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LP55231: The lamp cannot be lighten

Part Number: LP55231
Other Parts Discussed in Thread: LP5562

Hi Sir,

We encountered a problem with the LP55231 application. According to the Linux driver provided by TI website, the waveform was captured at the Brightness node, but the default voltage of the low level was up to 2V, so the lamp couldn't be lit. Our lamp is 3.3V connected to the positive pole, which needs the output channel of driver IC connected to the negative pole.

The waveform of brightness node as follows:

The driver code can be refer to below document:

/*
 * LP5562 LED driver
 *
 * Copyright (C) 2013 Texas Instruments
 *
 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
 *
 * 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.
 */

#include <linux/delay.h>
#include <linux/firmware.h>
#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_data/leds-lp55xx.h>
#include <linux/slab.h>

#include "leds-lp55xx-common.h"

#define LP5562_PROGRAM_LENGTH		32
#define LP5562_MAX_LEDS			4

/* ENABLE Register 00h */
#define LP5562_REG_ENABLE		0x00
#define LP5562_EXEC_ENG1_M		0x30
#define LP5562_EXEC_ENG2_M		0x0C
#define LP5562_EXEC_ENG3_M		0x03
#define LP5562_EXEC_M			0x3F
#define LP5562_MASTER_ENABLE		0x40	/* Chip master enable */
#define LP5562_LOGARITHMIC_PWM		0x80	/* Logarithmic PWM adjustment */
#define LP5562_EXEC_RUN			0x2A
#define LP5562_ENABLE_DEFAULT	\
	(LP5562_MASTER_ENABLE | LP5562_LOGARITHMIC_PWM)
#define LP5562_ENABLE_RUN_PROGRAM	\
	(LP5562_ENABLE_DEFAULT | LP5562_EXEC_RUN)

/* OPMODE Register 01h */
#define LP5562_REG_OP_MODE		0x01
#define LP5562_MODE_ENG1_M		0x30
#define LP5562_MODE_ENG2_M		0x0C
#define LP5562_MODE_ENG3_M		0x03
#define LP5562_LOAD_ENG1		0x10
#define LP5562_LOAD_ENG2		0x04
#define LP5562_LOAD_ENG3		0x01
#define LP5562_RUN_ENG1			0x20
#define LP5562_RUN_ENG2			0x08
#define LP5562_RUN_ENG3			0x02
#define LP5562_ENG1_IS_LOADING(mode)	\
	((mode & LP5562_MODE_ENG1_M) == LP5562_LOAD_ENG1)
#define LP5562_ENG2_IS_LOADING(mode)	\
	((mode & LP5562_MODE_ENG2_M) == LP5562_LOAD_ENG2)
#define LP5562_ENG3_IS_LOADING(mode)	\
	((mode & LP5562_MODE_ENG3_M) == LP5562_LOAD_ENG3)

/* BRIGHTNESS Registers */
#define LP5562_REG_R_PWM		0x04
#define LP5562_REG_G_PWM		0x03
#define LP5562_REG_B_PWM		0x02
#define LP5562_REG_W_PWM		0x0E

/* CURRENT Registers */
#define LP5562_REG_R_CURRENT		0x07
#define LP5562_REG_G_CURRENT		0x06
#define LP5562_REG_B_CURRENT		0x05
#define LP5562_REG_W_CURRENT		0x0F

/* CONFIG Register 08h */
#define LP5562_REG_CONFIG		0x08
#define LP5562_PWM_HF			0x40
#define LP5562_PWRSAVE_EN		0x20
#define LP5562_CLK_INT			0x01	/* Internal clock */
#define LP5562_DEFAULT_CFG		(LP5562_PWM_HF | LP5562_PWRSAVE_EN)

/* RESET Register 0Dh */
#define LP5562_REG_RESET		0x0D
#define LP5562_RESET			0xFF

/* PROGRAM ENGINE Registers */
#define LP5562_REG_PROG_MEM_ENG1	0x10
#define LP5562_REG_PROG_MEM_ENG2	0x30
#define LP5562_REG_PROG_MEM_ENG3	0x50

/* LEDMAP Register 70h */
#define LP5562_REG_ENG_SEL		0x70
#define LP5562_ENG_SEL_PWM		0
#define LP5562_ENG_FOR_RGB_M		0x3F
#define LP5562_ENG_SEL_RGB		0x1B	/* R:ENG1, G:ENG2, B:ENG3 */
#define LP5562_ENG_FOR_W_M		0xC0
#define LP5562_ENG1_FOR_W		0x40	/* W:ENG1 */
#define LP5562_ENG2_FOR_W		0x80	/* W:ENG2 */
#define LP5562_ENG3_FOR_W		0xC0	/* W:ENG3 */

/* Program Commands */
#define LP5562_CMD_DISABLE		0x00
#define LP5562_CMD_LOAD			0x15
#define LP5562_CMD_RUN			0x2A
#define LP5562_CMD_DIRECT		0x3F
#define LP5562_PATTERN_OFF		0

static inline void lp5562_wait_opmode_done(void)
{
	/* operation mode change needs to be longer than 153 us */
	usleep_range(200, 300);
}

static inline void lp5562_wait_enable_done(void)
{
	/* it takes more 488 us to update ENABLE register */
	usleep_range(500, 600);
}

static void lp5562_set_led_current(struct lp55xx_led *led, u8 led_current)
{
	u8 addr[] = {
		LP5562_REG_R_CURRENT,
		LP5562_REG_G_CURRENT,
		LP5562_REG_B_CURRENT,
		LP5562_REG_W_CURRENT,
	};

	led->led_current = led_current;
	lp55xx_write(led->chip, addr[led->chan_nr], led_current);
}

static void lp5562_load_engine(struct lp55xx_chip *chip)
{
	enum lp55xx_engine_index idx = chip->engine_idx;
	u8 mask[] = {
		[LP55XX_ENGINE_1] = LP5562_MODE_ENG1_M,
		[LP55XX_ENGINE_2] = LP5562_MODE_ENG2_M,
		[LP55XX_ENGINE_3] = LP5562_MODE_ENG3_M,
	};

	u8 val[] = {
		[LP55XX_ENGINE_1] = LP5562_LOAD_ENG1,
		[LP55XX_ENGINE_2] = LP5562_LOAD_ENG2,
		[LP55XX_ENGINE_3] = LP5562_LOAD_ENG3,
	};

	lp55xx_update_bits(chip, LP5562_REG_OP_MODE, mask[idx], val[idx]);

	lp5562_wait_opmode_done();
}

static void lp5562_stop_engine(struct lp55xx_chip *chip)
{
	lp55xx_write(chip, LP5562_REG_OP_MODE, LP5562_CMD_DISABLE);
	lp5562_wait_opmode_done();
}

static void lp5562_run_engine(struct lp55xx_chip *chip, bool start)
{
	int ret;
	u8 mode;
	u8 exec;

