Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 845 insertions, 0 deletions

diff --git a/kernel/drivers/leds/leds-tca6507.c b/kernel/drivers/leds/leds-tca6507.c
new file mode 100644
index 000000000..20fa8e77f
--- /dev/null
+++ b/kernel/drivers/leds/leds-tca6507.c
@@ -0,0 +1,845 @@
+/*
+ * leds-tca6507
+ *
+ * The TCA6507 is a programmable LED controller that can drive 7
+ * separate lines either by holding them low, or by pulsing them
+ * with modulated width.
+ * The modulation can be varied in a simple pattern to produce a
+ * blink or double-blink.
+ *
+ * This driver can configure each line either as a 'GPIO' which is
+ * out-only (pull-up resistor required) or as an LED with variable
+ * brightness and hardware-assisted blinking.
+ *
+ * Apart from OFF and ON there are three programmable brightness
+ * levels which can be programmed from 0 to 15 and indicate how many
+ * 500usec intervals in each 8msec that the led is 'on'.  The levels
+ * are named MASTER, BANK0 and BANK1.
+ *
+ * There are two different blink rates that can be programmed, each
+ * with separate time for rise, on, fall, off and second-off.  Thus if
+ * 3 or more different non-trivial rates are required, software must
+ * be used for the extra rates. The two different blink rates must
+ * align with the two levels BANK0 and BANK1.  This driver does not
+ * support double-blink so 'second-off' always matches 'off'.
+ *
+ * Only 16 different times can be programmed in a roughly logarithmic
+ * scale from 64ms to 16320ms.  To be precise the possible times are:
+ *    0, 64, 128, 192, 256, 384, 512, 768,
+ *    1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
+ *
+ * Times that cannot be closely matched with these must be handled in
+ * software.  This driver allows 12.5% error in matching.
+ *
+ * This driver does not allow rise/fall rates to be set explicitly.
+ * When trying to match a given 'on' or 'off' period, an appropriate
+ * pair of 'change' and 'hold' times are chosen to get a close match.
+ * If the target delay is even, the 'change' number will be the
+ * smaller; if odd, the 'hold' number will be the smaller.
+
+ * Choosing pairs of delays with 12.5% errors allows us to match
+ * delays in the ranges: 56-72, 112-144, 168-216, 224-27504,
+ * 28560-36720.
+ * 26% of the achievable sums can be matched by multiple pairings.
+ * For example 1536 == 1536+0, 1024+512, or 768+768.
+ * This driver will always choose the pairing with the least
+ * maximum - 768+768 in this case.  Other pairings are not available.
+ *
+ * Access to the 3 levels and 2 blinks are on a first-come,
+ * first-served basis.  Access can be shared by multiple leds if they
+ * have the same level and either same blink rates, or some don't
+ * blink.  When a led changes, it relinquishes access and tries again,
+ * so it might lose access to hardware blink.
+ *
+ * If a blink engine cannot be allocated, software blink is used.  If
+ * the desired brightness cannot be allocated, the closest available
+ * non-zero brightness is used.  As 'full' is always available, the
+ * worst case would be to have two different blink rates at '1', with
+ * Max at '2', then other leds will have to choose between '2' and
+ * '16'.  Hopefully this is not likely.
+ *
+ * Each bank (BANK0 and BANK1) has two usage counts - LEDs using the
+ * brightness and LEDs using the blink.  It can only be reprogrammed
+ * when the appropriate counter is zero.  The MASTER level has a
+ * single usage count.
+ *
+ * Each LED has programmable 'on' and 'off' time as milliseconds.
+ * With each there is a flag saying if it was explicitly requested or
+ * defaulted.  Similarly the banks know if each time was explicit or a
+ * default.  Defaults are permitted to be changed freely - they are
+ * not recognised when matching.
+ *
+ *
+ * An led-tca6507 device must be provided with platform data or
+ * configured via devicetree.
+ *
+ * The platform-data lists for each output: the name, default trigger,
+ * and whether the signal is being used as a GPIO rather than an LED.
+ * 'struct led_plaform_data' is used for this.  If 'name' is NULL, the
+ * output isn't used.  If 'flags' is TCA6507_MAKE_GPIO, the output is
+ * a GPO.  The "struct led_platform_data" can be embedded in a "struct
+ * tca6507_platform_data" which adds a 'gpio_base' for the GPIOs, and
+ * a 'setup' callback which is called once the GPIOs are available.
+ *
+ * When configured via devicetree there is one child for each output.
