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? 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. 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; >