[PATCH] i2c: ast_i2c: Remove SCL direct drive mode

[Ryan Chen]

> -----Original Message-----
> From: Joel Stanley <joel at jms.id.au>
> Sent: Thursday, May 19, 2022 8:28 AM
> To: Eddie James <eajames at linux.ibm.com>; Ryan Chen
> <ryan_chen at aspeedtech.com>; BMC-SW <BMC-SW at aspeedtech.com>
> Cc: U-Boot Mailing List <u-boot at lists.denx.de>; hs at denx.de
> Subject: Re: [PATCH] i2c: ast_i2c: Remove SCL direct drive mode
> 
> On Wed, 11 May 2022 at 20:52, Eddie James <eajames at 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 at linux.ibm.com>
> 
> Reviewed-by: Joel Stanley <joel at jms.id.au>
> 
Reviewed-by: ryan_chen <ryan_chen at 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
> >