	/* stop engine */
	if (!start) {
		lp55xx_write(chip, LP5562_REG_ENABLE, LP5562_ENABLE_DEFAULT);
		lp5562_wait_enable_done();
		lp5562_stop_engine(chip);
		lp55xx_write(chip, LP5562_REG_ENG_SEL, LP5562_ENG_SEL_PWM);
		lp55xx_write(chip, LP5562_REG_OP_MODE, LP5562_CMD_DIRECT);
		lp5562_wait_opmode_done();
		return;
	}

	/*
	 * To run the engine,
	 * operation mode and enable register should updated at the same time
	 */

	ret = lp55xx_read(chip, LP5562_REG_OP_MODE, &mode);
	if (ret)
		return;

	ret = lp55xx_read(chip, LP5562_REG_ENABLE, &exec);
	if (ret)
		return;

	/* change operation mode to RUN only when each engine is loading */
	if (LP5562_ENG1_IS_LOADING(mode)) {
		mode = (mode & ~LP5562_MODE_ENG1_M) | LP5562_RUN_ENG1;
		exec = (exec & ~LP5562_EXEC_ENG1_M) | LP5562_RUN_ENG1;
	}

	if (LP5562_ENG2_IS_LOADING(mode)) {
		mode = (mode & ~LP5562_MODE_ENG2_M) | LP5562_RUN_ENG2;
		exec = (exec & ~LP5562_EXEC_ENG2_M) | LP5562_RUN_ENG2;
	}

	if (LP5562_ENG3_IS_LOADING(mode)) {
		mode = (mode & ~LP5562_MODE_ENG3_M) | LP5562_RUN_ENG3;
		exec = (exec & ~LP5562_EXEC_ENG3_M) | LP5562_RUN_ENG3;
	}

	lp55xx_write(chip, LP5562_REG_OP_MODE, mode);
	lp5562_wait_opmode_done();

	lp55xx_update_bits(chip, LP5562_REG_ENABLE, LP5562_EXEC_M, exec);
	lp5562_wait_enable_done();
}

static int lp5562_update_firmware(struct lp55xx_chip *chip,
					const u8 *data, size_t size)
{
	enum lp55xx_engine_index idx = chip->engine_idx;
	u8 pattern[LP5562_PROGRAM_LENGTH] = {0};
	u8 addr[] = {
		[LP55XX_ENGINE_1] = LP5562_REG_PROG_MEM_ENG1,
		[LP55XX_ENGINE_2] = LP5562_REG_PROG_MEM_ENG2,
		[LP55XX_ENGINE_3] = LP5562_REG_PROG_MEM_ENG3,
	};
	unsigned cmd;
	char c[3];
	int program_size;
	int nrchars;
	int offset = 0;
	int ret;
	int i;

	/* clear program memory before updating */
	for (i = 0; i < LP5562_PROGRAM_LENGTH; i++)
		lp55xx_write(chip, addr[idx] + i, 0);

	i = 0;
	while ((offset < size - 1) && (i < LP5562_PROGRAM_LENGTH)) {
		/* separate sscanfs because length is working only for %s */
		ret = sscanf(data + offset, "%2s%n ", c, &nrchars);
		if (ret != 1)
			goto err;

		ret = sscanf(c, "%2x", &cmd);
		if (ret != 1)
			goto err;

		pattern[i] = (u8)cmd;
		offset += nrchars;
		i++;
	}

	/* Each instruction is 16bit long. Check that length is even */
	if (i % 2)
		goto err;

	program_size = i;
	for (i = 0; i < program_size; i++)
		lp55xx_write(chip, addr[idx] + i, pattern[i]);

	return 0;

err:
	dev_err(&chip->cl->dev, "wrong pattern format\n");
	return -EINVAL;
}

static void lp5562_firmware_loaded(struct lp55xx_chip *chip)
{
	const struct firmware *fw = chip->fw;

	if (fw->size > LP5562_PROGRAM_LENGTH) {
		dev_err(&chip->cl->dev, "firmware data size overflow: %zu\n",
			fw->size);
		return;
	}

	/*
	 * Program momery sequence
	 *  1) set engine mode to "LOAD"
	 *  2) write firmware data into program memory
	 */

	lp5562_load_engine(chip);
	lp5562_update_firmware(chip, fw->data, fw->size);
}

static int lp5562_post_init_device(struct lp55xx_chip *chip)
{
	int ret;
	u8 cfg = LP5562_DEFAULT_CFG;

	/* Set all PWMs to direct control mode */
	ret = lp55xx_write(chip, LP5562_REG_OP_MODE, LP5562_CMD_DIRECT);
	if (ret)
		return ret;

	lp5562_wait_opmode_done();

	/* Update configuration for the clock setting */
	if (!lp55xx_is_extclk_used(chip))
		cfg |= LP5562_CLK_INT;

	ret = lp55xx_write(chip, LP5562_REG_CONFIG, cfg);
	if (ret)
		return ret;

	/* Initialize all channels PWM to zero -> leds off */
	lp55xx_write(chip, LP5562_REG_R_PWM, 0);
	lp55xx_write(chip, LP5562_REG_G_PWM, 0);
	lp55xx_write(chip, LP5562_REG_B_PWM, 0);
	lp55xx_write(chip, LP5562_REG_W_PWM, 0);

	/* Set LED map as register PWM by default */
	lp55xx_write(chip, LP5562_REG_ENG_SEL, LP5562_ENG_SEL_PWM);

	return 0;
}

static void lp5562_led_brightness_work(struct work_struct *work)
{
	struct lp55xx_led *led = container_of(work, struct lp55xx_led,
					      brightness_work);
	struct lp55xx_chip *chip = led->chip;
	u8 addr[] = {
		LP5562_REG_R_PWM,
		LP5562_REG_G_PWM,
		LP5562_REG_B_PWM,
		LP5562_REG_W_PWM,
	};

	mutex_lock(&chip->lock);
	lp55xx_write(chip, addr[led->chan_nr], led->brightness);
	mutex_unlock(&chip->lock);
}

static void lp5562_write_program_memory(struct lp55xx_chip *chip,
					u8 base, const u8 *rgb, int size)
{
	int i;

	if (!rgb || size <= 0)
		return;

	for (i = 0; i < size; i++)
		lp55xx_write(chip, base + i, *(rgb + i));

	lp55xx_write(chip, base + i, 0);
	lp55xx_write(chip, base + i + 1, 0);
}

/* check the size of program count */
static inline bool _is_pc_overflow(struct lp55xx_predef_pattern *ptn)
{
	return ptn->size_r >= LP5562_PROGRAM_LENGTH ||
	       ptn->size_g >= LP5562_PROGRAM_LENGTH ||
	       ptn->size_b >= LP5562_PROGRAM_LENGTH;
}

static int lp5562_run_predef_led_pattern(struct lp55xx_chip *chip, int mode)
{
	struct lp55xx_predef_pattern *ptn;
	int i;

	if (mode == LP5562_PATTERN_OFF) {
		lp5562_run_engine(chip, false);
		return 0;
	}

	ptn = chip->pdata->patterns + (mode - 1);
	if (!ptn || _is_pc_overflow(ptn)) {
		dev_err(&chip->cl->dev, "invalid pattern data\n");
		return -EINVAL;
	}

	lp5562_stop_engine(chip);

