diff mbox series

[v3,4/6] i2c: npcm: Modify the client address assignment

Message ID 20240913101445.16513-5-kfting@nuvoton.com
State New
Headers show
Series None | expand

Commit Message

Tyrone Ting Sept. 13, 2024, 10:14 a.m. UTC 
From: Tyrone Ting <kfting@nuvoton.com>

Store the client address earlier since it might get called in
the i2c_recover_bus logic flow at the early stage of the function
npcm_i2c_master_xfer.

Signed-off-by: Tyrone Ting <kfting@nuvoton.com>
Reviewed-by: Tali Perry <tali.perry1@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Comments

Andy Shevchenko Sept. 13, 2024, 10:32 a.m. UTC | #1 
On Fri, Sep 13, 2024 at 06:14:44PM +0800, warp5tw@gmail.com wrote:
> From: Tyrone Ting <kfting@nuvoton.com>
> 
> Store the client address earlier since it might get called in
> the i2c_recover_bus logic flow at the early stage of the function
> npcm_i2c_master_xfer.

We refer to the functions as func().

...

> +	/*
> +	 * Previously, the address was stored w/o left-shift by one bit and
> +	 * with that shift in the following call to npcm_i2c_master_start_xmit.
> +	 *
> +	 * Since there are cases that the i2c_recover_bus gets called at the
> +	 * early stage of the function npcm_i2c_master_xfer, the address is

Ditto.

> +	 * stored with the shift and used in the i2c_recover_bus call.
> +	 *
> +	 * The address is stored from bit 1 to bit 7 in the register for
> +	 * sending the i2c address later so it's left-shifted by 1 bit.
> +	 */
Tyrone Ting Sept. 16, 2024, 1:37 a.m. UTC | #2 
Hi Andy:

Your comments will be addressed.

Andy Shevchenko <andriy.shevchenko@linux.intel.com> 於 2024年9月13日 週五 下午6:33寫道：
>
> On Fri, Sep 13, 2024 at 06:14:44PM +0800, warp5tw@gmail.com wrote:
> > From: Tyrone Ting <kfting@nuvoton.com>
> >
> > Store the client address earlier since it might get called in
> > the i2c_recover_bus logic flow at the early stage of the function
> > npcm_i2c_master_xfer.
>
> We refer to the functions as func().
>
> ...
>
> > +     /*
> > +      * Previously, the address was stored w/o left-shift by one bit and
> > +      * with that shift in the following call to npcm_i2c_master_start_xmit.
> > +      *
> > +      * Since there are cases that the i2c_recover_bus gets called at the
> > +      * early stage of the function npcm_i2c_master_xfer, the address is
>
> Ditto.
>
> > +      * stored with the shift and used in the i2c_recover_bus call.
> > +      *
> > +      * The address is stored from bit 1 to bit 7 in the register for
> > +      * sending the i2c address later so it's left-shifted by 1 bit.
> > +      */
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Thank you.

Regards,
Tyrone
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 68f3d47323ab..e52e65e63600 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2155,6 +2155,18 @@  static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 
 	} while (time_is_after_jiffies(time_left) && bus_busy);
 
+	/*
+	 * Previously, the address was stored w/o left-shift by one bit and
+	 * with that shift in the following call to npcm_i2c_master_start_xmit.
+	 *
+	 * Since there are cases that the i2c_recover_bus gets called at the
+	 * early stage of the function npcm_i2c_master_xfer, the address is
+	 * stored with the shift and used in the i2c_recover_bus call.
+	 *
+	 * The address is stored from bit 1 to bit 7 in the register for
+	 * sending the i2c address later so it's left-shifted by 1 bit.
+	 */
+	bus->dest_addr = slave_addr << 1;
 	if (bus_busy || bus->ber_state) {
 		iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
 		npcm_i2c_reset(bus);
@@ -2163,7 +2175,6 @@  static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	}
 
 	npcm_i2c_init_params(bus);
-	bus->dest_addr = slave_addr;
 	bus->msgs = msgs;
 	bus->msgs_num = num;
 	bus->cmd_err = 0;