[mirror_ubuntu-artful-kernel.git] / drivers / auxdisplay / ht16k33.c

/*
 * HT16K33 driver
 *
 * Author: Robin van der Gracht <robin@protonic.nl>
 *
 * Copyright: (C) 2016 Protonic Holland.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#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,
			      msecs_to_jiffies(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,
};

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_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;

	/* 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->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;

	/* 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");
		err = PTR_ERR(bl);
		goto err_fbdev_unregister;
	}

	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);

	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(&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>");
Commit	Line	Data
8992da44 RG	1	/*
	2	* HT16K33 driver
	3	*
	4	* Author: Robin van der Gracht <robin@protonic.nl>
	5	*
	6	* Copyright: (C) 2016 Protonic Holland.
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* General Public License for more details.
	16	*/
	17
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/i2c.h>
	22	#include <linux/of.h>
	23	#include <linux/fb.h>
	24	#include <linux/slab.h>
	25	#include <linux/backlight.h>
	26	#include <linux/input.h>
	27	#include <linux/input/matrix_keypad.h>
	28	#include <linux/workqueue.h>
	29	#include <linux/mm.h>
	30
	31	/* Registers */
	32	#define REG_SYSTEM_SETUP 0x20
	33	#define REG_SYSTEM_SETUP_OSC_ON BIT(0)
	34
	35	#define REG_DISPLAY_SETUP 0x80
	36	#define REG_DISPLAY_SETUP_ON BIT(0)
	37
	38	#define REG_ROWINT_SET 0xA0
	39	#define REG_ROWINT_SET_INT_EN BIT(0)
	40	#define REG_ROWINT_SET_INT_ACT_HIGH BIT(1)
	41
	42	#define REG_BRIGHTNESS 0xE0
	43
	44	/* Defines */
	45	#define DRIVER_NAME "ht16k33"
	46
	47	#define MIN_BRIGHTNESS 0x1
	48	#define MAX_BRIGHTNESS 0x10
	49
	50	#define HT16K33_MATRIX_LED_MAX_COLS 8
	51	#define HT16K33_MATRIX_LED_MAX_ROWS 16
	52	#define HT16K33_MATRIX_KEYPAD_MAX_COLS 3
	53	#define HT16K33_MATRIX_KEYPAD_MAX_ROWS 12
	54
	55	#define BYTES_PER_ROW (HT16K33_MATRIX_LED_MAX_ROWS / 8)
	56	#define HT16K33_FB_SIZE (HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW)
	57
	58	struct ht16k33_keypad {
cac513f1	59	struct i2c_client *client;
8992da44	60	struct input_dev *dev;
8992da44 RG	61	uint32_t cols;
	62	uint32_t rows;
	63	uint32_t row_shift;
	64	uint32_t debounce_ms;
	65	uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
cac513f1 DT	66
	67	wait_queue_head_t wait;
	68	bool stopped;
8992da44 RG	69	};
	70
	71	struct ht16k33_fbdev {
	72	struct fb_info *info;
	73	uint32_t refresh_rate;
	74	uint8_t *buffer;
	75	uint8_t *cache;
	76	struct delayed_work work;
	77	};
	78
	79	struct ht16k33_priv {
	80	struct i2c_client *client;
	81	struct ht16k33_keypad keypad;
	82	struct ht16k33_fbdev fbdev;
8992da44 RG	83	};
	84
	85	static struct fb_fix_screeninfo ht16k33_fb_fix = {
	86	.id = DRIVER_NAME,
	87	.type = FB_TYPE_PACKED_PIXELS,
	88	.visual = FB_VISUAL_MONO10,
	89	.xpanstep = 0,
	90	.ypanstep = 0,
	91	.ywrapstep = 0,
	92	.line_length = HT16K33_MATRIX_LED_MAX_ROWS,
	93	.accel = FB_ACCEL_NONE,
	94	};
	95
	96	static struct fb_var_screeninfo ht16k33_fb_var = {
	97	.xres = HT16K33_MATRIX_LED_MAX_ROWS,
	98	.yres = HT16K33_MATRIX_LED_MAX_COLS,
	99	.xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS,
