diff mbox series

[v4,5/9] clk: qcom: apss-ipq6018: ipq5332: add safe source switch for a53pll

Message ID 9ebae0e9780745091274562a2b9afd856241dbdc.1697694811.git.quic_varada@quicinc.com (mailing list archive)
State Superseded
Headers show
Series Enable cpufreq for IPQ5332 & IPQ9574 | expand

Commit Message

Varadarajan Narayanan Oct. 19, 2023, 8:40 a.m. UTC 
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.

Additionally, not all SKUs of IPQ53xx support scaling. Hence,
do the above to the SKUs that support scaling.

Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
---
v3:	devm_kzalloc for cpu_clk_notifier instead of global static
v2:	Handle ABORT_RATE_CHANGE
	Use local variable for apcs_alias0_clk_src.clkr.hw
	Use single line comment instead of multi line style
---
 drivers/clk/qcom/apss-ipq6018.c | 58 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

Comments

Dmitry Baryshkov Oct. 19, 2023, 1:21 p.m. UTC | #1 
On Thu, 19 Oct 2023 at 11:42, Varadarajan Narayanan
<quic_varada@quicinc.com> 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.
>
> Additionally, not all SKUs of IPQ53xx support scaling. Hence,
> do the above to the SKUs that support scaling.
>
> Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
> Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
> ---
> v3:     devm_kzalloc for cpu_clk_notifier instead of global static
> v2:     Handle ABORT_RATE_CHANGE
>         Use local variable for apcs_alias0_clk_src.clkr.hw
>         Use single line comment instead of multi line style
> ---
>  drivers/clk/qcom/apss-ipq6018.c | 58 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/qcom/apss-ipq6018.c b/drivers/clk/qcom/apss-ipq6018.c
> index 4e13a08..db65b0d 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 +87,68 @@ 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)
> +{
> +       struct clk_hw *hw;
> +       u8 index;
> +       int err;
> +
> +       if (action == PRE_RATE_CHANGE)
> +               index = P_GPLL0;
> +       else if (action == POST_RATE_CHANGE || action == ABORT_RATE_CHANGE)
> +               index = P_APSS_PLL_EARLY;
> +       else
> +               return NOTIFY_OK;
> +
> +       hw = &apcs_alias0_clk_src.clkr.hw;
> +       err = clk_rcg2_mux_closest_ops.set_parent(hw, index);
> +
> +       return notifier_from_errno(err);
> +}
> +
>  static int apss_ipq6018_probe(struct platform_device *pdev)
>  {
> +       struct notifier_block *cpu_clk_notifier;
>         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:
> +               cpu_clk_notifier = devm_kzalloc(&pdev->dev,
> +                                               sizeof(*cpu_clk_notifier),
> +                                               GFP_KERNEL);
> +               if (!cpu_clk_notifier)
> +                       return -ENOMEM;
> +
> +               cpu_clk_notifier->notifier_call = cpu_clk_notifier_fn;
> +
> +               ret = clk_notifier_register(apcs_alias0_clk_src.clkr.hw.clk,
> +                                           cpu_clk_notifier);

devm_clk_notifier_register sounds more future-proof.

Other than that:

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

> +               if (ret)
> +                       return ret;
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       return 0;
>  }
>
>  static struct platform_driver apss_ipq6018_driver = {
> --
> 2.7.4
>
diff mbox series

Patch

diff --git a/drivers/clk/qcom/apss-ipq6018.c b/drivers/clk/qcom/apss-ipq6018.c
index 4e13a08..db65b0d 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 +87,68 @@  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)
+{
+	struct clk_hw *hw;
+	u8 index;
+	int err;
+
+	if (action == PRE_RATE_CHANGE)
+		index = P_GPLL0;
+	else if (action == POST_RATE_CHANGE || action == ABORT_RATE_CHANGE)
+		index = P_APSS_PLL_EARLY;
+	else
+		return NOTIFY_OK;
+
+	hw = &apcs_alias0_clk_src.clkr.hw;
+	err = clk_rcg2_mux_closest_ops.set_parent(hw, index);
+
+	return notifier_from_errno(err);
+}
+
 static int apss_ipq6018_probe(struct platform_device *pdev)
 {
+	struct notifier_block *cpu_clk_notifier;
 	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:
+		cpu_clk_notifier = devm_kzalloc(&pdev->dev,
+						sizeof(*cpu_clk_notifier),
+						GFP_KERNEL);
+		if (!cpu_clk_notifier)
+			return -ENOMEM;
+
+		cpu_clk_notifier->notifier_call = cpu_clk_notifier_fn;
+
+		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 = {