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Subject[RFC PATCH v1 6/6] soc/tegra: regulators: Add regulators coupler for Tegra30
Date
Add regulators coupler for Tegra30 SoC's that performs voltage balancing
of a coupled regulators and thus provides voltage scaling functionality.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/soc/tegra/Kconfig | 6 +
drivers/soc/tegra/Makefile | 1 +
drivers/soc/tegra/regulators-tegra30.c | 256 +++++++++++++++++++++++++
3 files changed, 263 insertions(+)
create mode 100644 drivers/soc/tegra/regulators-tegra30.c

diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig
index 545c0da2e069..a5235af27644 100644
--- a/drivers/soc/tegra/Kconfig
+++ b/drivers/soc/tegra/Kconfig
@@ -139,3 +139,9 @@ config SOC_TEGRA20_VOLTAGE_COUPLER
def_bool y
depends on ARCH_TEGRA_2x_SOC
depends on REGULATOR
+
+config SOC_TEGRA30_VOLTAGE_COUPLER
+ bool "Voltage scaling support for Tegra30 SoC's"
+ def_bool y
+ depends on ARCH_TEGRA_3x_SOC
+ depends on REGULATOR
diff --git a/drivers/soc/tegra/Makefile b/drivers/soc/tegra/Makefile
index 9f0bdd53bef8..9c809c1814bd 100644
--- a/drivers/soc/tegra/Makefile
+++ b/drivers/soc/tegra/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_SOC_TEGRA_FLOWCTRL) += flowctrl.o
obj-$(CONFIG_SOC_TEGRA_PMC) += pmc.o
obj-$(CONFIG_SOC_TEGRA_POWERGATE_BPMP) += powergate-bpmp.o
obj-$(CONFIG_SOC_TEGRA20_VOLTAGE_COUPLER) += regulators-tegra20.o
+obj-$(CONFIG_SOC_TEGRA30_VOLTAGE_COUPLER) += regulators-tegra30.o
diff --git a/drivers/soc/tegra/regulators-tegra30.c b/drivers/soc/tegra/regulators-tegra30.c
new file mode 100644
index 000000000000..ecd6a984e045
--- /dev/null
+++ b/drivers/soc/tegra/regulators-tegra30.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Voltage regulators coupling resolver for NVIDIA Tegra30
+ *
+ * Author: Dmitry Osipenko <digetx@gmail.com>
+ */
+
+#define pr_fmt(fmt) "tegra voltage-coupler: " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+
+#include <soc/tegra/fuse.h>
+
+struct tegra_regulators_coupler {
+ struct regulators_coupler coupler;
+ int core_min_uV;
+};
+
+static const char * const cpu_names[] = {
+ "vdd_cpu,vdd_sys",
+ "+V1.0_VDD_CPU",
+ "vdd_cpu",
+};
+
+static const char * const core_names[] = {
+ "tps62361-vout",
+ "tps62362-vout",
+ "vdd_core",
+};
+
+static inline struct tegra_regulators_coupler *
+to_tegra_coupler(struct regulators_coupler *coupler)
+{
+ return container_of(coupler, struct tegra_regulators_coupler, coupler);
+}
+
+static int tegra30_core_limit(struct tegra_regulators_coupler *tegra,
+ struct regulator_dev *core_rdev)
+{
+ if (tegra->core_min_uV > 0)
+ return tegra->core_min_uV;
+
+ tegra->core_min_uV = regulator_get_voltage_rdev(core_rdev);
+ if (tegra->core_min_uV > 0)
+ pr_info("core minimum voltage limited to %duV\n",
+ tegra->core_min_uV);
+
+ return tegra->core_min_uV;
+}
+
+static int tegra30_core_cpu_limit(int cpu_uV)
+{
+ if (cpu_uV < 800000)
+ return 950000;
+
+ if (cpu_uV < 900000)
+ return 1000000;
+
+ if (cpu_uV < 1000000)
+ return 1100000;
+
+ if (cpu_uV < 1100000)
+ return 1200000;
+
+ if (cpu_uV < 1250000) {
+ switch (tegra_sku_info.cpu_speedo_id) {
+ case 0 ... 1:
+ case 4:
+ case 7:
+ case 8:
+ return 1200000;
+
+ default:
+ return 1300000;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static int tegra30_voltage_update(struct tegra_regulators_coupler *tegra,
+ struct regulator_dev *cpu_rdev,
+ struct regulator_dev *core_rdev)
+{
+ int cpu_min_uV, cpu_max_uV = INT_MAX;
+ int core_min_uV, core_max_uV = INT_MAX;
+ int core_min_limited_uV;
+ int core_target_uV;
+ int cpu_target_uV;
+ int core_uV;
+ int cpu_uV;
+ int err;
+
+ /*
+ * The CORE voltage scaling is currently not hooked up in drivers,
+ * hence we will limit the minimum CORE voltage to the initial value.
