_LCD_BWIDTH      40
-#define DEFAULT_LCD_HWIDTH      64
 #define DEFAULT_LCD_CHARSET     LCD_CHARSET_NORMAL
 #define DEFAULT_LCD_PROTO       LCD_PROTO_PARALLEL
 
@@ -708,7 +707,7 @@ static void lcd_send_serial(int byte)
 }
 
 /* turn the backlight on or off */
-static void lcd_backlight(struct charlcd *charlcd, int on)
+static void lcd_backlight(struct charlcd *charlcd, enum charlcd_onoff on)
 {
 	if (lcd.pins.bl == PIN_NONE)
 		return;
@@ -724,7 +723,7 @@ static void lcd_backlight(struct charlcd *charlcd, int on)
 }
 
 /* send a command to the LCD panel in serial mode */
-static void lcd_write_cmd_s(struct charlcd *charlcd, int cmd)
+static void lcd_write_cmd_s(struct hd44780_common *hdc, int cmd)
 {
 	spin_lock_irq(&pprt_lock);
 	lcd_send_serial(0x1F);	/* R/W=W, RS=0 */
@@ -735,7 +734,7 @@ static void lcd_write_cmd_s(struct charlcd *charlcd, int cmd)
 }
 
 /* send data to the LCD panel in serial mode */
-static void lcd_write_data_s(struct charlcd *charlcd, int data)
+static void lcd_write_data_s(struct hd44780_common *hdc, int data)
 {
 	spin_lock_irq(&pprt_lock);
 	lcd_send_serial(0x5F);	/* R/W=W, RS=1 */
@@ -746,7 +745,7 @@ static void lcd_write_data_s(struct charlcd *charlcd, int data)
 }
 
 /* send a command to the LCD panel in 8 bits parallel mode */
-static void lcd_write_cmd_p8(struct charlcd *charlcd, int cmd)
+static void lcd_write_cmd_p8(struct hd44780_common *hdc, int cmd)
 {
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
@@ -768,7 +767,7 @@ static void lcd_write_cmd_p8(struct charlcd *charlcd, int cmd)
 }
 
 /* send data to the LCD panel in 8 bits parallel mode */
-static void lcd_write_data_p8(struct charlcd *charlcd, int data)
+static void lcd_write_data_p8(struct hd44780_common *hdc, int data)
 {
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
@@ -790,7 +789,7 @@ static void lcd_write_data_p8(struct charlcd *charlcd, int data)
 }
 
 /* send a command to the TI LCD panel */
-static void lcd_write_cmd_tilcd(struct charlcd *charlcd, int cmd)
+static void lcd_write_cmd_tilcd(struct hd44780_common *hdc, int cmd)
 {
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the control port */
@@ -800,7 +799,7 @@ static void lcd_write_cmd_tilcd(struct charlcd *charlcd, int cmd)
 }
 
 /* send data to the TI LCD panel */
-static void lcd_write_data_tilcd(struct charlcd *charlcd, int data)
+static void lcd_write_data_tilcd(struct hd44780_common *hdc, int data)
 {
 	spin_lock_irq(&pprt_lock);
 	/* present the data to the data port */
@@ -809,105 +808,50 @@ static void lcd_write_data_tilcd(struct charlcd *charlcd, int data)
 	spin_unlock_irq(&pprt_lock);
 }
 
