[RFC] regulator: core: Support for continuous voltage range

[RFC] regulator: core: Support for continuous voltage range

[Pawel Moll]

Some regulators can set any voltage within the constraints range,
not being limited to specified operating points.

This patch makes it possible to describe such regulator and makes
the regulator_is_supported_voltage() function behave correctly.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 drivers/regulator/core.c         |    5 +++++
 include/linux/regulator/driver.h |    3 +++
 2 files changed, 8 insertions(+)

Hi Mark,

This is roughly what we discussed last week. Alternatively, it could be
also a "universal" unsigned regulator_desc.flags field with #define
REGULATOR_FLAG_CONTINUOUS_VOLTAGE_RAGE 0x1.

Regards

Pawel

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 4838531..808928a 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1947,6 +1947,11 @@ int regulator_is_supported_voltage(struct regulator *regulator,
 			return ret;
 	}
 
+	/* Any voltage within constrains range is fine? */
+	if (rdev->desc->continuous_voltage_range)
+		return min_uV >= rdev->constraints->min_uV &&
+				max_uV <= rdev->constraints->max_uV;
+
 	ret = regulator_count_voltages(regulator);
 	if (ret < 0)
 		return ret;
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index bac4c87..2f915b9 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -171,6 +171,8 @@ enum regulator_type {
  * @type: Indicates if the regulator is a voltage or current regulator.
  * @owner: Module providing the regulator, used for refcounting.
  *
+ * @continuous_voltage_range: Indicates if the regulator can set any
+ *                            voltage within constrains range.
  * @n_voltages: Number of selectors available for ops.list_voltage().
  *
  * @min_uV: Voltage given by the lowest selector (if linear mapping)
@@ -189,6 +191,7 @@ struct regulator_desc {
 	const char *name;
 	const char *supply_name;
 	int id;
+	bool continuous_voltage_range;
 	unsigned n_voltages;
 	struct regulator_ops *ops;
 	int irq;
-- 
1.7.9.5

[PATCH v3] regulator: Versatile Express regulator driver

[Pawel Moll]

Implementation of the regulator framework driver for the
Versatile Express voltage control. Devices without
voltage constraints (ie. "regulator-[min|max]-microvolt"
properties in the DT node) are treated as fixed (or rather
read-only) regulators.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 .../devicetree/bindings/regulator/vexpress.txt     |   32 +++++
 drivers/regulator/Kconfig                          |    7 +
 drivers/regulator/Makefile                         |    1 +
 drivers/regulator/vexpress.c                       |  146 ++++++++++++++++++++
 4 files changed, 186 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/regulator/vexpress.txt
 create mode 100644 drivers/regulator/vexpress.c

Hi Mark,

This is an updated version of the VE driver, depending on the continuous
voltage range change instead of the linear mapping. I've also added the
DT node documentation.

Pawel

diff --git a/Documentation/devicetree/bindings/regulator/vexpress.txt b/Documentation/devicetree/bindings/regulator/vexpress.txt
new file mode 100644
index 0000000..d775f72
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/vexpress.txt
@@ -0,0 +1,32 @@
+Versatile Express voltage regulators
+------------------------------------
+
+Requires node properties:
+- "compatible" value: "arm,vexpress-volt"
+- "arm,vexpress-sysreg,func" when controlled via vexpress-sysreg
+  (see Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
+  for more details)
+
+Required regulator properties:
+- "regulator-name"
+- "regulator-always-on"
+
+Optional regulator properties:
+- "regulator-min-microvolt"
+- "regulator-max-microvolt"
+
+See Documentation/devicetree/bindings/regulator/regulator.txt
+for more details about the regulator properties.
+
+When no "regulator-[min|max]-microvolt" properties are defined,
+the device is treated as fixed (or rather "read-only") regulator.
+
+Example:
+	volt@0 {
+		compatible = "arm,vexpress-volt";
+		arm,vexpress-sysreg,func = <2 0>;
+		regulator-name = "Cores";
+		regulator-min-microvolt = <800000>;
+		regulator-max-microvolt = <1050000>;
+		regulator-always-on;
+	};
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 4e932cc..a823951 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -404,6 +404,13 @@ config REGULATOR_TWL4030
 	  This driver supports the voltage regulators provided by
 	  this family of companion chips.
 
