leds: driver for National Semiconductors LP5523 chip

LP5523 chip is nine channel led driver with programmable engines.  Driver
provides support for that chip for direct access via led class or via
programmable engines.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/leds/leds-lp5523.c

+/*
+ * lp5523.c - LP5523 LED Driver
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contact: Samu Onkalo <samu.p.onkalo@nokia.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/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/ctype.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/leds.h>
+#include <linux/leds-lp5523.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+
+#define LP5523_REG_ENABLE		0x00
+#define LP5523_REG_OP_MODE		0x01
+#define LP5523_REG_RATIOMETRIC_MSB	0x02
+#define LP5523_REG_RATIOMETRIC_LSB	0x03
+#define LP5523_REG_ENABLE_LEDS_MSB	0x04
+#define LP5523_REG_ENABLE_LEDS_LSB	0x05
+#define LP5523_REG_LED_CNTRL_BASE	0x06
+#define LP5523_REG_LED_PWM_BASE		0x16
+#define LP5523_REG_LED_CURRENT_BASE	0x26
+#define LP5523_REG_CONFIG		0x36
+#define LP5523_REG_CHANNEL1_PC		0x37
+#define LP5523_REG_CHANNEL2_PC		0x38
+#define LP5523_REG_CHANNEL3_PC		0x39
+#define LP5523_REG_STATUS		0x3a
+#define LP5523_REG_GPO			0x3b
+#define LP5523_REG_VARIABLE		0x3c
+#define LP5523_REG_RESET		0x3d
+#define LP5523_REG_TEMP_CTRL		0x3e
+#define LP5523_REG_TEMP_READ		0x3f
+#define LP5523_REG_TEMP_WRITE		0x40
+#define LP5523_REG_LED_TEST_CTRL	0x41
+#define LP5523_REG_LED_TEST_ADC		0x42
+#define LP5523_REG_ENG1_VARIABLE	0x45
+#define LP5523_REG_ENG2_VARIABLE	0x46
+#define LP5523_REG_ENG3_VARIABLE	0x47
+#define LP5523_REG_MASTER_FADER1	0x48
+#define LP5523_REG_MASTER_FADER2	0x49
+#define LP5523_REG_MASTER_FADER3	0x4a
+#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
+
+#define LP5523_CMD_LOAD			0x15 /* 00010101 */
+#define LP5523_CMD_RUN			0x2a /* 00101010 */
+#define LP5523_CMD_DISABLED		0x00 /* 00000000 */
+
+#define LP5523_ENABLE			0x40
+#define LP5523_AUTO_INC			0x40
+#define LP5523_PWR_SAVE			0x20
+#define LP5523_PWM_PWR_SAVE		0x04
+#define LP5523_CP_1			0x08
+#define LP5523_CP_1_5			0x10
+#define LP5523_CP_AUTO			0x18
+#define LP5523_INT_CLK			0x01
+#define LP5523_AUTO_CLK			0x02
+#define LP5523_EN_LEDTEST		0x80
+#define LP5523_LEDTEST_DONE		0x80
+
+#define LP5523_DEFAULT_CURRENT		50 /* microAmps */
+#define LP5523_PROGRAM_LENGTH		32 /* in bytes */
+#define LP5523_PROGRAM_PAGES		6
+#define LP5523_ADC_SHORTCIRC_LIM	80
+
+#define LP5523_LEDS			9
+#define LP5523_ENGINES			3
+
+#define LP5523_ENG_MASK_BASE		0x30 /* 00110000 */
+
+#define LP5523_ENG_STATUS_MASK          0x07 /* 00000111 */
+
+#define LP5523_IRQ_FLAGS                IRQF_TRIGGER_FALLING
+
+#define LP5523_EXT_CLK_USED		0x08
+
+#define LED_ACTIVE(mux, led)		(!!(mux & (0x0001 << led)))
+#define SHIFT_MASK(id)			(((id) - 1) * 2)
+
+struct lp5523_engine {
+	const struct attribute_group *attributes;
+	int		id;
+	u8		mode;
+	u8		prog_page;
+	u8		mux_page;
+	u16		led_mux;
+	u8		engine_mask;
+};
+
+struct lp5523_led {
+	int			id;
+	u8			chan_nr;
+	u8			led_current;
+	u8			max_current;
+	struct led_classdev     cdev;
+	struct work_struct	brightness_work;
+	u8			brightness;
+};
+
+struct lp5523_chip {
+	struct mutex		lock; /* Serialize control */
+	struct i2c_client	*client;
+	struct lp5523_engine	engines[LP5523_ENGINES];
+	struct lp5523_led	leds[LP5523_LEDS];
