root/drivers/auxdisplay/ht16k33.c
// SPDX-License-Identifier: GPL-2.0
/*
 * HT16K33 driver
 *
 * Author: Robin van der Gracht <robin@protonic.nl>
 *
 * Copyright: (C) 2016 Protonic Holland.
 * Copyright (C) 2021 Glider bv
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/property.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/container_of.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/leds.h>
#include <linux/workqueue.h>
#include <linux/mm.h>

#include <linux/map_to_7segment.h>
#include <linux/map_to_14segment.h>

#include <linux/unaligned.h>

#include "line-display.h"

/* Registers */
#define REG_SYSTEM_SETUP                0x20
#define REG_SYSTEM_SETUP_OSC_ON         BIT(0)

#define REG_DISPLAY_SETUP               0x80
#define REG_DISPLAY_SETUP_ON            BIT(0)
#define REG_DISPLAY_SETUP_BLINK_OFF     (0 << 1)
#define REG_DISPLAY_SETUP_BLINK_2HZ     (1 << 1)
#define REG_DISPLAY_SETUP_BLINK_1HZ     (2 << 1)
#define REG_DISPLAY_SETUP_BLINK_0HZ5    (3 << 1)

#define REG_ROWINT_SET                  0xA0
#define REG_ROWINT_SET_INT_EN           BIT(0)
#define REG_ROWINT_SET_INT_ACT_HIGH     BIT(1)

#define REG_BRIGHTNESS                  0xE0

/* Defines */
#define DRIVER_NAME                     "ht16k33"

#define MIN_BRIGHTNESS                  0x1
#define MAX_BRIGHTNESS                  0x10

#define HT16K33_MATRIX_LED_MAX_COLS     8
#define HT16K33_MATRIX_LED_MAX_ROWS     16
#define HT16K33_MATRIX_KEYPAD_MAX_COLS  3
#define HT16K33_MATRIX_KEYPAD_MAX_ROWS  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;
        uint32_t cols;
        uint32_t rows;
        uint32_t row_shift;
        uint32_t debounce_ms;
        uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];

        wait_queue_head_t wait;
        bool stopped;
};

struct ht16k33_fbdev {
        struct fb_info *info;
        uint32_t refresh_rate;
        uint8_t *buffer;
        uint8_t *cache;
};

struct ht16k33_priv {
        struct i2c_client *client;
        struct delayed_work work;
        struct led_classdev led;
        struct ht16k33_keypad keypad;
        union {
                struct ht16k33_fbdev fbdev;
                struct linedisp linedisp;
        };
        enum display_type type;
        uint8_t blink;
};

#define ht16k33_work_to_priv(p)                         \
        container_of(p, struct ht16k33_priv, work.work)

#define ht16k33_led_to_priv(p)                          \
        container_of(p, struct ht16k33_priv, led)

#define ht16k33_linedisp_to_priv(p)                     \
        container_of(p, struct ht16k33_priv, linedisp)

static const struct fb_fix_screeninfo ht16k33_fb_fix = {
        .id             = DRIVER_NAME,
        .type           = FB_TYPE_PACKED_PIXELS,
        .visual         = FB_VISUAL_MONO10,
        .xpanstep       = 0,
        .ypanstep       = 0,
        .ywrapstep      = 0,
        .line_length    = HT16K33_MATRIX_LED_MAX_ROWS,
        .accel          = FB_ACCEL_NONE,
};

static const struct fb_var_screeninfo ht16k33_fb_var = {
        .xres = HT16K33_MATRIX_LED_MAX_ROWS,
        .yres = HT16K33_MATRIX_LED_MAX_COLS,
        .xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS,
        .yres_virtual = HT16K33_MATRIX_LED_MAX_COLS,
        .bits_per_pixel = 1,
        .red = { 0, 1, 0 },
        .green = { 0, 1, 0 },
        .blue = { 0, 1, 0 },
        .left_margin = 0,
        .right_margin = 0,
        .upper_margin = 0,
        .lower_margin = 0,
        .vmode = FB_VMODE_NONINTERLACED,
};

static int ht16k33_display_on(struct ht16k33_priv *priv)
{
        uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON | priv->blink;

        return i2c_smbus_write_byte(priv->client, data);
}

static int ht16k33_display_off(struct ht16k33_priv *priv)
{
        return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
}