+ * The "reg" determines the output number and "compatible" determines
+ * whether it is an LED or a GPIO.  "linux,default-trigger" can set a
+ * default trigger.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/workqueue.h>
+#include <linux/leds-tca6507.h>
+#include <linux/of.h>
+
+/* LED select registers determine the source that drives LED outputs */
+#define TCA6507_LS_LED_OFF	0x0	/* Output HI-Z (off) */
+#define TCA6507_LS_LED_OFF1	0x1	/* Output HI-Z (off) - not used */
+#define TCA6507_LS_LED_PWM0	0x2	/* Output LOW with Bank0 rate */
+#define TCA6507_LS_LED_PWM1	0x3	/* Output LOW with Bank1 rate */
+#define TCA6507_LS_LED_ON	0x4	/* Output LOW (on) */
+#define TCA6507_LS_LED_MIR	0x5	/* Output LOW with Master Intensity */
+#define TCA6507_LS_BLINK0	0x6	/* Blink at Bank0 rate */
+#define TCA6507_LS_BLINK1	0x7	/* Blink at Bank1 rate */
+
+enum {
+	BANK0,
+	BANK1,
+	MASTER,
+};
+static int bank_source[3] = {
+	TCA6507_LS_LED_PWM0,
+	TCA6507_LS_LED_PWM1,
+	TCA6507_LS_LED_MIR,
+};
+static int blink_source[2] = {
+	TCA6507_LS_BLINK0,
+	TCA6507_LS_BLINK1,
+};
+
+/* PWM registers */
+#define	TCA6507_REG_CNT			11
+
+/*
+ * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output
+ * owns one bit in each register
+ */
+#define	TCA6507_FADE_ON			0x03
+#define	TCA6507_FULL_ON			0x04
+#define	TCA6507_FADE_OFF		0x05
+#define	TCA6507_FIRST_OFF		0x06
+#define	TCA6507_SECOND_OFF		0x07
+#define	TCA6507_MAX_INTENSITY		0x08
+#define	TCA6507_MASTER_INTENSITY	0x09
+#define	TCA6507_INITIALIZE		0x0A
+
+#define	INIT_CODE			0x8
+
+#define TIMECODES 16
+static int time_codes[TIMECODES] = {
+	0, 64, 128, 192, 256, 384, 512, 768,
+	1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320
+};
+
+/* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */
+static inline int TO_LEVEL(int brightness)
+{
+	return brightness >> 4;
+}
+
+/* ...and convert back */
+static inline int TO_BRIGHT(int level)
+{
+	if (level)
+		return (level << 4) | 0xf;
+	return 0;
+}
+
+#define NUM_LEDS 7
+struct tca6507_chip {
+	int			reg_set;	/* One bit per register where
+						 * a '1' means the register
+						 * should be written */
+	u8			reg_file[TCA6507_REG_CNT];
+	/* Bank 2 is Master Intensity and doesn't use times */
+	struct bank {
+		int level;
+		int ontime, offtime;
+		int on_dflt, off_dflt;
+		int time_use, level_use;
+	} bank[3];
+	struct i2c_client	*client;
+	struct work_struct	work;
+	spinlock_t		lock;
+
+	struct tca6507_led {
+		struct tca6507_chip	*chip;
+		struct led_classdev	led_cdev;
+		int			num;
+		int			ontime, offtime;
+		int			on_dflt, off_dflt;
+		int			bank;	/* Bank used, or -1 */
+		int			blink;	/* Set if hardware-blinking */
+	} leds[NUM_LEDS];
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip		gpio;
+	const char			*gpio_name[NUM_LEDS];
+	int				gpio_map[NUM_LEDS];
+#endif
+};
+
+static const struct i2c_device_id tca6507_id[] = {
+	{ "tca6507" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tca6507_id);
+
+static int choose_times(int msec, int *c1p, int *c2p)
+{
+	/*
+	 * Choose two timecodes which add to 'msec' as near as
+	 * possible.  The first returned is the 'on' or 'off' time.
+	 * The second is to be used as a 'fade-on' or 'fade-off' time.
+	 * If 'msec' is even, the first will not be smaller than the
+	 * second.  If 'msec' is odd, the first will not be larger
+	 * than the second.
+	 * If we cannot get a sum within 1/8 of 'msec' fail with
+	 * -EINVAL, otherwise return the sum that was achieved, plus 1
+	 * if the first is smaller.
+	 * If two possibilities are equally good (e.g. 512+0,
+	 * 256+256), choose the first pair so there is more
+	 * change-time visible (i.e. it is softer).
