[PATCH v2 0/3] Drop support for I2C 10 bit devices from I3C subsystem

[PATCH v2 0/3] Drop support for I2C 10 bit devices from I3C subsystem

[Przemyslaw Gaj]

I3C MIPI spec does not clearly say that I2C 10bit devices are supported. 
Additionally, it isn't possible to pass 10 bit device properly through DEFSLVS
command and reserve address for such device on secondary master side.

Przemyslaw Gaj (3):
  i3c: Drop support for I2C 10 bit addresing
  i3c: master: cdns: Drop support for I2C 10 bit addresing in Cadence
    I3C master
  dt-bindings: i3c: Document dropped support for I2C 10 bit devices

 Documentation/devicetree/bindings/i3c/i3c.txt | 4 +++-
 drivers/i3c/master.c                          | 9 +++++++++
 drivers/i3c/master/i3c-master-cdns.c          | 4 +---
 3 files changed, 13 insertions(+), 4 deletions(-)

-- 
2.8.3


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[PATCH v2 1/3] i3c: Drop support for I2C 10 bit addresing

[Przemyslaw Gaj]

This patch dropps support for I2C devices with 10 bit addressing. When I2C
device with 10 bit address is defined in DT, I3C master registration fails.

Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>

---

Main changes between v1 and v2 are:
- Add error message when registering I2C device with 10 bit address.

---
 drivers/i3c/master.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 2dc628d..8c1e365 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1962,6 +1962,15 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
 	if (ret)
 		return ret;
 
+	/* The I3C Specification does not clearly say I2C devices with 10-bit
+	 * address are supported. These devices can't be passed properly through
+	 * DEFSLVS command.
+	 */
+	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
+		dev_err(&master->dev, "I2C device with 10 bit address not supported.");
+		return -ENOTSUPP;
+	}
+
 	/* LVR is encoded in reg[2]. */
 	boardinfo->lvr = reg[2];
 
-- 
2.8.3


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[PATCH v2 2/3] i3c: master: cdns: Drop support for I2C 10 bit addresing in Cadence I3C master

[Przemyslaw Gaj]

Because this patch series dropped support for 10 bit I2C devices, support is
also dropped in Cadence I3C master driver.

Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
---
 drivers/i3c/master/i3c-master-cdns.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 8889a4f..1797fbf 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -1010,9 +1010,7 @@ static int cdns_i3c_master_attach_i2c_dev(struct i2c_dev_desc *dev)
 	master->free_rr_slots &= ~BIT(slot);
 	i2c_dev_set_master_data(dev, data);
 
-	writel(prepare_rr0_dev_address(dev->boardinfo->base.addr) |
-	       (dev->boardinfo->base.flags & I2C_CLIENT_TEN ?
-		DEV_ID_RR0_LVR_EXT_ADDR : 0),
+	writel(prepare_rr0_dev_address(dev->boardinfo->base.addr),
 	       master->regs + DEV_ID_RR0(data->id));
 	writel(dev->boardinfo->lvr, master->regs + DEV_ID_RR2(data->id));
 	writel(readl(master->regs + DEVS_CTRL) |
-- 
2.8.3


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[PATCH v2 3/3] dt-bindings: i3c: Document dropped support for I2C 10 bit devices

[Przemyslaw Gaj]

Because this patch series dropped support for 10 bit I2C devices, I'm
documenting this.

Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
---
 Documentation/devicetree/bindings/i3c/i3c.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i3c/i3c.txt b/Documentation/devicetree/bindings/i3c/i3c.txt
index ab729a0..4ffe059 100644
--- a/Documentation/devicetree/bindings/i3c/i3c.txt
+++ b/Documentation/devicetree/bindings/i3c/i3c.txt
@@ -39,7 +39,9 @@ valid here, but several new properties have been added.
 New constraint on existing properties:
 --------------------------------------
 - reg: contains 3 cells
-  + first cell : still encoding the I2C address
+  + first cell : still encoding the I2C address. 10 bit addressing is not
+    supported. Devices with 10 bit address can't be properly passed through
+    DEFSLVS command.
 
   + second cell: shall be 0
 
-- 
2.8.3


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Re: [PATCH v2 1/3] i3c: Drop support for I2C 10 bit addresing

[vitor]

On 26/02/19 14:28, Przemyslaw Gaj wrote:
> This patch dropps support for I2C devices with 10 bit addressing. When I2C
> device with 10 bit address is defined in DT, I3C master registration fails.
>
> Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
>
> ---
>
> Main changes between v1 and v2 are:
> - Add error message when registering I2C device with 10 bit address.
>
> ---
>  drivers/i3c/master.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 2dc628d..8c1e365 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -1962,6 +1962,15 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
>  	if (ret)
>  		return ret;
>  
> +	/* The I3C Specification does not clearly say I2C devices with 10-bit
> +	 * address are supported. These devices can't be passed properly through
> +	 * DEFSLVS command.
> +	 */

IMO we just need to say 10-bit address not used or not supported in i3c.

