regulator: add refgen regulator driver

Some Qualcomm Technologies, Inc. SoCs such as SDM845 utilize
reference bias generators for various internal PHY blocks.  These
are called REFGENs.  Add a driver to support REFGEN so that
consumers can vote based upon their runtime hardware needs.

Change-Id: I60681273cc1f9842844968bf4f0f682cdd28eb0d
Signed-off-by: David Collins <collinsd@codeaurora.org>

drivers/regulator/Kconfig

@@ -1057,6 +1057,15 @@ config REGULATOR_WM8994
 	  This driver provides support for the voltage regulators on the
 	  WM8994 CODEC.
 
+config REGULATOR_REFGEN
+	tristate "Qualcomm Technologies, Inc. REFGEN regulator driver"
+	depends on OF
+	help
+	  This driver supports control of the REFGEN reference bias generator
+	  block found on some Qualcomm Technologies Inc. SoCs.  A REFGEN
+	  it used by various PHY blocks found inside of the SoC.  It supports
+	  enable/disable control.
+
 config REGULATOR_RPMH
 	tristate "Qualcomm Technologies, Inc. Legacy RPMh regulator driver"
 	depends on QCOM_RPMH

drivers/regulator/Makefile

@@ -134,6 +134,7 @@ obj-$(CONFIG_REGULATOR_WM8350) += wm8350-regulator.o
 obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
 obj-$(CONFIG_REGULATOR_WM8994) += wm8994-regulator.o
 
+obj-$(CONFIG_REGULATOR_REFGEN) += refgen.o
 obj-$(CONFIG_REGULATOR_RPMH) += rpmh-regulator.o
 obj-$(CONFIG_REGULATOR_STUB) += stub-regulator.o
 

