On Wed, May 17, 2023 at 7:56 AM Lucas Stach <l.stach@xxxxxxxxxxxxxx> wrote:
>
> Hi Adam,
>
> Am Montag, dem 15.05.2023 um 18:57 -0500 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.
> > Since it can be optional, change the message from an error to
> > dev_info.
> >
> > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> > Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> > Tested-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> > Reviewed-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/bridge/samsung-dsim.c | 23 ++++++++++++++++-------
> > 1 file changed, 16 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> > index bf4b33d2de76..08266303c261 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1712,11 +1712,11 @@ static const struct mipi_dsi_host_ops samsung_dsim_ops = {
> > };
> >
> > static int samsung_dsim_of_read_u32(const struct device_node *np,
> > - const char *propname, u32 *out_value)
> > + const char *propname, u32 *out_value, bool optional)
> > {
> > int ret = of_property_read_u32(np, propname, out_value);
> >
> > - if (ret < 0)
> > + if (ret < 0 && !optional)
> > pr_err("%pOF: failed to get '%s' property\n", np, propname);
> >
> > return ret;
> > @@ -1726,20 +1726,29 @@ 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;
> > + &dsi->pll_clk_rate, 1);
> > +
> > + /* If it doesn't exist, read it from the clock instead of failing */
> > + if (ret < 0) {
> > + dev_info(dev, "Using sclk_mipi for pll clock frequency\n");
>
> While this is certainly helpful while debugging the driver, I don't
> think it warrants a info print. Remove or downgrade to dev_dbg?
I can move to dbg.
>
> On the other hand the changed driver behavior should be documented in
> the devicetree binding by moving "samsung,pll-clock-frequency" into the
> optional properties and spelling out which clock rate is used when the
> property is absent.
Once this series is accepted, I was planning on doing a binding patch
which describes the items that are now optional followed by a patch to
add DSI->HDMI for the Beacon boards. I can see the value in putting
the bindings patch in this series instead. I'll add it to the next
revision to cover both items that are now optional.
adam
>
> Regards,
> Lucas
>
> > + 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);
> > + }
> >
> > ret = samsung_dsim_of_read_u32(node, "samsung,burst-clock-frequency",
> > - &dsi->burst_clk_rate);
> > + &dsi->burst_clk_rate, 0);
> > if (ret < 0)
> > return ret;
> >
> > ret = samsung_dsim_of_read_u32(node, "samsung,esc-clock-frequency",
> > - &dsi->esc_clk_rate);
> > + &dsi->esc_clk_rate, 0);
> > if (ret < 0)
> > return ret;
> >
>