> +	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
> +		dev_err(&master->dev, "I2C device with 10 bit address not supported.");
> +		return -ENOTSUPP;
> +	}
> +
>  	/* LVR is encoded in reg[2]. */
>  	boardinfo->lvr = reg[2];
>  

Also need to change:

#define I2C_MAX_ADDR            GENMASK(9, 0)
to
#define I2C_MAX_ADDR            GENMASK(6, 0)
in master.h file

Not sure about:
unsigned long addrslots[((I2C_MAX_ADDR + 1) * 2) / BITS_PER_LONG];
@Boris can you check this part?

Best regards,
Vitor Soares

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Re: [PATCH v2 1/3] i3c: Drop support for I2C 10 bit addresing

[Boris Brezillon]

Hi Vitor,

On Wed, 27 Feb 2019 12:05:30 +0000
vitor <vitor.soares@synopsys.com> wrote:

> On 26/02/19 14:28, Przemyslaw Gaj wrote:
> > This patch dropps support for I2C devices with 10 bit addressing. When I2C
> > device with 10 bit address is defined in DT, I3C master registration fails.
> >
> > Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
> >
> > ---
> >
> > Main changes between v1 and v2 are:
> > - Add error message when registering I2C device with 10 bit address.
> >
> > ---
> >  drivers/i3c/master.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > index 2dc628d..8c1e365 100644
> > --- a/drivers/i3c/master.c
> > +++ b/drivers/i3c/master.c
> > @@ -1962,6 +1962,15 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
> >  	if (ret)
> >  		return ret;
> >  
> > +	/* The I3C Specification does not clearly say I2C devices with 10-bit
> > +	 * address are supported. These devices can't be passed properly through
> > +	 * DEFSLVS command.
> > +	 */  
> 
> IMO we just need to say 10-bit address not used or not supported in i3c.

I'd like to keep a clear comment on why it cannot supported right now
even though the spec is unclear about that. If the spec is updated to
state that I2C devs using extended addresses are forbidden, then we'll
update this comment accordingly.

> 
> > +	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
> > +		dev_err(&master->dev, "I2C device with 10 bit address not supported.");
> > +		return -ENOTSUPP;
> > +	}
> > +
> >  	/* LVR is encoded in reg[2]. */
> >  	boardinfo->lvr = reg[2];
> >    
> 
> Also need to change:
> 
> #define I2C_MAX_ADDR            GENMASK(9, 0)
> to
> #define I2C_MAX_ADDR            GENMASK(6, 0)
> in master.h file

Yep, you can reduce the address space.

> 
> Not sure about:
> unsigned long addrslots[((I2C_MAX_ADDR + 1) * 2) / BITS_PER_LONG];
> @Boris can you check this part?

This part is still valid, no need to update it as you already updated
I2C_MAX_ADDR.

Thanks for the review.

Boris

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Re: [PATCH v2 1/3] i3c: Drop support for I2C 10 bit addresing

[vitor]

Hi,

On 27/02/19 12:10, Boris Brezillon wrote:
> Hi Vitor,
>
> On Wed, 27 Feb 2019 12:05:30 +0000
> vitor <vitor.soares@synopsys.com> wrote:
>
>> On 26/02/19 14:28, Przemyslaw Gaj wrote:
>>> This patch dropps support for I2C devices with 10 bit addressing. When I2C
>>> device with 10 bit address is defined in DT, I3C master registration fails.
>>>
>>> Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
>>>
>>> ---
>>>
>>> Main changes between v1 and v2 are:
>>> - Add error message when registering I2C device with 10 bit address.
>>>
>>> ---
>>>  drivers/i3c/master.c | 9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>>
>>> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
>>> index 2dc628d..8c1e365 100644
>>> --- a/drivers/i3c/master.c
>>> +++ b/drivers/i3c/master.c
>>> @@ -1962,6 +1962,15 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
>>>  	if (ret)
>>>  		return ret;
>>>  
>>> +	/* The I3C Specification does not clearly say I2C devices with 10-bit
>>> +	 * address are supported. These devices can't be passed properly through
>>> +	 * DEFSLVS command.
>>> +	 */  
>> IMO we just need to say 10-bit address not used or not supported in i3c.
> I'd like to keep a clear comment on why it cannot supported right now
> even though the spec is unclear about that. If the spec is updated to
> state that I2C devs using extended addresses are forbidden, then we'll
> update this comment accordingly.

