staging: greybus: light: remove KERNEL_VERSION checks

No need to support older kernel versions in the Greybus Light driver, so
remove the checks as needed, we can now rely on all of the correct LED
core apis being present. And compile only if flash and v4l2 flash is
reachable.
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/kernel_ver.h

@@ -35,36 +35,6 @@
 #define MMC_POWER_UNDEFINED_SUPPORTED
 #endif
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
-/*
- * At this time the internal API for the set brightness was changed to the async
- * version, and one sync API was added to handle cases that need immediate
- * effect. Also, the led class flash and lock for sysfs access was introduced.
- */
-#define LED_HAVE_SET_SYNC
-#define LED_HAVE_FLASH
-#define LED_HAVE_LOCK
-#include <linux/led-class-flash.h>
-#endif
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)
-/*
- * New change in LED api, the set_sync operation was renamed to set_blocking and
- * the workqueue is now handle by core. So, only one set operation is need.
- */
-#undef LED_HAVE_SET_SYNC
-#define LED_HAVE_SET_BLOCKING
-#endif
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
-/*
- * New helper functions for registering/unregistering flash led devices as v4l2
- * subdevices were added.
- */
-#define V4L2_HAVE_FLASH
-#include <media/v4l2-flash-led-class.h>
-#endif
-
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 1, 0)
 /*
  * Power supply get by name need to drop reference after call

drivers/staging/greybus/light.c

@@ -9,9 +9,11 @@
 
 #include <linux/kernel.h>
 #include <linux/leds.h>
+#include <linux/led-class-flash.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/version.h>
+#include <media/v4l2-flash-led-class.h>
 
 #include "greybus.h"
 #include "greybus_protocols.h"
@@ -30,11 +32,8 @@ struct gb_channel {
 	struct attribute		**attrs;
 	struct attribute_group		*attr_group;
 	const struct attribute_group	**attr_groups;
-#ifndef LED_HAVE_SET_BLOCKING
-	struct work_struct		work_brightness_set;
-#endif
 	struct led_classdev		*led;
-#ifdef LED_HAVE_FLASH
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
 	struct led_classdev_flash	fled;
 	struct led_flash_setting	intensity_uA;
 	struct led_flash_setting	timeout_us;
@@ -58,7 +57,7 @@ struct gb_light {
 	struct gb_channel	*channels;
 	bool			has_flash;
 	bool			ready;
-#ifdef V4L2_HAVE_FLASH
+#if IS_REACHABLE(CONFIG_V4L2_FLASH_LED_CLASS)
 	struct v4l2_flash	*v4l2_flash;
 #endif
 };
@@ -88,7 +87,7 @@ static bool is_channel_flash(struct gb_channel *channel)
 				   | GB_CHANNEL_MODE_INDICATOR));
 }
 
-#ifdef LED_HAVE_FLASH
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
 static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
 {
 	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(cdev);
@@ -157,7 +156,7 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
 
 	return __gb_lights_flash_intensity_set(channel, intensity);
 }
-#else /* LED_HAVE_FLASH */
+#else
 static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
 {
 	return container_of(cdev, struct gb_channel, cled);
@@ -172,12 +171,11 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
 {
 	return 0;
 }
-#endif /* !LED_HAVE_FLASH */
+#endif
 
 static int gb_lights_color_set(struct gb_channel *channel, u32 color);
 static int gb_lights_fade_set(struct gb_channel *channel);
 
-#ifdef LED_HAVE_LOCK
 static void led_lock(struct led_classdev *cdev)
 {
 	mutex_lock(&cdev->led_access);
@@ -187,15 +185,6 @@ static void led_unlock(struct led_classdev *cdev)
 {
 	mutex_unlock(&cdev->led_access);
 }
-#else
-static void led_lock(struct led_classdev *cdev)
-{
-}
-
-static void led_unlock(struct led_classdev *cdev)
-{
-}
-#endif /* !LED_HAVE_LOCK */
 