	/* Set LED map as RGB */
	lp55xx_write(chip, LP5562_REG_ENG_SEL, LP5562_ENG_SEL_RGB);

	/* Load engines */
	for (i = LP55XX_ENGINE_1; i <= LP55XX_ENGINE_3; i++) {
		chip->engine_idx = i;
		lp5562_load_engine(chip);
	}

	/* Clear program registers */
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG1, 0);
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG1 + 1, 0);
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG2, 0);
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG2 + 1, 0);
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG3, 0);
	lp55xx_write(chip, LP5562_REG_PROG_MEM_ENG3 + 1, 0);

	/* Program engines */
	lp5562_write_program_memory(chip, LP5562_REG_PROG_MEM_ENG1,
				ptn->r, ptn->size_r);
	lp5562_write_program_memory(chip, LP5562_REG_PROG_MEM_ENG2,
				ptn->g, ptn->size_g);
	lp5562_write_program_memory(chip, LP5562_REG_PROG_MEM_ENG3,
				ptn->b, ptn->size_b);

	/* Run engines */
	lp5562_run_engine(chip, true);

	return 0;
}

static ssize_t lp5562_store_pattern(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t len)
{
	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
	struct lp55xx_chip *chip = led->chip;
	struct lp55xx_predef_pattern *ptn = chip->pdata->patterns;
	int num_patterns = chip->pdata->num_patterns;
	unsigned long mode;
	int ret;

	ret = kstrtoul(buf, 0, &mode);
	if (ret)
		return ret;

	if (mode > num_patterns || !ptn)
		return -EINVAL;

	mutex_lock(&chip->lock);
	ret = lp5562_run_predef_led_pattern(chip, mode);
	mutex_unlock(&chip->lock);

	if (ret)
		return ret;

	return len;
}

static ssize_t lp5562_store_engine_mux(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t len)
{
	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
	struct lp55xx_chip *chip = led->chip;
	u8 mask;
	u8 val;

	/* LED map
	 * R ... Engine 1 (fixed)
	 * G ... Engine 2 (fixed)
	 * B ... Engine 3 (fixed)
	 * W ... Engine 1 or 2 or 3
	 */

	if (sysfs_streq(buf, "RGB")) {
		mask = LP5562_ENG_FOR_RGB_M;
		val = LP5562_ENG_SEL_RGB;
	} else if (sysfs_streq(buf, "W")) {
		enum lp55xx_engine_index idx = chip->engine_idx;

		mask = LP5562_ENG_FOR_W_M;
		switch (idx) {
		case LP55XX_ENGINE_1:
			val = LP5562_ENG1_FOR_W;
			break;
		case LP55XX_ENGINE_2:
			val = LP5562_ENG2_FOR_W;
			break;
		case LP55XX_ENGINE_3:
			val = LP5562_ENG3_FOR_W;
			break;
		default:
			return -EINVAL;
		}

	} else {
		dev_err(dev, "choose RGB or W\n");
		return -EINVAL;
	}

	mutex_lock(&chip->lock);
	lp55xx_update_bits(chip, LP5562_REG_ENG_SEL, mask, val);
	mutex_unlock(&chip->lock);

	return len;
}

static LP55XX_DEV_ATTR_WO(led_pattern, lp5562_store_pattern);
static LP55XX_DEV_ATTR_WO(engine_mux, lp5562_store_engine_mux);

static struct attribute *lp5562_attributes[] = {
	&dev_attr_led_pattern.attr,
	&dev_attr_engine_mux.attr,
	NULL,
};

static const struct attribute_group lp5562_group = {
	.attrs = lp5562_attributes,
};

/* Chip specific configurations */
static struct lp55xx_device_config lp5562_cfg = {
	.max_channel  = LP5562_MAX_LEDS,
	.reset = {
		.addr = LP5562_REG_RESET,
		.val  = LP5562_RESET,
	},
	.enable = {
		.addr = LP5562_REG_ENABLE,
		.val  = LP5562_ENABLE_DEFAULT,
	},
	.post_init_device   = lp5562_post_init_device,
	.set_led_current    = lp5562_set_led_current,
	.brightness_work_fn = lp5562_led_brightness_work,
	.run_engine         = lp5562_run_engine,
	.firmware_cb        = lp5562_firmware_loaded,
	.dev_attr_group     = &lp5562_group,
};

static int lp5562_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int ret;
	struct lp55xx_chip *chip;
	struct lp55xx_led *led;
	struct lp55xx_platform_data *pdata = dev_get_platdata(&client->dev);
	struct device_node *np = client->dev.of_node;

	if (!pdata) {
		if (np) {
			pdata = lp55xx_of_populate_pdata(&client->dev, np);
			if (IS_ERR(pdata))
				return PTR_ERR(pdata);
		} else {
			dev_err(&client->dev, "no platform data\n");
			return -EINVAL;
		}
	}

	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	led = devm_kzalloc(&client->dev,
			sizeof(*led) * pdata->num_channels, GFP_KERNEL);
	if (!led)
		return -ENOMEM;

	chip->cl = client;
	chip->pdata = pdata;
	chip->cfg = &lp5562_cfg;

	mutex_init(&chip->lock);

	i2c_set_clientdata(client, led);

	ret = lp55xx_init_device(chip);
	if (ret)
		goto err_init;

	ret = lp55xx_register_leds(led, chip);
	if (ret)
		goto err_register_leds;

	ret = lp55xx_register_sysfs(chip);
	if (ret) {
		dev_err(&client->dev, "registering sysfs failed\n");
		goto err_register_sysfs;
	}

	return 0;

err_register_sysfs:
	lp55xx_unregister_leds(led, chip);
err_register_leds:
	lp55xx_deinit_device(chip);
err_init:
	return ret;
}

static int lp5562_remove(struct i2c_client *client)
{
	struct lp55xx_led *led = i2c_get_clientdata(client);
	struct lp55xx_chip *chip = led->chip;

	lp5562_stop_engine(chip);

	lp55xx_unregister_sysfs(chip);
	lp55xx_unregister_leds(led, chip);
	lp55xx_deinit_device(chip);

	return 0;
}

static const struct i2c_device_id lp5562_id[] = {
	{ "lp5562", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, lp5562_id);

#ifdef CONFIG_OF
static const struct of_device_id of_lp5562_leds_match[] = {
	{ .compatible = "ti,lp5562", },
	{},
};

MODULE_DEVICE_TABLE(of, of_lp5562_leds_match);
#endif

static struct i2c_driver lp5562_driver = {
	.driver = {
		.name	= "lp5562",
		.of_match_table = of_match_ptr(of_lp5562_leds_match),
	},
	.probe		= lp5562_probe,
	.remove		= lp5562_remove,
	.id_table	= lp5562_id,
};

module_i2c_driver(lp5562_driver);

MODULE_DESCRIPTION("Texas Instruments LP5562 LED Driver");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");

Is there any problem with the configuration? Or can u give us some suggestion for this problem? 