+	struct lp5523_platform_data *pdata;
+	u8			num_channels;
+	u8			num_leds;
+};
+
+#define cdev_to_led(c)          container_of(c, struct lp5523_led, cdev)
+
+static struct lp5523_chip *engine_to_lp5523(struct lp5523_engine *engine)
+{
+	return container_of(engine, struct lp5523_chip,
+			    engines[engine->id - 1]);
+}
+
+static struct lp5523_chip *led_to_lp5523(struct lp5523_led *led)
+{
+	return container_of(led, struct lp5523_chip,
+			    leds[led->id]);
+}
+
+static int lp5523_set_mode(struct lp5523_engine *engine, u8 mode);
+static int lp5523_set_engine_mode(struct lp5523_engine *engine, u8 mode);
+static int lp5523_load_program(struct lp5523_engine *engine, u8 *pattern);
+
+static void lp5523_led_brightness_work(struct work_struct *work);
+
+static int lp5523_write(struct i2c_client *client, u8 reg, u8 value)
+{
+	return i2c_smbus_write_byte_data(client, reg, value);
+}
+
+static int lp5523_read(struct i2c_client *client, u8 reg, u8 *buf)
+{
+	s32 ret = i2c_smbus_read_byte_data(client, reg);
+
+	if (ret < 0)
+		return -EIO;
+
+	*buf = ret;
+	return 0;
+}
+
+static int lp5523_detect(struct i2c_client *client)
+{
+	int ret;
+	u8 buf;
+
+	ret = lp5523_write(client, LP5523_REG_ENABLE, 0x40);
+	if (ret)
+		return ret;
+	ret = lp5523_read(client, LP5523_REG_ENABLE, &buf);
+	if (ret)
+		return ret;
+	if (buf == 0x40)
+		return 0;
+	else
+		return -ENODEV;
+}
+
+static int lp5523_configure(struct i2c_client *client)
+{
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	int ret = 0;
+	u8 status;
+
+	/* one pattern per engine setting led mux start and stop addresses */
+	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},
+	};
+
+	lp5523_write(client, LP5523_REG_RESET, 0xff);
+
+	usleep_range(10000, 100000);
+
+	ret |= lp5523_write(client, LP5523_REG_ENABLE, LP5523_ENABLE);
+	/* Chip startup time after reset is 500 us */
+	usleep_range(1000, 10000);
+
+	ret |= lp5523_write(client, LP5523_REG_CONFIG,
+			    LP5523_AUTO_INC | LP5523_PWR_SAVE |
+			    LP5523_CP_AUTO | LP5523_AUTO_CLK |
+			    LP5523_PWM_PWR_SAVE);
+
+	/* turn on all leds */
+	ret |= lp5523_write(client, LP5523_REG_ENABLE_LEDS_MSB, 0x01);
+	ret |= lp5523_write(client, LP5523_REG_ENABLE_LEDS_LSB, 0xff);
+
+	/* hardcode 32 bytes of memory for each engine from program memory */
+	ret |= lp5523_write(client, LP5523_REG_CH1_PROG_START, 0x00);
+	ret |= lp5523_write(client, LP5523_REG_CH2_PROG_START, 0x10);
+	ret |= lp5523_write(client, LP5523_REG_CH3_PROG_START, 0x20);
+
+	/* write led mux address space for each channel */
+	ret |= lp5523_load_program(&chip->engines[0], pattern[0]);
+	ret |= lp5523_load_program(&chip->engines[1], pattern[1]);
+	ret |= lp5523_load_program(&chip->engines[2], pattern[2]);
+
+	if (ret) {
+		dev_err(&client->dev, "could not load mux programs\n");
+		return -1;
+	}
+
+	/* set all engines exec state and mode to run 00101010 */
+	ret |= lp5523_write(client, LP5523_REG_ENABLE,
+			    (LP5523_CMD_RUN | LP5523_ENABLE));
+
+	ret |= lp5523_write(client, LP5523_REG_OP_MODE, LP5523_CMD_RUN);
+
+	if (ret) {
+		dev_err(&client->dev, "could not start mux programs\n");
+		return -1;
+	}
+
+	/* Wait 3ms and check the engine status */
+	usleep_range(3000, 20000);
+	lp5523_read(client, LP5523_REG_STATUS, &status);
+	status &= LP5523_ENG_STATUS_MASK;
+
+	if (status == LP5523_ENG_STATUS_MASK) {
+		dev_dbg(&client->dev, "all engines configured\n");
