auxdisplay: ht16k33: Driver for LED controller

Holtek ht16k33 RAM mapping 16*8 LED controller driver with keyscan

-------------------------------------------------------------------------------

Required properties:

- compatible:		"holtek,ht16k33"

- reg:			I2C slave address of the chip.

- interrupt-parent:	A phandle pointing to the interrupt controller

			serving the interrupt for this chip.

- interrupts:		Interrupt specification for the key pressed interrupt.

- refresh-rate-hz:	Display update interval in HZ.

- debounce-delay-ms:	Debouncing interval time in milliseconds.

- linux,keymap: 	The keymap for keys as described in the binding

			document (devicetree/bindings/input/matrix-keymap.txt).

Optional properties:

- linux,no-autorepeat:	Disable keyrepeat.

- default-brightness-level: Initial brightness level [0-15] (default: 15).

Example:

&i2c1 {

	ht16k33: ht16k33@70 {

		compatible = "holtek,ht16k33";

		reg = <0x70>;

		refresh-rate-hz = <20>;

		debounce-delay-ms = <50>;

		interrupt-parent = <&gpio4>;

		interrupts = <5 (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_EDGE_RISING)>;

		linux,keymap = <

			MATRIX_KEY(2, 0, KEY_F6)

			MATRIX_KEY(3, 0, KEY_F8)

			MATRIX_KEY(4, 0, KEY_F10)

			MATRIX_KEY(5, 0, KEY_F4)

			MATRIX_KEY(6, 0, KEY_F2)

			MATRIX_KEY(2, 1, KEY_F5)

			MATRIX_KEY(3, 1, KEY_F7)

			MATRIX_KEY(4, 1, KEY_F9)

			MATRIX_KEY(5, 1, KEY_F3)

			MATRIX_KEY(6, 1, KEY_F1)

		>;

	};

};

	  development boards such as the MIPS Boston, MIPS Malta & MIPS SEAD3

	  from Imagination Technologies.

config HT16K33

	tristate "Holtek Ht16K33 LED controller with keyscan"

	depends on FB && OF && I2C && INPUT

	select INPUT_MATRIXKMAP

	select FB_BACKLIGHT

	help

	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8

	  LED controller driver with keyscan.

endif # AUXDISPLAY

obj-$(CONFIG_KS0108)		+= ks0108.o

obj-$(CONFIG_CFAG12864B)	+= cfag12864b.o cfag12864bfb.o

obj-$(CONFIG_IMG_ASCII_LCD)	+= img-ascii-lcd.o

obj-$(CONFIG_HT16K33)		+= ht16k33.o

/*

 * 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 input_dev *dev;

	spinlock_t lock;

	struct delayed_work work;

	uint32_t cols;

	uint32_t rows;

	uint32_t row_shift;

	uint32_t debounce_ms;

	uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];

};

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;

	struct workqueue_struct *workqueue;

};

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;

	queue_delayed_work(priv->workqueue, &fbdev->work,

		msecs_to_jiffies(HZ / fbdev->refresh_rate));

}

static void ht16k33_keypad_queue(struct ht16k33_priv *priv)

{

	struct ht16k33_keypad *keypad = &priv->keypad;

	queue_delayed_work(priv->workqueue, &keypad->work,

		msecs_to_jiffies(keypad->debounce_ms));

}

/*

 * 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_keypad_start(struct input_dev *dev)

{

	struct ht16k33_priv *priv = input_get_drvdata(dev);

	struct ht16k33_keypad *keypad = &priv->keypad;

	/*

	 * Schedule an immediate key scan to capture current key state;

	 * columns will be activated and IRQs be enabled after the scan.

	 */

	queue_delayed_work(priv->workqueue, &keypad->work, 0);

	return 0;

}

static void ht16k33_keypad_stop(struct input_dev *dev)

{

	struct ht16k33_priv *priv = input_get_drvdata(dev);

	struct ht16k33_keypad *keypad = &priv->keypad;

	cancel_delayed_work(&keypad->work);

	/*

	 * ht16k33_keypad_scan() will leave IRQs enabled;

	 * we should disable them now.