Thanks,

Best regards

  • Hi Lumina, 

    Is LP55231 controlled by LP5562 Linux driver? Please provide the schematic if applicable and I will collect some feedback from our Linux experts on this issue.

    Best Regards,

    Aaron Bing

  • Hi Aaron,

    The Linux driver of  LP55231 is as below document.:

    /*
     * lp5523.c - LP5523, LP55231 LED Driver
     *
     * Copyright (C) 2010 Nokia Corporation
     * Copyright (C) 2012 Texas Instruments
     *
     * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
     *          Milo(Woogyom) Kim <milo.kim@ti.com>
     *
     * 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.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
     * 02110-1301 USA
     */
    
    #include <linux/delay.h>
    #include <linux/firmware.h>
    #include <linux/i2c.h>
    #include <linux/leds.h>
    #include <linux/module.h>
    #include <linux/mutex.h>
    #include <linux/of.h>
    #include <linux/platform_data/leds-lp55xx.h>
    #include <linux/slab.h>
    
    #include "leds-lp55xx-common.h"
    
    #define LP5523_PROGRAM_LENGTH		32	/* bytes */
    /* Memory is used like this:
       0x00 engine 1 program
       0x10 engine 2 program
       0x20 engine 3 program
       0x30 engine 1 muxing info
       0x40 engine 2 muxing info
       0x50 engine 3 muxing info
    */
    #define LP5523_MAX_LEDS			9
    
    /* Registers */
    #define LP5523_REG_ENABLE		0x00
    #define LP5523_REG_OP_MODE		0x01
    #define LP5523_REG_ENABLE_LEDS_MSB	0x04
    #define LP5523_REG_ENABLE_LEDS_LSB	0x05
    #define LP5523_REG_LED_CTRL_BASE	0x06
    #define LP5523_REG_LED_PWM_BASE		0x16
    #define LP5523_REG_LED_CURRENT_BASE	0x26
    #define LP5523_REG_CONFIG		0x36
    #define LP5523_REG_STATUS		0x3A
    #define LP5523_REG_RESET		0x3D
    #define LP5523_REG_LED_TEST_CTRL	0x41
    #define LP5523_REG_LED_TEST_ADC		0x42
    #define LP5523_REG_MASTER_FADER_BASE	0x48
    #define LP5523_REG_CH1_PROG_START	0x4C
    #define LP5523_REG_CH2_PROG_START	0x4D
    #define LP5523_REG_CH3_PROG_START	0x4E
    #define LP5523_REG_PROG_PAGE_SEL	0x4F
    #define LP5523_REG_PROG_MEM		0x50
    
    /* Bit description in registers */
    #define LP5523_ENABLE			0x40
    #define LP5523_AUTO_INC			0x40
    #define LP5523_PWR_SAVE			0x20
    #define LP5523_PWM_PWR_SAVE		0x04
    #define LP5523_CP_AUTO			0x18
    #define LP5523_AUTO_CLK			0x02
    
    #define LP5523_EN_LEDTEST		0x80
    #define LP5523_LEDTEST_DONE		0x80
    #define LP5523_RESET			0xFF
    #define LP5523_ADC_SHORTCIRC_LIM	80
    #define LP5523_EXT_CLK_USED		0x08
    #define LP5523_ENG_STATUS_MASK		0x07
    
    #define LP5523_FADER_MAPPING_MASK	0xC0
    #define LP5523_FADER_MAPPING_SHIFT	6
    
    /* Memory Page Selection */
    #define LP5523_PAGE_ENG1		0
    #define LP5523_PAGE_ENG2		1
    #define LP5523_PAGE_ENG3		2
    #define LP5523_PAGE_MUX1		3
    #define LP5523_PAGE_MUX2		4
    #define LP5523_PAGE_MUX3		5
    
    /* Program Memory Operations */
    #define LP5523_MODE_ENG1_M		0x30	/* Operation Mode Register */
    #define LP5523_MODE_ENG2_M		0x0C
    #define LP5523_MODE_ENG3_M		0x03
    #define LP5523_LOAD_ENG1		0x10
    #define LP5523_LOAD_ENG2		0x04
    #define LP5523_LOAD_ENG3		0x01
    
    #define LP5523_ENG1_IS_LOADING(mode)	\
    	((mode & LP5523_MODE_ENG1_M) == LP5523_LOAD_ENG1)
    #define LP5523_ENG2_IS_LOADING(mode)	\
    	((mode & LP5523_MODE_ENG2_M) == LP5523_LOAD_ENG2)
    #define LP5523_ENG3_IS_LOADING(mode)	\
    	((mode & LP5523_MODE_ENG3_M) == LP5523_LOAD_ENG3)
    
    #define LP5523_EXEC_ENG1_M		0x30	/* Enable Register */
    #define LP5523_EXEC_ENG2_M		0x0C
    #define LP5523_EXEC_ENG3_M		0x03
    #define LP5523_EXEC_M			0x3F
    #define LP5523_RUN_ENG1			0x20
    #define LP5523_RUN_ENG2			0x08
    #define LP5523_RUN_ENG3			0x02
    
    #define LED_ACTIVE(mux, led)		(!!(mux & (0x0001 << led)))
    
    enum lp5523_chip_id {
    	LP5523,
    	LP55231,
    };
    
    static int lp5523_init_program_engine(struct lp55xx_chip *chip);
    
    static inline void lp5523_wait_opmode_done(void)
    {
    	usleep_range(1000, 2000);
    }
    
    static void lp5523_set_led_current(struct lp55xx_led *led, u8 led_current)
    {
    	led->led_current = led_current;
    	lp55xx_write(led->chip, LP5523_REG_LED_CURRENT_BASE + led->chan_nr,
    		led_current);
    }
    
    static int lp5523_post_init_device(struct lp55xx_chip *chip)
    {
    	int ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_ENABLE, LP5523_ENABLE);
    	if (ret)
    		return ret;
    
    	/* Chip startup time is 500 us, 1 - 2 ms gives some margin */
    	usleep_range(1000, 2000);
    
    	ret = lp55xx_write(chip, LP5523_REG_CONFIG,
    			    LP5523_AUTO_INC | LP5523_PWR_SAVE |
    			    LP5523_CP_AUTO | LP5523_AUTO_CLK |
    			    LP5523_PWM_PWR_SAVE);
    	if (ret)
    		return ret;
    
