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path: root/drivers/video/fbdev/amba-clcd.c
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Diffstat (limited to 'drivers/video/fbdev/amba-clcd.c')
-rw-r--r--drivers/video/fbdev/amba-clcd.c27
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/video/fbdev/amba-clcd.c b/drivers/video/fbdev/amba-clcd.c
index beadd3edaa1..6ad23bd3523 100644
--- a/drivers/video/fbdev/amba-clcd.c
+++ b/drivers/video/fbdev/amba-clcd.c
@@ -24,6 +24,7 @@
#include <linux/list.h>
#include <linux/amba/bus.h>
#include <linux/amba/clcd.h>
+#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/hardirq.h>
#include <linux/dma-mapping.h>
@@ -638,9 +639,7 @@ static int clcdfb_of_init_tft_panel(struct clcd_fb *fb, u32 r0, u32 g0, u32 b0)
if (g0 != panels[i].g0)
continue;
if (r0 == panels[i].r0 && b0 == panels[i].b0)
- fb->panel->caps = panels[i].caps & CLCD_CAP_RGB;
- if (r0 == panels[i].b0 && b0 == panels[i].r0)
- fb->panel->caps = panels[i].caps & CLCD_CAP_BGR;
+ fb->panel->caps = panels[i].caps;
}
return fb->panel->caps ? 0 : -EINVAL;
@@ -650,6 +649,7 @@ static int clcdfb_of_init_display(struct clcd_fb *fb)
{
struct device_node *endpoint;
int err;
+ unsigned int bpp;
u32 max_bandwidth;
u32 tft_r0b0g0[3];
@@ -667,11 +667,22 @@ static int clcdfb_of_init_display(struct clcd_fb *fb)
err = of_property_read_u32(fb->dev->dev.of_node, "max-memory-bandwidth",
&max_bandwidth);
- if (!err)
- fb->panel->bpp = 8 * max_bandwidth / (fb->panel->mode.xres *
- fb->panel->mode.yres * fb->panel->mode.refresh);
- else
- fb->panel->bpp = 32;
+ if (!err) {
+ /*
+ * max_bandwidth is in bytes per second and pixclock in
+ * pico-seconds, so the maximum allowed bits per pixel is
+ * 8 * max_bandwidth / (PICOS2KHZ(pixclock) * 1000)
+ * Rearrange this calculation to avoid overflow and then ensure
+ * result is a valid format.
+ */
+ bpp = max_bandwidth / (1000 / 8)
+ / PICOS2KHZ(fb->panel->mode.pixclock);
+ bpp = rounddown_pow_of_two(bpp);
+ if (bpp > 32)
+ bpp = 32;
+ } else
+ bpp = 32;
+ fb->panel->bpp = bpp;
#ifdef CONFIG_CPU_BIG_ENDIAN
fb->panel->cntl |= CNTL_BEBO;