+	} else {
+		dev_info(&client->dev, "status == %x\n", status);
+		dev_err(&client->dev, "cound not configure LED engine\n");
+		return -1;
+	}
+
+	dev_info(&client->dev, "disabling engines\n");
+
+	ret |= lp5523_write(client, LP5523_REG_OP_MODE, LP5523_CMD_DISABLED);
+
+	return ret;
+}
+
+static int lp5523_set_engine_mode(struct lp5523_engine *engine, u8 mode)
+{
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+	int ret;
+	u8 engine_state;
+
+	ret = lp5523_read(client, LP5523_REG_OP_MODE, &engine_state);
+	if (ret)
+		goto fail;
+
+	engine_state &= ~(engine->engine_mask);
+
+	/* set mode only for this engine */
+	mode &= engine->engine_mask;
+
+	engine_state |= mode;
+
+	ret |= lp5523_write(client, LP5523_REG_OP_MODE, engine_state);
+fail:
+	return ret;
+}
+
+static int lp5523_load_mux(struct lp5523_engine *engine, u16 mux)
+{
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+	int ret = 0;
+
+	ret |= lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);
+
+	ret |= lp5523_write(client, LP5523_REG_PROG_PAGE_SEL, engine->mux_page);
+	ret |= lp5523_write(client, LP5523_REG_PROG_MEM,
+			    (u8)(mux >> 8));
+	ret |= lp5523_write(client, LP5523_REG_PROG_MEM + 1, (u8)(mux));
+	engine->led_mux = mux;
+
+	return ret;
+}
+
+static int lp5523_load_program(struct lp5523_engine *engine, u8 *pattern)
+{
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+
+	int ret = 0;
+
+	ret |= lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);
+
+	ret |= lp5523_write(client, LP5523_REG_PROG_PAGE_SEL,
+			    engine->prog_page);
+	ret |= i2c_smbus_write_i2c_block_data(client, LP5523_REG_PROG_MEM,
+					      LP5523_PROGRAM_LENGTH, pattern);
+
+	return ret;
+}
+
+static int lp5523_run_program(struct lp5523_engine *engine)
+{
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+	int ret;
+
+	ret = lp5523_write(client, LP5523_REG_ENABLE,
+					LP5523_CMD_RUN | LP5523_ENABLE);
+	if (ret)
+		goto fail;
+
+	ret = lp5523_set_engine_mode(engine, LP5523_CMD_RUN);
+fail:
+	return ret;
+}
+
+static int lp5523_mux_parse(const char *buf, u16 *mux, size_t len)
+{
+	int i;
+	u16 tmp_mux = 0;
+	len = len < LP5523_LEDS ? len : LP5523_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_LEDS; i++)
+		pos += sprintf(array + pos, "%x", LED_ACTIVE(led_mux, i));
+
+	array[pos] = '\0';
+}
+
+/*--------------------------------------------------------------*/
+/*			Sysfs interface				*/
+/*--------------------------------------------------------------*/
+
+static ssize_t show_engine_leds(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	char mux[LP5523_LEDS + 1];
+
+	lp5523_mux_to_array(chip->engines[nr - 1].led_mux, mux);
+
+	return sprintf(buf, "%s\n", mux);
+}
+
+#define show_leds(nr)							\
+static ssize_t show_engine##nr##_leds(struct device *dev,		\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	return show_engine_leds(dev, attr, buf, nr);			\
+}
+show_leds(1)
+show_leds(2)
+show_leds(3)
+
+static ssize_t store_engine_leds(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t len, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	u16 mux = 0;
+
+	if (lp5523_mux_parse(buf, &mux, len))
+		return -EINVAL;
+
+	if (lp5523_load_mux(&chip->engines[nr - 1], mux))
+		return -EINVAL;
+
+	return len;
+}
+
+#define store_leds(nr)						\
+static ssize_t store_engine##nr##_leds(struct device *dev,	\
+			     struct device_attribute *attr,	\