    	/* turn on all leds */
    	ret = lp55xx_write(chip, LP5523_REG_ENABLE_LEDS_MSB, 0x01);
    	if (ret)
    		return ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_ENABLE_LEDS_LSB, 0xff);
    	if (ret)
    		return ret;
    
    	return lp5523_init_program_engine(chip);
    }
    
    static void lp5523_load_engine(struct lp55xx_chip *chip)
    {
    	enum lp55xx_engine_index idx = chip->engine_idx;
    	u8 mask[] = {
    		[LP55XX_ENGINE_1] = LP5523_MODE_ENG1_M,
    		[LP55XX_ENGINE_2] = LP5523_MODE_ENG2_M,
    		[LP55XX_ENGINE_3] = LP5523_MODE_ENG3_M,
    	};
    
    	u8 val[] = {
    		[LP55XX_ENGINE_1] = LP5523_LOAD_ENG1,
    		[LP55XX_ENGINE_2] = LP5523_LOAD_ENG2,
    		[LP55XX_ENGINE_3] = LP5523_LOAD_ENG3,
    	};
    
    	lp55xx_update_bits(chip, LP5523_REG_OP_MODE, mask[idx], val[idx]);
    
    	lp5523_wait_opmode_done();
    }
    
    static void lp5523_load_engine_and_select_page(struct lp55xx_chip *chip)
    {
    	enum lp55xx_engine_index idx = chip->engine_idx;
    	u8 page_sel[] = {
    		[LP55XX_ENGINE_1] = LP5523_PAGE_ENG1,
    		[LP55XX_ENGINE_2] = LP5523_PAGE_ENG2,
    		[LP55XX_ENGINE_3] = LP5523_PAGE_ENG3,
    	};
    
    	lp5523_load_engine(chip);
    
    	lp55xx_write(chip, LP5523_REG_PROG_PAGE_SEL, page_sel[idx]);
    }
    
    static void lp5523_stop_all_engines(struct lp55xx_chip *chip)
    {
    	lp55xx_write(chip, LP5523_REG_OP_MODE, 0);
    	lp5523_wait_opmode_done();
    }
    
    static void lp5523_stop_engine(struct lp55xx_chip *chip)
    {
    	enum lp55xx_engine_index idx = chip->engine_idx;
    	u8 mask[] = {
    		[LP55XX_ENGINE_1] = LP5523_MODE_ENG1_M,
    		[LP55XX_ENGINE_2] = LP5523_MODE_ENG2_M,
    		[LP55XX_ENGINE_3] = LP5523_MODE_ENG3_M,
    	};
    
    	lp55xx_update_bits(chip, LP5523_REG_OP_MODE, mask[idx], 0);
    
    	lp5523_wait_opmode_done();
    }
    
    static void lp5523_turn_off_channels(struct lp55xx_chip *chip)
    {
    	int i;
    
    	for (i = 0; i < LP5523_MAX_LEDS; i++)
    		lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + i, 0);
    }
    
    static void lp5523_run_engine(struct lp55xx_chip *chip, bool start)
    {
    	int ret;
    	u8 mode;
    	u8 exec;
    
    	/* stop engine */
    	if (!start) {
    		lp5523_stop_engine(chip);
    		lp5523_turn_off_channels(chip);
    		return;
    	}
    
    	/*
    	 * To run the engine,
    	 * operation mode and enable register should updated at the same time
    	 */
    
    	ret = lp55xx_read(chip, LP5523_REG_OP_MODE, &mode);
    	if (ret)
    		return;
    
    	ret = lp55xx_read(chip, LP5523_REG_ENABLE, &exec);
    	if (ret)
    		return;
    
    	/* change operation mode to RUN only when each engine is loading */
    	if (LP5523_ENG1_IS_LOADING(mode)) {
    		mode = (mode & ~LP5523_MODE_ENG1_M) | LP5523_RUN_ENG1;
    		exec = (exec & ~LP5523_EXEC_ENG1_M) | LP5523_RUN_ENG1;
    	}
    
    	if (LP5523_ENG2_IS_LOADING(mode)) {
    		mode = (mode & ~LP5523_MODE_ENG2_M) | LP5523_RUN_ENG2;
    		exec = (exec & ~LP5523_EXEC_ENG2_M) | LP5523_RUN_ENG2;
    	}
    
    	if (LP5523_ENG3_IS_LOADING(mode)) {
    		mode = (mode & ~LP5523_MODE_ENG3_M) | LP5523_RUN_ENG3;
    		exec = (exec & ~LP5523_EXEC_ENG3_M) | LP5523_RUN_ENG3;
    	}
    
    	lp55xx_write(chip, LP5523_REG_OP_MODE, mode);
    	lp5523_wait_opmode_done();
    
    	lp55xx_update_bits(chip, LP5523_REG_ENABLE, LP5523_EXEC_M, exec);
    }
    
    static int lp5523_init_program_engine(struct lp55xx_chip *chip)
    {
    	int i;
    	int j;
    	int ret;
    	u8 status;
    	/* one pattern per engine setting LED MUX start and stop addresses */
    	static const u8 pattern[][LP5523_PROGRAM_LENGTH] =  {
    		{ 0x9c, 0x30, 0x9c, 0xb0, 0x9d, 0x80, 0xd8, 0x00, 0},
    		{ 0x9c, 0x40, 0x9c, 0xc0, 0x9d, 0x80, 0xd8, 0x00, 0},
    		{ 0x9c, 0x50, 0x9c, 0xd0, 0x9d, 0x80, 0xd8, 0x00, 0},
    	};
    
    	/* hardcode 32 bytes of memory for each engine from program memory */
    	ret = lp55xx_write(chip, LP5523_REG_CH1_PROG_START, 0x00);
    	if (ret)
    		return ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_CH2_PROG_START, 0x10);
    	if (ret)
    		return ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_CH3_PROG_START, 0x20);
    	if (ret)
    		return ret;
    
    	/* write LED MUX address space for each engine */
    	for (i = LP55XX_ENGINE_1; i <= LP55XX_ENGINE_3; i++) {
    		chip->engine_idx = i;
    		lp5523_load_engine_and_select_page(chip);
    
    		for (j = 0; j < LP5523_PROGRAM_LENGTH; j++) {
    			ret = lp55xx_write(chip, LP5523_REG_PROG_MEM + j,
    					pattern[i - 1][j]);
    			if (ret)
    				goto out;
    		}
    	}
    
    	lp5523_run_engine(chip, true);
    
