The i3c bus spec define a bus configuration where the i2c devices
doesn't have the 50ns filter yet they allow the SDR max speed.
This patch introduce the limited bus mode so the users can use
a higher speed on presence of i2c devices index 1.
Signed-off-by: Vitor Soares <[email protected]>
Cc: Boris Brezillon <[email protected]>
Cc: <[email protected]>
---
drivers/i3c/master.c | 5 +++++
include/linux/i3c/master.h | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 1c4a86a..46d3774 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -463,6 +463,7 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
static const char * const i3c_bus_mode_strings[] = {
[I3C_BUS_MODE_PURE] = "pure",
[I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
+ [I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
[I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
};
@@ -575,6 +576,7 @@ int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
break;
case I3C_BUS_MODE_MIXED_FAST:
+ case I3C_BUS_MODE_MIXED_LIMITED:
if (!i3cbus->scl_rate.i3c)
i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
if (!i3cbus->scl_rate.i2c)
@@ -2481,6 +2483,9 @@ int i3c_master_register(struct i3c_master_controller *master,
mode = I3C_BUS_MODE_MIXED_FAST;
break;
case I3C_LVR_I2C_INDEX(1):
+ if (mode < I3C_BUS_MODE_MIXED_LIMITED)
+ mode = I3C_BUS_MODE_MIXED_LIMITED;
+ break;
case I3C_LVR_I2C_INDEX(2):
if (mode < I3C_BUS_MODE_MIXED_SLOW)
mode = I3C_BUS_MODE_MIXED_SLOW;
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 44fb3cf..740235e 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -250,12 +250,17 @@ struct i3c_device {
* the bus. The only impact in this mode is that the
* high SCL pulse has to stay below 50ns to trick I2C
* devices when transmitting I3C frames
+ * @I3C_BUS_MODE_MIXED_LIMITED: I2C devices without 50ns spike filter are
+ * present on the bus. However they allows
+ * compliance up to the maximum SDR SCL clock
+ * frequency.
* @I3C_BUS_MODE_MIXED_SLOW: I2C devices without 50ns spike filter are present
* on the bus
*/
enum i3c_bus_mode {
I3C_BUS_MODE_PURE,
I3C_BUS_MODE_MIXED_FAST,
+ I3C_BUS_MODE_MIXED_LIMITED,
I3C_BUS_MODE_MIXED_SLOW,
};
--
2.7.4
Hi Vitor,
On Mon, 15 Apr 2019 20:46:42 +0200
Vitor Soares <[email protected]> wrote:
> The i3c bus spec define a bus configuration where the i2c devices
^defines I2C devices...
> doesn't have the 50ns filter yet they allow the SDR max speed.
^don't ^ a 50ns filter but support SCL running at SDR max
rate (12MHz).
>
> This patch introduce the limited bus mode so the users can use
^introduces ^ so that users
> a higher speed on presence of i2c devices index 1.
^in
>
> Signed-off-by: Vitor Soares <[email protected]>
> Cc: Boris Brezillon <[email protected]>
> Cc: <[email protected]>
> ---
> drivers/i3c/master.c | 5 +++++
> include/linux/i3c/master.h | 5 +++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 1c4a86a..46d3774 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -463,6 +463,7 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
> static const char * const i3c_bus_mode_strings[] = {
> [I3C_BUS_MODE_PURE] = "pure",
> [I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
> + [I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
> [I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
> };
>
> @@ -575,6 +576,7 @@ int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
> i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> break;
> case I3C_BUS_MODE_MIXED_FAST:
> + case I3C_BUS_MODE_MIXED_LIMITED:
> if (!i3cbus->scl_rate.i3c)
> i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> if (!i3cbus->scl_rate.i2c)
> @@ -2481,6 +2483,9 @@ int i3c_master_register(struct i3c_master_controller *master,
> mode = I3C_BUS_MODE_MIXED_FAST;
> break;
> case I3C_LVR_I2C_INDEX(1):
> + if (mode < I3C_BUS_MODE_MIXED_LIMITED)
> + mode = I3C_BUS_MODE_MIXED_LIMITED;
> + break;
> case I3C_LVR_I2C_INDEX(2):
> if (mode < I3C_BUS_MODE_MIXED_SLOW)
> mode = I3C_BUS_MODE_MIXED_SLOW;
> diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> index 44fb3cf..740235e 100644
> --- a/include/linux/i3c/master.h
> +++ b/include/linux/i3c/master.h
> @@ -250,12 +250,17 @@ struct i3c_device {
> * the bus. The only impact in this mode is that the
> * high SCL pulse has to stay below 50ns to trick I2C
> * devices when transmitting I3C frames
> + * @I3C_BUS_MODE_MIXED_LIMITED: I2C devices without 50ns spike filter are
> + * present on the bus. However they allows
> + * compliance up to the maximum SDR SCL clock
> + * frequency.
