* [PATCH v1 2/3] soc/tegra: regulators: Add regulators coupler for Tegra20
2019-07-15 19:45 [PATCH v1 0/3] Support regulators coupling on NVIDIA Tegra20/30 Dmitry Osipenko
2019-07-15 19:45 ` [PATCH v1 1/3] dt-bindings: regulator: Document regulators coupling of NVIDIA Tegra20/30 SoCs Dmitry Osipenko
@ 2019-07-15 19:45 ` Dmitry Osipenko
2019-07-15 19:45 ` [PATCH v1 3/3] soc/tegra: regulators: Add regulators coupler for Tegra30 Dmitry Osipenko
2 siblings, 0 replies; 4+ messages in thread
From: Dmitry Osipenko @ 2019-07-15 19:45 UTC (permalink / raw)
To: Rob Herring, Thierry Reding, Peter De Schrijver, Jonathan Hunter,
Mark Brown
Cc: devicetree, linux-tegra, linux-kernel
Add regulators coupler for Tegra20 SoCs that performs voltage balancing
of a coupled regulators and thus provides voltage scaling functionality.
There are 3 coupled regulators on all Tegra20 SoCs: CORE, RTC and CPU.
The CORE and RTC voltages shall be in range of 170mV from each other and
they both shall be higher than the CPU voltage by at least 120mV. This
sounds like it could be handle by a generic voltage balancer, but the CORE
voltage scaling isn't implemented in any of the upstream drivers yet.
It will take quite some time and effort to hook up voltage scaling for
all of the drivers, hence we will use a custom coupler that will manage
the CPU voltage scaling for the starter.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/soc/tegra/Kconfig | 6 +
drivers/soc/tegra/Makefile | 1 +
drivers/soc/tegra/regulators-tegra20.c | 350 +++++++++++++++++++++++++
3 files changed, 357 insertions(+)
create mode 100644 drivers/soc/tegra/regulators-tegra20.c
diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig
index d98c69efb7e0..7986ab80e07a 100644
--- a/drivers/soc/tegra/Kconfig
+++ b/drivers/soc/tegra/Kconfig
@@ -14,6 +14,7 @@ config ARCH_TEGRA_2x_SOC
select PL310_ERRATA_769419 if CACHE_L2X0
select SOC_TEGRA_FLOWCTRL
select SOC_TEGRA_PMC
+ select SOC_TEGRA20_VOLTAGE_COUPLER
select TEGRA_TIMER
help
Support for NVIDIA Tegra AP20 and T20 processors, based on the
@@ -134,3 +135,8 @@ config SOC_TEGRA_POWERGATE_BPMP
def_bool y
depends on PM_GENERIC_DOMAINS
depends on TEGRA_BPMP
+
+config SOC_TEGRA20_VOLTAGE_COUPLER
+ bool "Voltage scaling support for Tegra20 SoCs"
+ depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST
+
diff --git a/drivers/soc/tegra/Makefile b/drivers/soc/tegra/Makefile
index 902759fe5f4d..9f0bdd53bef8 100644
--- a/drivers/soc/tegra/Makefile
+++ b/drivers/soc/tegra/Makefile
@@ -5,3 +5,4 @@ obj-y += common.o
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
diff --git a/drivers/soc/tegra/regulators-tegra20.c b/drivers/soc/tegra/regulators-tegra20.c
new file mode 100644
index 000000000000..12c8206cea16
--- /dev/null
+++ b/drivers/soc/tegra/regulators-tegra20.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Voltage regulators coupler for NVIDIA Tegra20
+// Copyright (C) 2019 GRATE-DRIVER project
+//
+// Voltage constraints borrowed from downstream kernel sources
+// Copyright (C) 2010-2011 NVIDIA Corporation
+
+#define pr_fmt(fmt) "tegra voltage-coupler: " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regulator/coupler.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+
+struct tegra_regulator_coupler {
+ struct regulator_coupler coupler;
+ struct regulator_dev *core_rdev;
+ struct regulator_dev *cpu_rdev;
+ struct regulator_dev *rtc_rdev;
+ int core_min_uV;
+};
+
+static inline struct tegra_regulator_coupler *
+to_tegra_coupler(struct regulator_coupler *coupler)
+{
+ return container_of(coupler, struct tegra_regulator_coupler, coupler);
+}
+
+static int tegra20_core_limit(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *core_rdev)
+{
+ int core_min_uV = 0;
+ int core_max_uV;
+ int core_cur_uV;
+ int err;
+
+ if (tegra->core_min_uV > 0)
+ return tegra->core_min_uV;
+
+ core_cur_uV = regulator_get_voltage_rdev(core_rdev);
+ if (core_cur_uV < 0)
+ return core_cur_uV;
+
+ core_max_uV = max(core_cur_uV, 1200000);
+
+ err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
+ if (err)
+ return err;
+
+ /*
+ * Limit minimum CORE voltage to a value left from bootloader or,
+ * if it's unreasonably low value, to the most common 1.2v or to
+ * whatever maximum value defined via board's device-tree.
