auxdisplay: ht16k33: Add support for segment displays

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>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
index b41fdc5..42fc7b1 100644 (file)
--- 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 8993d27..9ce9271 100644 (file)
--- 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;
@@ -335,6 +390,51 @@ 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)
 {
@@ -479,9 +579,56 @@ err_fbdev_buffer:
        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, 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;
@@ -496,6 +643,9 @@ 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);
@@ -520,8 +670,19 @@ 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)
@@ -530,9 +691,21 @@ 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;
 }
@@ -544,7 +717,16 @@ 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);