diff mbox

[v2,1/2] i2c: mediatek: Reset DMA engine in hardware init function

Message ID 1438845731-17805-2-git-send-email-eddie.huang@mediatek.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eddie Huang (黃智傑) Aug. 6, 2015, 7:22 a.m. UTC 
Reset DMA in hardware init function to avoid unknown hardware state
before do any I2C operation.

Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
---
 drivers/i2c/busses/i2c-mt65xx.c |    6 ++++++
 1 file changed, 6 insertions(+)

Comments

Daniel Kurtz Aug. 11, 2015, 8:32 a.m. UTC | #1 
On Thu, Aug 6, 2015 at 3:22 PM, Eddie Huang <eddie.huang@mediatek.com> wrote:
> Reset DMA in hardware init function to avoid unknown hardware state
> before do any I2C operation.
>
> Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
> Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>

Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>

> ---
>  drivers/i2c/busses/i2c-mt65xx.c |    6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index 9920eef..e28ad4c 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -59,6 +59,7 @@
>  #define I2C_DMA_START_EN               0x0001
>  #define I2C_DMA_INT_FLAG_NONE          0x0000
>  #define I2C_DMA_CLR_FLAG               0x0000
> +#define I2C_DMA_HARD_RST               0x0002
>
>  #define I2C_DEFAULT_SPEED              100000  /* hz */
>  #define MAX_FS_MODE_SPEED              400000
> @@ -81,6 +82,7 @@ enum DMA_REGS_OFFSET {
>         OFFSET_INT_FLAG = 0x0,
>         OFFSET_INT_EN = 0x04,
>         OFFSET_EN = 0x08,
> +       OFFSET_RST = 0x0c,
>         OFFSET_CON = 0x18,
>         OFFSET_TX_MEM_ADDR = 0x1c,
>         OFFSET_RX_MEM_ADDR = 0x20,
> @@ -262,6 +264,10 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
>                       I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
>         writew(control_reg, i2c->base + OFFSET_CONTROL);
>         writew(I2C_DELAY_LEN, i2c->base + OFFSET_DELAY_LEN);
> +
> +       writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
> +       udelay(50);
> +       writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
>  }
>
>  /*
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
Wolfram Sang Aug. 11, 2015, 2:55 p.m. UTC | #2 
On Thu, Aug 06, 2015 at 03:22:10PM +0800, Eddie Huang wrote:
> Reset DMA in hardware init function to avoid unknown hardware state
> before do any I2C operation.
> 
> Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
> Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>

Applied to for-next, thanks!
diff mbox

Patch

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 9920eef..e28ad4c 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -59,6 +59,7 @@ 
 #define I2C_DMA_START_EN		0x0001
 #define I2C_DMA_INT_FLAG_NONE		0x0000
 #define I2C_DMA_CLR_FLAG		0x0000
+#define I2C_DMA_HARD_RST		0x0002
 
 #define I2C_DEFAULT_SPEED		100000	/* hz */
 #define MAX_FS_MODE_SPEED		400000
@@ -81,6 +82,7 @@  enum DMA_REGS_OFFSET {
 	OFFSET_INT_FLAG = 0x0,
 	OFFSET_INT_EN = 0x04,
 	OFFSET_EN = 0x08,
+	OFFSET_RST = 0x0c,
 	OFFSET_CON = 0x18,
 	OFFSET_TX_MEM_ADDR = 0x1c,
 	OFFSET_RX_MEM_ADDR = 0x20,
@@ -262,6 +264,10 @@  static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 		      I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
 	writew(control_reg, i2c->base + OFFSET_CONTROL);
 	writew(I2C_DELAY_LEN, i2c->base + OFFSET_DELAY_LEN);
+
+	writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
+	udelay(50);
+	writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
 }
 
 /*