+			     const char *buf, size_t len)	\
+{								\
+	return store_engine_leds(dev, attr, buf, len, nr);	\
+}
+store_leds(1)
+store_leds(2)
+store_leds(3)
+
+static ssize_t lp5523_selftest(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	int i, ret, pos = 0;
+	int led = 0;
+	u8 status, adc, vdd;
+
+	mutex_lock(&chip->lock);
+
+	ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
+	if (ret < 0)
+		goto fail;
+
+	/* Check that ext clock is really in use if requested */
+	if ((chip->pdata) && (chip->pdata->clock_mode == LP5523_CLOCK_EXT))
+		if  ((status & LP5523_EXT_CLK_USED) == 0)
+			goto fail;
+
+	/* Measure VDD (i.e. VBAT) first (channel 16 corresponds to VDD) */
+	lp5523_write(chip->client, LP5523_REG_LED_TEST_CTRL,
+				    LP5523_EN_LEDTEST | 16);
+	usleep_range(3000, 10000);
+	ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
+	if (!(status & LP5523_LEDTEST_DONE))
+		usleep_range(3000, 10000);
+
+	ret |= lp5523_read(chip->client, LP5523_REG_LED_TEST_ADC, &vdd);
+	vdd--;	/* There may be some fluctuation in measurement */
+
+	for (i = 0; i < LP5523_LEDS; i++) {
+		/* Skip non-existing channels */
+		if (chip->pdata->led_config[i].led_current == 0)
+			continue;
+
+		/* Set default current */
+		lp5523_write(chip->client,
+			LP5523_REG_LED_CURRENT_BASE + i,
+			chip->pdata->led_config[i].led_current);
+
+		lp5523_write(chip->client, LP5523_REG_LED_PWM_BASE + i, 0xff);
+		/* let current stabilize 2ms before measurements start */
+		usleep_range(2000, 10000);
+		lp5523_write(chip->client,
+			     LP5523_REG_LED_TEST_CTRL,
+			     LP5523_EN_LEDTEST | i);
+		/* ledtest takes 2.7ms */
+		usleep_range(3000, 10000);
+		ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
+		if (!(status & LP5523_LEDTEST_DONE))
+			usleep_range(3000, 10000);
+		ret |= lp5523_read(chip->client, LP5523_REG_LED_TEST_ADC, &adc);
+
+		if (adc >= vdd || adc < LP5523_ADC_SHORTCIRC_LIM)
+			pos += sprintf(buf + pos, "LED %d FAIL\n", i);
+
+		lp5523_write(chip->client, LP5523_REG_LED_PWM_BASE + i, 0x00);
+
+		/* Restore current */
+		lp5523_write(chip->client,
+			LP5523_REG_LED_CURRENT_BASE + i,
+			chip->leds[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;
+}
+
+static void lp5523_set_brightness(struct led_classdev *cdev,
+			     enum led_brightness brightness)
+{
+	struct lp5523_led *led = cdev_to_led(cdev);
+
+	led->brightness = (u8)brightness;
+
+	schedule_work(&led->brightness_work);
+}
+
+static void lp5523_led_brightness_work(struct work_struct *work)
+{
+	struct lp5523_led *led = container_of(work,
+					      struct lp5523_led,
+					      brightness_work);
+	struct lp5523_chip *chip = led_to_lp5523(led);
+	struct i2c_client *client = chip->client;
+
+	mutex_lock(&chip->lock);
+
+	lp5523_write(client, LP5523_REG_LED_PWM_BASE + led->chan_nr,
+		     led->brightness);
+
+	mutex_unlock(&chip->lock);
+}
+
+static int lp5523_do_store_load(struct lp5523_engine *engine,
+				const char *buf, size_t len)
+{
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+	int  ret, nrchars, offset = 0, i = 0;
+	char c[3];
+	unsigned cmd;
+	u8 pattern[LP5523_PROGRAM_LENGTH] = {0};
+
+	while ((offset < len - 1) && (i < LP5523_PROGRAM_LENGTH)) {
+		/* separate sscanfs because length is working only for %s */
+		ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);
+		ret = sscanf(c, "%2x", &cmd);
+		if (ret != 1)
+			goto fail;