	 */

	disable_irq_nosync(priv->client->irq);

}

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);

}

/*

 * This gets the keys from keypad and reports it to input subsystem

 */

static void ht16k33_keypad_scan(struct work_struct *work)

{

	struct ht16k33_keypad *keypad =

		container_of(work, struct ht16k33_keypad, work.work);

	struct ht16k33_priv *priv =

		container_of(keypad, struct ht16k33_priv, keypad);

	const unsigned short *keycodes = keypad->dev->keycode;

	uint16_t bits_changed, new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];

	uint8_t data[HT16K33_MATRIX_KEYPAD_MAX_COLS * 2];

	int row, col, code;

	bool reschedule = false;

	if (i2c_smbus_read_i2c_block_data(priv->client, 0x40, 6, data) != 6) {

		dev_err(&priv->client->dev, "Failed to read key data\n");

		goto end;

	}

	for (col = 0; col < keypad->cols; col++) {

		new_state[col] = (data[col * 2 + 1] << 8) | data[col * 2];

		if (new_state[col])

			reschedule = true;

		bits_changed = keypad->last_key_state[col] ^ new_state[col];

		while (bits_changed) {

			row = ffs(bits_changed) - 1;

			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));

			bits_changed &= ~BIT(row);

		}

	}

	input_sync(keypad->dev);

	memcpy(keypad->last_key_state, new_state, sizeof(new_state));

end:

	if (reschedule)

		ht16k33_keypad_queue(priv);

	else

		enable_irq(priv->client->irq);

}

static irqreturn_t ht16k33_irq_thread(int irq, void *dev)

{

	struct ht16k33_priv *priv = dev;

	disable_irq_nosync(priv->client->irq);

	ht16k33_keypad_queue(priv);

	return IRQ_HANDLED;

}

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,

};

static int ht16k33_probe(struct i2c_client *client,

				  const struct i2c_device_id *id)

{

	int err;

	uint32_t rows, cols, dft_brightness;

	struct backlight_device *bl;

	struct backlight_properties bl_props;

	struct ht16k33_priv *priv;

	struct ht16k33_keypad *keypad;

	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;

	keypad = &priv->keypad;

	priv->workqueue = create_singlethread_workqueue(DRIVER_NAME "-wq");

	if (priv->workqueue == NULL)

		return -ENOMEM;

	err = ht16k33_initialize(priv);

	if (err)

		goto err_destroy_wq;

	/* 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) {

		err = -ENOMEM;

		goto err_free_fbdev;

	}

	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;

	/* Keypad */

	keypad->dev = devm_input_allocate_device(&client->dev);

	if (!keypad->dev) {

		err = -ENOMEM;

		goto err_fbdev_unregister;

	}

	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");

		goto err_fbdev_unregister;

	}

	err = devm_request_threaded_irq(&client->dev, client->irq, NULL,

					ht16k33_irq_thread,

					IRQF_TRIGGER_RISING | IRQF_ONESHOT,

					DRIVER_NAME, priv);

	if (err) {

		dev_err(&client->dev, "irq request failed %d, error %d\n",

			client->irq, err);

		goto err_fbdev_unregister;

	}

	disable_irq_nosync(client->irq);

	rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;

	cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;

	err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);

	if (err)

		goto err_fbdev_unregister;

	err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,

					 keypad->dev);

	if (err) {

		dev_err(&client->dev, "failed to build keymap\n");

		goto err_fbdev_unregister;

	}

	input_set_drvdata(keypad->dev, priv);

	keypad->rows = rows;

	keypad->cols = cols;

	keypad->row_shift = get_count_order(cols);

	INIT_DELAYED_WORK(&keypad->work, ht16k33_keypad_scan);

	err = input_register_device(keypad->dev);

	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_keypad_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_keypad_unregister:

	input_unregister_device(keypad->dev);

err_fbdev_unregister:

	unregister_framebuffer(fbdev->info);

err_fbdev_info:

	framebuffer_release(fbdev->info);

err_fbdev_buffer:

	free_page((unsigned long) fbdev->buffer);

err_free_fbdev:

	kfree(fbdev);

err_destroy_wq:

	destroy_workqueue(priv->workqueue);

	return err;

}

static int ht16k33_remove(struct i2c_client *client)

{

	struct ht16k33_priv *priv = i2c_get_clientdata(client);

	struct ht16k33_keypad *keypad = &priv->keypad;

	struct ht16k33_fbdev *fbdev = &priv->fbdev;

	ht16k33_keypad_stop(keypad->dev);

	cancel_delayed_work(&fbdev->work);

	unregister_framebuffer(fbdev->info);

	framebuffer_release(fbdev->info);

	free_page((unsigned long) fbdev->buffer);

	destroy_workqueue(priv->workqueue);

	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>");