[PATCH 1/2] amba_pl022: Fix driver clock enable/disable balance issues
flat view
STALE5925d
From: wellsk40 at gmail.com <hidden>
Date: 2010-08-03 16:03:58
Subsystem:
framebuffer layer, the rest · Maintainers:
Helge Deller, Linus Torvalds
From: Kevin Wells <redacted> The pl022 clock enable and disable calls can become unbalanced. This code prevents clk_disable() from being called until clk_enable() has been called first. Note the LCP32xx arch (and probably other archs too) requires clocks for the AMBA peripheral enabled prior to any register access. This patch alone won't prevent register access without an active clock. --- drivers/video/amba-clcd.c | 10 ++++++++-- include/linux/amba/clcd.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/video/amba-clcd.c b/drivers/video/amba-clcd.c
index afe21e6..1c2c683 100644
--- a/drivers/video/amba-clcd.c
+++ b/drivers/video/amba-clcd.c@@ -80,7 +80,10 @@ static void clcdfb_disable(struct clcd_fb *fb) /* * Disable CLCD clock source. */ - clk_disable(fb->clk); + if (fb->clk_enabled) { + fb->clk_enabled = false; + clk_disable(fb->clk); + } } static void clcdfb_enable(struct clcd_fb *fb, u32 cntl)
@@ -88,7 +91,10 @@ static void clcdfb_enable(struct clcd_fb *fb, u32 cntl) /* * Enable the CLCD clock source. */ - clk_enable(fb->clk); + if (!fb->clk_enabled) { + fb->clk_enabled = true; + clk_enable(fb->clk); + } /* * Bring up by first enabling..
diff --git a/include/linux/amba/clcd.h b/include/linux/amba/clcd.h
index ca16c38..7bbf26a 100644
--- a/include/linux/amba/clcd.h
+++ b/include/linux/amba/clcd.h@@ -142,6 +142,7 @@ struct clcd_fb { struct fb_info fb; struct amba_device *dev; struct clk *clk; + bool clk_enabled; struct clcd_panel *panel; struct clcd_board *board; void *board_data;
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1.7.1.1