+		pattern[i] = (u8)cmd;
+
+		offset += nrchars;
+		i++;
+	}
+
+	/* Each instruction is 16bit long. Check that length is even */
+	if (i % 2)
+		goto fail;
+
+	mutex_lock(&chip->lock);
+
+	ret = lp5523_load_program(engine, pattern);
+	mutex_unlock(&chip->lock);
+
+	if (ret) {
+		dev_err(&client->dev, "failed loading pattern\n");
+		return ret;
+	}
+
+	return len;
+fail:
+	dev_err(&client->dev, "wrong pattern format\n");
+	return -EINVAL;
+}
+
+static ssize_t store_engine_load(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	return lp5523_do_store_load(&chip->engines[nr - 1], buf, len);
+}
+
+#define store_load(nr)							\
+static ssize_t store_engine##nr##_load(struct device *dev,		\
+				     struct device_attribute *attr,	\
+				     const char *buf, size_t len)	\
+{									\
+	return store_engine_load(dev, attr, buf, len, nr);		\
+}
+store_load(1)
+store_load(2)
+store_load(3)
+
+static ssize_t show_engine_mode(struct device *dev,
+				struct device_attribute *attr,
+				char *buf, int nr)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	switch (chip->engines[nr - 1].mode) {
+	case LP5523_CMD_RUN:
+		return sprintf(buf, "run\n");
+	case LP5523_CMD_LOAD:
+		return sprintf(buf, "load\n");
+	case LP5523_CMD_DISABLED:
+		return sprintf(buf, "disabled\n");
+	default:
+		return sprintf(buf, "disabled\n");
+	}
+}
+
+#define show_mode(nr)							\
+static ssize_t show_engine##nr##_mode(struct device *dev,		\
+				    struct device_attribute *attr,	\
+				    char *buf)				\
+{									\
+	return show_engine_mode(dev, attr, buf, nr);			\
+}
+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 i2c_client *client = to_i2c_client(dev);
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	struct lp5523_engine *engine = &chip->engines[nr - 1];
+	mutex_lock(&chip->lock);
+
+	if (!strncmp(buf, "run", 3))
+		lp5523_set_mode(engine, LP5523_CMD_RUN);
+	else if (!strncmp(buf, "load", 4))
+		lp5523_set_mode(engine, LP5523_CMD_LOAD);
+	else if (!strncmp(buf, "disabled", 8))
+		lp5523_set_mode(engine, LP5523_CMD_DISABLED);
+
+	mutex_unlock(&chip->lock);
+	return len;
+}
+
+#define store_mode(nr)							\
+static ssize_t store_engine##nr##_mode(struct device *dev,		\
+				     struct device_attribute *attr,	\
+				     const char *buf, size_t len)	\
+{									\
+	return store_engine_mode(dev, attr, buf, len, nr);		\
+}
+store_mode(1)
+store_mode(2)
+store_mode(3)
+
+static ssize_t show_max_current(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct lp5523_led *led = cdev_to_led(led_cdev);
+
+	return sprintf(buf, "%d\n", led->max_current);
+}
+
+static ssize_t show_current(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct lp5523_led *led = cdev_to_led(led_cdev);
+
+	return sprintf(buf, "%d\n", led->led_current);
+}
+
+static ssize_t store_current(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t len)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct lp5523_led *led = cdev_to_led(led_cdev);
+	struct lp5523_chip *chip = led_to_lp5523(led);
+	ssize_t ret;
+	unsigned long curr;
+
+	if (strict_strtoul(buf, 0, &curr))
+		return -EINVAL;
+
+	if (curr > led->max_current)
+		return -EINVAL;
+
+	mutex_lock(&chip->lock);
+	ret = lp5523_write(chip->client,
+			LP5523_REG_LED_CURRENT_BASE + led->chan_nr,
+			(u8)curr);
+	mutex_unlock(&chip->lock);
+
+	if (ret < 0)
+		return ret;
+
+	led->led_current = (u8)curr;
+
+	return len;
+}