+ */
+ tegra->core_min_uV = core_max_uV;
+
+ pr_info("core minimum voltage limited to %duV\n", tegra->core_min_uV);
+
+ return tegra->core_min_uV;
+}
+
+static int tegra20_core_rtc_max_spread(struct regulator_dev *core_rdev,
+ struct regulator_dev *rtc_rdev)
+{
+ struct coupling_desc *c_desc = &core_rdev->coupling_desc;
+ struct regulator_dev *rdev;
+ int max_spread;
+ unsigned int i;
+
+ for (i = 1; i < c_desc->n_coupled; i++) {
+ max_spread = core_rdev->constraints->max_spread[i - 1];
+ rdev = c_desc->coupled_rdevs[i];
+
+ if (rdev == rtc_rdev && max_spread)
+ return max_spread;
+ }
+
+ pr_err_once("rtc-core max-spread is undefined in device-tree\n");
+
+ return 150000;
+}
+
+static int tegra20_core_rtc_update(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *core_rdev,
+ struct regulator_dev *rtc_rdev,
+ int cpu_uV, int cpu_min_uV)
+{
+ int core_min_uV, core_max_uV = INT_MAX;
+ int rtc_min_uV, rtc_max_uV = INT_MAX;
+ int core_target_uV;
+ int rtc_target_uV;
+ int max_spread;
+ int core_uV;
+ int rtc_uV;
+ int err;
+
+ /*
+ * RTC and CORE voltages should be no more than 170mV from each other,
+ * CPU should be below RTC and CORE by at least 120mV. This applies
+ * to all Tegra20 SoC's.
+ */
+ max_spread = tegra20_core_rtc_max_spread(core_rdev, rtc_rdev);
+
+ /*
+ * The core voltage scaling is currently not hooked up in drivers,
+ * hence we will limit the minimum core voltage to a reasonable value.
+ * This should be good enough for the time being.
+ */
+ core_min_uV = tegra20_core_limit(tegra, core_rdev);
+ if (core_min_uV < 0)
+ return core_min_uV;
+
+ err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
+ if (err)
+ return err;
+
+ err = regulator_check_consumers(core_rdev, &core_min_uV, &core_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ core_min_uV = max(cpu_min_uV + 125000, core_min_uV);
+ if (core_min_uV > core_max_uV)
+ return -EINVAL;
+
+ core_uV = regulator_get_voltage_rdev(core_rdev);
+ if (core_uV < 0)
+ return core_uV;
+
+ if (cpu_uV + 120000 > core_uV)
+ pr_err("core-cpu voltage constraint violated: %d %d\n",
+ core_uV, cpu_uV + 120000);
+
+ rtc_uV = regulator_get_voltage_rdev(rtc_rdev);
+ if (rtc_uV < 0)
+ return rtc_uV;
+
+ if (cpu_uV + 120000 > rtc_uV)
+ pr_err("rtc-cpu voltage constraint violated: %d %d\n",
+ rtc_uV, cpu_uV + 120000);
+
+ if (abs(core_uV - rtc_uV) > 170000)
+ pr_err("core-rtc voltage constraint violated: %d %d\n",
+ core_uV, rtc_uV);
+
+ rtc_min_uV = max(cpu_min_uV + 125000, core_min_uV - max_spread);
+
+ err = regulator_check_voltage(rtc_rdev, &rtc_min_uV, &rtc_max_uV);
+ if (err)
+ return err;
+
+ while (core_uV != core_min_uV || rtc_uV != rtc_min_uV) {
+ if (core_uV < core_min_uV) {
+ core_target_uV = min(core_uV + max_spread, core_min_uV);
+ core_target_uV = min(rtc_uV + max_spread, core_target_uV);
+ } else {
+ core_target_uV = max(core_uV - max_spread, core_min_uV);
+ core_target_uV = max(rtc_uV - max_spread, core_target_uV);
+ }
+
+ 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;
+
+ if (rtc_uV < rtc_min_uV) {
+ rtc_target_uV = min(rtc_uV + max_spread, rtc_min_uV);
+ rtc_target_uV = min(core_uV + max_spread, rtc_target_uV);
+ } else {
+ rtc_target_uV = max(rtc_uV - max_spread, rtc_min_uV);
+ rtc_target_uV = max(core_uV - max_spread, rtc_target_uV);
+ }
+
+ err = regulator_set_voltage_rdev(rtc_rdev,
+ rtc_target_uV,
+ rtc_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ rtc_uV = rtc_target_uV;
+ }
+
+ return 0;
+}
+
+static int tegra20_core_voltage_update(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *cpu_rdev,
+ struct regulator_dev *core_rdev,
+ struct regulator_dev *rtc_rdev)
