[PATCH] i2c: ast_i2c: Remove SCL direct drive mode
SCL direct drive mode prevents communication with devices that do clock stretching, so disable. The Linux driver doesn't use this mode, and the engine can handle clock stretching.
Signed-off-by: Eddie James eajames@linux.ibm.com --- drivers/i2c/ast_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c index 2d3fecaa14..8b24a260c0 100644 --- a/drivers/i2c/ast_i2c.c +++ b/drivers/i2c/ast_i2c.c @@ -76,7 +76,7 @@ static void ast_i2c_init_bus(struct udevice *dev) /* Enable Master Mode. Assuming single-master */ writel(I2CD_MASTER_EN | I2CD_M_SDA_LOCK_EN - | I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN, + | I2CD_MULTI_MASTER_DIS, &priv->regs->fcr); /* Enable Interrupts */ writel(I2CD_INTR_TX_ACK
Hello Eddie,
On 11.05.22 22:52, Eddie James wrote:
SCL direct drive mode prevents communication with devices that do clock stretching, so disable. The Linux driver doesn't use this mode, and the engine can handle clock stretching.
My first thought was why not make this option configurable, as I do not know if there is any user of this mode configuration.
But as linux does not use this option, we may can disable it.
Signed-off-by: Eddie James eajames@linux.ibm.com
drivers/i2c/ast_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Heiko Schocher hs@denx.de
It would be good to have here more comments from users of this driver.
bye, Heiko
On Wed, 11 May 2022 at 20:52, Eddie James eajames@linux.ibm.com wrote:
SCL direct drive mode prevents communication with devices that do clock stretching, so disable. The Linux driver doesn't use this mode, and the engine can handle clock stretching.
Signed-off-by: Eddie James eajames@linux.ibm.com
Reviewed-by: Joel Stanley joel@jms.id.au
I have added the aspeed team to cc for their review.
Ryan, we discovered this fix when testing the tpm i2c driver on the ast2600.
drivers/i2c/ast_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c index 2d3fecaa14..8b24a260c0 100644 --- a/drivers/i2c/ast_i2c.c +++ b/drivers/i2c/ast_i2c.c @@ -76,7 +76,7 @@ static void ast_i2c_init_bus(struct udevice *dev) /* Enable Master Mode. Assuming single-master */ writel(I2CD_MASTER_EN | I2CD_M_SDA_LOCK_EN
| I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN,
| I2CD_MULTI_MASTER_DIS, &priv->regs->fcr); /* Enable Interrupts */ writel(I2CD_INTR_TX_ACK-- 2.27.0
-----Original Message----- From: Joel Stanley joel@jms.id.au Sent: Thursday, May 19, 2022 8:28 AM To: Eddie James eajames@linux.ibm.com; Ryan Chen ryan_chen@aspeedtech.com; BMC-SW BMC-SW@aspeedtech.com Cc: U-Boot Mailing List u-boot@lists.denx.de; hs@denx.de Subject: Re: [PATCH] i2c: ast_i2c: Remove SCL direct drive mode
On Wed, 11 May 2022 at 20:52, Eddie James eajames@linux.ibm.com wrote:
SCL direct drive mode prevents communication with devices that do clock stretching, so disable. The Linux driver doesn't use this mode, and the engine can handle clock stretching.
Signed-off-by: Eddie James eajames@linux.ibm.com
Reviewed-by: Joel Stanley joel@jms.id.au
Reviewed-by: ryan_chen ryan_chen@aspeedtech.com
I have added the aspeed team to cc for their review.
Ryan, we discovered this fix when testing the tpm i2c driver on the ast2600.
Yes, it should remove. Thank for inform.
drivers/i2c/ast_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c index 2d3fecaa14..8b24a260c0 100644 --- a/drivers/i2c/ast_i2c.c +++ b/drivers/i2c/ast_i2c.c @@ -76,7 +76,7 @@ static void ast_i2c_init_bus(struct udevice *dev) /* Enable Master Mode. Assuming single-master */ writel(I2CD_MASTER_EN | I2CD_M_SDA_LOCK_EN
| I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN,
| I2CD_MULTI_MASTER_DIS, &priv->regs->fcr); /* Enable Interrupts */ writel(I2CD_INTR_TX_ACK-- 2.27.0
Hello Eddie,
On 11.05.22 22:52, Eddie James wrote:
SCL direct drive mode prevents communication with devices that do clock stretching, so disable. The Linux driver doesn't use this mode, and the engine can handle clock stretching.
Signed-off-by: Eddie James eajames@linux.ibm.com
drivers/i2c/ast_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Applied to u-boot-i2c master
Thanks!
bye, Heiko
participants (4)
-
Eddie James -
Heiko Schocher -
Joel Stanley -
Ryan Chen