[16/17] auxdisplay: ht16k33: Add support for segment displays
diff mbox series

Message ID 20210322144848.1065067-17-geert@linux-m68k.org
State New, archived
Headers show
Series
  • auxdisplay: ht16k33: Add character display support
Related show

Commit Message

Geert Uytterhoeven March 22, 2021, 2:48 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.
---
 drivers/auxdisplay/ht16k33.c | 198 +++++++++++++++++++++++++++++++++--
 1 file changed, 191 insertions(+), 7 deletions(-)

Comments

Robin van der Gracht March 29, 2021, 7:08 a.m. UTC | #1
Hello Geert,

On 2021-03-22 15:48, 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.
> ---
>  drivers/auxdisplay/ht16k33.c | 198 +++++++++++++++++++++++++++++++++--
>  1 file changed, 191 insertions(+), 7 deletions(-)
> 
...
> 
> +static int ht16k33_seg_probe(struct i2c_client *client,
> +			     struct ht16k33_priv *priv, uint32_t brightness)
> +{
> +	struct ht16k33_seg *seg = &priv->seg;
> +	struct device *dev = &client->dev;
> +	int err;
> +
> +	err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
> +	if (err)
> +		return err;
> +
> +	switch (priv->type) {
> +	case DISP_MATRIX:
> +		/* not handled here */
> +		break;

This 'case' shouldn't happen. Having said that, the break here will 
still
cause the linedisp_register() function to be called for the DISP_MATRIX 
type.
If you'd like to handle this case, a return (or setting 'err') should
prevent this.

> +
> +	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;

Groetjes/Kind regards,
Robin van der Gracht
Geert Uytterhoeven March 29, 2021, 7:15 a.m. UTC | #2
Hoi Robin,

On Mon, Mar 29, 2021 at 9:09 AM Robin van der Gracht <robin@protonic.nl> wrote:
> On 2021-03-22 15:48, 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.
> > ---
> >  drivers/auxdisplay/ht16k33.c | 198 +++++++++++++++++++++++++++++++++--
> >  1 file changed, 191 insertions(+), 7 deletions(-)
> >
> ...
> >
> > +static int ht16k33_seg_probe(struct i2c_client *client,
> > +                          struct ht16k33_priv *priv, uint32_t brightness)
> > +{
> > +     struct ht16k33_seg *seg = &priv->seg;
> > +     struct device *dev = &client->dev;
> > +     int err;
> > +
> > +     err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
> > +     if (err)
> > +             return err;
> > +
> > +     switch (priv->type) {
> > +     case DISP_MATRIX:
> > +             /* not handled here */
> > +             break;
>
> This 'case' shouldn't happen. Having said that, the break here will
> still
> cause the linedisp_register() function to be called for the DISP_MATRIX
> type.
> If you'd like to handle this case, a return (or setting 'err') should
> prevent this.

This function is never called if priv->type == DISP_MATRIX, so this
cannot happen.  However, gcc complains if not all enum values are
handled in a switch() statement, hence the dummy case.

Is there a better way to handle this?

> > +     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;

Gr{oetje,eeting}s,

                        Geert
Robin van der Gracht March 29, 2021, 7:30 a.m. UTC | #3
On 2021-03-29 09:15, Geert Uytterhoeven wrote:
> Hoi Robin,
> 
> On Mon, Mar 29, 2021 at 9:09 AM Robin van der Gracht 
> <robin@protonic.nl> wrote:
>> On 2021-03-22 15:48, 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.
>> > ---
>> >  drivers/auxdisplay/ht16k33.c | 198 +++++++++++++++++++++++++++++++++--
>> >  1 file changed, 191 insertions(+), 7 deletions(-)
>> >
>> ...
>> >
>> > +static int ht16k33_seg_probe(struct i2c_client *client,
>> > +                          struct ht16k33_priv *priv, uint32_t brightness)
>> > +{
>> > +     struct ht16k33_seg *seg = &priv->seg;
>> > +     struct device *dev = &client->dev;
>> > +     int err;
>> > +
>> > +     err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
>> > +     if (err)
>> > +             return err;
>> > +
>> > +     switch (priv->type) {
>> > +     case DISP_MATRIX:
>> > +             /* not handled here */
>> > +             break;
>> 
>> This 'case' shouldn't happen. Having said that, the break here will
>> still
>> cause the linedisp_register() function to be called for the 
>> DISP_MATRIX
>> type.
>> If you'd like to handle this case, a return (or setting 'err') should
>> prevent this.
> 
> This function is never called if priv->type == DISP_MATRIX, so this
> cannot happen.  However, gcc complains if not all enum values are
> handled in a switch() statement, hence the dummy case.

I see. But if it's there it should work right? :P

> Is there a better way to handle this?

How about adding the default case:

default:
     /* not handled */
     err = -EINVAL;

Groetjes/Kind regards,
Robin van der Gracht

Patch
diff mbox series

diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 11d86960fbc5d8c1..0b502a6039f89c6b 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>
@@ -17,9 +18,18 @@ 
 #include <linux/backlight.h>
 #include <linux/input.h>
 #include <linux/input/matrix_keypad.h>
+#include <linux/leds.h>
+#include <linux/of_device.h>
 #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 +57,12 @@ 
 #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 +83,25 @@  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 +131,33 @@  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 +382,51 @@  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)
 {
@@ -473,10 +575,57 @@  static int ht16k33_fbdev_probe(struct i2c_client *client,
 	return err;
 }
 
+static int ht16k33_seg_probe(struct i2c_client *client,
+			     struct ht16k33_priv *priv, uint32_t brightness)
+{
+	struct ht16k33_seg *seg = &priv->seg;
+	struct device *dev = &client->dev;
+	int err;
+
+	err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
+	if (err)
+		return err;
+
+	switch (priv->type) {
+	case DISP_MATRIX:
+		/* not handled here */
+		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;
 	struct device_node *node = dev->of_node;
+	const struct of_device_id *id;
 	struct ht16k33_priv *priv;
 	uint32_t dft_brightness;
 	int err;
@@ -491,6 +640,9 @@  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);
@@ -515,8 +667,19 @@  static int ht16k33_probe(struct i2c_client *client)
 			return err;
 	}
 
-	/* Frame Buffer Display */
-	return ht16k33_fbdev_probe(client, priv, dft_brightness);
+	switch (priv->type) {
+	case DISP_MATRIX:
+		/* Frame Buffer Display */
+		err = ht16k33_fbdev_probe(client, priv, dft_brightness);
+		break;
+
+	case DISP_QUAD_7SEG:
+	case DISP_QUAD_14SEG:
+		/* Segment Display */
+		err = ht16k33_seg_probe(client, priv, dft_brightness);
+		break;
+	}
+	return err;
 }
 
 static int ht16k33_remove(struct i2c_client *client)
@@ -525,9 +688,21 @@  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;
 }
@@ -539,7 +714,16 @@  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);