static int ht16k33_brightness_set(struct ht16k33_priv *priv,
                                  unsigned int brightness)
{
        int err;

        if (brightness == 0) {
                priv->blink = REG_DISPLAY_SETUP_BLINK_OFF;
                return ht16k33_display_off(priv);
        }

        err = ht16k33_display_on(priv);
        if (err)
                return err;

        return i2c_smbus_write_byte(priv->client,
                                    REG_BRIGHTNESS | (brightness - 1));
}

static int ht16k33_brightness_set_blocking(struct led_classdev *led_cdev,
                                           enum led_brightness brightness)
{
        struct ht16k33_priv *priv = ht16k33_led_to_priv(led_cdev);

        return ht16k33_brightness_set(priv, brightness);
}

static int ht16k33_blink_set(struct led_classdev *led_cdev,
                             unsigned long *delay_on, unsigned long *delay_off)
{
        struct ht16k33_priv *priv = ht16k33_led_to_priv(led_cdev);
        unsigned int delay;
        uint8_t blink;
        int err;

        if (!*delay_on && !*delay_off) {
                blink = REG_DISPLAY_SETUP_BLINK_1HZ;
                delay = 1000;
        } else if (*delay_on <= 750) {
                blink = REG_DISPLAY_SETUP_BLINK_2HZ;
                delay = 500;
        } else if (*delay_on <= 1500) {
                blink = REG_DISPLAY_SETUP_BLINK_1HZ;
                delay = 1000;
        } else {
                blink = REG_DISPLAY_SETUP_BLINK_0HZ5;
                delay = 2000;
        }

        err = i2c_smbus_write_byte(priv->client,
                                   REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON |
                                   blink);
        if (err)
                return err;

        priv->blink = blink;
        *delay_on = *delay_off = delay;
        return 0;
}

static void ht16k33_fb_queue(struct ht16k33_priv *priv)
{
        struct ht16k33_fbdev *fbdev = &priv->fbdev;

        schedule_delayed_work(&priv->work, HZ / fbdev->refresh_rate);
}

/*
 * This gets the fb data from cache and copies it to ht16k33 display RAM
 */
static void ht16k33_fb_update(struct work_struct *work)
{
        struct ht16k33_priv *priv = ht16k33_work_to_priv(work);
        struct ht16k33_fbdev *fbdev = &priv->fbdev;

        uint8_t *p1, *p2;
        int len, pos = 0, first = -1;

        p1 = fbdev->cache;
        p2 = fbdev->buffer;

        /* Search for the first byte with changes */
        while (pos < HT16K33_FB_SIZE && first < 0) {
                if (*(p1++) - *(p2++))
                        first = pos;
                pos++;
        }

        /* No changes found */
        if (first < 0)
                goto requeue;

        len = HT16K33_FB_SIZE - first;
        p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
        p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;

        /* Determine i2c transfer length */
        while (len > 1) {
                if (*(p1--) - *(p2--))
                        break;
                len--;
        }

        p1 = fbdev->cache + first;
        p2 = fbdev->buffer + first;
        if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
                memcpy(p1, p2, len);
requeue:
        ht16k33_fb_queue(priv);
}

static int ht16k33_initialize(struct ht16k33_priv *priv)
{
        uint8_t data[HT16K33_FB_SIZE];
        uint8_t byte;
        int err;

        /* Clear RAM (8 * 16 bits) */
        memset(data, 0, sizeof(data));
        err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
        if (err)
                return err;

        /* Turn on internal oscillator */
        byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
        err = i2c_smbus_write_byte(priv->client, byte);
        if (err)
                return err;

        /* Configure INT pin */
        byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
        if (priv->client->irq > 0)
                byte |= REG_ROWINT_SET_INT_EN;
        return i2c_smbus_write_byte(priv->client, byte);
}

static int ht16k33_bl_update_status(struct backlight_device *bl)
{
        const int brightness = backlight_get_brightness(bl);
        struct ht16k33_priv *priv = bl_get_data(bl);

        return ht16k33_brightness_set(priv, brightness);
}

static const struct backlight_ops ht16k33_bl_ops = {
        .update_status  = ht16k33_bl_update_status,
};