	100	.yres_virtual = HT16K33_MATRIX_LED_MAX_COLS,
	101	.bits_per_pixel = 1,
	102	.red = { 0, 1, 0 },
	103	.green = { 0, 1, 0 },
	104	.blue = { 0, 1, 0 },
	105	.left_margin = 0,
	106	.right_margin = 0,
	107	.upper_margin = 0,
	108	.lower_margin = 0,
	109	.vmode = FB_VMODE_NONINTERLACED,
	110	};
	111
	112	static int ht16k33_display_on(struct ht16k33_priv *priv)
	113	{
	114	uint8_t data = REG_DISPLAY_SETUP \| REG_DISPLAY_SETUP_ON;
	115
	116	return i2c_smbus_write_byte(priv->client, data);
	117	}
	118
	119	static int ht16k33_display_off(struct ht16k33_priv *priv)
	120	{
	121	return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
	122	}
	123
	124	static void ht16k33_fb_queue(struct ht16k33_priv *priv)
	125	{
	126	struct ht16k33_fbdev *fbdev = &priv->fbdev;
	127
8fa8bea7 DT	128	schedule_delayed_work(&fbdev->work,
8fa8bea7 DT	129	msecs_to_jiffies(HZ / fbdev->refresh_rate));
8992da44 RG	130	}
8992da44 RG	131
8992da44 RG	132	/*
	133	* This gets the fb data from cache and copies it to ht16k33 display RAM
	134	*/
	135	static void ht16k33_fb_update(struct work_struct *work)
	136	{
	137	struct ht16k33_fbdev *fbdev =
	138	container_of(work, struct ht16k33_fbdev, work.work);
	139	struct ht16k33_priv *priv =
	140	container_of(fbdev, struct ht16k33_priv, fbdev);
	141
	142	uint8_t p1, p2;
	143	int len, pos = 0, first = -1;
	144
	145	p1 = fbdev->cache;
	146	p2 = fbdev->buffer;
	147
	148	/* Search for the first byte with changes */
	149	while (pos < HT16K33_FB_SIZE && first < 0) {
	150	if ((p1++) - (p2++))
	151	first = pos;
	152	pos++;
	153	}
	154
	155	/* No changes found */
	156	if (first < 0)
	157	goto requeue;
	158
	159	len = HT16K33_FB_SIZE - first;
	160	p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
	161	p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;
	162
	163	/* Determine i2c transfer length */
	164	while (len > 1) {
	165	if ((p1--) - (p2--))
	166	break;
	167	len--;
	168	}
	169
	170	p1 = fbdev->cache + first;
	171	p2 = fbdev->buffer + first;
	172	if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
	173	memcpy(p1, p2, len);
	174	requeue:
	175	ht16k33_fb_queue(priv);
	176	}
	177
8992da44 RG	178	static int ht16k33_initialize(struct ht16k33_priv *priv)
	179	{
	180	uint8_t byte;
	181	int err;
	182	uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];
	183
	184	/* Clear RAM (8 * 16 bits) */
	185	memset(data, 0, sizeof(data));
	186	err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
	187	if (err)
	188	return err;
	189
	190	/* Turn on internal oscillator */
	191	byte = REG_SYSTEM_SETUP_OSC_ON \| REG_SYSTEM_SETUP;
	192	err = i2c_smbus_write_byte(priv->client, byte);
	193	if (err)
	194	return err;
	195
	196	/* Configure INT pin */
	197	byte = REG_ROWINT_SET \| REG_ROWINT_SET_INT_ACT_HIGH;
	198	if (priv->client->irq > 0)
	199	byte \|= REG_ROWINT_SET_INT_EN;
	200	return i2c_smbus_write_byte(priv->client, byte);
	201	}
	202
8992da44 RG	203	static int ht16k33_bl_update_status(struct backlight_device *bl)
	204	{
	205	int brightness = bl->props.brightness;
	206	struct ht16k33_priv *priv = bl_get_data(bl);
	207
	208	if (bl->props.power != FB_BLANK_UNBLANK \|\|
	209	bl->props.fb_blank != FB_BLANK_UNBLANK \|\|
	210	bl->props.state & BL_CORE_FBBLANK \|\| brightness == 0) {
	211	return ht16k33_display_off(priv);
	212	}
	213
	214	ht16k33_display_on(priv);
	215	return i2c_smbus_write_byte(priv->client,
	216	REG_BRIGHTNESS \| (brightness - 1));
