diff mbox series

[v6,17/19] auxdisplay: ht16k33: Add support for segment displays

Message ID 20210914143835.511051-18-geert@linux-m68k.org
State New
Headers show
Series auxdisplay: ht16k33: Add character display support | expand

Commit Message

Geert Uytterhoeven Sept. 14, 2021, 2:38 p.m. UTC
The Holtek HT16K33 LED controller is not only used for driving
dot-matrix displays, but also for driving segment displays.

Add support for 4-digit 7-segment and quad 14-segment alphanumeric
displays, like the Adafruit 7-segment and 14-segment display backpack
and FeatherWing expansion boards.  Use the character line display core
support to display a message, which will be scrolled if it doesn't fit.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
The 7-segment support is based on schematics, and untested on actual
hardware.

v6:
  - No changes,

v5:
  - No changes,

v4:
  - No changes,

v3:
  - Pass "dev" instead of "client" to ht16k33_seg_probe(),
  - Remove unneeded inclusion of <linux/leds.h> and <linux/of_device.h>,

v2:
  - Move "select LINEDISP" to this patch,
  - Set "err = -EINVAL" in switch() case that cannot happen.
---
 drivers/auxdisplay/Kconfig   |   1 +
 drivers/auxdisplay/ht16k33.c | 196 +++++++++++++++++++++++++++++++++--
 2 files changed, 190 insertions(+), 7 deletions(-)

Comments

Robin van der Gracht Sept. 30, 2021, 7:37 a.m. UTC | #1
Acked-by: Robin van der Gracht <robin@protonic.nl>


On 2021-09-14 16:38, Geert Uytterhoeven wrote:
> The Holtek HT16K33 LED controller is not only used for driving

> dot-matrix displays, but also for driving segment displays.

> 

> Add support for 4-digit 7-segment and quad 14-segment alphanumeric

> displays, like the Adafruit 7-segment and 14-segment display backpack

> and FeatherWing expansion boards.  Use the character line display core

> support to display a message, which will be scrolled if it doesn't fit.

> 

> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

> ---

> The 7-segment support is based on schematics, and untested on actual

> hardware.

> 

> v6:

>   - No changes,

> 

> v5:

>   - No changes,

> 

> v4:

>   - No changes,

> 

> v3:

>   - Pass "dev" instead of "client" to ht16k33_seg_probe(),

>   - Remove unneeded inclusion of <linux/leds.h> and <linux/of_device.h>,

> 

> v2:

>   - Move "select LINEDISP" to this patch,

>   - Set "err = -EINVAL" in switch() case that cannot happen.

> ---

>  drivers/auxdisplay/Kconfig   |   1 +

>  drivers/auxdisplay/ht16k33.c | 196 +++++++++++++++++++++++++++++++++--

>  2 files changed, 190 insertions(+), 7 deletions(-)

> 

> diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig

> index b41fdc5f7bf72a1b..42fc7b155de09dbc 100644

> --- a/drivers/auxdisplay/Kconfig

> +++ b/drivers/auxdisplay/Kconfig

> @@ -176,6 +176,7 @@ config HT16K33

>  	select FB_SYS_IMAGEBLIT

>  	select INPUT_MATRIXKMAP

>  	select FB_BACKLIGHT

> +	select LINEDISP

>  	help

>  	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8

>  	  LED controller driver with keyscan.

> diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c

> index 27ac167dae74bd82..3b555e119e326cec 100644

> --- a/drivers/auxdisplay/ht16k33.c

> +++ b/drivers/auxdisplay/ht16k33.c

> @@ -5,6 +5,7 @@

>   * Author: Robin van der Gracht <robin@protonic.nl>

>   *

>   * Copyright: (C) 2016 Protonic Holland.