+	 */
+	int c1, c2;
+	int tmax = msec * 9 / 8;
+	int tmin = msec * 7 / 8;
+	int diff = 65536;
+
+	/* We start at '1' to ensure we never even think of choosing a
+	 * total time of '0'.
+	 */
+	for (c1 = 1; c1 < TIMECODES; c1++) {
+		int t = time_codes[c1];
+		if (t*2 < tmin)
+			continue;
+		if (t > tmax)
+			break;
+		for (c2 = 0; c2 <= c1; c2++) {
+			int tt = t + time_codes[c2];
+			int d;
+			if (tt < tmin)
+				continue;
+			if (tt > tmax)
+				break;
+			/* This works! */
+			d = abs(msec - tt);
+			if (d >= diff)
+				continue;
+			/* Best yet */
+			*c1p = c1;
+			*c2p = c2;
+			diff = d;
+			if (d == 0)
+				return msec;
+		}
+	}
+	if (diff < 65536) {
+		int actual;
+		if (msec & 1) {
+			c1 = *c2p;
+			*c2p = *c1p;
+			*c1p = c1;
+		}
+		actual = time_codes[*c1p] + time_codes[*c2p];
+		if (*c1p < *c2p)
+			return actual + 1;
+		else
+			return actual;
+	}
+	/* No close match */
+	return -EINVAL;
+}
+
+/*
+ * Update the register file with the appropriate 3-bit state for the
+ * given led.
+ */
+static void set_select(struct tca6507_chip *tca, int led, int val)
+{
+	int mask = (1 << led);
+	int bit;
+
+	for (bit = 0; bit < 3; bit++) {
+		int n = tca->reg_file[bit] & ~mask;
+		if (val & (1 << bit))
+			n |= mask;
+		if (tca->reg_file[bit] != n) {
+			tca->reg_file[bit] = n;
+			tca->reg_set |= (1 << bit);
+		}
+	}
+}
+
+/* Update the register file with the appropriate 4-bit code for one
+ * bank or other.  This can be used for timers, for levels, or for
+ * initialization.
+ */
+static void set_code(struct tca6507_chip *tca, int reg, int bank, int new)
+{
+	int mask = 0xF;
+	int n;
+	if (bank) {
+		mask <<= 4;
+		new <<= 4;
+	}
+	n = tca->reg_file[reg] & ~mask;
+	n |= new;
+	if (tca->reg_file[reg] != n) {
+		tca->reg_file[reg] = n;
+		tca->reg_set |= 1 << reg;
+	}
+}
+
+/* Update brightness level. */
+static void set_level(struct tca6507_chip *tca, int bank, int level)
+{
+	switch (bank) {
+	case BANK0:
+	case BANK1:
+		set_code(tca, TCA6507_MAX_INTENSITY, bank, level);
+		break;
+	case MASTER:
+		set_code(tca, TCA6507_MASTER_INTENSITY, 0, level);
+		break;
+	}
+	tca->bank[bank].level = level;
+}
+
+/* Record all relevant time codes for a given bank */
+static void set_times(struct tca6507_chip *tca, int bank)
+{
+	int c1, c2;
+	int result;
+
+	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
+	dev_dbg(&tca->client->dev,
+		"Chose on  times %d(%d) %d(%d) for %dms\n",
+		c1, time_codes[c1],
+		c2, time_codes[c2], tca->bank[bank].ontime);
+	set_code(tca, TCA6507_FADE_ON, bank, c2);
+	set_code(tca, TCA6507_FULL_ON, bank, c1);
+	tca->bank[bank].ontime = result;
+
+	result = choose_times(tca->bank[bank].offtime, &c1, &c2);
+	dev_dbg(&tca->client->dev,
+		"Chose off times %d(%d) %d(%d) for %dms\n",
+		c1, time_codes[c1],
+		c2, time_codes[c2], tca->bank[bank].offtime);
+	set_code(tca, TCA6507_FADE_OFF, bank, c2);
+	set_code(tca, TCA6507_FIRST_OFF, bank, c1);
+	set_code(tca, TCA6507_SECOND_OFF, bank, c1);
+	tca->bank[bank].offtime = result;
