[PATCH v4] regulator: qcom-saw: Add support for SAW regulators

From: Georgi Djakov
Date: Tue Feb 09 2016 - 08:13:17 EST

The SAW (Subsystem Power Manager and Adaptive Voltage Scaling Wrapper)
is part of the SPM subsystem. It is a hardware block in the Qualcomm
chipsets that regulates the power to the CPU cores on platform such as
apq8064, msm8974, apq8084 and others.

Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
---

Changes since v3 (https://lkml.org/lkml/2016/2/3/829)
* Add MFD dependency to Kconfig
* Rename SAW2 to SAW as we may support other SAW generations than just 2
* Increase timeout to 100us

Changes since v2 (https://lkml.org/lkml/2016/1/28/481)
* Address the comments from Mark. Thanks!
- Implement regulator_get_voltage_sel() instead of regulator_get_voltage()
- Add cpu_relax() in the loop
- Specify ramp_delay
- Drop the legacy "regulator-name" property

Changes since v1 (https://lkml.org/lkml/2015/12/18/629)
* Move into a separate regulator driver

.../bindings/regulator/qcom,saw-regulator.txt | 31 +++
drivers/regulator/Kconfig | 12 +
drivers/regulator/Makefile | 1 +
drivers/regulator/qcom_saw-regulator.c | 229 ++++++++++++++++++++
4 files changed, 273 insertions(+)
create mode 100644 Documentation/devicetree/bindings/regulator/qcom,saw-regulator.txt
create mode 100644 drivers/regulator/qcom_saw-regulator.c

diff --git a/Documentation/devicetree/bindings/regulator/qcom,saw-regulator.txt b/Documentation/devicetree/bindings/regulator/qcom,saw-regulator.txt
new file mode 100644
index 000000000000..977fec08b2ae
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/qcom,saw-regulator.txt
@@ -0,0 +1,31 @@
+Qualcomm SAW Regulators
+
+SAW (Subsystem Power Manager and Adaptive Voltage Scaling Wrapper) is a hardware
+block in the Qualcomm chipsets that regulates the power to the CPU cores on devices
+such as APQ8064, MSM8974, APQ8084 and others.
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,apq8064-saw2-v1.1-regulator"
+
+Example:
+ saw0: power-controller@2089000 {
+ compatible = "qcom,apq8064-saw2-v1.1-cpu", "qcom,saw2", "syscon", "simple-mfd";
+ reg = <0x02089000 0x1000>, <0x02009000 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ saw0_regulator: regulator@2089000 {
+ compatible = "qcom,apq8064-saw2-v1.1-regulator";
+ regulator-always-on;
+ regulator-min-microvolt = <825000>;
+ regulator-max-microvolt = <1250000>;
+ };
+ };
+
+
+ &CPU0 {
+ cpu-supply = <&saw0_regulator>;
+ };
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 74a6354eaefa..6d5f4fce1d75 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -558,6 +558,18 @@ config REGULATOR_QCOM_RPM
Qualcomm RPM as a module. The module will be named
"qcom_rpm-regulator".