I'm not sure if the terms aren't the same, but let's keep the comment.

>
>>> +	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
>>> +		dev_err(&master->dev, "I2C device with 10 bit address not supported.");
>>> +		return -ENOTSUPP;
>>> +	}
>>> +
>>>  	/* LVR is encoded in reg[2]. */
>>>  	boardinfo->lvr = reg[2];
>>>    
>> Also need to change:
>>
>> #define I2C_MAX_ADDR            GENMASK(9, 0)
>> to
>> #define I2C_MAX_ADDR            GENMASK(6, 0)
>> in master.h file
> Yep, you can reduce the address space.
>
>> Not sure about:
>> unsigned long addrslots[((I2C_MAX_ADDR + 1) * 2) / BITS_PER_LONG];
>> @Boris can you check this part?
> This part is still valid, no need to update it as you already updated
> I2C_MAX_ADDR.
>
> Thanks for the review.
>
> Boris

Also we can make i2c_algorithm.functionality = I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C, and in this way we won't need ->i2c_func() and avoid the I2C_FUNC_10BIT_ADDR flag on host controller side.

Best regards,
Vitor Soares


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Re: [PATCH v2 1/3] i3c: Drop support for I2C 10 bit addresing

[Boris Brezillon]

On Wed, 27 Feb 2019 12:52:42 +0000
vitor <vitor.soares@synopsys.com> wrote:

> Hi,
> 
> On 27/02/19 12:10, Boris Brezillon wrote:
> > Hi Vitor,
> >
> > On Wed, 27 Feb 2019 12:05:30 +0000
> > vitor <vitor.soares@synopsys.com> wrote:
> >  
> >> On 26/02/19 14:28, Przemyslaw Gaj wrote:  
> >>> This patch dropps support for I2C devices with 10 bit addressing. When I2C
> >>> device with 10 bit address is defined in DT, I3C master registration fails.
> >>>
> >>> Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
> >>>
> >>> ---
> >>>
> >>> Main changes between v1 and v2 are:
> >>> - Add error message when registering I2C device with 10 bit address.
> >>>
> >>> ---
> >>>  drivers/i3c/master.c | 9 +++++++++
> >>>  1 file changed, 9 insertions(+)
> >>>
> >>> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> >>> index 2dc628d..8c1e365 100644
> >>> --- a/drivers/i3c/master.c
> >>> +++ b/drivers/i3c/master.c
> >>> @@ -1962,6 +1962,15 @@ of_i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
> >>>  	if (ret)
> >>>  		return ret;
> >>>  
> >>> +	/* The I3C Specification does not clearly say I2C devices with 10-bit

Nitpick: please do not use net-style comments in the I3C subsystem.

Use

/*
 * blablabla
 */

instead.

> >>> +	 * address are supported. These devices can't be passed properly through
> >>> +	 * DEFSLVS command.
> >>> +	 */    
> >> IMO we just need to say 10-bit address not used or not supported in i3c.  
> > I'd like to keep a clear comment on why it cannot supported right now
> > even though the spec is unclear about that. If the spec is updated to
> > state that I2C devs using extended addresses are forbidden, then we'll
> > update this comment accordingly.  
> 
> I'm not sure if the terms aren't the same,

Don't understand what you mean, sorry.

>but let's keep the comment.
> 
> >  
> >>> +	if (boardinfo->base.flags & I2C_CLIENT_TEN) {
> >>> +		dev_err(&master->dev, "I2C device with 10 bit address not supported.");
> >>> +		return -ENOTSUPP;
> >>> +	}
> >>> +
> >>>  	/* LVR is encoded in reg[2]. */
> >>>  	boardinfo->lvr = reg[2];
> >>>      
> >> Also need to change:
> >>
> >> #define I2C_MAX_ADDR            GENMASK(9, 0)
> >> to
> >> #define I2C_MAX_ADDR            GENMASK(6, 0)
> >> in master.h file  
> > Yep, you can reduce the address space.
> >  
> >> Not sure about:
> >> unsigned long addrslots[((I2C_MAX_ADDR + 1) * 2) / BITS_PER_LONG];
> >> @Boris can you check this part?  
> > This part is still valid, no need to update it as you already updated
> > I2C_MAX_ADDR.
> >
> > Thanks for the review.
> >
> > Boris  
> 
> Also we can make i2c_algorithm.functionality = I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C, and in this way we won't need ->i2c_func() and avoid the I2C_FUNC_10BIT_ADDR flag on host controller side.

Ack. Let's rip ->i2c_func() out and return I2C_FUNC_SMBUS_EMUL |
I2C_FUNC_I2C for everyone. We'll add it back if some drivers want to
support SMBUS natively or if 10bit addressing appears to be needed at
some point.

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