drivers/regulator/refgen.c

@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2017, 2019, The Linux Foundation. All rights reserved. */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+#define REFGEN_REG_BIAS_EN		0x08
+#define REFGEN_BIAS_EN_MASK		GENMASK(2, 0)
+#define REFGEN_BIAS_EN_ENABLE		0x7
+#define REFGEN_BIAS_EN_DISABLE		0x6
+
+#define REFGEN_REG_BG_CTRL		0x14
+#define REFGEN_BG_CTRL_MASK		GENMASK(2, 1)
+#define REFGEN_BG_CTRL_ENABLE		0x6
+#define REFGEN_BG_CTRL_DISABLE		0x4
+
+#define REFGEN_REG_PWRDWN_CTRL5		0x80
+#define REFGEN_PWRDWN_CTRL5_MASK	GENMASK(0, 0)
+#define REFGEN_PWRDWN_CTRL5_ENABLE	0x1
+#define REFGEN_PWRDWN_CTRL5_DISABLE	0x0
+
+struct refgen {
+	struct regulator_desc	rdesc;
+	struct regulator_dev	*rdev;
+	void __iomem		*addr;
+};
+
+static void masked_writel(u32 val, u32 mask, void __iomem *addr)
+{
+	u32 reg;
+
+	reg = readl_relaxed(addr);
+	reg = (reg & ~mask) | (val & mask);
+	writel_relaxed(reg, addr);
+}
+
+static int refgen_enable(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+
+	masked_writel(REFGEN_BG_CTRL_ENABLE, REFGEN_BG_CTRL_MASK,
+			vreg->addr + REFGEN_REG_BG_CTRL);
+	writel_relaxed(REFGEN_BIAS_EN_ENABLE, vreg->addr + REFGEN_REG_BIAS_EN);
+
+	return 0;
+}
+
+static int refgen_disable(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+
+	writel_relaxed(REFGEN_BIAS_EN_DISABLE, vreg->addr + REFGEN_REG_BIAS_EN);
+	masked_writel(REFGEN_BG_CTRL_DISABLE, REFGEN_BG_CTRL_MASK,
+			vreg->addr + REFGEN_REG_BG_CTRL);
+
+	return 0;
+}
+
+static int refgen_is_enabled(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+	u32 val;
+
+	val = readl_relaxed(vreg->addr + REFGEN_REG_BG_CTRL);
+	if ((val & REFGEN_BG_CTRL_MASK) != REFGEN_BG_CTRL_ENABLE)
+		return 0;
+
+	val = readl_relaxed(vreg->addr + REFGEN_REG_BIAS_EN);
+	if ((val & REFGEN_BIAS_EN_MASK) != REFGEN_BIAS_EN_ENABLE)
+		return 0;
+
+	return 1;
+}
+
+static struct regulator_ops refgen_ops = {
+	.enable		= refgen_enable,
+	.disable	= refgen_disable,
+	.is_enabled	= refgen_is_enabled,
+};
+
+static int refgen_kona_enable(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+
+	masked_writel(REFGEN_PWRDWN_CTRL5_ENABLE, REFGEN_PWRDWN_CTRL5_MASK,
+			vreg->addr + REFGEN_REG_PWRDWN_CTRL5);
+
+	return 0;
+}
+
+static int refgen_kona_disable(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+
+	masked_writel(REFGEN_PWRDWN_CTRL5_DISABLE, REFGEN_PWRDWN_CTRL5_MASK,
+			vreg->addr + REFGEN_REG_PWRDWN_CTRL5);
+
+	return 0;
+}
+
+static int refgen_kona_is_enabled(struct regulator_dev *rdev)
+{
+	struct refgen *vreg = rdev_get_drvdata(rdev);
+	u32 val;
+
+	val = readl_relaxed(vreg->addr + REFGEN_REG_PWRDWN_CTRL5);
+
+	return (val & REFGEN_PWRDWN_CTRL5_MASK) == REFGEN_PWRDWN_CTRL5_ENABLE;
+}
+
+static struct regulator_ops refgen_kona_ops = {
+	.enable		= refgen_kona_enable,
+	.disable	= refgen_kona_disable,
+	.is_enabled	= refgen_kona_is_enabled,
+};
+
+static const struct of_device_id refgen_match_table[] = {
+	{ .compatible = "qcom,refgen-regulator", .data = &refgen_ops},
+	{ .compatible = "qcom,refgen-sdm845-regulator", .data = &refgen_ops},
+	{ .compatible = "qcom,refgen-kona-regulator", .data = &refgen_kona_ops},
+	{}
+};
+
+static int refgen_probe(struct platform_device *pdev)
+{
+	struct regulator_config config = {};
+	struct regulator_init_data *init_data = NULL;
+	struct device *dev = &pdev->dev;
+	struct regulator_desc *rdesc;
+	struct resource *res;
+	struct refgen *vreg;
+	int rc;
+
+	vreg = devm_kzalloc(dev, sizeof(*vreg), GFP_KERNEL);
+	if (!vreg)
+		return -ENOMEM;
+
+	if (!dev->of_node) {
+		dev_err(dev, "%s: device tree node missing\n", __func__);
+		return -ENODEV;
+	}
+
+	vreg->rdesc.ops = of_device_get_match_data(dev);
+	if (!vreg->rdesc.ops) {
+		dev_err(dev, "%s: could not find compatible string match\n",
+			__func__);
+		return -ENODEV;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res || !res->start) {
+		dev_err(dev, "reg address is missing\n");
+		return -EINVAL;
+	}
+
+	vreg->addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(vreg->addr)) {
+		rc = PTR_ERR(vreg->addr);
+		dev_err(dev, "ioremap failed, rc=%d\n", rc);
+		return rc;
+	}
+
+	init_data = of_get_regulator_init_data(dev, dev->of_node, &vreg->rdesc);
+	if (!init_data)
+		return -ENOMEM;
+
+	if (init_data->constraints.name == NULL) {
+		dev_err(dev, "%s: regulator-name not specified\n", __func__);
+		return -EINVAL;
+	}
+
+	if (of_get_property(dev->of_node, "parent-supply", NULL))
+		init_data->supply_regulator = "parent";
+
+	rdesc = &vreg->rdesc;
+
+	rdesc->name = "refgen";
+	rdesc->id = pdev->id;
+	rdesc->owner = THIS_MODULE;
+	rdesc->type = REGULATOR_VOLTAGE;
+
+	config.dev = dev;
+	config.init_data = init_data;
+	config.driver_data = vreg;
+	config.of_node = dev->of_node;
+
+	vreg->rdev = devm_regulator_register(dev, rdesc, &config);
+	if (IS_ERR(vreg->rdev)) {
+		rc = PTR_ERR(vreg->rdev);
+		if (rc != -EPROBE_DEFER)
+			dev_err(dev, "%s: regulator register failed\n",
+				__func__);
+		return rc;
+	}
+
+	return 0;
+}
+
+static struct platform_driver refgen_driver = {
+	.probe = refgen_probe,
+	.driver = {
+		.name = "qcom,refgen-regulator",
+		.of_match_table = refgen_match_table,
+	},
+};
+
+static int __init refgen_init(void)
+{
+	return platform_driver_register(&refgen_driver);
+}
+arch_initcall(refgen_init);
+
+static void __exit refgen_exit(void)
+{
+	platform_driver_unregister(&refgen_driver);
+}
+module_exit(refgen_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("refgen regulator driver");