Am Donnerstag, 4. Mai 2023, 14:57:01 CEST schrieb Adam Ford:
> On Thu, May 4, 2023 at 7:40 AM Alexander Stein
>
> <alexander.stein@xxxxxxxxxxxxxxx> wrote:
> > Hi Adam,
> >
> > Am Donnerstag, 4. Mai 2023, 14:00:08 CEST schrieb Adam Ford:
> > > On Thu, May 4, 2023 at 4:21 AM Alexander Stein
> > >
> > > <alexander.stein@xxxxxxxxxxxxxxx> wrote:
> > > > Am Dienstag, 2. Mai 2023, 03:07:55 CEST schrieb Adam Ford:
> > > > > Make the pll-clock-frequency optional. If it's present, use it
> > > > > to maintain backwards compatibility with existing hardware. If it
> > > > > is absent, read clock rate of "sclk_mipi" to determine the rate.
> > > > >
> > > > > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> > > > > Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> > > > > ---
> > > > >
> > > > > drivers/gpu/drm/bridge/samsung-dsim.c | 12 ++++++++++--
> > > > > 1 file changed, 10 insertions(+), 2 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> > > > > b/drivers/gpu/drm/bridge/samsung-dsim.c index
> > > > > bf4b33d2de76..2dc02a9e37c0
> > > > > 100644
> > > > > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > > > > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > > > > @@ -1726,12 +1726,20 @@ static int samsung_dsim_parse_dt(struct
> > > > > samsung_dsim *dsi) {
> > > > >
> > > > > struct device *dev = dsi->dev;
> > > > > struct device_node *node = dev->of_node;
> > > > >
> > > > > + struct clk *pll_clk;
> > > > >
> > > > > int ret;
> > > > >
> > > > > ret = samsung_dsim_of_read_u32(node,
> > > > > "samsung,pll-clock-frequency",
> > > > >
> > > > > &dsi->pll_clk_rate);
> > > > >
> > > > > - if (ret < 0)
> > > > > - return ret;
> > > > > +
> > > > > + /* If it doesn't exist, read it from the clock instead of
> > > > > failing
> > > > > */
> > > > > + if (ret < 0) {
> > > > > + pll_clk = devm_clk_get(dev, "sclk_mipi");
> > > > > + if (!IS_ERR(pll_clk))
> > > > > + dsi->pll_clk_rate = clk_get_rate(pll_clk);
> > > > > + else
> > > > > + return PTR_ERR(pll_clk);
> > > > > + }
> > > >
> > > > Now that 'samsung,pll-clock-frequency' is optional the error in
> > > > samsung_dsim_of_read_u32() should be changed. Otherwise you will get
> > > >
> > > > > /soc@0/bus@32c00000/dsi@32e10000: failed to get 'samsung,pll-clock-
> > > >
> > > > frequency' property
> > >
> > > I'll change the message from err to info with a message that reads "no
> > > samsung,pll-clock-frequency, using pixel clock"
> > >
> > > Does that work?
> >
> > Having just a info is totally fine with me. Thanks.
> > Although your suggested message somehow implies (to me) using pixel clock
> > is just a fallback. I'm a bit concerned some might think
> > "samsung,pll-clock- frequency" should be provided in DT. But this might
> > just be me.
>
> Oops, I got the PLL and burst burst clock confused. I think both
> burst-clock and pll clock messages should get updates.
>
> The pll clock should say something like "samsung,pll-clock-frequency
> not defined, using sclk_mipi"
>
> The imx8m n/m/p have the sclk_mipi defined in the device tree, and
> this patch allows them to not have
> to manually set the pll clock since it can be read. This allows to
> people to change the frequency of the PLL in
> in one place and let the driver read it instead of having to set the
> value in two places for the same clock.
That's why I would like to make it sound less error-like.
How about "Using sclk_mipi for pll clock frequency"?
> For the burst clock, I'd like to propose
> "samsung,burst-clock-frequency not defined, using pixel clock"
Similar to above how about "Using pixel clock for burst clock frequency"?
> Does that work for you?
But I'm okay with both ways. Up to you.
Thanks and best regards,
Alexander
> > frequency
> >
> >
> > Best regards,
> > Alexander
> >
> > > adam
> > >
> > > > Best regards,
> > > > Alexander
> > > >
> > > > > ret = samsung_dsim_of_read_u32(node, "samsung,burst-clock-
> > > >
> > > > frequency",
> > > >
> > > > > &dsi->burst_clk_rate);
> > > >
> > > > --
> > > > TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> > > > Amtsgericht München, HRB 105018
> > > > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> > > > http://www.tq-group.com/
> >
> > --
> > TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> > Amtsgericht München, HRB 105018
> > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> > http://www.tq-group.com/
--
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
http://www.tq-group.com/
