[RFC PATCH 3/8] cpufreq: qcom-nvmem: provide vmin constraint for early Kraits

Dmitry Baryshkov
2023-07-02T17:50:54Z

Early Krait CPUs required that core voltage was not below 1.15 V.
Implement this requirement by adding separate config_regulators
callback.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
drivers/cpufreq/qcom-cpufreq-nvmem.c | 67 +++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c
index 113f35668048..9312c8ab62a8 100644
--- a/drivers/cpufreq/qcom-cpufreq-nvmem.c
+++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c
@@ -30,6 +30,8 @@
#include <linux/slab.h>
#include <linux/soc/qcom/smem.h>

+#include <asm/cputype.h>
+
#include <dt-bindings/arm/qcom,ids.h>

struct qcom_cpufreq_drv;
@@ -257,6 +259,66 @@ static const struct qcom_cpufreq_match_data match_data_apq8064 = {
.regulator_names = apq8064_regulator_names,
};

+static const int krait_needs_vmin(void)
+{
+ switch (read_cpuid_id()) {
+ case 0x511F04D0: /* KR28M2A20 */
+ case 0x511F04D1: /* KR28M2A21 */
+ case 0x510F06F0: /* KR28M4A10 */
+ return 1;
+ default:
+ return 0;
+ };
+}
+
+#define KRAIT_VMIN 1150000
+#define KRAIT_VMIN_MAX (KRAIT_VMIN + 25000)
+static int krait_config_regulator_vmin(struct device *dev,
+ struct dev_pm_opp *old_opp, struct dev_pm_opp *new_opp,
+ struct regulator **regulators, unsigned int count)
+{
+ struct regulator *reg = regulators[0];
+ struct dev_pm_opp_supply supply;
+ int ret;
+
+ /* This function only supports single regulator per device */
+ if (WARN_ON(count > 1)) {
+ dev_err(dev, "multiple regulators are not supported\n");
+ return -EINVAL;
+ }
+
+ if (IS_ERR(reg)) {
+ dev_dbg(dev, "%s: regulator not available: %ld\n", __func__,
+ PTR_ERR(reg));
+ return 0;
+ }
+
+ ret = dev_pm_opp_get_supplies(new_opp, &supply);
+ if (WARN_ON(ret))
+ return ret;
+
+ if (supply.u_volt_min < KRAIT_VMIN) {
+ supply.u_volt_min = KRAIT_VMIN;
+ supply.u_volt = KRAIT_VMIN;
+ supply.u_volt_max = KRAIT_VMIN_MAX;
+ }
+
+ dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__,
+ supply.u_volt_min, supply.u_volt, supply.u_volt_max);
+
+ ret = regulator_set_voltage_triplet(reg,
+ supply.u_volt_min,
+ supply.u_volt,
+ supply.u_volt_max);
+ if (ret)
+ dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+ __func__, supply.u_volt_min, supply.u_volt,
+ supply.u_volt_max, ret);
+
+ return ret;
+}
+
+
static int qcom_cpufreq_probe(struct platform_device *pdev)
{
struct qcom_cpufreq_drv *drv;
@@ -344,8 +406,11 @@ static int qcom_cpufreq_probe(struct platform_device *pdev)
config.virt_devs = NULL;
}

- if (drv->data->regulator_names)
+ if (drv->data->regulator_names) {
config.regulator_names = drv->data->regulator_names;
+ if (krait_needs_vmin())
+ config.config_regulators = krait_config_regulator_vmin;
+ }

if (config.supported_hw ||
config.genpd_names ||
--
2.39.2