> + * Copyright (C) 2021 Glider bv

>   */

> 

>  #include <linux/kernel.h>

> @@ -20,6 +21,13 @@

>  #include <linux/workqueue.h>

>  #include <linux/mm.h>

> 

> +#include <linux/map_to_7segment.h>

> +#include <linux/map_to_14segment.h>

> +

> +#include <asm/unaligned.h>

> +

> +#include "line-display.h"

> +

>  /* Registers */

>  #define REG_SYSTEM_SETUP		0x20

>  #define REG_SYSTEM_SETUP_OSC_ON		BIT(0)

> @@ -47,6 +55,12 @@

>  #define BYTES_PER_ROW		(HT16K33_MATRIX_LED_MAX_ROWS / 8)

>  #define HT16K33_FB_SIZE		(HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW)

> 

> +enum display_type {

> +	DISP_MATRIX = 0,

> +	DISP_QUAD_7SEG,

> +	DISP_QUAD_14SEG,

> +};

> +

>  struct ht16k33_keypad {

>  	struct i2c_client *client;

>  	struct input_dev *dev;

> @@ -67,11 +81,25 @@ struct ht16k33_fbdev {

>  	uint8_t *cache;

>  };

> 

> +struct ht16k33_seg {

> +	struct linedisp linedisp;

> +	union {

> +		struct seg7_conversion_map seg7;

> +		struct seg14_conversion_map seg14;

> +	} map;

> +	unsigned int map_size;

> +	char curr[4];

> +};

> +

>  struct ht16k33_priv {

>  	struct i2c_client *client;

>  	struct delayed_work work;

>  	struct ht16k33_keypad keypad;

> -	struct ht16k33_fbdev fbdev;

> +	union {

> +		struct ht16k33_fbdev fbdev;

> +		struct ht16k33_seg seg;

> +	};

> +	enum display_type type;

>  };

> 

>  static const struct fb_fix_screeninfo ht16k33_fb_fix = {

> @@ -101,6 +129,33 @@ static const struct fb_var_screeninfo ht16k33_fb_var = 

> {

>  	.vmode = FB_VMODE_NONINTERLACED,

>  };

> 

> +static const SEG7_DEFAULT_MAP(initial_map_seg7);

> +static const SEG14_DEFAULT_MAP(initial_map_seg14);

> +

> +static ssize_t map_seg_show(struct device *dev, struct device_attribute 

> *attr,

> +			    char *buf)

> +{

> +	struct ht16k33_priv *priv = dev_get_drvdata(dev);

> +

> +	memcpy(buf, &priv->seg.map, priv->seg.map_size);

> +	return priv->seg.map_size;

> +}

> +

> +static ssize_t map_seg_store(struct device *dev, struct device_attribute 

> *attr,

> +			     const char *buf, size_t cnt)

> +{

> +	struct ht16k33_priv *priv = dev_get_drvdata(dev);

> +

> +	if (cnt != priv->seg.map_size)

> +		return -EINVAL;

> +

> +	memcpy(&priv->seg.map, buf, cnt);

> +	return cnt;

> +}

> +

> +static DEVICE_ATTR(map_seg7, 0644, map_seg_show, map_seg_store);

> +static DEVICE_ATTR(map_seg14, 0644, map_seg_show, map_seg_store);

> +

>  static int ht16k33_display_on(struct ht16k33_priv *priv)

>  {

>  	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;

> @@ -325,6 +380,51 @@ static void ht16k33_keypad_stop(struct input_dev *dev)

>  	disable_irq(keypad->client->irq);

>  }

> 

> +static void ht16k33_linedisp_update(struct linedisp *linedisp)

> +{

> +	struct ht16k33_priv *priv = container_of(linedisp, struct ht16k33_priv,

> +						 seg.linedisp);

> +

> +	schedule_delayed_work(&priv->work, 0);

> +}

> +

> +static void ht16k33_seg7_update(struct work_struct *work)

> +{

> +	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,

> +						 work.work);

> +	struct ht16k33_seg *seg = &priv->seg;

> +	char *s = seg->curr;

> +	uint8_t buf[9];

> +

> +	buf[0] = map_to_seg7(&seg->map.seg7, *s++);

> +	buf[1] = 0;

> +	buf[2] = map_to_seg7(&seg->map.seg7, *s++);

> +	buf[3] = 0;

> +	buf[4] = 0;

> +	buf[5] = 0;

> +	buf[6] = map_to_seg7(&seg->map.seg7, *s++);