+
+	set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE);
+}
+
+/* Write all needed register of tca6507 */
+
+static void tca6507_work(struct work_struct *work)
+{
+	struct tca6507_chip *tca = container_of(work, struct tca6507_chip,
+						work);
+	struct i2c_client *cl = tca->client;
+	int set;
+	u8 file[TCA6507_REG_CNT];
+	int r;
+
+	spin_lock_irq(&tca->lock);
+	set = tca->reg_set;
+	memcpy(file, tca->reg_file, TCA6507_REG_CNT);
+	tca->reg_set = 0;
+	spin_unlock_irq(&tca->lock);
+
+	for (r = 0; r < TCA6507_REG_CNT; r++)
+		if (set & (1<<r))
+			i2c_smbus_write_byte_data(cl, r, file[r]);
+}
+
+static void led_release(struct tca6507_led *led)
+{
+	/* If led owns any resource, release it. */
+	struct tca6507_chip *tca = led->chip;
+	if (led->bank >= 0) {
+		struct bank *b = tca->bank + led->bank;
+		if (led->blink)
+			b->time_use--;
+		b->level_use--;
+	}
+	led->blink = 0;
+	led->bank = -1;
+}
+
+static int led_prepare(struct tca6507_led *led)
+{
+	/* Assign this led to a bank, configuring that bank if
+	 * necessary. */
+	int level = TO_LEVEL(led->led_cdev.brightness);
+	struct tca6507_chip *tca = led->chip;
+	int c1, c2;
+	int i;
+	struct bank *b;
+	int need_init = 0;
+
+	led->led_cdev.brightness = TO_BRIGHT(level);
+	if (level == 0) {
+		set_select(tca, led->num, TCA6507_LS_LED_OFF);
+		return 0;
+	}
+
+	if (led->ontime == 0 || led->offtime == 0) {
+		/*
+		 * Just set the brightness, choosing first usable
+		 * bank.  If none perfect, choose best.  Count
+		 * backwards so we check MASTER bank first to avoid
+		 * wasting a timer.
+		 */
+		int best = -1;/* full-on */
+		int diff = 15-level;
+
+		if (level == 15) {
+			set_select(tca, led->num, TCA6507_LS_LED_ON);
+			return 0;
+		}
+
+		for (i = MASTER; i >= BANK0; i--) {
+			int d;
+			if (tca->bank[i].level == level ||
+			    tca->bank[i].level_use == 0) {
+				best = i;
+				break;
+			}
+			d = abs(level - tca->bank[i].level);
+			if (d < diff) {
+				diff = d;
+				best = i;
+			}
+		}
+		if (best == -1) {
+			/* Best brightness is full-on */
+			set_select(tca, led->num, TCA6507_LS_LED_ON);
+			led->led_cdev.brightness = LED_FULL;
+			return 0;
+		}
+
+		if (!tca->bank[best].level_use)
+			set_level(tca, best, level);
+
+		tca->bank[best].level_use++;
+		led->bank = best;
+		set_select(tca, led->num, bank_source[best]);
+		led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level);
+		return 0;
+	}
+
+	/*
+	 * We have on/off time so we need to try to allocate a timing
+	 * bank.  First check if times are compatible with hardware
+	 * and give up if not.
+	 */
+	if (choose_times(led->ontime, &c1, &c2) < 0)
+		return -EINVAL;
+	if (choose_times(led->offtime, &c1, &c2) < 0)
+		return -EINVAL;
+
+	for (i = BANK0; i <= BANK1; i++) {
+		if (tca->bank[i].level_use == 0)
+			/* not in use - it is ours! */
+			break;
+		if (tca->bank[i].level != level)
+			/* Incompatible level - skip */
+			/* FIX: if timer matches we maybe should consider
+			 * this anyway...