/*
 * Blank events will be passed to the actual device handling the backlight when
 * we return zero here.
 */
static int ht16k33_blank(int blank, struct fb_info *info)
{
        return 0;
}

static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
        struct ht16k33_priv *priv = info->par;
        struct page *pages = virt_to_page(priv->fbdev.buffer);

        vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);

        return vm_map_pages_zero(vma, &pages, 1);
}

static const struct fb_ops ht16k33_fb_ops = {
        .owner = THIS_MODULE,
        __FB_DEFAULT_SYSMEM_OPS_RDWR,
        .fb_blank = ht16k33_blank,
        __FB_DEFAULT_SYSMEM_OPS_DRAW,
        .fb_mmap = ht16k33_mmap,
};

/*
 * This gets the keys from keypad and reports it to input subsystem.
 * Returns true if a key is pressed.
 */
static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
{
        const unsigned short *keycodes = keypad->dev->keycode;
        u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
        __le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
        unsigned long bits_changed;
        int row, col, code;
        int rc;
        bool pressed = false;

        rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
                                           sizeof(data), (u8 *)data);
        if (rc != sizeof(data)) {
                dev_err(&keypad->client->dev,
                        "Failed to read key data, rc=%d\n", rc);
                return false;
        }

        for (col = 0; col < keypad->cols; col++) {
                new_state[col] = le16_to_cpu(data[col]);
                if (new_state[col])
                        pressed = true;
                bits_changed = keypad->last_key_state[col] ^ new_state[col];

                for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
                        code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
                        input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
                        input_report_key(keypad->dev, keycodes[code],
                                         new_state[col] & BIT(row));
                }
        }
        input_sync(keypad->dev);
        memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);

        return pressed;
}

static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
{
        struct ht16k33_keypad *keypad = dev;

        do {
                wait_event_timeout(keypad->wait, keypad->stopped,
                                    msecs_to_jiffies(keypad->debounce_ms));
                if (keypad->stopped)
                        break;
        } while (ht16k33_keypad_scan(keypad));

        return IRQ_HANDLED;
}

static int ht16k33_keypad_start(struct input_dev *dev)
{
        struct ht16k33_keypad *keypad = input_get_drvdata(dev);

        keypad->stopped = false;
        mb();
        enable_irq(keypad->client->irq);

        return 0;
}

static void ht16k33_keypad_stop(struct input_dev *dev)
{
        struct ht16k33_keypad *keypad = input_get_drvdata(dev);

        keypad->stopped = true;
        mb();
        wake_up(&keypad->wait);
        disable_irq(keypad->client->irq);
}

static void ht16k33_seg7_update(struct work_struct *work)
{
        struct ht16k33_priv *priv = ht16k33_work_to_priv(work);
        struct linedisp_map *map = priv->linedisp.map;
        char *s = priv->linedisp.buf;
        uint8_t buf[9];

        buf[0] = map_to_seg7(&map->map.seg7, *s++);
        buf[1] = 0;
        buf[2] = map_to_seg7(&map->map.seg7, *s++);
        buf[3] = 0;
        buf[4] = 0;
        buf[5] = 0;
        buf[6] = map_to_seg7(&map->map.seg7, *s++);
        buf[7] = 0;
        buf[8] = map_to_seg7(&map->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 = ht16k33_work_to_priv(work);
        struct linedisp_map *map = priv->linedisp.map;
        char *s = priv->linedisp.buf;
        uint8_t buf[8];

        put_unaligned_le16(map_to_seg14(&map->map.seg14, *s++), buf + 0);
        put_unaligned_le16(map_to_seg14(&map->map.seg14, *s++), buf + 2);
        put_unaligned_le16(map_to_seg14(&map->map.seg14, *s++), buf + 4);
        put_unaligned_le16(map_to_seg14(&map->map.seg14, *s++), buf + 6);

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

static int ht16k33_linedisp_get_map_type(struct linedisp *linedisp)
{
        struct ht16k33_priv *priv = ht16k33_linedisp_to_priv(linedisp);

        switch (priv->type) {
        case DISP_QUAD_7SEG:
                INIT_DELAYED_WORK(&priv->work, ht16k33_seg7_update);
                return LINEDISP_MAP_SEG7;

        case DISP_QUAD_14SEG:
                INIT_DELAYED_WORK(&priv->work, ht16k33_seg14_update);
                return LINEDISP_MAP_SEG14;

        default:
                return -EINVAL;
        }
}

static void ht16k33_linedisp_update(struct linedisp *linedisp)
{
        struct ht16k33_priv *priv = ht16k33_linedisp_to_priv(linedisp);