> +	buf[7] = 0;

> +	buf[8] = map_to_seg7(&seg->map.seg7, *s++);

> +

> +	i2c_smbus_write_i2c_block_data(priv->client, 0, ARRAY_SIZE(buf), buf);

> +}

> +

> +static void ht16k33_seg14_update(struct work_struct *work)

> +{

> +	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,

> +						 work.work);

> +	struct ht16k33_seg *seg = &priv->seg;

> +	char *s = seg->curr;

> +	uint8_t buf[8];

> +

> +	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf);

> +	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 2);

> +	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 4);

> +	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 6);

> +

> +	i2c_smbus_write_i2c_block_data(priv->client, 0, ARRAY_SIZE(buf), buf);

> +}

> +

>  static int ht16k33_keypad_probe(struct i2c_client *client,

>  				struct ht16k33_keypad *keypad)

>  {

> @@ -469,9 +569,56 @@ static int ht16k33_fbdev_probe(struct device *dev,

> struct ht16k33_priv *priv,

>  	return err;

>  }

> 

> +static int ht16k33_seg_probe(struct device *dev, struct ht16k33_priv *priv,

> +			     uint32_t brightness)

> +{

> +	struct ht16k33_seg *seg = &priv->seg;

> +	int err;

> +

> +	err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);

> +	if (err)

> +		return err;

> +

> +	switch (priv->type) {

> +	case DISP_MATRIX:

> +		/* not handled here */

> +		err = -EINVAL;

> +		break;

> +

> +	case DISP_QUAD_7SEG:

> +		INIT_DELAYED_WORK(&priv->work, ht16k33_seg7_update);

> +		seg->map.seg7 = initial_map_seg7;

> +		seg->map_size = sizeof(seg->map.seg7);

> +		err = device_create_file(dev, &dev_attr_map_seg7);

> +		break;

> +

> +	case DISP_QUAD_14SEG:

> +		INIT_DELAYED_WORK(&priv->work, ht16k33_seg14_update);

> +		seg->map.seg14 = initial_map_seg14;

> +		seg->map_size = sizeof(seg->map.seg14);

> +		err = device_create_file(dev, &dev_attr_map_seg14);

> +		break;

> +	}

> +	if (err)

> +		return err;

> +

> +	err = linedisp_register(&seg->linedisp, dev, 4, seg->curr,

> +				ht16k33_linedisp_update);

> +	if (err)

> +		goto err_remove_map_file;

> +

> +	return 0;

> +

> +err_remove_map_file:

> +	device_remove_file(dev, &dev_attr_map_seg7);

> +	device_remove_file(dev, &dev_attr_map_seg14);

> +	return err;

> +}

> +

>  static int ht16k33_probe(struct i2c_client *client)

>  {

>  	struct device *dev = &client->dev;

> +	const struct of_device_id *id;

>  	struct ht16k33_priv *priv;

>  	uint32_t dft_brightness;

>  	int err;

> @@ -486,6 +633,9 @@ static int ht16k33_probe(struct i2c_client *client)

>  		return -ENOMEM;

> 

>  	priv->client = client;

> +	id = i2c_of_match_device(dev->driver->of_match_table, client);

> +	if (id)

> +		priv->type = (uintptr_t)id->data;

>  	i2c_set_clientdata(client, priv);

> 

>  	err = ht16k33_initialize(priv);

> @@ -510,8 +660,19 @@ static int ht16k33_probe(struct i2c_client *client)

>  			return err;

>  	}

> 

> -	/* Frame Buffer Display */

> -	return ht16k33_fbdev_probe(dev, priv, dft_brightness);

> +	switch (priv->type) {

> +	case DISP_MATRIX:

> +		/* Frame Buffer Display */

> +		err = ht16k33_fbdev_probe(dev, priv, dft_brightness);

> +		break;

> +

> +	case DISP_QUAD_7SEG:

> +	case DISP_QUAD_14SEG:

> +		/* Segment Display */

> +		err = ht16k33_seg_probe(dev, priv, dft_brightness);

> +		break;