However they support
SCL clock running at maximum SDR rate
(12.5MHz).
> * @I3C_BUS_MODE_MIXED_SLOW: I2C devices without 50ns spike filter are present
> * on the bus
> */
> enum i3c_bus_mode {
> I3C_BUS_MODE_PURE,
> I3C_BUS_MODE_MIXED_FAST,
> + I3C_BUS_MODE_MIXED_LIMITED,
> I3C_BUS_MODE_MIXED_SLOW,
> };
>
The code itself looks good.
Thanks,
Boris
Hi Boris,
From: Boris Brezillon <[email protected]>
Date: Tue, Apr 16, 2019 at 07:00:49
> Hi Vitor,
>
> On Mon, 15 Apr 2019 20:46:42 +0200
> Vitor Soares <[email protected]> wrote:
>
> > The i3c bus spec define a bus configuration where the i2c devices
>
> ^defines I2C devices...
>
> > doesn't have the 50ns filter yet they allow the SDR max speed.
>
> ^don't ^ a 50ns filter but support SCL running at SDR max
> rate (12MHz).
>
> >
> > This patch introduce the limited bus mode so the users can use
>
> ^introduces ^ so that users
>
> > a higher speed on presence of i2c devices index 1.
>
> ^in
>
> >
> > Signed-off-by: Vitor Soares <[email protected]>
> > Cc: Boris Brezillon <[email protected]>
> > Cc: <[email protected]>
> > ---
> > drivers/i3c/master.c | 5 +++++
> > include/linux/i3c/master.h | 5 +++++
> > 2 files changed, 10 insertions(+)
> >
> > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > index 1c4a86a..46d3774 100644
> > --- a/drivers/i3c/master.c
> > +++ b/drivers/i3c/master.c
> > @@ -463,6 +463,7 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
> > static const char * const i3c_bus_mode_strings[] = {
> > [I3C_BUS_MODE_PURE] = "pure",
> > [I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
> > + [I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
> > [I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
> > };
> >
> > @@ -575,6 +576,7 @@ int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
> > i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> > break;
> > case I3C_BUS_MODE_MIXED_FAST:
> > + case I3C_BUS_MODE_MIXED_LIMITED:
> > if (!i3cbus->scl_rate.i3c)
> > i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
> > if (!i3cbus->scl_rate.i2c)
> > @@ -2481,6 +2483,9 @@ int i3c_master_register(struct i3c_master_controller *master,
> > mode = I3C_BUS_MODE_MIXED_FAST;
> > break;
> > case I3C_LVR_I2C_INDEX(1):
> > + if (mode < I3C_BUS_MODE_MIXED_LIMITED)
> > + mode = I3C_BUS_MODE_MIXED_LIMITED;
> > + break;
> > case I3C_LVR_I2C_INDEX(2):
> > if (mode < I3C_BUS_MODE_MIXED_SLOW)
> > mode = I3C_BUS_MODE_MIXED_SLOW;
> > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > index 44fb3cf..740235e 100644
> > --- a/include/linux/i3c/master.h
> > +++ b/include/linux/i3c/master.h
> > @@ -250,12 +250,17 @@ struct i3c_device {
> > * the bus. The only impact in this mode is that the
> > * high SCL pulse has to stay below 50ns to trick I2C
> > * devices when transmitting I3C frames
> > + * @I3C_BUS_MODE_MIXED_LIMITED: I2C devices without 50ns spike filter are
> > + * present on the bus. However they allows
> > + * compliance up to the maximum SDR SCL clock
> > + * frequency.
>
> However they support
> SCL clock running at maximum SDR rate
> (12.5MHz).
>
> > * @I3C_BUS_MODE_MIXED_SLOW: I2C devices without 50ns spike filter are present
> > * on the bus
> > */
> > enum i3c_bus_mode {
> > I3C_BUS_MODE_PURE,
> > I3C_BUS_MODE_MIXED_FAST,
> > + I3C_BUS_MODE_MIXED_LIMITED,
> > I3C_BUS_MODE_MIXED_SLOW,
> > };
> >
>
> The code itself looks good.
>
> Thanks,
>
> Boris
Thanks for your feedback I will address the fixes next version.
Best regards,
Vitor Soares