    	/* Let the programs run for couple of ms and check the engine status */
    	usleep_range(3000, 6000);
    	lp55xx_read(chip, LP5523_REG_STATUS, &status);
    	status &= LP5523_ENG_STATUS_MASK;
    
    	if (status != LP5523_ENG_STATUS_MASK) {
    		dev_err(&chip->cl->dev,
    			"cound not configure LED engine, status = 0x%.2x\n",
    			status);
    		ret = -1;
    	}
    
    out:
    	lp5523_stop_all_engines(chip);
    	return ret;
    }
    
    static int lp5523_update_program_memory(struct lp55xx_chip *chip,
    					const u8 *data, size_t size)
    {
    	u8 pattern[LP5523_PROGRAM_LENGTH] = {0};
    	unsigned cmd;
    	char c[3];
    	int nrchars;
    	int ret;
    	int offset = 0;
    	int i = 0;
    
    	while ((offset < size - 1) && (i < LP5523_PROGRAM_LENGTH)) {
    		/* separate sscanfs because length is working only for %s */
    		ret = sscanf(data + offset, "%2s%n ", c, &nrchars);
    		if (ret != 1)
    			goto err;
    
    		ret = sscanf(c, "%2x", &cmd);
    		if (ret != 1)
    			goto err;
    
    		pattern[i] = (u8)cmd;
    		offset += nrchars;
    		i++;
    	}
    
    	/* Each instruction is 16bit long. Check that length is even */
    	if (i % 2)
    		goto err;
    
    	for (i = 0; i < LP5523_PROGRAM_LENGTH; i++) {
    		ret = lp55xx_write(chip, LP5523_REG_PROG_MEM + i, pattern[i]);
    		if (ret)
    			return -EINVAL;
    	}
    
    	return size;
    
    err:
    	dev_err(&chip->cl->dev, "wrong pattern format\n");
    	return -EINVAL;
    }
    
    static void lp5523_firmware_loaded(struct lp55xx_chip *chip)
    {
    	const struct firmware *fw = chip->fw;
    
    	if (fw->size > LP5523_PROGRAM_LENGTH) {
    		dev_err(&chip->cl->dev, "firmware data size overflow: %zu\n",
    			fw->size);
    		return;
    	}
    
    	/*
    	 * Program momery sequence
    	 *  1) set engine mode to "LOAD"
    	 *  2) write firmware data into program memory
    	 */
    
    	lp5523_load_engine_and_select_page(chip);
    	lp5523_update_program_memory(chip, fw->data, fw->size);
    }
    
    static ssize_t show_engine_mode(struct device *dev,
    				struct device_attribute *attr,
    				char *buf, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	enum lp55xx_engine_mode mode = chip->engines[nr - 1].mode;
    
    	switch (mode) {
    	case LP55XX_ENGINE_RUN:
    		return sprintf(buf, "run\n");
    	case LP55XX_ENGINE_LOAD:
    		return sprintf(buf, "load\n");
    	case LP55XX_ENGINE_DISABLED:
    	default:
    		return sprintf(buf, "disabled\n");
    	}
    }
    show_mode(1)
    show_mode(2)
    show_mode(3)
    
    static ssize_t store_engine_mode(struct device *dev,
    				 struct device_attribute *attr,
    				 const char *buf, size_t len, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	struct lp55xx_engine *engine = &chip->engines[nr - 1];
    
    	mutex_lock(&chip->lock);
    
    	chip->engine_idx = nr;
    
    	if (!strncmp(buf, "run", 3)) {
    		lp5523_run_engine(chip, true);
    		engine->mode = LP55XX_ENGINE_RUN;
    	} else if (!strncmp(buf, "load", 4)) {
    		lp5523_stop_engine(chip);
    		lp5523_load_engine(chip);
    		engine->mode = LP55XX_ENGINE_LOAD;
    	} else if (!strncmp(buf, "disabled", 8)) {
    		lp5523_stop_engine(chip);
    		engine->mode = LP55XX_ENGINE_DISABLED;
    	}
    
    	mutex_unlock(&chip->lock);
    
    	return len;
    }
    store_mode(1)
    store_mode(2)
    store_mode(3)
    
    static int lp5523_mux_parse(const char *buf, u16 *mux, size_t len)
    {
    	u16 tmp_mux = 0;
    	int i;
    
    	len = min_t(int, len, LP5523_MAX_LEDS);
    
    	for (i = 0; i < len; i++) {
    		switch (buf[i]) {
    		case '1':
    			tmp_mux |= (1 << i);
    			break;
    		case '0':
    			break;
    		case '\n':
    			i = len;
    			break;
    		default:
    			return -1;
    		}
    	}
    	*mux = tmp_mux;
    
    	return 0;
    }
    
    static void lp5523_mux_to_array(u16 led_mux, char *array)
    {
    	int i, pos = 0;
    	for (i = 0; i < LP5523_MAX_LEDS; i++)
    		pos += sprintf(array + pos, "%x", LED_ACTIVE(led_mux, i));
    
    	array[pos] = '\0';
    }
    
    static ssize_t show_engine_leds(struct device *dev,
    			    struct device_attribute *attr,
    			    char *buf, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	char mux[LP5523_MAX_LEDS + 1];
    
    	lp5523_mux_to_array(chip->engines[nr - 1].led_mux, mux);
    
    	return sprintf(buf, "%s\n", mux);
    }
    show_leds(1)
    show_leds(2)
    show_leds(3)
    
    static int lp5523_load_mux(struct lp55xx_chip *chip, u16 mux, int nr)
    {
    	struct lp55xx_engine *engine = &chip->engines[nr - 1];
    	int ret;
    	u8 mux_page[] = {
    		[LP55XX_ENGINE_1] = LP5523_PAGE_MUX1,
    		[LP55XX_ENGINE_2] = LP5523_PAGE_MUX2,
    		[LP55XX_ENGINE_3] = LP5523_PAGE_MUX3,
    	};
    
    	lp5523_load_engine(chip);
    
    	ret = lp55xx_write(chip, LP5523_REG_PROG_PAGE_SEL, mux_page[nr]);
    	if (ret)
    		return ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_PROG_MEM , (u8)(mux >> 8));
    	if (ret)
    		return ret;
    
    	ret = lp55xx_write(chip, LP5523_REG_PROG_MEM + 1, (u8)(mux));
    	if (ret)
    		return ret;
    
    	engine->led_mux = mux;
    	return 0;
    }
    
    static ssize_t store_engine_leds(struct device *dev,
    			     struct device_attribute *attr,
    			     const char *buf, size_t len, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	struct lp55xx_engine *engine = &chip->engines[nr - 1];
    	u16 mux = 0;
    	ssize_t ret;
    
    	if (lp5523_mux_parse(buf, &mux, len))
    		return -EINVAL;
    
    	mutex_lock(&chip->lock);
    
    	chip->engine_idx = nr;
    	ret = -EINVAL;
    
    	if (engine->mode != LP55XX_ENGINE_LOAD)
    		goto leave;
    
    	if (lp5523_load_mux(chip, mux, nr))
    		goto leave;
    
    	ret = len;
    leave:
    	mutex_unlock(&chip->lock);
    	return ret;
    }
    store_leds(1)
    store_leds(2)
    store_leds(3)
    
    static ssize_t store_engine_load(struct device *dev,
    			     struct device_attribute *attr,
    			     const char *buf, size_t len, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	int ret;
    
    	mutex_lock(&chip->lock);
    
    	chip->engine_idx = nr;
    	lp5523_load_engine_and_select_page(chip);
    	ret = lp5523_update_program_memory(chip, buf, len);
    
    	mutex_unlock(&chip->lock);
    
    	return ret;
    }
    store_load(1)
    store_load(2)
    store_load(3)
    
    static ssize_t lp5523_selftest(struct device *dev,
    			       struct device_attribute *attr,
    			       char *buf)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	struct lp55xx_platform_data *pdata = chip->pdata;
    	int i, ret, pos = 0;
    	u8 status, adc, vdd;
    
    	mutex_lock(&chip->lock);
    