> +	}

> +	return err;

>  }

> 

>  static int ht16k33_remove(struct i2c_client *client)

> @@ -520,9 +681,21 @@ static int ht16k33_remove(struct i2c_client *client)

>  	struct ht16k33_fbdev *fbdev = &priv->fbdev;

> 

>  	cancel_delayed_work_sync(&priv->work);

> -	unregister_framebuffer(fbdev->info);

> -	framebuffer_release(fbdev->info);

> -	free_page((unsigned long) fbdev->buffer);

> +

> +	switch (priv->type) {

> +	case DISP_MATRIX:

> +		unregister_framebuffer(fbdev->info);

> +		framebuffer_release(fbdev->info);

> +		free_page((unsigned long)fbdev->buffer);

> +		break;

> +

> +	case DISP_QUAD_7SEG:

> +	case DISP_QUAD_14SEG:

> +		linedisp_unregister(&priv->seg.linedisp);

> +		device_remove_file(&client->dev, &dev_attr_map_seg7);

> +		device_remove_file(&client->dev, &dev_attr_map_seg14);

> +		break;

> +	}

> 

>  	return 0;

>  }

> @@ -534,7 +707,16 @@ static const struct i2c_device_id ht16k33_i2c_match[] = 

> {

>  MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);

> 

>  static const struct of_device_id ht16k33_of_match[] = {

> -	{ .compatible = "holtek,ht16k33", },

> +	{

> +		/* 0.56" 4-Digit 7-Segment FeatherWing Display (Red) */

> +		.compatible = "adafruit,3108", .data = (void *)DISP_QUAD_7SEG,

> +	}, {

> +		/* 0.54" Quad Alphanumeric FeatherWing Display (Red) */

> +		.compatible = "adafruit,3130", .data = (void *)DISP_QUAD_14SEG,

> +	}, {

> +		/* Generic, assumed Dot-Matrix Display */

> +		.compatible = "holtek,ht16k33", .data = (void *)DISP_MATRIX,

> +	},

>  	{ }

>  };

>  MODULE_DEVICE_TABLE(of, ht16k33_of_match);
diff mbox series

Patch

diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
index b41fdc5f7bf72a1b..42fc7b155de09dbc 100644
--- a/drivers/auxdisplay/Kconfig
+++ b/drivers/auxdisplay/Kconfig
@@ -176,6 +176,7 @@  config HT16K33
 	select FB_SYS_IMAGEBLIT
 	select INPUT_MATRIXKMAP
 	select FB_BACKLIGHT
+	select LINEDISP
 	help
 	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8
 	  LED controller driver with keyscan.
diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 27ac167dae74bd82..3b555e119e326cec 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -5,6 +5,7 @@ 
  * Author: Robin van der Gracht <robin@protonic.nl>
  *
  * Copyright: (C) 2016 Protonic Holland.
+ * Copyright (C) 2021 Glider bv
  */
 
 #include <linux/kernel.h>
@@ -20,6 +21,13 @@ 
 #include <linux/workqueue.h>
 #include <linux/mm.h>
 
+#include <linux/map_to_7segment.h>
+#include <linux/map_to_14segment.h>
+
+#include <asm/unaligned.h>
+
+#include "line-display.h"
+
 /* Registers */
 #define REG_SYSTEM_SETUP		0x20
 #define REG_SYSTEM_SETUP_OSC_ON		BIT(0)
@@ -47,6 +55,12 @@ 
 #define BYTES_PER_ROW		(HT16K33_MATRIX_LED_MAX_ROWS / 8)
 #define HT16K33_FB_SIZE		(HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW)
 
+enum display_type {
+	DISP_MATRIX = 0,
+	DISP_QUAD_7SEG,
+	DISP_QUAD_14SEG,
+};
+
 struct ht16k33_keypad {
 	struct i2c_client *client;
 	struct input_dev *dev;
@@ -67,11 +81,25 @@  struct ht16k33_fbdev {
 	uint8_t *cache;
 };
 
