diff mbox series

[v2,01/10] spi: atmel-quadspi: cache MR value to avoid a write access

Message ID 20190131161515.21605-2-tudor.ambarus@microchip.com (mailing list archive)
State Superseded
Headers show
Series spi: atmel-quadspi: introduce sam9x60 qspi controller | expand

Commit Message

Tudor Ambarus Jan. 31, 2019, 4:15 p.m. UTC
From: Tudor Ambarus <tudor.ambarus@microchip.com>

Cache MR value to avoid write access when setting the controller
in Serial Memory Mode (SMM). SMM is set in exec_op() and not at
probe time, to let room for future regular SPI support.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
v2: cache MR value instead of moving the write access at probe

 drivers/spi/atmel-quadspi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Boris Brezillon Jan. 31, 2019, 4:55 p.m. UTC | #1
On Thu, 31 Jan 2019 16:15:28 +0000
<Tudor.Ambarus@microchip.com> wrote:

> From: Tudor Ambarus <tudor.ambarus@microchip.com>
> 
> Cache MR value to avoid write access when setting the controller
> in Serial Memory Mode (SMM). SMM is set in exec_op() and not at
> probe time, to let room for future regular SPI support.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> v2: cache MR value instead of moving the write access at probe
> 
>  drivers/spi/atmel-quadspi.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
> index ddc712410812..fe05aee5d845 100644
> --- a/drivers/spi/atmel-quadspi.c
> +++ b/drivers/spi/atmel-quadspi.c
> @@ -155,6 +155,7 @@ struct atmel_qspi {
>  	struct clk		*clk;
>  	struct platform_device	*pdev;
>  	u32			pending;
> +	u32			mr;
>  	struct completion	cmd_completion;
>  };
>  
> @@ -238,7 +239,9 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  	icr = QSPI_ICR_INST(op->cmd.opcode);
>  	ifr = QSPI_IFR_INSTEN;
>  
> -	qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
> +	/* Set the QSPI controller in Serial Memory Mode */
> +	if (!(aq->mr & QSPI_MR_SMM))

	if (aq->mr != QSPI_MR_SMM)

> +		qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);

You need to update ->mr here.

>  
>  	mode = find_mode(op);
>  	if (mode < 0)
Tudor Ambarus Feb. 1, 2019, 6:51 a.m. UTC | #2
On 01/31/2019 06:55 PM, Boris Brezillon wrote:
> On Thu, 31 Jan 2019 16:15:28 +0000
> <Tudor.Ambarus@microchip.com> wrote:
> 
>> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>>
>> Cache MR value to avoid write access when setting the controller
>> in Serial Memory Mode (SMM). SMM is set in exec_op() and not at
>> probe time, to let room for future regular SPI support.
>>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
>> ---
>> v2: cache MR value instead of moving the write access at probe
>>
>>  drivers/spi/atmel-quadspi.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
>> index ddc712410812..fe05aee5d845 100644
>> --- a/drivers/spi/atmel-quadspi.c
>> +++ b/drivers/spi/atmel-quadspi.c
>> @@ -155,6 +155,7 @@ struct atmel_qspi {
>>  	struct clk		*clk;
>>  	struct platform_device	*pdev;
>>  	u32			pending;
>> +	u32			mr;
>>  	struct completion	cmd_completion;
>>  };
>>  
>> @@ -238,7 +239,9 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>  	icr = QSPI_ICR_INST(op->cmd.opcode);
>>  	ifr = QSPI_IFR_INSTEN;
>>  
>> -	qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
>> +	/* Set the QSPI controller in Serial Memory Mode */
>> +	if (!(aq->mr & QSPI_MR_SMM))
> 
> 	if (aq->mr != QSPI_MR_SMM)

then I should probably rename mr to smm.

> 
>> +		qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
> 
> You need to update ->mr here.

of course, thanks!

> 
>>  
>>  	mode = find_mode(op);
>>  	if (mode < 0)
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
diff mbox series

Patch

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index ddc712410812..fe05aee5d845 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -155,6 +155,7 @@  struct atmel_qspi {
 	struct clk		*clk;
 	struct platform_device	*pdev;
 	u32			pending;
+	u32			mr;
 	struct completion	cmd_completion;
 };
 
@@ -238,7 +239,9 @@  static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 	icr = QSPI_ICR_INST(op->cmd.opcode);
 	ifr = QSPI_IFR_INSTEN;
 
-	qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
+	/* Set the QSPI controller in Serial Memory Mode */
+	if (!(aq->mr & QSPI_MR_SMM))
+		qspi_writel(aq, QSPI_MR, QSPI_MR_SMM);
 
 	mode = find_mode(op);
 	if (mode < 0)