    	ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
    	if (ret < 0)
    		goto fail;
    
    	/* Check that ext clock is really in use if requested */
    	if (pdata->clock_mode == LP55XX_CLOCK_EXT) {
    		if  ((status & LP5523_EXT_CLK_USED) == 0)
    			goto fail;
    	}
    
    	/* Measure VDD (i.e. VBAT) first (channel 16 corresponds to VDD) */
    	lp55xx_write(chip, LP5523_REG_LED_TEST_CTRL, LP5523_EN_LEDTEST | 16);
    	usleep_range(3000, 6000); /* ADC conversion time is typically 2.7 ms */
    	ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
    	if (ret < 0)
    		goto fail;
    
    	if (!(status & LP5523_LEDTEST_DONE))
    		usleep_range(3000, 6000); /* Was not ready. Wait little bit */
    
    	ret = lp55xx_read(chip, LP5523_REG_LED_TEST_ADC, &vdd);
    	if (ret < 0)
    		goto fail;
    
    	vdd--;	/* There may be some fluctuation in measurement */
    
    	for (i = 0; i < LP5523_MAX_LEDS; i++) {
    		/* Skip non-existing channels */
    		if (pdata->led_config[i].led_current == 0)
    			continue;
    
    		/* Set default current */
    		lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + i,
    			pdata->led_config[i].led_current);
    
    		lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + i, 0xff);
    		/* let current stabilize 2 - 4ms before measurements start */
    		usleep_range(2000, 4000);
    		lp55xx_write(chip, LP5523_REG_LED_TEST_CTRL,
    			     LP5523_EN_LEDTEST | i);
    		/* ADC conversion time is 2.7 ms typically */
    		usleep_range(3000, 6000);
    		ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
    		if (ret < 0)
    			goto fail;
    
    		if (!(status & LP5523_LEDTEST_DONE))
    			usleep_range(3000, 6000);/* Was not ready. Wait. */
    
    		ret = lp55xx_read(chip, LP5523_REG_LED_TEST_ADC, &adc);
    		if (ret < 0)
    			goto fail;
    
    		if (adc >= vdd || adc < LP5523_ADC_SHORTCIRC_LIM)
    			pos += sprintf(buf + pos, "LED %d FAIL\n", i);
    
    		lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + i, 0x00);
    
    		/* Restore current */
    		lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + i,
    			led->led_current);
    		led++;
    	}
    	if (pos == 0)
    		pos = sprintf(buf, "OK\n");
    	goto release_lock;
    fail:
    	pos = sprintf(buf, "FAIL\n");
    
    release_lock:
    	mutex_unlock(&chip->lock);
    
    	return pos;
    }
    
    #define show_fader(nr)						\
    static ssize_t show_master_fader##nr(struct device *dev,	\
    			    struct device_attribute *attr,	\
    			    char *buf)				\
    {								\
    	return show_master_fader(dev, attr, buf, nr);		\
    }
    
    #define store_fader(nr)						\
    static ssize_t store_master_fader##nr(struct device *dev,	\
    			     struct device_attribute *attr,	\
    			     const char *buf, size_t len)	\
    {								\
    	return store_master_fader(dev, attr, buf, len, nr);	\
    }
    
    static ssize_t show_master_fader(struct device *dev,
    				 struct device_attribute *attr,
    				 char *buf, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	int ret;
    	u8 val;
    
    	mutex_lock(&chip->lock);
    	ret = lp55xx_read(chip, LP5523_REG_MASTER_FADER_BASE + nr - 1, &val);
    	mutex_unlock(&chip->lock);
    
    	if (ret == 0)
    		ret = sprintf(buf, "%u\n", val);
    
    	return ret;
    }
    show_fader(1)
    show_fader(2)
    show_fader(3)
    
    static ssize_t store_master_fader(struct device *dev,
    				  struct device_attribute *attr,
    				  const char *buf, size_t len, int nr)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	int ret;
    	unsigned long val;
    
    	if (kstrtoul(buf, 0, &val))
    		return -EINVAL;
    
    	if (val > 0xff)
    		return -EINVAL;
    
    	mutex_lock(&chip->lock);
    	ret = lp55xx_write(chip, LP5523_REG_MASTER_FADER_BASE + nr - 1,
    			   (u8)val);
    	mutex_unlock(&chip->lock);
    
    	if (ret == 0)
    		ret = len;
    
    	return ret;
    }
    store_fader(1)
    store_fader(2)
    store_fader(3)
    
    static ssize_t show_master_fader_leds(struct device *dev,
    				      struct device_attribute *attr,
    				      char *buf)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	int i, ret, pos = 0;
    	u8 val;
    
    	mutex_lock(&chip->lock);
    
    	for (i = 0; i < LP5523_MAX_LEDS; i++) {
    		ret = lp55xx_read(chip, LP5523_REG_LED_CTRL_BASE + i, &val);
    		if (ret)
    			goto leave;
    
    		val = (val & LP5523_FADER_MAPPING_MASK)
    			>> LP5523_FADER_MAPPING_SHIFT;
    		if (val > 3) {
    			ret = -EINVAL;
    			goto leave;
    		}
    		buf[pos++] = val + '0';
    	}
    	buf[pos++] = '\n';
    	ret = pos;
    leave:
    	mutex_unlock(&chip->lock);
    	return ret;
    }
    
    static ssize_t store_master_fader_leds(struct device *dev,
    				       struct device_attribute *attr,
    				       const char *buf, size_t len)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
    	struct lp55xx_chip *chip = led->chip;
    	int i, n, ret;
    	u8 val;
    
    	n = min_t(int, len, LP5523_MAX_LEDS);
    
    	mutex_lock(&chip->lock);
    
    	for (i = 0; i < n; i++) {
    		if (buf[i] >= '0' && buf[i] <= '3') {
    			val = (buf[i] - '0') << LP5523_FADER_MAPPING_SHIFT;
    			ret = lp55xx_update_bits(chip,
    						 LP5523_REG_LED_CTRL_BASE + i,
    						 LP5523_FADER_MAPPING_MASK,
    						 val);
    			if (ret)
    				goto leave;
    		} else {
    			ret = -EINVAL;
    			goto leave;
    		}
    	}
    	ret = len;
    leave:
    	mutex_unlock(&chip->lock);
    	return ret;
    }
    
    static void lp5523_led_brightness_work(struct work_struct *work)
    {
    	struct lp55xx_led *led = container_of(work, struct lp55xx_led,
    					      brightness_work);
    	struct lp55xx_chip *chip = led->chip;
    	printk("[emdoorVR]:%s:  --->\n",__func__);
    
    	mutex_lock(&chip->lock);
    	lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr,
    		     led->brightness);
    	mutex_unlock(&chip->lock);
    }
    