+struct ht16k33_seg {
+	struct linedisp linedisp;
+	union {
+		struct seg7_conversion_map seg7;
+		struct seg14_conversion_map seg14;
+	} map;
+	unsigned int map_size;
+	char curr[4];
+};
+
 struct ht16k33_priv {
 	struct i2c_client *client;
 	struct delayed_work work;
 	struct ht16k33_keypad keypad;
-	struct ht16k33_fbdev fbdev;
+	union {
+		struct ht16k33_fbdev fbdev;
+		struct ht16k33_seg seg;
+	};
+	enum display_type type;
 };
 
 static const struct fb_fix_screeninfo ht16k33_fb_fix = {
@@ -101,6 +129,33 @@  static const struct fb_var_screeninfo ht16k33_fb_var = {
 	.vmode = FB_VMODE_NONINTERLACED,
 };
 
+static const SEG7_DEFAULT_MAP(initial_map_seg7);
+static const SEG14_DEFAULT_MAP(initial_map_seg14);
+
+static ssize_t map_seg_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct ht16k33_priv *priv = dev_get_drvdata(dev);
+
+	memcpy(buf, &priv->seg.map, priv->seg.map_size);
+	return priv->seg.map_size;
+}
+
+static ssize_t map_seg_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t cnt)
+{
+	struct ht16k33_priv *priv = dev_get_drvdata(dev);
+
+	if (cnt != priv->seg.map_size)
+		return -EINVAL;
+
+	memcpy(&priv->seg.map, buf, cnt);
+	return cnt;
+}
+
+static DEVICE_ATTR(map_seg7, 0644, map_seg_show, map_seg_store);
+static DEVICE_ATTR(map_seg14, 0644, map_seg_show, map_seg_store);
+
 static int ht16k33_display_on(struct ht16k33_priv *priv)
 {
 	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;
@@ -325,6 +380,51 @@  static void ht16k33_keypad_stop(struct input_dev *dev)
 	disable_irq(keypad->client->irq);
 }
 
+static void ht16k33_linedisp_update(struct linedisp *linedisp)
+{
+	struct ht16k33_priv *priv = container_of(linedisp, struct ht16k33_priv,
+						 seg.linedisp);
+
+	schedule_delayed_work(&priv->work, 0);
+}
+
+static void ht16k33_seg7_update(struct work_struct *work)
+{
+	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,
+						 work.work);
+	struct ht16k33_seg *seg = &priv->seg;
+	char *s = seg->curr;
+	uint8_t buf[9];
+
+	buf[0] = map_to_seg7(&seg->map.seg7, *s++);
+	buf[1] = 0;
+	buf[2] = map_to_seg7(&seg->map.seg7, *s++);
+	buf[3] = 0;
+	buf[4] = 0;
+	buf[5] = 0;
+	buf[6] = map_to_seg7(&seg->map.seg7, *s++);
+	buf[7] = 0;
+	buf[8] = map_to_seg7(&seg->map.seg7, *s++);
+
+	i2c_smbus_write_i2c_block_data(priv->client, 0, ARRAY_SIZE(buf), buf);
+}
+
+static void ht16k33_seg14_update(struct work_struct *work)
+{
+	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,
+						 work.work);
+	struct ht16k33_seg *seg = &priv->seg;
+	char *s = seg->curr;
+	uint8_t buf[8];
+
+	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf);
+	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 2);
+	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 4);
+	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf + 6);
+
+	i2c_smbus_write_i2c_block_data(priv->client, 0, ARRAY_SIZE(buf), buf);
+}
+
 static int ht16k33_keypad_probe(struct i2c_client *client,
 				struct ht16k33_keypad *keypad)
 {
@@ -469,9 +569,56 @@  static int ht16k33_fbdev_probe(struct device *dev, struct ht16k33_priv *priv,
 	return err;
 }
 