+			 */
+			continue;
+
+		if (tca->bank[i].time_use == 0)
+			/* Timer not in use, and level matches - use it */
+			break;
+
+		if (!(tca->bank[i].on_dflt ||
+		      led->on_dflt ||
+		      tca->bank[i].ontime == led->ontime))
+			/* on time is incompatible */
+			continue;
+
+		if (!(tca->bank[i].off_dflt ||
+		      led->off_dflt ||
+		      tca->bank[i].offtime == led->offtime))
+			/* off time is incompatible */
+			continue;
+
+		/* looks like a suitable match */
+		break;
+	}
+
+	if (i > BANK1)
+		/* Nothing matches - how sad */
+		return -EINVAL;
+
+	b = &tca->bank[i];
+	if (b->level_use == 0)
+		set_level(tca, i, level);
+	b->level_use++;
+	led->bank = i;
+
+	if (b->on_dflt ||
+	    !led->on_dflt ||
+	    b->time_use == 0) {
+		b->ontime = led->ontime;
+		b->on_dflt = led->on_dflt;
+		need_init = 1;
+	}
+
+	if (b->off_dflt ||
+	    !led->off_dflt ||
+	    b->time_use == 0) {
+		b->offtime = led->offtime;
+		b->off_dflt = led->off_dflt;
+		need_init = 1;
+	}
+
+	if (need_init)
+		set_times(tca, i);
+
+	led->ontime = b->ontime;
+	led->offtime = b->offtime;
+
+	b->time_use++;
+	led->blink = 1;
+	led->led_cdev.brightness = TO_BRIGHT(b->level);
+	set_select(tca, led->num, blink_source[i]);
+	return 0;
+}
+
+static int led_assign(struct tca6507_led *led)
+{
+	struct tca6507_chip *tca = led->chip;
+	int err;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tca->lock, flags);
+	led_release(led);
+	err = led_prepare(led);
+	if (err) {
+		/*
+		 * Can only fail on timer setup.  In that case we need
+		 * to re-establish as steady level.
+		 */
+		led->ontime = 0;
+		led->offtime = 0;
+		led_prepare(led);
+	}
+	spin_unlock_irqrestore(&tca->lock, flags);
+
+	if (tca->reg_set)
+		schedule_work(&tca->work);
+	return err;
+}
+
+static void tca6507_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)
+{
+	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
+					       led_cdev);
+	led->led_cdev.brightness = brightness;
+	led->ontime = 0;
+	led->offtime = 0;
+	led_assign(led);
+}
+
+static int tca6507_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)
+{
+	struct tca6507_led *led = container_of(led_cdev, struct tca6507_led,
+					       led_cdev);
+
+	if (*delay_on == 0)
+		led->on_dflt = 1;
+	else if (delay_on != &led_cdev->blink_delay_on)
+		led->on_dflt = 0;
+	led->ontime = *delay_on;
+
+	if (*delay_off == 0)
+		led->off_dflt = 1;
+	else if (delay_off != &led_cdev->blink_delay_off)
+		led->off_dflt = 0;
+	led->offtime = *delay_off;
+
+	if (led->ontime == 0)
+		led->ontime = 512;
+	if (led->offtime == 0)
+		led->offtime = 512;
+
+	if (led->led_cdev.brightness == LED_OFF)
+		led->led_cdev.brightness = LED_FULL;
+	if (led_assign(led) < 0) {
+		led->ontime = 0;
+		led->offtime = 0;
+		led->led_cdev.brightness = LED_OFF;
+		return -EINVAL;
+	}
+	*delay_on = led->ontime;
+	*delay_off = led->offtime;
+	return 0;
+}
+
+#ifdef CONFIG_GPIOLIB
+static void tca6507_gpio_set_value(struct gpio_chip *gc,
+				   unsigned offset, int val)
+{
+	struct tca6507_chip *tca = container_of(gc, struct tca6507_chip, gpio);
+	unsigned long flags;
+
+	spin_lock_irqsave(&tca->lock, flags);
+	/*
+	 * 'OFF' is floating high, and 'ON' is pulled down, so it has
+	 * the inverse sense of 'val'.
