rk fb: add the judgement that if the variable dev_drv is null pointer

diff --git a/drivers/video/rockchip/rk_fb.c b/drivers/video/rockchip/rk_fb.c
index 2fbb3104e64b197520886c6714802aa44ee8d847..261066da6fd1e974719cc53757211d364fbcea03 100755 (executable)
--- a/drivers/video/rockchip/rk_fb.c
+++ b/drivers/video/rockchip/rk_fb.c
@@ -566,7 +566,10 @@ u64 rk_fb_get_prmry_screen_framedone_t(void)
 {
        struct rk_lcdc_driver *dev_drv = rk_get_prmry_lcdc_drv();
 
-       return dev_drv->frame_time.framedone_t;
+       if (unlikely(!dev_drv))
+               return 0;
+       else
+               return dev_drv->frame_time.framedone_t;
 }
 
 /*
@@ -575,8 +578,12 @@ u64 rk_fb_get_prmry_screen_framedone_t(void)
 int rk_fb_set_prmry_screen_status(int status)
 {
        struct rk_lcdc_driver *dev_drv = rk_get_prmry_lcdc_drv();
-       struct rk_screen *screen = dev_drv->cur_screen;
+       struct rk_screen *screen;
 
+       if (unlikely(!dev_drv))
+               return 0;
+
+       screen = dev_drv->cur_screen;
        switch (status) {
        case SCREEN_PREPARE_DDR_CHANGE:
                if (screen->type == SCREEN_MIPI
@@ -625,7 +632,11 @@ static struct rk_lcdc_driver *rk_get_extend_lcdc_drv(void)
 u32 rk_fb_get_prmry_screen_pixclock(void)
 {
        struct rk_lcdc_driver *dev_drv = rk_get_prmry_lcdc_drv();
-       return dev_drv->pixclock;
+
+       if (unlikely(!dev_drv))
+               return 0;
+       else
+               return dev_drv->pixclock;
 }
 
 int rk_fb_poll_prmry_screen_vblank(void)