+static int ht16k33_seg_probe(struct device *dev, struct ht16k33_priv *priv,
+			     uint32_t brightness)
+{
+	struct ht16k33_seg *seg = &priv->seg;
+	int err;
+
+	err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
+	if (err)
+		return err;
+
+	switch (priv->type) {
+	case DISP_MATRIX:
+		/* not handled here */
+		err = -EINVAL;
+		break;
+
+	case DISP_QUAD_7SEG:
+		INIT_DELAYED_WORK(&priv->work, ht16k33_seg7_update);
+		seg->map.seg7 = initial_map_seg7;
+		seg->map_size = sizeof(seg->map.seg7);
+		err = device_create_file(dev, &dev_attr_map_seg7);
+		break;
+
+	case DISP_QUAD_14SEG:
+		INIT_DELAYED_WORK(&priv->work, ht16k33_seg14_update);
+		seg->map.seg14 = initial_map_seg14;
+		seg->map_size = sizeof(seg->map.seg14);
+		err = device_create_file(dev, &dev_attr_map_seg14);
+		break;
+	}
+	if (err)
+		return err;
+
+	err = linedisp_register(&seg->linedisp, dev, 4, seg->curr,
+				ht16k33_linedisp_update);
+	if (err)
+		goto err_remove_map_file;
+
+	return 0;
+
+err_remove_map_file:
+	device_remove_file(dev, &dev_attr_map_seg7);
+	device_remove_file(dev, &dev_attr_map_seg14);
+	return err;
+}
+
 static int ht16k33_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
+	const struct of_device_id *id;
 	struct ht16k33_priv *priv;
 	uint32_t dft_brightness;
 	int err;
@@ -486,6 +633,9 @@  static int ht16k33_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	priv->client = client;
+	id = i2c_of_match_device(dev->driver->of_match_table, client);
+	if (id)
+		priv->type = (uintptr_t)id->data;
 	i2c_set_clientdata(client, priv);
 
 	err = ht16k33_initialize(priv);
@@ -510,8 +660,19 @@  static int ht16k33_probe(struct i2c_client *client)
 			return err;
 	}
 
-	/* Frame Buffer Display */
-	return ht16k33_fbdev_probe(dev, priv, dft_brightness);
+	switch (priv->type) {
+	case DISP_MATRIX:
+		/* Frame Buffer Display */
+		err = ht16k33_fbdev_probe(dev, priv, dft_brightness);
+		break;
+
+	case DISP_QUAD_7SEG:
+	case DISP_QUAD_14SEG:
+		/* Segment Display */
+		err = ht16k33_seg_probe(dev, priv, dft_brightness);
+		break;
+	}
+	return err;
 }
 
 static int ht16k33_remove(struct i2c_client *client)
@@ -520,9 +681,21 @@  static int ht16k33_remove(struct i2c_client *client)
 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
 
 	cancel_delayed_work_sync(&priv->work);
-	unregister_framebuffer(fbdev->info);
-	framebuffer_release(fbdev->info);
-	free_page((unsigned long) fbdev->buffer);
+
+	switch (priv->type) {
+	case DISP_MATRIX:
+		unregister_framebuffer(fbdev->info);
+		framebuffer_release(fbdev->info);
+		free_page((unsigned long)fbdev->buffer);
+		break;
+
+	case DISP_QUAD_7SEG:
+	case DISP_QUAD_14SEG:
+		linedisp_unregister(&priv->seg.linedisp);
+		device_remove_file(&client->dev, &dev_attr_map_seg7);
+		device_remove_file(&client->dev, &dev_attr_map_seg14);
+		break;
+	}
 
 	return 0;
 }
@@ -534,7 +707,16 @@  static const struct i2c_device_id ht16k33_i2c_match[] = {
 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
 
 static const struct of_device_id ht16k33_of_match[] = {
-	{ .compatible = "holtek,ht16k33", },
+	{
+		/* 0.56" 4-Digit 7-Segment FeatherWing Display (Red) */
+		.compatible = "adafruit,3108", .data = (void *)DISP_QUAD_7SEG,
+	}, {
+		/* 0.54" Quad Alphanumeric FeatherWing Display (Red) */
+		.compatible = "adafruit,3130", .data = (void *)DISP_QUAD_14SEG,
+	}, {
+		/* Generic, assumed Dot-Matrix Display */
+		.compatible = "holtek,ht16k33", .data = (void *)DISP_MATRIX,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ht16k33_of_match);