	217	}
	218
	219	static int ht16k33_bl_check_fb(struct backlight_device bl, struct fb_info fi)
	220	{
	221	struct ht16k33_priv *priv = bl_get_data(bl);
	222
	223	return (fi == NULL) \|\| (fi->par == priv);
	224	}
	225
	226	static const struct backlight_ops ht16k33_bl_ops = {
	227	.update_status = ht16k33_bl_update_status,
	228	.check_fb = ht16k33_bl_check_fb,
	229	};
	230
	231	static int ht16k33_mmap(struct fb_info info, struct vm_area_struct vma)
	232	{
	233	struct ht16k33_priv *priv = info->par;
	234
	235	return vm_insert_page(vma, vma->vm_start,
	236	virt_to_page(priv->fbdev.buffer));
	237	}
	238
	239	static struct fb_ops ht16k33_fb_ops = {
	240	.owner = THIS_MODULE,
	241	.fb_read = fb_sys_read,
	242	.fb_write = fb_sys_write,
	243	.fb_fillrect = sys_fillrect,
	244	.fb_copyarea = sys_copyarea,
	245	.fb_imageblit = sys_imageblit,
	246	.fb_mmap = ht16k33_mmap,
	247	};
	248
cac513f1 DT	249	/*
	250	* This gets the keys from keypad and reports it to input subsystem.
	251	* Returns true if a key is pressed.
	252	*/
	253	static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
	254	{
	255	const unsigned short *keycodes = keypad->dev->keycode;
	256	u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
6ef0c333	257	__le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
cac513f1 DT	258	unsigned long bits_changed;
cac513f1 DT	259	int row, col, code;
6ef0c333	260	int rc;
cac513f1 DT	261	bool pressed = false;
cac513f1 DT	262
6ef0c333 DT	263	rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
	264	sizeof(data), (u8 *)data);
	265	if (rc != sizeof(data)) {
	266	dev_err(&keypad->client->dev,
	267	"Failed to read key data, rc=%d\n", rc);
cac513f1 DT	268	return false;
	269	}
	270
	271	for (col = 0; col < keypad->cols; col++) {
6ef0c333	272	new_state[col] = le16_to_cpu(data[col]);
cac513f1 DT	273	if (new_state[col])
	274	pressed = true;
	275	bits_changed = keypad->last_key_state[col] ^ new_state[col];
	276
	277	for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
	278	code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
	279	input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
	280	input_report_key(keypad->dev, keycodes[code],
	281	new_state[col] & BIT(row));
	282	}
	283	}
	284	input_sync(keypad->dev);
e1f990c2	285	memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
cac513f1 DT	286
	287	return pressed;
	288	}
	289
	290	static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
	291	{
	292	struct ht16k33_keypad *keypad = dev;
	293
	294	do {
	295	wait_event_timeout(keypad->wait, keypad->stopped,
	296	msecs_to_jiffies(keypad->debounce_ms));
	297	if (keypad->stopped)
	298	break;
	299	} while (ht16k33_keypad_scan(keypad));
	300
	301	return IRQ_HANDLED;
	302	}
	303
	304	static int ht16k33_keypad_start(struct input_dev *dev)
	305	{
	306	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
	307
	308	keypad->stopped = false;
	309	mb();
	310	enable_irq(keypad->client->irq);
	311
	312	return 0;
	313	}
	314
	315	static void ht16k33_keypad_stop(struct input_dev *dev)
	316	{
	317	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
	318
	319	keypad->stopped = true;
	320	mb();
	321	wake_up(&keypad->wait);
	322	disable_irq(keypad->client->irq);
	323	}
	324
	325	static int ht16k33_keypad_probe(struct i2c_client *client,
	326	struct ht16k33_keypad *keypad)
	327	{
	328	struct device_node *node = client->dev.of_node;
