[U-Boot] [PATCH] kw_spi: fix clock prescaler computation
The computation was not correct with low clock values: setting a 1MHz clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 629 (Serial Memory Interface Configuration Register).
Signed-off-by: Valentin Longchamp valentin.longchamp@keymile.com cc: Holger Brunck holger.brunck@keymile.com cc: Prafulla Wadaskar prafulla@marvell.com --- arch/arm/include/asm/arch-kirkwood/spi.h | 1 + drivers/spi/kirkwood_spi.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h b/arch/arm/include/asm/arch-kirkwood/spi.h index 1d5043f..5a38dc5 100644 --- a/arch/arm/include/asm/arch-kirkwood/spi.h +++ b/arch/arm/include/asm/arch-kirkwood/spi.h @@ -38,6 +38,7 @@ struct kwspi_registers { };
#define KWSPI_CLKPRESCL_MASK 0x1f +#define KWSPI_CLKPRESCL_MIN 0x12 #define KWSPI_CSN_ACT 1 /* Activates serial memory interface */ #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c index ee14669..9b3f6a4 100644 --- a/drivers/spi/kirkwood_spi.c +++ b/drivers/spi/kirkwood_spi.c @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
/* calculate spi clock prescaller using max_hz */ - data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK; - data |= 0x10; + data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10; + data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data; + data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
/* program spi clock prescaller using max_hz */ writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
Hi Prafulla,
I haven't received feedback about this patch from you. Can I please kindly remind you about it since I am about to send patches that deal with SPI clk setting.
Thank you.
On 06/29/2012 02:17 PM, Valentin Longchamp wrote:
The computation was not correct with low clock values: setting a 1MHz clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 629 (Serial Memory Interface Configuration Register).
Signed-off-by: Valentin Longchamp valentin.longchamp@keymile.com cc: Holger Brunck holger.brunck@keymile.com cc: Prafulla Wadaskar prafulla@marvell.com
arch/arm/include/asm/arch-kirkwood/spi.h | 1 + drivers/spi/kirkwood_spi.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h b/arch/arm/include/asm/arch-kirkwood/spi.h index 1d5043f..5a38dc5 100644 --- a/arch/arm/include/asm/arch-kirkwood/spi.h +++ b/arch/arm/include/asm/arch-kirkwood/spi.h @@ -38,6 +38,7 @@ struct kwspi_registers { };
#define KWSPI_CLKPRESCL_MASK 0x1f +#define KWSPI_CLKPRESCL_MIN 0x12 #define KWSPI_CSN_ACT 1 /* Activates serial memory interface */ #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c index ee14669..9b3f6a4 100644 --- a/drivers/spi/kirkwood_spi.c +++ b/drivers/spi/kirkwood_spi.c @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
/* calculate spi clock prescaller using max_hz */
- data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
- data |= 0x10;
data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10;
data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data;
data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
/* program spi clock prescaller using max_hz */ writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
-----Original Message----- From: Valentin Longchamp [mailto:valentin.longchamp@keymile.com] Sent: 14 August 2012 15:02 To: Prafulla Wadaskar Cc: u-boot@lists.denx.de; Holger Brunck Subject: Re: [PATCH] kw_spi: fix clock prescaler computation
Hi Prafulla,
I haven't received feedback about this patch from you. Can I please kindly remind you about it since I am about to send patches that deal with SPI clk setting.
Dear Valentin My bad :-( I am really sorry about this. I missed this patch. Please find my comments in lined.
Thank you.
On 06/29/2012 02:17 PM, Valentin Longchamp wrote:
The computation was not correct with low clock values: setting a
1MHz
clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 629 (Serial Memory Interface Configuration Register).
I think this is table 600 (ref: MV-S104860-00 Rev. E specs available on extranet) This is a cosmetic change.
Otherwise I ack for this patch.
Please kindly let me know, should I pull this patch or you will resend it with above change?
Regards... Prafulla . . .
Hi Prafulla,
On 08/14/2012 03:15 PM, Prafulla Wadaskar wrote:
-----Original Message----- From: Valentin Longchamp [mailto:valentin.longchamp@keymile.com] Sent: 14 August 2012 15:02 To: Prafulla Wadaskar Cc: u-boot@lists.denx.de; Holger Brunck Subject: Re: [PATCH] kw_spi: fix clock prescaler computation
Hi Prafulla,
I haven't received feedback about this patch from you. Can I please kindly remind you about it since I am about to send patches that deal with SPI clk setting.
Dear Valentin My bad :-( I am really sorry about this. I missed this patch. Please find my comments in lined.
Thank you.
On 06/29/2012 02:17 PM, Valentin Longchamp wrote:
The computation was not correct with low clock values: setting a
1MHz
clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 629 (Serial Memory Interface Configuration Register).
I think this is table 600 (ref: MV-S104860-00 Rev. E specs available on extranet) This is a cosmetic change.
Otherwise I ack for this patch.
Please kindly let me know, should I pull this patch or you will resend it with above change?
Ok, I had taken rev. C of the document as a reference, I will resend the patch with the updated commit message.
Valentin
The computation was not correct with low clock values: setting a 1MHz clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 600 (Serial Memory Interface Configuration Register).
