[PATCH v2 0/2] Mediatek I2C fixup

[PATCH v2 0/2] Mediatek I2C fixup

[Eddie Huang]

This series provide two patches to optimize mediatek i2c driver.
The first patch will reset dma hardware in init function to make sure
hardware work in good state. The second patch fix i2c interrupt handling
for ACK error. All these patches base on 4.2-rc1.

Change in v2:
Fix multi-transfer fail bug - in mtk_i2c_irq(), call complete()
if get I2C_RS_TRANSFER interrupt

Eddie Huang (2):
  i2c: mediatek: Reset DMA engine in hardware init function
  i2c: mediatek: Fixup i2c ack error interrupt handling

 drivers/i2c/busses/i2c-mt65xx.c |   21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

-- 
1.7.9.5

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

[Eddie Huang]

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(+)

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

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

[Daniel Kurtz]

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

[Wolfram Sang]

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!

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[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Eddie Huang]

When occur i2c ack error, i2c controller generate two interrupts,
first is the ack error interrupt, then the complete interrupt.
i2c interrupt handler should keep the two interrupt value, and only
call complete() for the complete interrupt.

Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
---
 drivers/i2c/busses/i2c-mt65xx.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index e28ad4c..c02e6c0 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -557,15 +557,22 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 {
 	struct mtk_i2c *i2c = dev_id;
 	u16 restart_flag = 0;
+	u16 intr_stat;
 
 	if (i2c->dev_comp->auto_restart)
 		restart_flag = I2C_RS_TRANSFER;
 
-	i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
-	writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR
-		| I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
+	intr_stat = readw(i2c->base + OFFSET_INTR_STAT);
+	writew(intr_stat, i2c->base + OFFSET_INTR_STAT);
 
-	complete(&i2c->msg_complete);
+	/*
+	 * when occurs ack error, i2c controller generate two interrupts
+	 * first is the ack error interrupt, then the complete interrupt
+	 * i2c->irq_stat need keep the two interrupt value.
+	 */
+	i2c->irq_stat |= intr_stat;
+	if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
+		complete(&i2c->msg_complete);
 
 	return IRQ_HANDLED;
 }
-- 
1.7.9.5

[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Daniel Kurtz]

On Thu, Aug 6, 2015 at 3:22 PM, Eddie Huang <eddie.huang@mediatek.com> wrote:
> When occur i2c ack error, i2c controller generate two interrupts,
> first is the ack error interrupt, then the complete interrupt.
> i2c interrupt handler should keep the two interrupt value, and only
> call complete() for the complete interrupt.
>
> 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 |   15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index e28ad4c..c02e6c0 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -557,15 +557,22 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
>  {
>         struct mtk_i2c *i2c = dev_id;
>         u16 restart_flag = 0;
> +       u16 intr_stat;
>
>         if (i2c->dev_comp->auto_restart)
>                 restart_flag = I2C_RS_TRANSFER;
>
> -       i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
> -       writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR
> -               | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
> +       intr_stat = readw(i2c->base + OFFSET_INTR_STAT);
> +       writew(intr_stat, i2c->base + OFFSET_INTR_STAT);
>
> -       complete(&i2c->msg_complete);
> +       /*
> +        * when occurs ack error, i2c controller generate two interrupts
> +        * first is the ack error interrupt, then the complete interrupt
> +        * i2c->irq_stat need keep the two interrupt value.
> +        */
> +       i2c->irq_stat |= intr_stat;
> +       if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
> +               complete(&i2c->msg_complete);
>
>         return IRQ_HANDLED;
>  }
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Wolfram Sang]

On Thu, Aug 06, 2015 at 03:22:11PM +0800, Eddie Huang wrote:
> When occur i2c ack error, i2c controller generate two interrupts,
> first is the ack error interrupt, then the complete interrupt.
> i2c interrupt handler should keep the two interrupt value, and only
> call complete() for the complete interrupt.
> 
> Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
> Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>

Applied to for-next, thanks!

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[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Daniel Kurtz]

Hi Wolfram,

On Tue, Aug 11, 2015 at 10:55 PM, Wolfram Sang <wsa@the-dreams.de> wrote:
> On Thu, Aug 06, 2015 at 03:22:11PM +0800, Eddie Huang wrote:
>> When occur i2c ack error, i2c controller generate two interrupts,
>> first is the ack error interrupt, then the complete interrupt.
>> i2c interrupt handler should keep the two interrupt value, and only
>> call complete() for the complete interrupt.
>>
>> Signed-off-by: Liguo Zhang <liguo.zhang@mediatek.com>
>> Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
>
> Applied to for-next, thanks!

I don't see them in [0].
[0] https://git.kernel.org/cgit/linux/kernel/git/wsa/linux.git/log/?h=i2c/for-next

Am I not looking in the right place?
Or, did I not wait long enough?

Thanks!
-Dan

[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Wolfram Sang]

> Or, did I not wait long enough?

This.

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[PATCH v2 0/2] Mediatek I2C Fixup

[Liguo Zhang]

This series contain two patches, first is to optimize Mediatek I2C driver to use WRRD
if hardware support auto restart. Because auto restart will issue auto restart
interrupt, change to use WRRD can reduce interrupt latency. The second is to fix
multi transfer error in high speed mode. If hardware support auto restart, need driver
to send master code first.

Change in v2:
fix i2c checkpatch error.

Liguo Zhang (2):
  i2c: mediatek: add i2c first write then read optimization
  i2c: mediatek: fix i2c multi transfer issue in high speed mode

 drivers/i2c/busses/i2c-mt65xx.c | 78 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 72 insertions(+), 6 deletions(-)

--
1.8.1.1.dirty