Re: [PATCH v1 04/10] clk: qcom: apss-ipq6018: ipq5332: add safe source switch for a53pll
From: Dmitry Baryshkov <hidden>
Date: 2023-09-07 16:24:27
Also in:
linux-arm-msm, linux-clk, linux-devicetree, lkml
On Thu, 7 Sept 2023 at 08:22, Varadarajan Narayanan [off-list ref] 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.
quoted hunk ↗ jump to hunk
Signed-off-by: Kathiravan T <redacted> Signed-off-by: Varadarajan Narayanan <redacted> --- 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