+{
+ int cpu_uV;
+
+ cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
+ if (cpu_uV < 0)
+ return cpu_uV;
+
+ return tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
+ cpu_uV, cpu_uV);
+}
+
+static int tegra20_cpu_voltage_update(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *cpu_rdev,
+ struct regulator_dev *core_rdev,
+ struct regulator_dev *rtc_rdev)
+{
+ int cpu_max_uV = INT_MAX;
+ int cpu_min_uV = 0;
+ int cpu_uV;
+ int err;
+
+ err = regulator_check_voltage(cpu_rdev, &cpu_min_uV, &cpu_max_uV);
+ if (err)
+ return err;
+
+ err = regulator_check_consumers(cpu_rdev, &cpu_min_uV, &cpu_max_uV,
+ PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ cpu_uV = regulator_get_voltage_rdev(cpu_rdev);
+ if (cpu_uV < 0)
+ return cpu_uV;
+
+ if (cpu_min_uV > cpu_uV) {
+ err = tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
+ cpu_uV, cpu_min_uV);
+ if (err)
+ return err;
+
+ err = regulator_set_voltage_rdev(cpu_rdev, cpu_min_uV,
+ cpu_max_uV, PM_SUSPEND_ON);
+ if (err)
+ return err;
+ } else if (cpu_min_uV < cpu_uV) {
+ err = regulator_set_voltage_rdev(cpu_rdev, cpu_min_uV,
+ cpu_max_uV, PM_SUSPEND_ON);
+ if (err)
+ return err;
+
+ err = tegra20_core_rtc_update(tegra, core_rdev, rtc_rdev,
+ cpu_uV, cpu_min_uV);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int tegra20_regulator_balance_voltage(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev,
+ suspend_state_t state)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+ struct regulator_dev *core_rdev = tegra->core_rdev;
+ struct regulator_dev *cpu_rdev = tegra->cpu_rdev;
+ struct regulator_dev *rtc_rdev = tegra->rtc_rdev;
+
+ if ((core_rdev != rdev && cpu_rdev != rdev && rtc_rdev != rdev) ||
+ state != PM_SUSPEND_ON) {
+ pr_err("regulators are not coupled properly\n");
+ return -EINVAL;
+ }
+
+ if (rdev == cpu_rdev)
+ return tegra20_cpu_voltage_update(tegra, cpu_rdev,
+ core_rdev, rtc_rdev);
+
+ if (rdev == core_rdev)
+ return tegra20_core_voltage_update(tegra, cpu_rdev,
+ core_rdev, rtc_rdev);
+
+ pr_err("changing %s voltage not permitted\n", rdev_get_name(rtc_rdev));
+
+ return -EPERM;
+}
+
+static int tegra20_regulator_attach(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+ struct device_node *np = rdev->dev.of_node;
+
+ if (of_property_read_bool(np, "nvidia,tegra-core-regulator") &&
+ !tegra->core_rdev) {
+ tegra->core_rdev = rdev;
+ return 0;
+ }
+
+ if (of_property_read_bool(np, "nvidia,tegra-rtc-regulator") &&
+ !tegra->rtc_rdev) {
+ tegra->rtc_rdev = rdev;
+ return 0;
+ }
+
+ if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") &&
+ !tegra->cpu_rdev) {
+ tegra->cpu_rdev = rdev;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int tegra20_regulator_detach(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+
+ if (tegra->core_rdev == rdev) {
+ tegra->core_rdev = NULL;
+ return 0;
+ }
+
+ if (tegra->rtc_rdev == rdev) {
+ tegra->rtc_rdev = NULL;
+ return 0;
+ }
+
+ if (tegra->cpu_rdev == rdev) {
+ tegra->cpu_rdev = NULL;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static struct tegra_regulator_coupler tegra20_coupler = {
+ .coupler = {
+ .attach_regulator = tegra20_regulator_attach,
+ .detach_regulator = tegra20_regulator_detach,
+ .balance_voltage = tegra20_regulator_balance_voltage,
+ },
+};
+
+static int __init tegra_regulator_coupler_init(void)
+{
+ if (!of_machine_is_compatible("nvidia,tegra20"))
+ return 0;
+
+ return regulator_coupler_register(&tegra20_coupler.coupler);
+}
+arch_initcall(tegra_regulator_coupler_init);
--
2.22.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v1 3/3] soc/tegra: regulators: Add regulators coupler for Tegra30
