The clock phase degree may be between -360 to 360.
If the data signal is leading to the clock, the signedness
of clock phase is postive, otherwise, the signedness
is negative.
Signed-off-by: Chin-Ting Kuo <[email protected]>
---
drivers/mmc/core/host.c | 10 ++++++----
include/linux/mmc/host.h | 2 ++
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index d4683b1d263f..c2de7cbc7838 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -214,14 +214,16 @@ static void mmc_retune_timer(struct timer_list *t)
static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
struct mmc_clk_phase *phase)
{
- int degrees[2] = {0};
+ int degrees[4] = {0};
int rc;
- rc = device_property_read_u32_array(dev, prop, degrees, 2);
+ rc = device_property_read_u32_array(dev, prop, degrees, 4);
phase->valid = !rc;
if (phase->valid) {
- phase->in_deg = degrees[0];
- phase->out_deg = degrees[1];
+ phase->inv_in_deg = degrees[0] ? true : false;
+ phase->in_deg = degrees[1];
+ phase->inv_out_deg = degrees[2] ? true : false;
+ phase->out_deg = degrees[3];
}
}
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0c0c9a0fdf57..3c13010683e0 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -82,7 +82,9 @@ struct mmc_ios {
struct mmc_clk_phase {
bool valid;
+ bool inv_in_deg;
u16 in_deg;
+ bool inv_out_deg;
u16 out_deg;
};
--
2.17.1
On Wed, 22 Sep 2021, at 20:01, Chin-Ting Kuo wrote:
> The clock phase degree may be between -360 to 360.
> If the data signal is leading to the clock, the signedness
> of clock phase is postive, otherwise, the signedness
> is negative.
>
> Signed-off-by: Chin-Ting Kuo <[email protected]>
The implementation here can't be changed without a change to the
binding documentation:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/mmc-controller.yaml?h=v5.15-rc7#n345
> ---
> drivers/mmc/core/host.c | 10 ++++++----
> include/linux/mmc/host.h | 2 ++
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index d4683b1d263f..c2de7cbc7838 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -214,14 +214,16 @@ static void mmc_retune_timer(struct timer_list *t)
> static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
> struct mmc_clk_phase *phase)
> {
> - int degrees[2] = {0};
> + int degrees[4] = {0};
> int rc;
>
> - rc = device_property_read_u32_array(dev, prop, degrees, 2);
> + rc = device_property_read_u32_array(dev, prop, degrees, 4);
> phase->valid = !rc;
> if (phase->valid) {
> - phase->in_deg = degrees[0];
> - phase->out_deg = degrees[1];
> + phase->inv_in_deg = degrees[0] ? true : false;
> + phase->in_deg = degrees[1];
> + phase->inv_out_deg = degrees[2] ? true : false;
> + phase->out_deg = degrees[3];
This fundamentally breaks any in-tree users. We can't do this.
In terms of the binding, if negative phase values are something we must
do, we can just extend the value range to include [-359, -1] right?
That avoids changing the type of the value positions in the manner this
patch does.
Andrew
Hi Andrew,
> -----Original Message-----
> From: Andrew Jeffery <[email protected]>
> Sent: Tuesday, October 26, 2021 8:53 AM
> Subject: Re: [PATCH 04/10] mmc: Add invert flag for clock phase signedness
>
> On Wed, 22 Sep 2021, at 20:01, Chin-Ting Kuo wrote:
> > The clock phase degree may be between -360 to 360.
> > If the data signal is leading to the clock, the signedness of clock
> > phase is postive, otherwise, the signedness is negative.
> >
> > Signed-off-by: Chin-Ting Kuo <[email protected]>
>
> The implementation here can't be changed without a change to the binding
> documentation:
>
Okay, the binding document will be changed in the next patch version.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Docume
> ntation/devicetree/bindings/mmc/mmc-controller.yaml?h=v5.15-rc7#n345
>
> > ---
> > drivers/mmc/core/host.c | 10 ++++++---- include/linux/mmc/host.h |
> > 2 ++
> > 2 files changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index
> > d4683b1d263f..c2de7cbc7838 100644
> > --- a/drivers/mmc/core/host.c
> > +++ b/drivers/mmc/core/host.c
> > @@ -214,14 +214,16 @@ static void mmc_retune_timer(struct timer_list
> > *t) static void mmc_of_parse_timing_phase(struct device *dev, const char
> *prop,
> > struct mmc_clk_phase *phase) {
> > - int degrees[2] = {0};
> > + int degrees[4] = {0};
> > int rc;
> >
> > - rc = device_property_read_u32_array(dev, prop, degrees, 2);
> > + rc = device_property_read_u32_array(dev, prop, degrees, 4);
> > phase->valid = !rc;
> > if (phase->valid) {
> > - phase->in_deg = degrees[0];
> > - phase->out_deg = degrees[1];
> > + phase->inv_in_deg = degrees[0] ? true : false;
> > + phase->in_deg = degrees[1];
> > + phase->inv_out_deg = degrees[2] ? true : false;
> > + phase->out_deg = degrees[3];
>
> This fundamentally breaks any in-tree users. We can't do this.
>
> In terms of the binding, if negative phase values are something we must do,
> we can just extend the value range to include [-359, -1] right?
Yes, agree it and I tried it before. But, it seems that the device tree doesn't support
negative value with "-" prefixed and there is no device tree related API used to get
the negative value from .dts. Thus, I tried to add an additional flag to present
negative value.
> That avoids changing the type of the value positions in the manner this patch
> does.
>
> Andrew
Chin-Ting
On Sat, 6 Nov 2021, at 20:32, Chin-Ting Kuo wrote:
> Hi Andrew,
>>> > - rc = device_property_read_u32_array(dev, prop, degrees, 2);
>> > + rc = device_property_read_u32_array(dev, prop, degrees, 4);
>> > phase->valid = !rc;
>> > if (phase->valid) {
>> > - phase->in_deg = degrees[0];
>> > - phase->out_deg = degrees[1];
>> > + phase->inv_in_deg = degrees[0] ? true : false;
>> > + phase->in_deg = degrees[1];
>> > + phase->inv_out_deg = degrees[2] ? true : false;
>> > + phase->out_deg = degrees[3];
>>
>> This fundamentally breaks any in-tree users. We can't do this.
>>
>> In terms of the binding, if negative phase values are something we must do,
>> we can just extend the value range to include [-359, -1] right?
>
> Yes, agree it and I tried it before. But, it seems that the device tree
> doesn't support
> negative value with "-" prefixed and there is no device tree related
> API used to get
> the negative value from .dts. Thus, I tried to add an additional flag
> to present
> negative value.
>
Hmm. Still, I don't think we can break the binding this way.
Rob, Ulf, Adrian: What are your thoughts on handling phase offsets in
[-360, 360] in the binding? Do we append the flag field? Add a separate
property? I don't think interleaving the flags is desirable, though
interested in your thoughts.
Andrew