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

static const struct linedisp_ops ht16k33_linedisp_ops = {
        .get_map_type = ht16k33_linedisp_get_map_type,
        .update = ht16k33_linedisp_update,
};

static int ht16k33_led_probe(struct device *dev, struct led_classdev *led,
                             unsigned int brightness)
{
        struct led_init_data init_data = {};
        int err;

        /* The LED is optional */
        init_data.fwnode = device_get_named_child_node(dev, "led");
        if (!init_data.fwnode)
                return 0;

        init_data.devicename = "auxdisplay";
        init_data.devname_mandatory = true;

        led->brightness_set_blocking = ht16k33_brightness_set_blocking;
        led->blink_set = ht16k33_blink_set;
        led->flags = LED_CORE_SUSPENDRESUME;
        led->brightness = brightness;
        led->max_brightness = MAX_BRIGHTNESS;

        err = devm_led_classdev_register_ext(dev, led, &init_data);
        fwnode_handle_put(init_data.fwnode);
        if (err)
                dev_err(dev, "Failed to register LED\n");

        return err;
}

static int ht16k33_keypad_probe(struct i2c_client *client,
                                struct ht16k33_keypad *keypad)
{
        struct device *dev = &client->dev;
        u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
        u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
        int err;

        keypad->client = client;
        init_waitqueue_head(&keypad->wait);

        keypad->dev = devm_input_allocate_device(dev);
        if (!keypad->dev)
                return -ENOMEM;

        input_set_drvdata(keypad->dev, keypad);

        keypad->dev->name = DRIVER_NAME"-keypad";
        keypad->dev->id.bustype = BUS_I2C;
        keypad->dev->open = ht16k33_keypad_start;
        keypad->dev->close = ht16k33_keypad_stop;

        if (!device_property_read_bool(dev, "linux,no-autorepeat"))
                __set_bit(EV_REP, keypad->dev->evbit);

        err = device_property_read_u32(dev, "debounce-delay-ms",
                                       &keypad->debounce_ms);
        if (err) {
                dev_err(dev, "key debounce delay not specified\n");
                return err;
        }

        err = matrix_keypad_parse_properties(dev, &rows, &cols);
        if (err)
                return err;
        if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
            cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
                dev_err(dev, "%u rows or %u cols out of range in DT\n", rows,
                        cols);
                return -ERANGE;
        }

        keypad->rows = rows;
        keypad->cols = cols;
        keypad->row_shift = get_count_order(cols);

        err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
                                         keypad->dev);
        if (err) {
                dev_err(dev, "failed to build keymap\n");
                return err;
        }

        err = devm_request_threaded_irq(dev, client->irq, NULL,
                                        ht16k33_keypad_irq_thread,
                                        IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
                                        DRIVER_NAME, keypad);
        if (err) {
                dev_err(dev, "irq request failed %d, error %d\n", client->irq,
                        err);
                return err;
        }

        ht16k33_keypad_stop(keypad->dev);

        return input_register_device(keypad->dev);
}

static int ht16k33_fbdev_probe(struct device *dev, struct ht16k33_priv *priv,
                               uint32_t brightness)
{
        struct ht16k33_fbdev *fbdev = &priv->fbdev;
        struct backlight_device *bl = NULL;
        int err;

        if (priv->led.dev) {
                err = ht16k33_brightness_set(priv, brightness);
                if (err)
                        return err;
        } else {
                /* backwards compatibility with DT lacking an led subnode */
                struct backlight_properties bl_props;

                memset(&bl_props, 0, sizeof(struct backlight_properties));
                bl_props.type = BACKLIGHT_RAW;
                bl_props.max_brightness = MAX_BRIGHTNESS;

                bl = devm_backlight_device_register(dev, DRIVER_NAME"-bl", dev,
                                                    priv, &ht16k33_bl_ops,
                                                    &bl_props);
                if (IS_ERR(bl)) {
                        dev_err(dev, "failed to register backlight\n");
                        return PTR_ERR(bl);
                }

                bl->props.brightness = brightness;
                ht16k33_bl_update_status(bl);
        }