2019-07-15 19:45 [PATCH v1 0/3] Support regulators coupling on NVIDIA Tegra20/30 Dmitry Osipenko
2019-07-15 19:45 ` [PATCH v1 1/3] dt-bindings: regulator: Document regulators coupling of NVIDIA Tegra20/30 SoCs Dmitry Osipenko
2019-07-15 19:45 ` [PATCH v1 2/3] soc/tegra: regulators: Add regulators coupler for Tegra20 Dmitry Osipenko
@ 2019-07-15 19:45 ` Dmitry Osipenko
2 siblings, 0 replies; 4+ messages in thread
From: Dmitry Osipenko @ 2019-07-15 19:45 UTC (permalink / raw)
To: Rob Herring, Thierry Reding, Peter De Schrijver, Jonathan Hunter,
Mark Brown
Cc: devicetree, linux-tegra, linux-kernel
Add regulators coupler for Tegra30 SoCs that performs voltage balancing
of a coupled regulators and thus provides voltage scaling functionality.
There are 2 coupled regulators on all Tegra30 SoCs: CORE and CPU. The
coupled regulator voltages shall be in a range of 300mV from each other
and CORE voltage shall be higher than the CPU by N mV, where N depends
on the CPU voltage.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/soc/tegra/Kconfig | 4 +
drivers/soc/tegra/Makefile | 1 +
drivers/soc/tegra/regulators-tegra30.c | 302 +++++++++++++++++++++++++
3 files changed, 307 insertions(+)
create mode 100644 drivers/soc/tegra/regulators-tegra30.c
diff --git a/drivers/soc/tegra/Kconfig b/drivers/soc/tegra/Kconfig
index 7986ab80e07a..bc86dc2f4198 100644
--- a/drivers/soc/tegra/Kconfig
+++ b/drivers/soc/tegra/Kconfig
@@ -28,6 +28,7 @@ config ARCH_TEGRA_3x_SOC
select PL310_ERRATA_769419 if CACHE_L2X0
select SOC_TEGRA_FLOWCTRL
select SOC_TEGRA_PMC
+ select SOC_TEGRA30_VOLTAGE_COUPLER
select TEGRA_TIMER
help
Support for NVIDIA Tegra T30 processor family, based on the
@@ -140,3 +141,6 @@ config SOC_TEGRA20_VOLTAGE_COUPLER
bool "Voltage scaling support for Tegra20 SoCs"
depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST
+config SOC_TEGRA30_VOLTAGE_COUPLER
+ bool "Voltage scaling support for Tegra30 SoCs"
+ depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
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..7af22bacb088
--- /dev/null
+++ b/drivers/soc/tegra/regulators-tegra30.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Voltage regulators coupler for NVIDIA Tegra30
+// Copyright (C) 2019 GRATE-DRIVER project
+//
+// Voltage constraints borrowed from downstream kernel sources
+// Copyright (C) 2010-2011 NVIDIA Corporation
+
+#define pr_fmt(fmt) "tegra voltage-coupler: " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regulator/coupler.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+
+#include <soc/tegra/fuse.h>
+
+struct tegra_regulator_coupler {
+ struct regulator_coupler coupler;
+ struct regulator_dev *core_rdev;
+ struct regulator_dev *cpu_rdev;
+ int core_min_uV;
+};
+
+static inline struct tegra_regulator_coupler *
+to_tegra_coupler(struct regulator_coupler *coupler)
+{
+ return container_of(coupler, struct tegra_regulator_coupler, coupler);
+}
+
+static int tegra30_core_limit(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *core_rdev)
+{
+ int core_min_uV = 0;
+ int core_max_uV;
+ int core_cur_uV;
+ int err;
+
+ if (tegra->core_min_uV > 0)
+ return tegra->core_min_uV;
+
+ core_cur_uV = regulator_get_voltage_rdev(core_rdev);
+ if (core_cur_uV < 0)
+ return core_cur_uV;
+
+ core_max_uV = max(core_cur_uV, 1200000);
+
+ err = regulator_check_voltage(core_rdev, &core_min_uV, &core_max_uV);
+ if (err)
+ return err;
+
+ /*
+ * Limit minimum CORE voltage to a value left from bootloader or,
+ * if it's unreasonably low value, to the most common 1.2v or to
+ * whatever maximum value defined via board's device-tree.