+
+/* led class device attributes */
+static DEVICE_ATTR(led_current, S_IRUGO | S_IWUGO, show_current, store_current);
+static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);
+
+static struct attribute *lp5523_led_attributes[] = {
+	&dev_attr_led_current.attr,
+	&dev_attr_max_current.attr,
+	NULL,
+};
+
+static struct attribute_group lp5523_led_attribute_group = {
+	.attrs = lp5523_led_attributes
+};
+
+/* device attributes */
+static DEVICE_ATTR(engine1_mode, S_IRUGO | S_IWUGO,
+		   show_engine1_mode, store_engine1_mode);
+static DEVICE_ATTR(engine2_mode, S_IRUGO | S_IWUGO,
+		   show_engine2_mode, store_engine2_mode);
+static DEVICE_ATTR(engine3_mode, S_IRUGO | S_IWUGO,
+		   show_engine3_mode, store_engine3_mode);
+static DEVICE_ATTR(engine1_leds, S_IRUGO | S_IWUGO,
+		   show_engine1_leds, store_engine1_leds);
+static DEVICE_ATTR(engine2_leds, S_IRUGO | S_IWUGO,
+		   show_engine2_leds, store_engine2_leds);
+static DEVICE_ATTR(engine3_leds, S_IRUGO | S_IWUGO,
+		   show_engine3_leds, store_engine3_leds);
+static DEVICE_ATTR(engine1_load, S_IWUGO, NULL, store_engine1_load);
+static DEVICE_ATTR(engine2_load, S_IWUGO, NULL, store_engine2_load);
+static DEVICE_ATTR(engine3_load, S_IWUGO, NULL, store_engine3_load);
+static DEVICE_ATTR(selftest, S_IRUGO, lp5523_selftest, NULL);
+
+static struct attribute *lp5523_attributes[] = {
+	&dev_attr_engine1_mode.attr,
+	&dev_attr_engine2_mode.attr,
+	&dev_attr_engine3_mode.attr,
+	&dev_attr_selftest.attr,
+	NULL
+};
+
+static struct attribute *lp5523_engine1_attributes[] = {
+	&dev_attr_engine1_load.attr,
+	&dev_attr_engine1_leds.attr,
+	NULL
+};
+
+static struct attribute *lp5523_engine2_attributes[] = {
+	&dev_attr_engine2_load.attr,
+	&dev_attr_engine2_leds.attr,
+	NULL
+};
+
+static struct attribute *lp5523_engine3_attributes[] = {
+	&dev_attr_engine3_load.attr,
+	&dev_attr_engine3_leds.attr,
+	NULL
+};
+
+static const struct attribute_group lp5523_group = {
+	.attrs = lp5523_attributes,
+};
+
+static const struct attribute_group lp5523_engine_group[] = {
+	{.attrs = lp5523_engine1_attributes },
+	{.attrs = lp5523_engine2_attributes },
+	{.attrs = lp5523_engine3_attributes },
+};
+
+static int lp5523_register_sysfs(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	int ret;
+
+	ret = sysfs_create_group(&dev->kobj, &lp5523_group);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void lp5523_unregister_sysfs(struct i2c_client *client)
+{
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	struct device *dev = &client->dev;
+	int i;
+
+	sysfs_remove_group(&dev->kobj, &lp5523_group);
+
+	for (i = 0; i < ARRAY_SIZE(chip->engines); i++)
+		if (chip->engines[i].mode == LP5523_CMD_LOAD)
+			sysfs_remove_group(&dev->kobj, &lp5523_engine_group[i]);
+
+	for (i = 0; i < chip->num_leds; i++)
+		sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
+				&lp5523_led_attribute_group);
+}
+
+/*--------------------------------------------------------------*/
+/*			Set chip operating mode			*/
+/*--------------------------------------------------------------*/
+static int lp5523_set_mode(struct lp5523_engine *engine, u8 mode)
+{
+	/*  engine to chip */
+	struct lp5523_chip *chip = engine_to_lp5523(engine);
+	struct i2c_client *client = chip->client;
+	struct device *dev = &client->dev;
+	int ret = 0;
+
+	/* if in that mode already do nothing, except for run */