+config REGULATOR_QCOM_SAW
+ tristate "Qualcomm SAW regulator driver"
+ depends on (ARCH_QCOM || COMPILE_TEST) && MFD_SYSCON
+ help
+ If you say yes to this option, support will be included for the
+ regulators providing power to the CPU cores on devices such as
+ APQ8064.
+
+ Say M here if you want to include support for the CPU core voltage
+ regulators as a module. The module will be named
+ "qcom_saw-regulator".
+
config REGULATOR_QCOM_SMD_RPM
tristate "Qualcomm SMD based RPM regulator driver"
depends on QCOM_SMD_RPM
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 348cfd727350..75a0b4a8f1b2 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_REGULATOR_MC13XXX_CORE) += mc13xxx-regulator-core.o
obj-$(CONFIG_REGULATOR_MT6311) += mt6311-regulator.o
obj-$(CONFIG_REGULATOR_MT6397) += mt6397-regulator.o
obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
+obj-$(CONFIG_REGULATOR_QCOM_SAW)+= qcom_saw-regulator.o
obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
obj-$(CONFIG_REGULATOR_QCOM_SPMI) += qcom_spmi-regulator.o
obj-$(CONFIG_REGULATOR_PALMAS) += palmas-regulator.o
diff --git a/drivers/regulator/qcom_saw-regulator.c b/drivers/regulator/qcom_saw-regulator.c
new file mode 100644
index 000000000000..c800f16adaf0
--- /dev/null
+++ b/drivers/regulator/qcom_saw-regulator.c
@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 2016, Linaro Limited. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+
+#define SPM_REG_STS_1 0x10
+#define SPM_REG_VCTL 0x14
+#define SPM_REG_PMIC_DATA_0 0x28
+#define SPM_REG_PMIC_DATA_1 0x2c
+#define SPM_REG_RST 0x30
+
+struct saw_vreg {
+ struct device *dev;
+ struct regmap *regmap;
+ struct regulator_desc rdesc;
+ struct regulator_dev *rdev;
+ unsigned int sel;
+};
+
+struct spm_vlevel_data {
+ struct saw_vreg *vreg;
+ unsigned int sel;
+};
+
+static int saw_regulator_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct saw_vreg *vreg = rdev_get_drvdata(rdev);
+
+ return vreg->sel;
+}
+
+static void smp_set_vdd(void *data)
+{
+ struct spm_vlevel_data *vdata = (struct spm_vlevel_data *)data;
+ struct saw_vreg *vreg = vdata->vreg;
+ unsigned long new_sel = vdata->sel;
+ u32 val, new_val;
+ u32 vctl, data0, data1;
+ unsigned long timeout;
+
+ if (vreg->sel == new_sel)
+ return;
+
+ regmap_read(vreg->regmap, SPM_REG_VCTL, &vctl);
+ regmap_read(vreg->regmap, SPM_REG_PMIC_DATA_0, &data0);
+ regmap_read(vreg->regmap, SPM_REG_PMIC_DATA_1, &data1);
+
+ /* select the band */
+ val = 0x80 | new_sel;
+
+ vctl &= ~0xff;
+ vctl |= val;
+
+ data0 &= ~0xff;
+ data0 |= val;
+
+ data1 &= ~0x3f;
+ data1 |= val & 0x3f;
+ data1 &= ~0x3f0000;
+ data1 |= ((val & 0x3f) << 16);
+
+ regmap_write(vreg->regmap, SPM_REG_RST, 1);
+ regmap_write(vreg->regmap, SPM_REG_VCTL, vctl);
+ regmap_write(vreg->regmap, SPM_REG_PMIC_DATA_0, data0);
+ regmap_write(vreg->regmap, SPM_REG_PMIC_DATA_1, data1);
+
+ timeout = jiffies + usecs_to_jiffies(100);
+ do {
+ regmap_read(vreg->regmap, SPM_REG_STS_1, &new_val);
+ new_val &= 0xff;
+ if (new_val == val) {
+ vreg->sel = new_sel;
+ return;
+ }
+
+ cpu_relax();
+
+ } while (time_before(jiffies, timeout));
+
+ pr_err("%s: Voltage not changed: %#x\n", __func__, new_val);
+}
+
+static int saw_regulator_set_voltage_sel(struct regulator_dev *rdev,
+ unsigned selector)
+{
+ struct saw_vreg *vreg = rdev_get_drvdata(rdev);
+ struct spm_vlevel_data data;
+ int cpu = rdev_get_id(rdev);
+
+ data.vreg = vreg;
+ data.sel = selector;
+
+ return smp_call_function_single(cpu, smp_set_vdd, &data, true);
+}
+
+static struct regulator_ops saw_regulator_ops = {
+ .list_voltage = regulator_list_voltage_linear_range,
+ .set_voltage_sel = saw_regulator_set_voltage_sel,
+ .get_voltage_sel = saw_regulator_get_voltage_sel,
+ .set_voltage_time_sel = regulator_set_voltage_time_sel,
+};
+
+static struct regulator_desc saw_regulator = {
+ .owner = THIS_MODULE,
+ .type = REGULATOR_VOLTAGE,
+ .ops = &saw_regulator_ops,
+ .linear_ranges = (struct regulator_linear_range[]) {
+ REGULATOR_LINEAR_RANGE(700000, 0, 56, 12500),
+ },
+ .n_linear_ranges = 1,
+ .n_voltages = 57,
+ .ramp_delay = 1250,
+};
+
+static struct saw_vreg *saw_get_drv(struct platform_device *pdev,
+ int *vreg_cpu)
+{
+ struct saw_vreg *vreg = NULL;
+ struct device_node *cpu_node, *saw_node;
+ int cpu;
+ bool found;
+
+ for_each_possible_cpu(cpu) {
+ cpu_node = of_cpu_device_node_get(cpu);
+ if (!cpu_node)
+ continue;
+ saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
+ found = (saw_node == pdev->dev.of_node->parent);
+ of_node_put(saw_node);
+ of_node_put(cpu_node);
+ if (found)
+ break;
+ }
+
+ if (found) {
+ vreg = devm_kzalloc(&pdev->dev, sizeof(*vreg), GFP_KERNEL);
+ if (vreg)
+ *vreg_cpu = cpu;
+ }
+
+ return vreg;
+}
+
+static const struct of_device_id qcom_saw_regulator_match[] = {
+ { .compatible = "qcom,apq8064-saw2-v1.1-regulator" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, qcom_saw_regulator_match);
+
+static int qcom_saw_regulator_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct device_node *saw_np;
+ struct saw_vreg *vreg;
+ struct regulator_config config = { };
+ int ret = 0, cpu = 0;
+ char name[] = "kraitXX";
+
+ vreg = saw_get_drv(pdev, &cpu);
+ if (!vreg)
+ return -EINVAL;
+
+ saw_np = of_get_parent(np);
+ if (!saw_np)
+ return -ENODEV;
+
+ vreg->regmap = syscon_node_to_regmap(saw_np);
+ of_node_put(saw_np);
+ if (IS_ERR(config.regmap))
+ return PTR_ERR(config.regmap);
+
+ snprintf(name, sizeof(name), "krait%d", cpu);
+
+ config.regmap = vreg->regmap;
+ config.dev = &pdev->dev;
+ config.of_node = np;
+ config.driver_data = vreg;
+
+ vreg->rdesc = saw_regulator;
+ vreg->rdesc.id = cpu;
+ vreg->rdesc.name = name;
+ config.init_data = of_get_regulator_init_data(&pdev->dev,
+ pdev->dev.of_node,
+ &vreg->rdesc);
+
+ vreg->rdev = devm_regulator_register(&pdev->dev, &vreg->rdesc, &config);
+ if (IS_ERR(vreg->rdev)) {
+ ret = PTR_ERR(vreg->rdev);
+ dev_err(dev, "failed to register SAW regulator: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct platform_driver qcom_saw_regulator_driver = {
+ .driver = {
+ .name = "qcom-saw-regulator",
+ .of_match_table = qcom_saw_regulator_match,
+ },
+ .probe = qcom_saw_regulator_probe,
+};
+
+module_platform_driver(qcom_saw_regulator_driver);
+
+MODULE_ALIAS("platform:qcom-saw-regulator");
+MODULE_DESCRIPTION("Qualcomm SAW regulator driver");
+MODULE_AUTHOR("Georgi Djakov <georgi.djakov@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");