        /* Framebuffer (2 bytes per column) */
        BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
        fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
        if (!fbdev->buffer)
                return -ENOMEM;

        fbdev->cache = devm_kmalloc(dev, HT16K33_FB_SIZE, GFP_KERNEL);
        if (!fbdev->cache) {
                err = -ENOMEM;
                goto err_fbdev_buffer;
        }

        fbdev->info = framebuffer_alloc(0, dev);
        if (!fbdev->info) {
                err = -ENOMEM;
                goto err_fbdev_buffer;
        }

        err = device_property_read_u32(dev, "refresh-rate-hz",
                                       &fbdev->refresh_rate);
        if (err) {
                dev_err(dev, "refresh rate not specified\n");
                goto err_fbdev_info;
        }
        fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);

        INIT_DELAYED_WORK(&priv->work, ht16k33_fb_update);
        fbdev->info->fbops = &ht16k33_fb_ops;
        fbdev->info->flags |= FBINFO_VIRTFB;
        fbdev->info->screen_buffer = fbdev->buffer;
        fbdev->info->screen_size = HT16K33_FB_SIZE;
        fbdev->info->fix = ht16k33_fb_fix;
        fbdev->info->var = ht16k33_fb_var;
        fbdev->info->bl_dev = bl;
        fbdev->info->pseudo_palette = NULL;
        fbdev->info->par = priv;

        err = register_framebuffer(fbdev->info);
        if (err)
                goto err_fbdev_info;

        ht16k33_fb_queue(priv);
        return 0;

err_fbdev_info:
        framebuffer_release(fbdev->info);
err_fbdev_buffer:
        free_page((unsigned long) fbdev->buffer);

        return err;
}

static int ht16k33_seg_probe(struct device *dev, struct ht16k33_priv *priv,
                             uint32_t brightness)
{
        struct linedisp *linedisp = &priv->linedisp;
        int err;

        err = ht16k33_brightness_set(priv, brightness);
        if (err)
                return err;

        return linedisp_register(linedisp, dev, 4, &ht16k33_linedisp_ops);
}

static int ht16k33_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct ht16k33_priv *priv;
        uint32_t dft_brightness;
        int err;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_err(dev, "i2c_check_functionality error\n");
                return -EIO;
        }

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->client = client;
        priv->type = (uintptr_t)i2c_get_match_data(client);

        i2c_set_clientdata(client, priv);

        err = ht16k33_initialize(priv);
        if (err)
                return err;

        err = device_property_read_u32(dev, "default-brightness-level",
                                       &dft_brightness);
        if (err) {
                dft_brightness = MAX_BRIGHTNESS;
        } else if (dft_brightness > MAX_BRIGHTNESS) {
                dev_warn(dev,
                         "invalid default brightness level: %u, using %u\n",
                         dft_brightness, MAX_BRIGHTNESS);
                dft_brightness = MAX_BRIGHTNESS;
        }

        /* LED */
        err = ht16k33_led_probe(dev, &priv->led, dft_brightness);
        if (err)
                return err;

        /* Keypad */
        if (client->irq > 0) {
                err = ht16k33_keypad_probe(client, &priv->keypad);
                if (err)
                        return err;
        }

        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;

        default:
                return -EINVAL;
        }
        return err;
}

static void ht16k33_remove(struct i2c_client *client)
{
        struct ht16k33_priv *priv = i2c_get_clientdata(client);
        struct ht16k33_fbdev *fbdev = &priv->fbdev;

        cancel_delayed_work_sync(&priv->work);

        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->linedisp);
                break;

        default:
                break;
        }
}

static const struct i2c_device_id ht16k33_i2c_match[] = {
        { "3108", DISP_QUAD_7SEG },
        { "3130", DISP_QUAD_14SEG },
        { "ht16k33", DISP_MATRIX },
        { }
};
MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);

static const struct of_device_id ht16k33_of_match[] = {
        {
                /* 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);

static struct i2c_driver ht16k33_driver = {
        .probe          = ht16k33_probe,
        .remove         = ht16k33_remove,
        .driver         = {
                .name           = DRIVER_NAME,
                .of_match_table = ht16k33_of_match,
        },
        .id_table = ht16k33_i2c_match,
};
module_i2c_driver(ht16k33_driver);

MODULE_DESCRIPTION("Holtek HT16K33 driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("LINEDISP");
MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");