+ */
+ tegra->core_min_uV = core_max_uV;
+
+ 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 ... 8:
+ return 1200000;
+
+ default:
+ return 1300000;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static int tegra30_voltage_update(struct tegra_regulator_coupler *tegra,
+ struct regulator_dev *cpu_rdev,
+ struct regulator_dev *core_rdev)
+{
+ int core_min_uV, core_max_uV = INT_MAX;
+ int cpu_min_uV, cpu_max_uV = INT_MAX;
+ int core_min_limited_uV;
+ int core_target_uV;
+ int cpu_target_uV;
+ int core_max_step;
+ int cpu_max_step;
+ int max_spread;
+ int core_uV;
+ int cpu_uV;
+ int err;
+
+ /*
+ * CPU voltage should not got lower than 300mV from the CORE.
+ * CPU voltage should stay below the CORE by 100mV+, depending
+ * by the CORE voltage. This applies to all Tegra30 SoC's.
+ */
+ max_spread = cpu_rdev->constraints->max_spread[0];
+ cpu_max_step = cpu_rdev->constraints->max_uV_step;
+ core_max_step = core_rdev->constraints->max_uV_step;
+
+ if (!max_spread) {
+ pr_err_once("cpu-core max-spread is undefined in device-tree\n");
+ max_spread = 300000;
+ }
+
+ if (!cpu_max_step) {
+ pr_err_once("cpu max-step is undefined in device-tree\n");
+ cpu_max_step = 150000;
+ }
+
+ if (!core_max_step) {
+ pr_err_once("core max-step is undefined in device-tree\n");
+ core_max_step = 150000;
+ }
+
+ /*
+ * The CORE voltage scaling is currently not hooked up in drivers,
+ * hence we will limit the minimum CORE voltage to a reasonable 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 - max_spread;
+
+ 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 + cpu_max_step, cpu_min_uV);
+ } else {
+ cpu_target_uV = max(cpu_uV - cpu_max_step, cpu_min_uV);
+ cpu_target_uV = max(core_uV - max_spread, 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 + core_max_step);
+ core_target_uV = min(core_target_uV, cpu_uV + max_spread);
+ } else {
+ core_target_uV = max(core_target_uV, core_uV - core_max_step);
+ }
+
+ 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 int tegra30_regulator_balance_voltage(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev,
+ suspend_state_t state)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+ struct regulator_dev *core_rdev = tegra->core_rdev;
+ struct regulator_dev *cpu_rdev = tegra->cpu_rdev;
+
+ if ((core_rdev != rdev && cpu_rdev != 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 int tegra30_regulator_attach(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+ struct device_node *np = rdev->dev.of_node;
+
+ if (of_property_read_bool(np, "nvidia,tegra-core-regulator") &&
+ !tegra->core_rdev) {
+ tegra->core_rdev = rdev;
+ return 0;
+ }
+
+ if (of_property_read_bool(np, "nvidia,tegra-cpu-regulator") &&
+ !tegra->cpu_rdev) {
+ tegra->cpu_rdev = rdev;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int tegra30_regulator_detach(struct regulator_coupler *coupler,
+ struct regulator_dev *rdev)
+{
+ struct tegra_regulator_coupler *tegra = to_tegra_coupler(coupler);
+
+ if (tegra->core_rdev == rdev) {
+ tegra->core_rdev = NULL;
+ return 0;
+ }
+
+ if (tegra->cpu_rdev == rdev) {
+ tegra->cpu_rdev = NULL;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static struct tegra_regulator_coupler tegra30_coupler = {
+ .coupler = {
+ .attach_regulator = tegra30_regulator_attach,
+ .detach_regulator = tegra30_regulator_detach,
+ .balance_voltage = tegra30_regulator_balance_voltage,
+ },
+};
+
+static int __init tegra_regulator_coupler_init(void)
+{
+ if (!of_machine_is_compatible("nvidia,tegra30"))
+ return 0;
+
+ return regulator_coupler_register(&tegra30_coupler.coupler);
+}
+arch_initcall(tegra_regulator_coupler_init);
--
2.22.0
^ permalink raw reply related [flat|nested] 4+ messages in thread