On Thu, 7 Sept 2023 at 08:22, Varadarajan Narayanan <quic_varada@xxxxxxxxxxx> wrote: > > Stromer Plus PLL found on IPQ53xx doesn't support dynamic > frequency scaling. To achieve the same, we need to park the APPS > PLL source to GPLL0, re configure the PLL and then switch the > source to APSS_PLL_EARLY. > > To support this, register a clock notifier to get the PRE_RATE > and POST_RATE notification. Change the APSS PLL source to GPLL0 > when PRE_RATE notification is received, then configure the PLL > and then change back the source to APSS_PLL_EARLY. This means that we are changing the parents behind the back of CCF, which is not great. > > Signed-off-by: Kathiravan T <quic_kathirav@xxxxxxxxxxx> > Signed-off-by: Varadarajan Narayanan <quic_varada@xxxxxxxxxxx> > --- > drivers/clk/qcom/apss-ipq6018.c | 54 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 53 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/qcom/apss-ipq6018.c b/drivers/clk/qcom/apss-ipq6018.c > index 4e13a08..ffb6ab5 100644 > --- a/drivers/clk/qcom/apss-ipq6018.c > +++ b/drivers/clk/qcom/apss-ipq6018.c > @@ -9,8 +9,11 @@ > #include <linux/clk-provider.h> > #include <linux/regmap.h> > #include <linux/module.h> > +#include <linux/clk.h> > +#include <linux/soc/qcom/smem.h> > > #include <dt-bindings/clock/qcom,apss-ipq.h> > +#include <dt-bindings/arm/qcom,ids.h> > > #include "common.h" > #include "clk-regmap.h" > @@ -84,15 +87,64 @@ static const struct qcom_cc_desc apss_ipq6018_desc = { > .num_clks = ARRAY_SIZE(apss_ipq6018_clks), > }; > > +static int cpu_clk_notifier_fn(struct notifier_block *nb, unsigned long action, > + void *data) > +{ > + u8 index; > + int err; > + > + if (action == PRE_RATE_CHANGE) > + index = P_GPLL0; I don't see P_GPLL0 being supported in the ipq6018 driver. > + else if (action == POST_RATE_CHANGE) > + index = P_APSS_PLL_EARLY; You also have to handle ABORT_RATE_CHANGE here. > + else > + return 0; > + > + err = clk_rcg2_mux_closest_ops.set_parent(&apcs_alias0_clk_src.clkr.hw, > + index); > + > + return notifier_from_errno(err); > +} > + > +static struct notifier_block cpu_clk_notifier = { > + .notifier_call = cpu_clk_notifier_fn, > +}; > + > static int apss_ipq6018_probe(struct platform_device *pdev) > { > struct regmap *regmap; > + u32 soc_id; > + int ret; > + > + ret = qcom_smem_get_soc_id(&soc_id); > + if (ret) > + return ret; > > regmap = dev_get_regmap(pdev->dev.parent, NULL); > if (!regmap) > return -ENODEV; > > - return qcom_cc_really_probe(pdev, &apss_ipq6018_desc, regmap); > + ret = qcom_cc_really_probe(pdev, &apss_ipq6018_desc, regmap); > + if (ret) > + return ret; > + > + switch (soc_id) { > + /* > + * Only below variants of IPQ53xx support scaling > + */ > + case QCOM_ID_IPQ5332: > + case QCOM_ID_IPQ5322: > + case QCOM_ID_IPQ5300: Please use compat strings instead of using the soc-id. > + ret = clk_notifier_register(apcs_alias0_clk_src.clkr.hw.clk, > + &cpu_clk_notifier); > + if (ret) > + return ret; > + break; > + default: > + break; > + } > + > + return 0; > } > > static struct platform_driver apss_ipq6018_driver = { > -- > 2.7.4 > -- With best wishes Dmitry