diff options
Diffstat (limited to 'drivers/auxdisplay/ht16k33.c')
| -rw-r--r-- | drivers/auxdisplay/ht16k33.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c new file mode 100644 index 000000000..03a87dd1f --- /dev/null +++ b/drivers/auxdisplay/ht16k33.c @@ -0,0 +1,554 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HT16K33 driver + * + * Author: Robin van der Gracht <robin@protonic.nl> + * + * Copyright: (C) 2016 Protonic Holland. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/i2c.h> +#include <linux/of.h> +#include <linux/fb.h> +#include <linux/slab.h> +#include <linux/backlight.h> +#include <linux/input.h> +#include <linux/input/matrix_keypad.h> +#include <linux/workqueue.h> +#include <linux/mm.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_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) + +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 delayed_work work; +}; + +struct ht16k33_priv { + struct i2c_client *client; + struct ht16k33_keypad keypad; + struct ht16k33_fbdev fbdev; +}; + +static 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 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; + + 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 void ht16k33_fb_queue(struct ht16k33_priv *priv) +{ + struct ht16k33_fbdev *fbdev = &priv->fbdev; + + schedule_delayed_work(&fbdev->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_fbdev *fbdev = + container_of(work, struct ht16k33_fbdev, work.work); + struct ht16k33_priv *priv = + container_of(fbdev, struct ht16k33_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 byte; + int err; + uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2]; + + /* 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) +{ + int brightness = bl->props.brightness; + struct ht16k33_priv *priv = bl_get_data(bl); + + if (bl->props.power != FB_BLANK_UNBLANK || + bl->props.fb_blank != FB_BLANK_UNBLANK || + bl->props.state & BL_CORE_FBBLANK || brightness == 0) { + return ht16k33_display_off(priv); + } + + ht16k33_display_on(priv); + return i2c_smbus_write_byte(priv->client, + REG_BRIGHTNESS | (brightness - 1)); +} + +static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi) +{ + struct ht16k33_priv *priv = bl_get_data(bl); + + return (fi == NULL) || (fi->par == priv); +} + +static const struct backlight_ops ht16k33_bl_ops = { + .update_status = ht16k33_bl_update_status, + .check_fb = ht16k33_bl_check_fb, +}; + +/* + * 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; + + return vm_insert_page(vma, vma->vm_start, + virt_to_page(priv->fbdev.buffer)); +} + +static struct fb_ops ht16k33_fb_ops = { + .owner = THIS_MODULE, + .fb_read = fb_sys_read, + .fb_write = fb_sys_write, + .fb_blank = ht16k33_blank, + .fb_fillrect = sys_fillrect, + .fb_copyarea = sys_copyarea, + .fb_imageblit = sys_imageblit, + .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 int ht16k33_keypad_probe(struct i2c_client *client, + struct ht16k33_keypad *keypad) +{ + struct device_node *node = client->dev.of_node; + 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(&client->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 (!of_get_property(node, "linux,no-autorepeat", NULL)) + __set_bit(EV_REP, keypad->dev->evbit); + + err = of_property_read_u32(node, "debounce-delay-ms", + &keypad->debounce_ms); + if (err) { + dev_err(&client->dev, "key debounce delay not specified\n"); + return err; + } + + err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols); + if (err) + return err; + if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS || + cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) { + dev_err(&client->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(&client->dev, "failed to build keymap\n"); + return err; + } + + err = devm_request_threaded_irq(&client->dev, client->irq, + NULL, ht16k33_keypad_irq_thread, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT, + DRIVER_NAME, keypad); + if (err) { + dev_err(&client->dev, "irq request failed %d, error %d\n", + client->irq, err); + return err; + } + + ht16k33_keypad_stop(keypad->dev); + + err = input_register_device(keypad->dev); + if (err) + return err; + + return 0; +} + +static int ht16k33_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int err; + uint32_t dft_brightness; + struct backlight_device *bl; + struct backlight_properties bl_props; + struct ht16k33_priv *priv; + struct ht16k33_fbdev *fbdev; + struct device_node *node = client->dev.of_node; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_err(&client->dev, "i2c_check_functionality error\n"); + return -EIO; + } + + if (client->irq <= 0) { + dev_err(&client->dev, "No IRQ specified\n"); + return -EINVAL; + } + + priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->client = client; + i2c_set_clientdata(client, priv); + fbdev = &priv->fbdev; + + err = ht16k33_initialize(priv); + if (err) + return err; + + /* Backlight */ + memset(&bl_props, 0, sizeof(struct backlight_properties)); + bl_props.type = BACKLIGHT_RAW; + bl_props.max_brightness = MAX_BRIGHTNESS; + + bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl", + &client->dev, priv, + &ht16k33_bl_ops, &bl_props); + if (IS_ERR(bl)) { + dev_err(&client->dev, "failed to register backlight\n"); + return PTR_ERR(bl); + } + + err = of_property_read_u32(node, "default-brightness-level", + &dft_brightness); + if (err) { + dft_brightness = MAX_BRIGHTNESS; + } else if (dft_brightness > MAX_BRIGHTNESS) { + dev_warn(&client->dev, + "invalid default brightness level: %u, using %u\n", + dft_brightness, MAX_BRIGHTNESS); + dft_brightness = MAX_BRIGHTNESS; + } + + bl->props.brightness = dft_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(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL); + if (!fbdev->cache) { + err = -ENOMEM; + goto err_fbdev_buffer; + } + + fbdev->info = framebuffer_alloc(0, &client->dev); + if (!fbdev->info) { + err = -ENOMEM; + goto err_fbdev_buffer; + } + + err = of_property_read_u32(node, "refresh-rate-hz", + &fbdev->refresh_rate); + if (err) { + dev_err(&client->dev, "refresh rate not specified\n"); + goto err_fbdev_info; + } + fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS); + + INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update); + fbdev->info->fbops = &ht16k33_fb_ops; + fbdev->info->screen_base = (char __iomem *) 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->flags = FBINFO_FLAG_DEFAULT; + fbdev->info->par = priv; + + err = register_framebuffer(fbdev->info); + if (err) + goto err_fbdev_info; + + err = ht16k33_keypad_probe(client, &priv->keypad); + if (err) + goto err_fbdev_unregister; + + ht16k33_fb_queue(priv); + return 0; + +err_fbdev_unregister: + unregister_framebuffer(fbdev->info); +err_fbdev_info: + framebuffer_release(fbdev->info); +err_fbdev_buffer: + free_page((unsigned long) fbdev->buffer); + + return err; +} + +static int ht16k33_remove(struct i2c_client *client) +{ + struct ht16k33_priv *priv = i2c_get_clientdata(client); + struct ht16k33_fbdev *fbdev = &priv->fbdev; + + cancel_delayed_work_sync(&fbdev->work); + unregister_framebuffer(fbdev->info); + framebuffer_release(fbdev->info); + free_page((unsigned long) fbdev->buffer); + + return 0; +} + +static const struct i2c_device_id ht16k33_i2c_match[] = { + { "ht16k33", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match); + +static const struct of_device_id ht16k33_of_match[] = { + { .compatible = "holtek,ht16k33", }, + { } +}; +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 = of_match_ptr(ht16k33_of_match), + }, + .id_table = ht16k33_i2c_match, +}; +module_i2c_driver(ht16k33_driver); + +MODULE_DESCRIPTION("Holtek HT16K33 driver"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>"); |