+	if (mode == engine->mode && mode != LP5523_CMD_RUN)
+		return 0;
+
+	if (mode == LP5523_CMD_RUN) {
+		ret = lp5523_run_program(engine);
+	} else if (mode == LP5523_CMD_LOAD) {
+		lp5523_set_engine_mode(engine, LP5523_CMD_DISABLED);
+		lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);
+
+		ret = sysfs_create_group(&dev->kobj, engine->attributes);
+		if (ret)
+			return ret;
+	} else if (mode == LP5523_CMD_DISABLED) {
+		lp5523_set_engine_mode(engine, LP5523_CMD_DISABLED);
+	}
+
+	/* remove load attribute from sysfs if not in load mode */
+	if (engine->mode == LP5523_CMD_LOAD && mode != LP5523_CMD_LOAD)
+		sysfs_remove_group(&dev->kobj, engine->attributes);
+
+	engine->mode = mode;
+
+	return ret;
+}
+
+/*--------------------------------------------------------------*/
+/*			Probe, Attach, Remove			*/
+/*--------------------------------------------------------------*/
+static int __init lp5523_init_engine(struct lp5523_engine *engine, int id)
+{
+	if (id < 1 || id > LP5523_ENGINES)
+		return -1;
+	engine->id = id;
+	engine->engine_mask = LP5523_ENG_MASK_BASE >> SHIFT_MASK(id);
+	engine->prog_page = id - 1;
+	engine->mux_page = id + 2;
+	engine->attributes = &lp5523_engine_group[id - 1];
+
+	return 0;
+}
+
+static int __init lp5523_init_led(struct lp5523_led *led, struct device *dev,
+			   int chan, struct lp5523_platform_data *pdata)
+{
+	char name[32];
+	int res;
+
+	if (chan >= LP5523_LEDS)
+		return -EINVAL;
+
+	if (pdata->led_config[chan].led_current) {
+		led->led_current = pdata->led_config[chan].led_current;
+		led->max_current = pdata->led_config[chan].max_current;
+		led->chan_nr = pdata->led_config[chan].chan_nr;
+
+		if (led->chan_nr >= LP5523_LEDS) {
+			dev_err(dev, "Use channel numbers between 0 and %d\n",
+				LP5523_LEDS - 1);
+			return -EINVAL;
+		}
+
+		snprintf(name, 32, "lp5523:channel%d", chan);
+
+		led->cdev.name = name;
+		led->cdev.brightness_set = lp5523_set_brightness;
+		res = led_classdev_register(dev, &led->cdev);
+		if (res < 0) {
+			dev_err(dev, "couldn't register led on channel %d\n",
+				chan);
+			return res;
+		}
+		res = sysfs_create_group(&led->cdev.dev->kobj,
+				&lp5523_led_attribute_group);
+		if (res < 0) {
+			dev_err(dev, "couldn't register current attribute\n");
+			led_classdev_unregister(&led->cdev);
+			return res;
+		}
+	} else {
+		led->led_current = 0;
+	}
+	return 0;
+}
+
+static struct i2c_driver lp5523_driver;
+
+static int lp5523_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct lp5523_chip		*chip;
+	struct lp5523_platform_data	*pdata;
+	int ret, i, led;
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, chip);
+	chip->client = client;
+
+	pdata = client->dev.platform_data;
+
+	if (!pdata) {
+		dev_err(&client->dev, "no platform data\n");
+		ret = -EINVAL;
+		goto fail1;
+	}
+
+	mutex_init(&chip->lock);
+
+	chip->pdata   = pdata;
+
+	if (pdata->setup_resources) {
+		ret = pdata->setup_resources();
+		if (ret < 0)
+			goto fail1;
+	}
+
+	if (pdata->enable) {
+		pdata->enable(0);
+		usleep_range(1000, 10000);
+		pdata->enable(1);
+		usleep_range(1000, 10000); /* Spec says min 500us */
+	}
+
+	ret = lp5523_detect(client);
+	if (ret)
+		goto fail2;
+
+	dev_info(&client->dev, "LP5523 Programmable led chip found\n");
+
+	/* Initialize engines */
+	for (i = 0; i < ARRAY_SIZE(chip->engines); i++) {
+		ret = lp5523_init_engine(&chip->engines[i], i + 1);
+		if (ret) {