    static LP55XX_DEV_ATTR_RW(engine1_mode, show_engine1_mode, store_engine1_mode);
    static LP55XX_DEV_ATTR_RW(engine2_mode, show_engine2_mode, store_engine2_mode);
    static LP55XX_DEV_ATTR_RW(engine3_mode, show_engine3_mode, store_engine3_mode);
    static LP55XX_DEV_ATTR_RW(engine1_leds, show_engine1_leds, store_engine1_leds);
    static LP55XX_DEV_ATTR_RW(engine2_leds, show_engine2_leds, store_engine2_leds);
    static LP55XX_DEV_ATTR_RW(engine3_leds, show_engine3_leds, store_engine3_leds);
    static LP55XX_DEV_ATTR_WO(engine1_load, store_engine1_load);
    static LP55XX_DEV_ATTR_WO(engine2_load, store_engine2_load);
    static LP55XX_DEV_ATTR_WO(engine3_load, store_engine3_load);
    static LP55XX_DEV_ATTR_RO(selftest, lp5523_selftest);
    static LP55XX_DEV_ATTR_RW(master_fader1, show_master_fader1,
    			  store_master_fader1);
    static LP55XX_DEV_ATTR_RW(master_fader2, show_master_fader2,
    			  store_master_fader2);
    static LP55XX_DEV_ATTR_RW(master_fader3, show_master_fader3,
    			  store_master_fader3);
    static LP55XX_DEV_ATTR_RW(master_fader_leds, show_master_fader_leds,
    			  store_master_fader_leds);
    
    static struct attribute *lp5523_attributes[] = {
    	&dev_attr_engine1_mode.attr,
    	&dev_attr_engine2_mode.attr,
    	&dev_attr_engine3_mode.attr,
    	&dev_attr_engine1_load.attr,
    	&dev_attr_engine2_load.attr,
    	&dev_attr_engine3_load.attr,
    	&dev_attr_engine1_leds.attr,
    	&dev_attr_engine2_leds.attr,
    	&dev_attr_engine3_leds.attr,
    	&dev_attr_selftest.attr,
    	&dev_attr_master_fader1.attr,
    	&dev_attr_master_fader2.attr,
    	&dev_attr_master_fader3.attr,
    	&dev_attr_master_fader_leds.attr,
    	NULL,
    };
    
    static const struct attribute_group lp5523_group = {
    	.attrs = lp5523_attributes,
    };
    
    /* Chip specific configurations */
    static struct lp55xx_device_config lp5523_cfg = {
    	.reset = {
    		.addr = LP5523_REG_RESET,
    		.val  = LP5523_RESET,
    	},
    	.enable = {
    		.addr = LP5523_REG_ENABLE,
    		.val  = LP5523_ENABLE,
    	},
    	.max_channel  = LP5523_MAX_LEDS,
    	.post_init_device   = lp5523_post_init_device,
    	.brightness_work_fn = lp5523_led_brightness_work,
    	.set_led_current    = lp5523_set_led_current,
    	.firmware_cb        = lp5523_firmware_loaded,
    	.run_engine         = lp5523_run_engine,
    	.dev_attr_group     = &lp5523_group,
    };
    
    static int lp5523_probe(struct i2c_client *client,
    			const struct i2c_device_id *id)
    {
    	int ret;
    	struct lp55xx_chip *chip;
    	struct lp55xx_led *led;
    	struct lp55xx_platform_data *pdata = dev_get_platdata(&client->dev);
    	struct device_node *np = client->dev.of_node;
    
    	printk("[emdoorVR]:%s: ++\n",__func__);
    
    	if (!pdata) {
    		if (np) {
    			pdata = lp55xx_of_populate_pdata(&client->dev, np);
    			if (IS_ERR(pdata))
    				return PTR_ERR(pdata);
    		} else {
    			dev_err(&client->dev, "no platform data\n");
    			return -EINVAL;
    		}
    	}
    
    	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
    	if (!chip)
    		return -ENOMEM;
    
    	led = devm_kzalloc(&client->dev,
    			sizeof(*led) * pdata->num_channels, GFP_KERNEL);
    	if (!led)
    		return -ENOMEM;
    
    	chip->cl = client;
    	chip->pdata = pdata;
    	chip->cfg = &lp5523_cfg;
    
    	mutex_init(&chip->lock);
    
    	i2c_set_clientdata(client, led);
    
    	ret = lp55xx_init_device(chip);
    	if (ret)
    		goto err_init;
    
    	dev_info(&client->dev, "%s Programmable led chip found\n", id->name);
    
    	ret = lp55xx_register_leds(led, chip);
    	if (ret)
    		goto err_register_leds;
    
    	ret = lp55xx_register_sysfs(chip);
    	if (ret) {
    		dev_err(&client->dev, "registering sysfs failed\n");
    		goto err_register_sysfs;
    	}
    	printk("[emdoorVR]:%s: end ! \n",__func__);
    
    	return 0;
    
    err_register_sysfs:
    	lp55xx_unregister_leds(led, chip);
    err_register_leds:
    	lp55xx_deinit_device(chip);
    err_init:
    	return ret;
    }
    
    static int lp5523_remove(struct i2c_client *client)
    {
    	struct lp55xx_led *led = i2c_get_clientdata(client);
    	struct lp55xx_chip *chip = led->chip;
    
    	lp5523_stop_all_engines(chip);
    	lp55xx_unregister_sysfs(chip);
    	lp55xx_unregister_leds(led, chip);
    	lp55xx_deinit_device(chip);
    
    	return 0;
    }
    
    static const struct i2c_device_id lp5523_id[] = {
    	{ "lp5523",  LP5523 },
    	{ "lp55231", LP55231 },
    	{ }
    };
    
    MODULE_DEVICE_TABLE(i2c, lp5523_id);
    
    #ifdef CONFIG_OF
    static const struct of_device_id of_lp5523_leds_match[] = {
    	{ .compatible = "national,lp5523", },
    	{ .compatible = "ti,lp55231", },
    	{},
    };
    
    MODULE_DEVICE_TABLE(of, of_lp5523_leds_match);
    #endif
    
    static struct i2c_driver lp5523_driver = {
    	.driver = {
    		.name	= "lp5523x",
    		.of_match_table = of_match_ptr(of_lp5523_leds_match),
    	},
    	.probe		= lp5523_probe,
    	.remove		= lp5523_remove,
    	.id_table	= lp5523_id,
    };
    
    module_i2c_driver(lp5523_driver);
    
    MODULE_AUTHOR("Mathias Nyman <mathias.nyman@nokia.com>");
    MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
    MODULE_DESCRIPTION("LP5523 LED engine");
    MODULE_LICENSE("GPL");
    

    The schematic is as below:

    LP5569RTWR SCH.pdf

    Thanks,

    Best Regards

  • Hi Lumina, 

    Sorry for the late response. Is the low-level voltage reduced to <0.5V now? I have checked the Linux driver code and corresponding schematic; no obvious issue is detected from inspection.

    Best Regards,

    Aaron Bing