Signed-off-by: Valentin Longchamp valentin.longchamp@keymile.com cc: Holger Brunck holger.brunck@keymile.com cc: Prafulla Wadaskar prafulla@marvell.com --- changes for v2: - table nb in commit message
arch/arm/include/asm/arch-kirkwood/spi.h | 1 + drivers/spi/kirkwood_spi.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h b/arch/arm/include/asm/arch-kirkwood/spi.h index 1d5043f..5a38dc5 100644 --- a/arch/arm/include/asm/arch-kirkwood/spi.h +++ b/arch/arm/include/asm/arch-kirkwood/spi.h @@ -38,6 +38,7 @@ struct kwspi_registers { };
#define KWSPI_CLKPRESCL_MASK 0x1f +#define KWSPI_CLKPRESCL_MIN 0x12 #define KWSPI_CSN_ACT 1 /* Activates serial memory interface */ #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c index ee14669..9b3f6a4 100644 --- a/drivers/spi/kirkwood_spi.c +++ b/drivers/spi/kirkwood_spi.c @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
/* calculate spi clock prescaller using max_hz */ - data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK; - data |= 0x10; + data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10; + data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data; + data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
/* program spi clock prescaller using max_hz */ writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
-----Original Message----- From: Valentin Longchamp [mailto:valentin.longchamp@keymile.com] Sent: 15 August 2012 21:02 To: u-boot@lists.denx.de Cc: Valentin Longchamp; Holger Brunck; Prafulla Wadaskar Subject: [PATCH v2] kw_spi: fix clock prescaler computation
The computation was not correct with low clock values: setting a 1MHz clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 600 (Serial Memory Interface Configuration Register).
Signed-off-by: Valentin Longchamp valentin.longchamp@keymile.com cc: Holger Brunck holger.brunck@keymile.com cc: Prafulla Wadaskar prafulla@marvell.com
changes for v2:
- table nb in commit message
arch/arm/include/asm/arch-kirkwood/spi.h | 1 + drivers/spi/kirkwood_spi.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h b/arch/arm/include/asm/arch-kirkwood/spi.h index 1d5043f..5a38dc5 100644 --- a/arch/arm/include/asm/arch-kirkwood/spi.h +++ b/arch/arm/include/asm/arch-kirkwood/spi.h @@ -38,6 +38,7 @@ struct kwspi_registers { };
#define KWSPI_CLKPRESCL_MASK 0x1f +#define KWSPI_CLKPRESCL_MIN 0x12 #define KWSPI_CSN_ACT 1 /* Activates serial memory interface */ #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c index ee14669..9b3f6a4 100644 --- a/drivers/spi/kirkwood_spi.c +++ b/drivers/spi/kirkwood_spi.c @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
/* calculate spi clock prescaller using max_hz */
- data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
- data |= 0x10;
data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10;
data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data;
data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
/* program spi clock prescaller using max_hz */ writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
--
Acked-by: Prafulla Wadaskar Prafulla@marvell.com Will pull this soon.
Regards... Prafulla . . .
-----Original Message----- From: Prafulla Wadaskar Sent: 16 August 2012 09:44 To: 'Valentin Longchamp'; u-boot@lists.denx.de Cc: Holger Brunck Subject: RE: [PATCH v2] kw_spi: fix clock prescaler computation
-----Original Message----- From: Valentin Longchamp [mailto:valentin.longchamp@keymile.com] Sent: 15 August 2012 21:02 To: u-boot@lists.denx.de Cc: Valentin Longchamp; Holger Brunck; Prafulla Wadaskar Subject: [PATCH v2] kw_spi: fix clock prescaler computation
The computation was not correct with low clock values: setting a
1MHz
clock would result in an overlap that would then configure a 25Mhz clock.
This patch implements a correct computation method according to the kirkwood functionnal spec. table 600 (Serial Memory Interface Configuration Register).
Signed-off-by: Valentin Longchamp valentin.longchamp@keymile.com cc: Holger Brunck holger.brunck@keymile.com cc: Prafulla Wadaskar prafulla@marvell.com
changes for v2:
- table nb in commit message
arch/arm/include/asm/arch-kirkwood/spi.h | 1 + drivers/spi/kirkwood_spi.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h b/arch/arm/include/asm/arch-kirkwood/spi.h index 1d5043f..5a38dc5 100644 --- a/arch/arm/include/asm/arch-kirkwood/spi.h +++ b/arch/arm/include/asm/arch-kirkwood/spi.h @@ -38,6 +38,7 @@ struct kwspi_registers { };
#define KWSPI_CLKPRESCL_MASK 0x1f +#define KWSPI_CLKPRESCL_MIN 0x12 #define KWSPI_CSN_ACT 1 /* Activates serial memory interface */ #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c index ee14669..9b3f6a4 100644 --- a/drivers/spi/kirkwood_spi.c +++ b/drivers/spi/kirkwood_spi.c @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int
bus,
unsigned int cs, writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
/* calculate spi clock prescaller using max_hz */
- data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
- data |= 0x10;
data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10;
data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data;
data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
/* program spi clock prescaller using max_hz */ writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
--
Acked-by: Prafulla Wadaskar Prafulla@marvell.com Will pull this soon.
Applied to u-boot-marvell.git to master branch by resolving merge conflict
Regards... Prafulla . . .
participants (2)
-
Prafulla Wadaskar -
Valentin Longchamp