kestrel/leds/trigger: implement led trigger driver for group pwm

pca9633 i2c leds driver supports group pwm which currently not utilized
by leds-pca963x driver.
This patch exposes various registers values via sysfs to user and can be
used to achieve group blinking and dimming.

Signed-off-by: Amitesh Singh <amitesh.singh@chargepoint.com>

Author: amiteshsingh-cpi

drivers/leds/leds-pca963x.c

@@ -32,6 +32,7 @@
 #include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/i2c-pca963x.h>
 
 /* LED select registers determine the source that drives LED outputs */
 #define PCA963X_LED_OFF		0x0	/* LED driver off */
@@ -371,6 +372,14 @@ static const struct of_device_id of_pca963x_match[] = {
 };
 MODULE_DEVICE_TABLE(of, of_pca963x_match);
 
+static struct i2c_client *g_client;
+
+struct i2c_client *i2c_get_pca963x_device(void)
+{
+   return g_client;
+}
+EXPORT_SYMBOL_GPL(i2c_get_pca963x_device);
+
 static int pca963x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -398,6 +407,8 @@ static int pca963x_probe(struct i2c_client *client,
 	chip->chipdef = chipdef;
 	chip->client = client;
 
+    g_client = client;
+
 	/* Turn off LEDs by default*/
 	for (i = 0; i < chipdef->n_leds / 4; i++)
 		i2c_smbus_write_byte_data(client, chipdef->ledout_base + i, 0x00);

drivers/leds/trigger/Kconfig

@@ -19,6 +19,14 @@ config LEDS_TRIGGER_TIMER
 
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_GRPPWM
+	tristate "LED Group PWM trigger"
+	help
+	  This allows LEDs to be controlled by group pwm feature,
+          supported by pca9633 i2c driver
+
+          if unsure, say Y.
+
 config LEDS_TRIGGER_ONESHOT
 	tristate "LED One-shot Trigger"
 	help

drivers/leds/trigger/Makefile

@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_GRPPWM)		+= ledtrig-grppwm.o