[media] v4l: atmel-isi: Should clear bits before set the hardware register

In the ISI driver it reads the config register to get original value,
then set the correct FRATE_DIV and YCC_SWAP_MODE directly. This will
cause some bits overlap.

So we need to clear these bits first, then set correct value. This patch
fix it.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/soc_camera/atmel-isi.c

@@ -132,6 +132,8 @@ static int configure_geometry(struct atmel_isi *isi, u32 width,
 	isi_writel(isi, ISI_CTRL, ISI_CTRL_DIS);
 
 	cfg2 = isi_readl(isi, ISI_CFG2);
+	/* Set YCC swap mode */
+	cfg2 &= ~ISI_CFG2_YCC_SWAP_MODE_MASK;
 	cfg2 |= cr;
 	/* Set width */
 	cfg2 &= ~(ISI_CFG2_IM_HSIZE_MASK);
@@ -346,6 +348,7 @@ static void start_dma(struct atmel_isi *isi, struct frame_buffer *buffer)
 	isi_writel(isi, ISI_DMA_C_CTRL, ISI_DMA_CTRL_FETCH | ISI_DMA_CTRL_DONE);
 	isi_writel(isi, ISI_DMA_CHER, ISI_DMA_CHSR_C_CH);
 
+	cfg1 &= ~ISI_CFG1_FRATE_DIV_MASK;
 	/* Enable linked list */
 	cfg1 |= isi->pdata->frate | ISI_CFG1_DISCR;
 

include/media/atmel-isi.h

@@ -56,6 +56,7 @@
 #define		ISI_CFG1_FRATE_DIV_6		(5 << 8)
 #define		ISI_CFG1_FRATE_DIV_7		(6 << 8)
 #define		ISI_CFG1_FRATE_DIV_8		(7 << 8)
+#define		ISI_CFG1_FRATE_DIV_MASK		(7 << 8)
 #define ISI_CFG1_DISCR				(1 << 11)
 #define ISI_CFG1_FULL_MODE			(1 << 12)
 
@@ -66,6 +67,7 @@
 #define		ISI_CFG2_YCC_SWAP_MODE_1	(1 << 28)
 #define		ISI_CFG2_YCC_SWAP_MODE_2	(2 << 28)
 #define		ISI_CFG2_YCC_SWAP_MODE_3	(3 << 28)
+#define		ISI_CFG2_YCC_SWAP_MODE_MASK	(3 << 28)
 #define ISI_CFG2_IM_VSIZE_OFFSET		0
 #define ISI_CFG2_IM_HSIZE_OFFSET		16
 #define ISI_CFG2_IM_VSIZE_MASK		(0x7FF << ISI_CFG2_IM_VSIZE_OFFSET)