[PATCH RESEND v2 03/25] drm/fb_helper: Create wrappers for fb_sys_read/write funcs

[Archit Taneja]

Some drm drivers populate their fb_ops with fb_sys_read/write fb sysfs
ops.

Create a drm_fb_helper function that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
- Remove unnecessary checks for non NULL fb_info

Signed-off-by: Archit Taneja <architt at codeaurora.org>
---
 drivers/gpu/drm/Kconfig         |  1 +
 drivers/gpu/drm/drm_fb_helper.c | 26 ++++++++++++++++++++++++++
 include/drm/drm_fb_helper.h     |  5 +++++
 3 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index c46ca31..6ab503b 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -37,6 +37,7 @@ config DRM_KMS_FB_HELPER
 	select FB
 	select FRAMEBUFFER_CONSOLE if !EXPERT
 	select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE
+	select FB_SYS_FOPS
 	help
 	  FBDEV helpers for KMS drivers.
 
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 2f8dd8d..abb36f9 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -777,6 +777,32 @@ void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper)
 }
 EXPORT_SYMBOL(drm_fb_helper_unlink_fbi);
 
+/**
+ * drm_fb_helper_sys_read - wrapper around fb_sys_read
+ * @fb_helper: driver-allocated fbdev helper
+ *
+ * A wrapper around fb_sys_read implemented by fbdev core
+ */
+ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	return fb_sys_read(info, buf, count, ppos);
+}
+EXPORT_SYMBOL(drm_fb_helper_sys_read);
+
+/**
+ * drm_fb_helper_sys_write - wrapper around fb_sys_write
+ * @fb_helper: driver-allocated fbdev helper
+ *
+ * A wrapper around fb_sys_write implemented by fbdev core
+ */
+ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	return fb_sys_write(info, buf, count, ppos);
+}
+EXPORT_SYMBOL(drm_fb_helper_sys_write);
+
 static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
 		     u16 blue, u16 regno, struct fb_info *info)
 {
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 4c90837..fc12368 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -147,6 +147,11 @@ void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
 
 void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper);
 
+ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
+			       size_t count, loff_t *ppos);
+ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf,
+				size_t count, loff_t *ppos);
+
 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info);
 
 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
-- 
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