 #define gb_lights_fade_attr(__dir)					\
 static ssize_t fade_##__dir##_show(struct device *dev,			\
@@ -444,39 +433,6 @@ static int __gb_lights_brightness_set(struct gb_channel *channel)
 	return ret;
 }
 
-#ifndef LED_HAVE_SET_BLOCKING
-static void gb_brightness_set_work(struct work_struct *work)
-{
-	struct gb_channel *channel = container_of(work, struct gb_channel,
-						  work_brightness_set);
-
-	__gb_lights_brightness_set(channel);
-}
-
-#ifdef LED_HAVE_SET_SYNC
-static int gb_brightness_set_sync(struct led_classdev *cdev,
-				  enum led_brightness value)
-{
-	struct gb_channel *channel = get_channel_from_cdev(cdev);
-
-	channel->led->brightness = value;
-
-	return __gb_lights_brightness_set(channel);
-}
-#endif
-
-static void gb_brightness_set(struct led_classdev *cdev,
-			      enum led_brightness value)
-{
-	struct gb_channel *channel = get_channel_from_cdev(cdev);
-
-	if (channel->releasing)
-		return;
-
-	cdev->brightness = value;
-	schedule_work(&channel->work_brightness_set);
-}
-#else /* LED_HAVE_SET_BLOCKING */
 static int gb_brightness_set(struct led_classdev *cdev,
 			     enum led_brightness value)
 {
@@ -486,7 +442,6 @@ static int gb_brightness_set(struct led_classdev *cdev,
 
 	return __gb_lights_brightness_set(channel);
 }
-#endif
 
 static enum led_brightness gb_brightness_get(struct led_classdev *cdev)
 
@@ -554,22 +509,13 @@ static void gb_lights_led_operations_set(struct gb_channel *channel,
 					 struct led_classdev *cdev)
 {
 	cdev->brightness_get = gb_brightness_get;
-#ifdef LED_HAVE_SET_SYNC
-	cdev->brightness_set_sync = gb_brightness_set_sync;
-#endif
-#ifdef LED_HAVE_SET_BLOCKING
 	cdev->brightness_set_blocking = gb_brightness_set;
-#endif
-#ifndef LED_HAVE_SET_BLOCKING
-	cdev->brightness_set = gb_brightness_set;
-	INIT_WORK(&channel->work_brightness_set, gb_brightness_set_work);
-#endif
 
 	if (channel->flags & GB_LIGHT_CHANNEL_BLINK)
 		cdev->blink_set = gb_blink_set;
 }
 
-#ifdef V4L2_HAVE_FLASH
+#if IS_REACHABLE(CONFIG_V4L2_FLASH_LED_CLASS)
 /* V4L2 specific helpers */
 static const struct v4l2_flash_ops v4l2_flash_ops;
 
@@ -655,7 +601,7 @@ static void gb_lights_light_v4l2_unregister(struct gb_light *light)
 }
 #endif
 
-#ifdef LED_HAVE_FLASH
+#if IS_REACHABLE(CONFIG_LEDS_CLASS_FLASH)
 /* Flash specific operations */
 static int gb_lights_flash_intensity_set(struct led_classdev_flash *fcdev,
 					 u32 brightness)
@@ -936,7 +882,7 @@ static void __gb_lights_flash_led_unregister(struct gb_channel *channel)
 {
 }
 
-#endif /* LED_HAVE_FLASH */
+#endif
 
 static int __gb_lights_led_register(struct gb_channel *channel)
 {
@@ -1132,9 +1078,6 @@ static int gb_lights_light_register(struct gb_light *light)
 
 static void gb_lights_channel_free(struct gb_channel *channel)
 {
-#ifndef LED_HAVE_SET_BLOCKING
-	flush_work(&channel->work_brightness_set);
-#endif
 	kfree(channel->attrs);
 	kfree(channel->attr_group);
 	kfree(channel->attr_groups);