+config REGULATOR_VEXPRESS
+	tristate "Versatile Express regulators"
+	depends on VEXPRESS_CONFIG
+	help
+	  This driver provides support for voltage regulators available
+	  on the ARM Ltd's Versatile Express platform.
+
 config REGULATOR_WM831X
 	tristate "Wolfson Microelectronics WM831x PMIC regulators"
 	depends on MFD_WM831X
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 3342615..0d4e10f 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_REGULATOR_TPS6586X) += tps6586x-regulator.o
 obj-$(CONFIG_REGULATOR_TPS65910) += tps65910-regulator.o
 obj-$(CONFIG_REGULATOR_TPS65912) += tps65912-regulator.o
 obj-$(CONFIG_REGULATOR_TWL4030) += twl-regulator.o
+obj-$(CONFIG_REGULATOR_VEXPRESS) += vexpress.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-isink.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-ldo.o
diff --git a/drivers/regulator/vexpress.c b/drivers/regulator/vexpress.c
new file mode 100644
index 0000000..1702945
--- /dev/null
+++ b/drivers/regulator/vexpress.c
@@ -0,0 +1,146 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 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.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#define DRVNAME "vexpress-regulator"
+#define pr_fmt(fmt) DRVNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/vexpress.h>
+
+struct vexpress_regulator {
+	struct regulator_desc desc;
+	struct regulator_dev *regdev;
+	struct vexpress_config_func *func;
+};
+
+static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
+{
+	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
+	u32 uV;
+	int err = vexpress_config_read(reg->func, 0, &uV);
+
+	return err ? err : uV;
+}
+
+static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
+		int min_uV, int max_uV, unsigned *selector)
+{
+	struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
+
+	return vexpress_config_write(reg->func, 0, min_uV);
+}
+
+static struct regulator_ops vexpress_regulator_ops_ro = {
+	.get_voltage = vexpress_regulator_get_voltage,
+};
+
+static struct regulator_ops vexpress_regulator_ops = {
+	.get_voltage = vexpress_regulator_get_voltage,
+	.set_voltage = vexpress_regulator_set_voltage,
+};
+
+static int vexpress_regulator_probe(struct platform_device *pdev)
+{
+	int err;
+	struct vexpress_regulator *reg;
+	struct regulator_init_data *init_data;
+	struct regulator_config config = { };
+
+	reg = devm_kzalloc(&pdev->dev, sizeof(*reg), GFP_KERNEL);
+	if (!reg) {
+		err = -ENOMEM;
+		goto error_kzalloc;
+	}
+
+	reg->func = vexpress_config_func_get_by_dev(&pdev->dev);
+	if (!reg->func) {
+		err = -ENXIO;
+		goto error_get_func;
+	}
+
+	reg->desc.name = dev_name(&pdev->dev);
+	reg->desc.type = REGULATOR_VOLTAGE;
+	reg->desc.owner = THIS_MODULE;
+	reg->desc.continuous_voltage_range = true;
+
+	init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node);
+	if (!init_data) {
+		err = -EINVAL;
+		goto error_get_regulator_init_data;
+	}
+
+	init_data->constraints.apply_uV = 0;
+	if (init_data->constraints.min_uV && init_data->constraints.max_uV)
+		reg->desc.ops = &vexpress_regulator_ops;
+	else
+		reg->desc.ops = &vexpress_regulator_ops_ro;
+
+	config.dev = &pdev->dev;
+	config.init_data = init_data;
+	config.driver_data = reg;
+	config.of_node = pdev->dev.of_node;
+
+	reg->regdev = regulator_register(&reg->desc, &config);
+	if (IS_ERR(reg->regdev)) {
+		err = PTR_ERR(reg->regdev);
+		goto error_regulator_register;
+	}
+
+	platform_set_drvdata(pdev, reg);
+
+	return 0;
+
+error_regulator_register:
+error_get_regulator_init_data:
+	vexpress_config_func_put(reg->func);
+error_get_func:
+error_kzalloc:
+	return err;
+}
+
+static int __devexit vexpress_regulator_remove(struct platform_device *pdev)
+{
+	struct vexpress_regulator *reg = platform_get_drvdata(pdev);
+
+	vexpress_config_func_put(reg->func);
+	regulator_unregister(reg->regdev);
+
+	return 0;
+}
+
+static struct of_device_id vexpress_regulator_of_match[] = {
+	{ .compatible = "arm,vexpress-volt", },
+};
+
+static struct platform_driver vexpress_regulator_driver = {
+	.probe = vexpress_regulator_probe,
+	.remove = __devexit_p(vexpress_regulator_remove),
+	.driver	= {
+		.name = DRVNAME,
+		.owner = THIS_MODULE,
+		.of_match_table = vexpress_regulator_of_match,
+	},
+};
+
+module_platform_driver(vexpress_regulator_driver);
+
+MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
+MODULE_DESCRIPTION("Versatile Express regulator");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:vexpress-regulator");
-- 
1.7.9.5

Re: [RFC] regulator: core: Support for continuous voltage range

[Mark Brown]

On Mon, Sep 24, 2012 at 06:56:53PM +0100, Pawel Moll wrote:
> Some regulators can set any voltage within the constraints range,
> not being limited to specified operating points.
> 
> This patch makes it possible to describe such regulator and makes
> the regulator_is_supported_voltage() function behave correctly.

Applied, thanks.

Re: [PATCH v3] regulator: Versatile Express regulator driver

[Mark Brown]

On Mon, Sep 24, 2012 at 06:56:54PM +0100, Pawel Moll wrote:
> Implementation of the regulator framework driver for the
> Versatile Express voltage control. Devices without
> voltage constraints (ie. "regulator-[min|max]-microvolt"
> properties in the DT node) are treated as fixed (or rather
> read-only) regulators.

Applied, thanks.