+			dev_err(&client->dev, "error initializing engine\n");
+			goto fail2;
+		}
+	}
+	ret = lp5523_configure(client);
+	if (ret < 0) {
+		dev_err(&client->dev, "error configuring chip\n");
+		goto fail2;
+	}
+
+	/* Initialize leds */
+	chip->num_channels = pdata->num_channels;
+	chip->num_leds = 0;
+	led = 0;
+	for (i = 0; i < pdata->num_channels; i++) {
+		/* Do not initialize channels that are not connected */
+		if (pdata->led_config[i].led_current == 0)
+			continue;
+
+		ret = lp5523_init_led(&chip->leds[led], &client->dev, i, pdata);
+		if (ret) {
+			dev_err(&client->dev, "error initializing leds\n");
+			goto fail3;
+		}
+		chip->num_leds++;
+
+		chip->leds[led].id = led;
+		/* Set LED current */
+		lp5523_write(client,
+			  LP5523_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
+			  chip->leds[led].led_current);
+
+		INIT_WORK(&(chip->leds[led].brightness_work),
+			lp5523_led_brightness_work);
+
+		led++;
+	}
+
+	ret = lp5523_register_sysfs(client);
+	if (ret) {
+		dev_err(&client->dev, "registering sysfs failed\n");
+		goto fail3;
+	}
+	return ret;
+fail3:
+	for (i = 0; i < chip->num_leds; i++) {
+		led_classdev_unregister(&chip->leds[i].cdev);
+		cancel_work_sync(&chip->leds[i].brightness_work);
+	}
+fail2:
+	if (pdata->enable)
+		pdata->enable(0);
+	if (pdata->release_resources)
+		pdata->release_resources();
+fail1:
+	kfree(chip);
+	return ret;
+}
+
+static int lp5523_remove(struct i2c_client *client)
+{
+	struct lp5523_chip *chip = i2c_get_clientdata(client);
+	int i;
+
+	lp5523_unregister_sysfs(client);
+
+	for (i = 0; i < chip->num_leds; i++) {
+		led_classdev_unregister(&chip->leds[i].cdev);
+		cancel_work_sync(&chip->leds[i].brightness_work);
+	}
+
+	if (chip->pdata->enable)
+		chip->pdata->enable(0);
+	if (chip->pdata->release_resources)
+		chip->pdata->release_resources();
+	kfree(chip);
+	return 0;
+}
+
+static const struct i2c_device_id lp5523_id[] = {
+	{ "lp5523", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, lp5523_id);
+
+static struct i2c_driver lp5523_driver = {
+	.driver = {
+		.name	= "lp5523",
+	},
+	.probe		= lp5523_probe,
+	.remove		= lp5523_remove,
+	.id_table	= lp5523_id,
+};
+
+static int __init lp5523_init(void)
+{
+	int ret;
+
+	ret = i2c_add_driver(&lp5523_driver);
+
+	if (ret < 0)
+		printk(KERN_ALERT "Adding lp5523 driver failed\n");
+
+	return ret;
+}
+
+static void __exit lp5523_exit(void)
+{
+	i2c_del_driver(&lp5523_driver);
+}
+
+module_init(lp5523_init);
+module_exit(lp5523_exit);
+
+MODULE_AUTHOR("Mathias Nyman <mathias.nyman@nokia.com>");
+MODULE_DESCRIPTION("LP5523 LED engine");
+MODULE_LICENSE("GPL");

include/linux/leds-lp5523.h

+/*
+ * LP5523 LED Driver
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contact: Samu Onkalo <samu.p.onkalo@nokia.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
+ */
+
+#ifndef __LINUX_LP5523_H
+#define __LINUX_LP5523_H
+
+/* See Documentation/leds/leds-lp5523.txt */
+
+struct lp5523_led_config {
+	u8		chan_nr;
+	u8		led_current; /* mA x10, 0 if led is not connected */
+	u8		max_current;
+};
+
+#define LP5523_CLOCK_AUTO	0
+#define LP5523_CLOCK_INT	1
+#define LP5523_CLOCK_EXT	2
+
+struct lp5523_platform_data {
+	struct lp5523_led_config *led_config;
+	u8	num_channels;
+	u8	clock_mode;
+	int	(*setup_resources)(void);
+	void	(*release_resources)(void);
+	void	(*enable)(bool state);
+};
+
+#endif /* __LINUX_LP5523_H */