On Thu, Sep 07, 2023 at 10:31:55AM +0200, Konrad Dybcio wrote:
> On 7.09.2023 07:21, Varadarajan Narayanan 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.
> >
> > 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;
> > + else if (action == POST_RATE_CHANGE)
> > + index = P_APSS_PLL_EARLY;
> > + else
> > + return 0;
> > +
> > + err = clk_rcg2_mux_closest_ops.set_parent(&apcs_alias0_clk_src.clkr.hw,
> > + index);
> Adding a variable for clk_hw within the apcs_alias0 clock would
> make this easier to digest, I think.
>
> And if we wanna be even less error-prone, you can reference the
> ops of this clock in an indirect way.
Will change it as
struct clk_hw *hw;
hw = &apcs_alias0_clk_src.clkr.hw;
err = hw->init->ops->set_parent(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
> > + */
> 1. /* Keep this in a 1-line comment */
Ok
> 2. why? explain the reasoning in the commit message
Ok
Thanks
Varada
> > + case QCOM_ID_IPQ5332:
> > + case QCOM_ID_IPQ5322:
> > + case QCOM_ID_IPQ5300:
> > + 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 = {
