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

[Lina Iyer <lina.iyer@linaro.org>]

On Tue, Feb 09 2016 at 06:13 -0700, Georgi Djakov wrote:
>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@linaro.org>
>---
>
>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
>+
These register offsets are SoC specific. You may want to follow the model
of drivers/soc/qcom/spm.c in getting register offsets.

While I see that you are only supporting APQ8064 with this patch, you
probably would want to think a bit far ahead. To support any other QCOM
SoC, you would need extensive changes.

>+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);
>+
builtin_platform_driver() perhaps ?

>+MODULE_ALIAS("platform:qcom-saw-regulator");
>+MODULE_DESCRIPTION("Qualcomm SAW regulator driver");
>+MODULE_AUTHOR("Georgi Djakov <georgi.djakov@linaro.org>");
>+MODULE_LICENSE("GPL v2");