+ * This should be good enough for the time being.
+ */
+ core_min_uV = tegra30_core_limit(tegra, core_rdev);
+ if (core_min_uV < 0)
+ return core_min_uV;
+
+ err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ cpu_min_uV = core_min_uV - 300000;
+
+ err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV);
+ if (err)
+ return err;
+
+ cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
+ if (cpu_uV < 0)
+ return cpu_uV;
+
+ core_uV = regulator_get_voltage_rdev(core_rdev);
+ if (core_uV < 0)
+ return core_uV;
+
+ /*
+ * Bootloader shall set up voltages correctly, but if it
+ * happens that there is a violation, then try to fix it
+ * at first.
+ */
+ core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
+ if (core_min_limited_uV < 0)
+ return core_min_limited_uV;
+
+ core_min_uV = max(core_min_uV, tegra30_core_cpu_limit(cpu_min_uV));
+
+ err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
+ if (err)
+ return err;
+
+ if (core_min_limited_uV > core_uV) {
+ pr_err("core voltage constraint violated: %d %d %d\n",
+ core_uV, core_min_limited_uV, cpu_uV);
+ goto update_core;
+ }
+
+ while (cpu_uV != cpu_min_uV || core_uV != core_min_uV) {
+ if (cpu_uV < cpu_min_uV) {
+ cpu_target_uV = min(cpu_uV + 100000, cpu_min_uV);
+ } else {
+ cpu_target_uV = max(cpu_uV - 100000, cpu_min_uV);
+ cpu_target_uV = max(core_uV - 300000, cpu_target_uV);
+ }
+
+ err = regulator_set_voltage_rdev(cpu_rdev,
+ cpu_target_uV,
+ cpu_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ cpu_uV = cpu_target_uV;
+update_core:
+ core_min_limited_uV = tegra30_core_cpu_limit(cpu_uV);
+ if (core_min_limited_uV < 0)
+ return core_min_limited_uV;
+
+ core_target_uV = max(core_min_limited_uV, core_min_uV);
+
+ if (core_uV < core_target_uV) {
+ core_target_uV = min(core_target_uV, core_uV + 100000);
+ core_target_uV = min(core_target_uV, cpu_uV + 300000);
+ } else {
+ core_target_uV = max(core_target_uV, core_uV - 100000);
+ }
+
+ err = regulator_set_voltage_rdev(core_rdev,
+ core_target_uV,
+ core_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ core_uV = core_target_uV;
+ }
+
+ return 0;
+}
+
+static struct regulator_dev *lookup_rdev(struct regulator_dev *rdev,
+ const char * const *names,
+ unsigned int num_names)
+{
+ struct coupling_desc *c_desc = &rdev->coupling_desc;
+ unsigned int i, k;
+
+ for (i = 0; i < num_names; i++) {
+ if (!strcmp(names[i], rdev_get_name(rdev)))
+ return rdev;
+ }
+
+ for (k = 0; k < c_desc->n_coupled; k++) {
+ rdev = c_desc->coupled_rdevs[k];
+
+ for (i = 0; i < num_names; i++) {
+ if (!strcmp(names[i], rdev_get_name(rdev)))
+ return rdev;
+ }
+ }
+
+ pr_err_once("%s: failed for %s\n", __func__, rdev_get_name(rdev));
+
+ for (i = 0; i < num_names; i++)
+ pr_err_once("%s: entry%u: %s\n", __func__, i, names[i]);
+
+ return NULL;
+}
+
+static int tegra30_regulator_balance_voltage(struct regulators_coupler *coupler,
+ struct regulator_dev *rdev,
+ suspend_state_t state)
+{
+ struct tegra_regulators_coupler *tegra = to_tegra_coupler(coupler);
+ struct regulator_dev *core_rdev;
+ struct regulator_dev *cpu_rdev;
+
+ core_rdev = lookup_rdev(rdev, core_names, ARRAY_SIZE(core_names));
+ cpu_rdev = lookup_rdev(rdev, cpu_names, ARRAY_SIZE(cpu_names));
+
+ if (!core_rdev || !cpu_rdev || state != PM_SUSPEND_ON) {
+ pr_err("regulators are not coupled properly\n");
+ return -EINVAL;
+ }
+
+ return tegra30_voltage_update(tegra, cpu_rdev, core_rdev);
+}
+
+static struct tegra_regulators_coupler tegra30_coupler = {
+ .coupler = {
+ .balance_voltage = tegra30_regulator_balance_voltage,
+ },
+};
+
+static int __init tegra_regulators_coupler_init(void)
+{
+ if (!of_machine_is_compatible("nvidia,tegra30"))
+ return 0;
+
+ return regulators_coupler_register(&tegra30_coupler.coupler);
+}
+arch_initcall(tegra_regulators_coupler_init);
--
2.21.0
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