+	 */
+	set_select(tca, tca->gpio_map[offset],
+		   val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON);
+	spin_unlock_irqrestore(&tca->lock, flags);
+	if (tca->reg_set)
+		schedule_work(&tca->work);
+}
+
+static int tca6507_gpio_direction_output(struct gpio_chip *gc,
+					  unsigned offset, int val)
+{
+	tca6507_gpio_set_value(gc, offset, val);
+	return 0;
+}
+
+static int tca6507_probe_gpios(struct i2c_client *client,
+			       struct tca6507_chip *tca,
+			       struct tca6507_platform_data *pdata)
+{
+	int err;
+	int i = 0;
+	int gpios = 0;
+
+	for (i = 0; i < NUM_LEDS; i++)
+		if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) {
+			/* Configure as a gpio */
+			tca->gpio_name[gpios] = pdata->leds.leds[i].name;
+			tca->gpio_map[gpios] = i;
+			gpios++;
+		}
+
+	if (!gpios)
+		return 0;
+
+	tca->gpio.label = "gpio-tca6507";
+	tca->gpio.names = tca->gpio_name;
+	tca->gpio.ngpio = gpios;
+	tca->gpio.base = pdata->gpio_base;
+	tca->gpio.owner = THIS_MODULE;
+	tca->gpio.direction_output = tca6507_gpio_direction_output;
+	tca->gpio.set = tca6507_gpio_set_value;
+	tca->gpio.dev = &client->dev;
+#ifdef CONFIG_OF_GPIO
+	tca->gpio.of_node = of_node_get(client->dev.of_node);
+#endif
+	err = gpiochip_add(&tca->gpio);
+	if (err) {
+		tca->gpio.ngpio = 0;
+		return err;
+	}
+	if (pdata->setup)
+		pdata->setup(tca->gpio.base, tca->gpio.ngpio);
+	return 0;
+}
+
+static void tca6507_remove_gpio(struct tca6507_chip *tca)
+{
+	if (tca->gpio.ngpio)
+		gpiochip_remove(&tca->gpio);
+}
+#else /* CONFIG_GPIOLIB */
+static int tca6507_probe_gpios(struct i2c_client *client,
+			       struct tca6507_chip *tca,
+			       struct tca6507_platform_data *pdata)
+{
+	return 0;
+}
+static void tca6507_remove_gpio(struct tca6507_chip *tca)
+{
+}
+#endif /* CONFIG_GPIOLIB */
+
+#ifdef CONFIG_OF
+static struct tca6507_platform_data *
+tca6507_led_dt_init(struct i2c_client *client)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct tca6507_platform_data *pdata;
+	struct led_info *tca_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	tca_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!tca_leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;
+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+		led.flags = 0;
+		if (of_property_match_string(child, "compatible", "gpio") >= 0)
+			led.flags |= TCA6507_MAKE_GPIO;
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
+			continue;
+
+		tca_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct tca6507_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = tca_leds;
+	pdata->leds.num_leds = NUM_LEDS;
+#ifdef CONFIG_GPIOLIB
+	pdata->gpio_base = -1;
+#endif
+	return pdata;
+}
+
+static const struct of_device_id of_tca6507_leds_match[] = {
+	{ .compatible = "ti,tca6507", },
+	{},
+};
+
+#else
+static struct tca6507_platform_data *
+tca6507_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int tca6507_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct tca6507_chip *tca;
+	struct i2c_adapter *adapter;
+	struct tca6507_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata || pdata->leds.num_leds != NUM_LEDS) {
+		pdata = tca6507_led_dt_init(client);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "Need %d entries in platform-data list\n",
+				NUM_LEDS);
+			return PTR_ERR(pdata);
+		}
+	}
+	tca = devm_kzalloc(&client->dev, sizeof(*tca), GFP_KERNEL);
+	if (!tca)
+		return -ENOMEM;
+
+	tca->client = client;
+	INIT_WORK(&tca->work, tca6507_work);
+	spin_lock_init(&tca->lock);
+	i2c_set_clientdata(client, tca);
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct tca6507_led *l = tca->leds + i;
+
+		l->chip = tca;
+		l->num = i;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = tca6507_brightness_set;
+			l->led_cdev.blink_set = tca6507_blink_set;
+			l->bank = -1;
+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);
+			if (err < 0)
+				goto exit;
+		}
+	}
+	err = tca6507_probe_gpios(client, tca, pdata);
+	if (err)
+		goto exit;
+	/* set all registers to known state - zero */
+	tca->reg_set = 0x7f;
+	schedule_work(&tca->work);
+
+	return 0;
+exit:
+	while (i--) {
+		if (tca->leds[i].led_cdev.name)
+			led_classdev_unregister(&tca->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int tca6507_remove(struct i2c_client *client)
+{
+	int i;
+	struct tca6507_chip *tca = i2c_get_clientdata(client);
+	struct tca6507_led *tca_leds = tca->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (tca_leds[i].led_cdev.name)
+			led_classdev_unregister(&tca_leds[i].led_cdev);
+	}
+	tca6507_remove_gpio(tca);
+	cancel_work_sync(&tca->work);
+
+	return 0;
+}
+
+static struct i2c_driver tca6507_driver = {
+	.driver   = {
+		.name    = "leds-tca6507",
+		.owner   = THIS_MODULE,
+		.of_match_table = of_match_ptr(of_tca6507_leds_match),
+	},
+	.probe    = tca6507_probe,
+	.remove   = tca6507_remove,
+	.id_table = tca6507_id,
+};
+
+module_i2c_driver(tca6507_driver);
+
+MODULE_AUTHOR("NeilBrown <neilb@suse.de>");
+MODULE_DESCRIPTION("TCA6507 LED/GPO driver");
+MODULE_LICENSE("GPL v2");