-/* fills the display with spaces and resets X/Y */
-static void lcd_clear_fast_s(struct charlcd *charlcd)
-{
-	int pos;
-
-	spin_lock_irq(&pprt_lock);
-	for (pos = 0; pos < charlcd->height * charlcd->hwidth; pos++) {
-		lcd_send_serial(0x5F);	/* R/W=W, RS=1 */
-		lcd_send_serial(' ' & 0x0F);
-		lcd_send_serial((' ' >> 4) & 0x0F);
-		/* the shortest data takes at least 40 us */
-		udelay(40);
-	}
-	spin_unlock_irq(&pprt_lock);
-}
-
-/* fills the display with spaces and resets X/Y */
-static void lcd_clear_fast_p8(struct charlcd *charlcd)
-{
-	int pos;
-
-	spin_lock_irq(&pprt_lock);
-	for (pos = 0; pos < charlcd->height * charlcd->hwidth; pos++) {
-		/* present the data to the data port */
-		w_dtr(pprt, ' ');
-
-		/* maintain the data during 20 us before the strobe */
-		udelay(20);
-
-		set_bit(LCD_BIT_E, bits);
-		set_bit(LCD_BIT_RS, bits);
-		clear_bit(LCD_BIT_RW, bits);
-		set_ctrl_bits();
-
-		/* maintain the strobe during 40 us */
-		udelay(40);
-
-		clear_bit(LCD_BIT_E, bits);
-		set_ctrl_bits();
-
-		/* the shortest data takes at least 45 us */
-		udelay(45);
-	}
-	spin_unlock_irq(&pprt_lock);
-}
-
-/* fills the display with spaces and resets X/Y */
-static void lcd_clear_fast_tilcd(struct charlcd *charlcd)
-{
-	int pos;
-
-	spin_lock_irq(&pprt_lock);
-	for (pos = 0; pos < charlcd->height * charlcd->hwidth; pos++) {
-		/* present the data to the data port */
-		w_dtr(pprt, ' ');
-		udelay(60);
-	}
-
-	spin_unlock_irq(&pprt_lock);
-}
-
-static const struct charlcd_ops charlcd_serial_ops = {
-	.write_cmd	= lcd_write_cmd_s,
-	.write_data	= lcd_write_data_s,
-	.clear_fast	= lcd_clear_fast_s,
-	.backlight	= lcd_backlight,
-};
-
-static const struct charlcd_ops charlcd_parallel_ops = {
-	.write_cmd	= lcd_write_cmd_p8,
-	.write_data	= lcd_write_data_p8,
-	.clear_fast	= lcd_clear_fast_p8,
-	.backlight	= lcd_backlight,
-};
-
-static const struct charlcd_ops charlcd_tilcd_ops = {
-	.write_cmd	= lcd_write_cmd_tilcd,
-	.write_data	= lcd_write_data_tilcd,
-	.clear_fast	= lcd_clear_fast_tilcd,
+static const struct charlcd_ops charlcd_ops = {
 	.backlight	= lcd_backlight,
+	.print		= hd44780_common_print,
+	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
+	.clear_display	= hd44780_common_clear_display,
+	.init_display	= hd44780_common_init_display,
+	.shift_cursor	= hd44780_common_shift_cursor,
+	.shift_display	= hd44780_common_shift_display,
+	.display	= hd44780_common_display,
+	.cursor		= hd44780_common_cursor,
+	.blink		= hd44780_common_blink,
+	.fontsize	= hd44780_common_fontsize,
+	.lines		= hd44780_common_lines,
+	.redefine_char	= hd44780_common_redefine_char,
 };
 
 /* initialize the LCD driver */
 static void lcd_init(void)
 {
 	struct charlcd *charlcd;
+	struct hd44780_common *hdc;
 
-	charlcd = charlcd_alloc(0);
-	if (!charlcd)
+	hdc = hd44780_common_alloc();
+	if (!hdc)
 		return;
 
+	charlcd = charlcd_alloc();
+	if (!charlcd) {
+		kfree(hdc);
+		return;
+	}
+
+	hdc->hd44780 = &lcd;
+	charlcd->drvdata = hdc;
+
 	/*
 	 * Init lcd struct with load-time values to preserve exact
 	 * current functionality (at least for now).
 	 */
 	charlcd->height = lcd_height;
 	charlcd->width = lcd_width;
-	charlcd->bwidth = lcd_bwidth;
-	charlcd->hwidth = lcd_hwidth;
+	hdc->bwidth = lcd_bwidth;
+	hdc->hwidth = lcd_hwidth;
 
 	switch (selected_lcd_type) {
 	case LCD_TYPE_OLD:
@@ -918,8 +862,8 @@ static void lcd_init(void)
 		lcd.pins.rs = PIN_AUTOLF;
 
 		charlcd->width = 40;
-		charlcd->bwidth = 40;
-		charlcd->hwidth = 64;
+		hdc->bwidth = 40;
+		hdc->hwidth = 64;
 		charlcd->height = 2;
 		break;
 	case LCD_TYPE_KS0074:
@@ -931,8 +875,8 @@ static void lcd_init(void)
 		lcd.pins.da = PIN_D0;
 
 		charlcd->width = 16;
-		charlcd->bwidth = 40;
-		charlcd->hwidth = 16;
+		hdc->bwidth = 40;
+		hdc->hwidth = 16;
 		charlcd->height = 2;
 		break;
 	case LCD_TYPE_NEXCOM:
@@ -944,8 +888,8 @@ static void lcd_init(void)
 		lcd.pins.rw = PIN_INITP;
 