	329	u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
	330	u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
	331	int err;
	332
	333	keypad->client = client;
	334	init_waitqueue_head(&keypad->wait);
	335
	336	keypad->dev = devm_input_allocate_device(&client->dev);
	337	if (!keypad->dev)
	338	return -ENOMEM;
	339
	340	input_set_drvdata(keypad->dev, keypad);
	341
	342	keypad->dev->name = DRIVER_NAME"-keypad";
	343	keypad->dev->id.bustype = BUS_I2C;
	344	keypad->dev->open = ht16k33_keypad_start;
	345	keypad->dev->close = ht16k33_keypad_stop;
	346
	347	if (!of_get_property(node, "linux,no-autorepeat", NULL))
	348	__set_bit(EV_REP, keypad->dev->evbit);
	349
350	err = of_property_read_u32(node, "debounce-delay-ms",
351	&keypad->debounce_ms);
352	if (err) {
353	dev_err(&client->dev, "key debounce delay not specified\n");
354	return err;
355	}
356
357	err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
358	if (err)
359	return err;
e1f990c2 AB	360	if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS \|\|
	361	cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
	362	dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
	363	rows, cols);
	364	return -ERANGE;
	365	}
cac513f1 DT	366
	367	keypad->rows = rows;
	368	keypad->cols = cols;
	369	keypad->row_shift = get_count_order(cols);
	370
	371	err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
	372	keypad->dev);
	373	if (err) {
	374	dev_err(&client->dev, "failed to build keymap\n");
	375	return err;
	376	}
	377
	378	err = devm_request_threaded_irq(&client->dev, client->irq,
	379	NULL, ht16k33_keypad_irq_thread,
	380	IRQF_TRIGGER_HIGH \| IRQF_ONESHOT,
	381	DRIVER_NAME, keypad);
	382	if (err) {
	383	dev_err(&client->dev, "irq request failed %d, error %d\n",
	384	client->irq, err);
	385	return err;
	386	}
	387
	388	ht16k33_keypad_stop(keypad->dev);
	389
	390	err = input_register_device(keypad->dev);
	391	if (err)
	392	return err;
	393
	394	return 0;
	395	}
	396
8992da44 RG	397	static int ht16k33_probe(struct i2c_client *client,
	398	const struct i2c_device_id *id)
	399	{
	400	int err;
cac513f1	401	uint32_t dft_brightness;
8992da44 RG	402	struct backlight_device *bl;
	403	struct backlight_properties bl_props;
	404	struct ht16k33_priv *priv;
8992da44 RG	405	struct ht16k33_fbdev *fbdev;
	406	struct device_node *node = client->dev.of_node;
	407
	408	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	409	dev_err(&client->dev, "i2c_check_functionality error\n");
	410	return -EIO;
	411	}
	412
	413	if (client->irq <= 0) {
	414	dev_err(&client->dev, "No IRQ specified\n");
	415	return -EINVAL;
	416	}
	417
	418	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
	419	if (!priv)
	420	return -ENOMEM;
	421
	422	priv->client = client;
	423	i2c_set_clientdata(client, priv);
	424	fbdev = &priv->fbdev;
8992da44	425
8992da44 RG	426	err = ht16k33_initialize(priv);
8992da44 RG	427	if (err)
8fa8bea7	428	return err;
8992da44 RG	429
	430	/* Framebuffer (2 bytes per column) */
	431	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
	432	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
8fa8bea7 DT	433	if (!fbdev->buffer)
8fa8bea7 DT	434	return -ENOMEM;
8992da44 RG	435
	436	fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
	437	if (!fbdev->cache) {
	438	err = -ENOMEM;
	439	goto err_fbdev_buffer;
	440	}
	441
	442	fbdev->info = framebuffer_alloc(0, &client->dev);
	443	if (!fbdev->info) {