 		charlcd->width = 16;
-		charlcd->bwidth = 40;
-		charlcd->hwidth = 64;
+		hdc->bwidth = 40;
+		hdc->hwidth = 64;
 		charlcd->height = 2;
 		break;
 	case LCD_TYPE_CUSTOM:
@@ -963,8 +907,8 @@ static void lcd_init(void)
 		lcd.pins.rs = PIN_SELECP;
 
 		charlcd->width = 16;
-		charlcd->bwidth = 40;
-		charlcd->hwidth = 64;
+		hdc->bwidth = 40;
+		hdc->hwidth = 64;
 		charlcd->height = 2;
 		break;
 	}
@@ -975,9 +919,9 @@ static void lcd_init(void)
 	if (lcd_width != NOT_SET)
 		charlcd->width = lcd_width;
 	if (lcd_bwidth != NOT_SET)
-		charlcd->bwidth = lcd_bwidth;
+		hdc->bwidth = lcd_bwidth;
 	if (lcd_hwidth != NOT_SET)
-		charlcd->hwidth = lcd_hwidth;
+		hdc->hwidth = lcd_hwidth;
 	if (lcd_charset != NOT_SET)
 		lcd.charset = lcd_charset;
 	if (lcd_proto != NOT_SET)
@@ -998,15 +942,17 @@ static void lcd_init(void)
 	/* this is used to catch wrong and default values */
 	if (charlcd->width <= 0)
 		charlcd->width = DEFAULT_LCD_WIDTH;
-	if (charlcd->bwidth <= 0)
-		charlcd->bwidth = DEFAULT_LCD_BWIDTH;
-	if (charlcd->hwidth <= 0)
-		charlcd->hwidth = DEFAULT_LCD_HWIDTH;
+	if (hdc->bwidth <= 0)
+		hdc->bwidth = DEFAULT_LCD_BWIDTH;
+	if (hdc->hwidth <= 0)
+		hdc->hwidth = DEFAULT_LCD_HWIDTH;
 	if (charlcd->height <= 0)
 		charlcd->height = DEFAULT_LCD_HEIGHT;
 
 	if (lcd.proto == LCD_PROTO_SERIAL) {	/* SERIAL */
-		charlcd->ops = &charlcd_serial_ops;
+		charlcd->ops = &charlcd_ops;
+		hdc->write_data = lcd_write_data_s;
+		hdc->write_cmd = lcd_write_cmd_s;
 
 		if (lcd.pins.cl == PIN_NOT_SET)
 			lcd.pins.cl = DEFAULT_LCD_PIN_SCL;
@@ -1014,7 +960,9 @@ static void lcd_init(void)
 			lcd.pins.da = DEFAULT_LCD_PIN_SDA;
 
 	} else if (lcd.proto == LCD_PROTO_PARALLEL) {	/* PARALLEL */
-		charlcd->ops = &charlcd_parallel_ops;
+		charlcd->ops = &charlcd_ops;
+		hdc->write_data = lcd_write_data_p8;
+		hdc->write_cmd = lcd_write_cmd_p8;
 
 		if (lcd.pins.e == PIN_NOT_SET)
 			lcd.pins.e = DEFAULT_LCD_PIN_E;
@@ -1023,7 +971,9 @@ static void lcd_init(void)
 		if (lcd.pins.rw == PIN_NOT_SET)
 			lcd.pins.rw = DEFAULT_LCD_PIN_RW;
 	} else {
-		charlcd->ops = &charlcd_tilcd_ops;
+		charlcd->ops = &charlcd_ops;
+		hdc->write_data = lcd_write_data_tilcd;
+		hdc->write_cmd = lcd_write_cmd_tilcd;
 	}
 
 	if (lcd.pins.bl == PIN_NOT_SET)
@@ -1620,7 +1570,7 @@ static void panel_attach(struct parport *port)
 	if (lcd.enabled)
 		charlcd_unregister(lcd.charlcd);
 err_unreg_device:
-	charlcd_free(lcd.charlcd);
+	kfree(lcd.charlcd);
 	lcd.charlcd = NULL;
 	parport_unregister_device(pprt);
 	pprt = NULL;
@@ -1647,7 +1597,8 @@ static void panel_detach(struct parport *port)
 	if (lcd.enabled) {
 		charlcd_unregister(lcd.charlcd);
 		lcd.initialized = false;
-		charlcd_free(lcd.charlcd);
+		kfree(lcd.charlcd->drvdata);
+		kfree(lcd.charlcd);
 		lcd.charlcd = NULL;
 	}