	444	err = -ENOMEM;
	445	goto err_fbdev_buffer;
	446	}
	447
	448	err = of_property_read_u32(node, "refresh-rate-hz",
	449	&fbdev->refresh_rate);
	450	if (err) {
	451	dev_err(&client->dev, "refresh rate not specified\n");
	452	goto err_fbdev_info;
	453	}
	454	fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
	455
	456	INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
	457	fbdev->info->fbops = &ht16k33_fb_ops;
	458	fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
	459	fbdev->info->screen_size = HT16K33_FB_SIZE;
	460	fbdev->info->fix = ht16k33_fb_fix;
	461	fbdev->info->var = ht16k33_fb_var;
	462	fbdev->info->pseudo_palette = NULL;
	463	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
	464	fbdev->info->par = priv;
	465
	466	err = register_framebuffer(fbdev->info);
	467	if (err)
	468	goto err_fbdev_info;
	469
cac513f1	470	err = ht16k33_keypad_probe(client, &priv->keypad);
8992da44 RG	471	if (err)
	472	goto err_fbdev_unregister;
	473
	474	/* Backlight */
	475	memset(&bl_props, 0, sizeof(struct backlight_properties));
	476	bl_props.type = BACKLIGHT_RAW;
	477	bl_props.max_brightness = MAX_BRIGHTNESS;
	478
	479	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
	480	&client->dev, priv,
	481	&ht16k33_bl_ops, &bl_props);
	482	if (IS_ERR(bl)) {
	483	dev_err(&client->dev, "failed to register backlight\n");
	484	err = PTR_ERR(bl);
cac513f1	485	goto err_fbdev_unregister;
8992da44 RG	486	}
	487
	488	err = of_property_read_u32(node, "default-brightness-level",
	489	&dft_brightness);
	490	if (err) {
	491	dft_brightness = MAX_BRIGHTNESS;
	492	} else if (dft_brightness > MAX_BRIGHTNESS) {
	493	dev_warn(&client->dev,
	494	"invalid default brightness level: %u, using %u\n",
	495	dft_brightness, MAX_BRIGHTNESS);
	496	dft_brightness = MAX_BRIGHTNESS;
	497	}
	498
	499	bl->props.brightness = dft_brightness;
	500	ht16k33_bl_update_status(bl);
	501
	502	ht16k33_fb_queue(priv);
	503	return 0;
	504
8992da44 RG	505	err_fbdev_unregister:
	506	unregister_framebuffer(fbdev->info);
	507	err_fbdev_info:
	508	framebuffer_release(fbdev->info);
	509	err_fbdev_buffer:
	510	free_page((unsigned long) fbdev->buffer);
8992da44 RG	511
	512	return err;
	513	}
	514
	515	static int ht16k33_remove(struct i2c_client *client)
	516	{
	517	struct ht16k33_priv *priv = i2c_get_clientdata(client);
8992da44 RG	518	struct ht16k33_fbdev *fbdev = &priv->fbdev;
8992da44 RG	519
8992da44 RG	520	cancel_delayed_work(&fbdev->work);
	521	unregister_framebuffer(fbdev->info);
	522	framebuffer_release(fbdev->info);
	523	free_page((unsigned long) fbdev->buffer);
	524
8992da44 RG	525	return 0;
	526	}
	527
	528	static const struct i2c_device_id ht16k33_i2c_match[] = {
	529	{ "ht16k33", 0 },
	530	{ }
	531	};
	532	MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
	533
	534	static const struct of_device_id ht16k33_of_match[] = {
	535	{ .compatible = "holtek,ht16k33", },
	536	{ }
	537	};
	538	MODULE_DEVICE_TABLE(of, ht16k33_of_match);
	539
	540	static struct i2c_driver ht16k33_driver = {
	541	.probe = ht16k33_probe,
	542	.remove = ht16k33_remove,
	543	.driver = {
	544	.name = DRIVER_NAME,
	545	.of_match_table = of_match_ptr(ht16k33_of_match),
	546	},
	547	.id_table = ht16k33_i2c_match,
	548	};
	549	module_i2c_driver(ht16k33_driver);
	550
	551	MODULE_DESCRIPTION("Holtek HT16K33 driver");
	552	MODULE_LICENSE("GPL");
	553	MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");