[PATCH RFC 2/3] ARM: regulator: add Freescale MXS regulator driver

[Stefan Wahren <info@lategoodbye.de>]

This patch adds driver support for Freescale i.MX23, i.MX28 on-chip regulators.
There are 4 voltage regulators: vddd, vdda, vddio, vddmem and 1 overall
current regulator.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 drivers/regulator/Kconfig         |   9 +
 drivers/regulator/Makefile        |   1 +
 drivers/regulator/mxs-regulator.c | 411 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 421 insertions(+)
 create mode 100644 drivers/regulator/mxs-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 7a3a061..e90e587 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -432,6 +432,15 @@ config REGULATOR_MC13892
 	  Say y here to support the regulators found on the Freescale MC13892
 	  PMIC.
 
+config REGULATOR_MXS
+	tristate "Freescale MXS on-chip regulators"
+	depends on ARCH_MXS
+	default y if ARCH_MXS
+	help
+	  Say y here to support Freescale MXS on-chip regulators.
+	  It is recommended that this option be enabled on i.MX23,
+	  i.MX28 platform.
+
 config REGULATOR_PALMAS
 	tristate "TI Palmas PMIC Regulators"
 	depends on MFD_PALMAS
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 25271f8..0f5b66c 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_REGULATOR_MAX77802) += max77802.o
 obj-$(CONFIG_REGULATOR_MC13783) += mc13783-regulator.o
 obj-$(CONFIG_REGULATOR_MC13892) += mc13892-regulator.o
 obj-$(CONFIG_REGULATOR_MC13XXX_CORE) +=  mc13xxx-regulator-core.o
+obj-$(CONFIG_REGULATOR_MXS) += mxs-regulator.o
 obj-$(CONFIG_REGULATOR_PALMAS) += palmas-regulator.o
 obj-$(CONFIG_REGULATOR_PFUZE100) += pfuze100-regulator.o
 obj-$(CONFIG_REGULATOR_TPS51632) += tps51632-regulator.o
diff --git a/drivers/regulator/mxs-regulator.c b/drivers/regulator/mxs-regulator.c
new file mode 100644
index 0000000..7d74518
--- /dev/null
+++ b/drivers/regulator/mxs-regulator.c
@@ -0,0 +1,411 @@
+/*
+ * Freescale STMP378X voltage regulators
+ *
+ * Embedded Alley Solutions, Inc <source@embeddedalley.com>
+ *
+ * Copyright (C) 2014 Stefan Wahren
+ * Copyright (C) 2010 Freescale Semiconductor, Inc.
+ * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/slab.h>
+
+#define HW_POWER_VDDDCTRL	(0x00000040)
+#define HW_POWER_VDDACTRL	(0x00000050)
+#define HW_POWER_VDDIOCTRL	(0x00000060)
+#define HW_POWER_STS	        (0x000000c0)
+
+#define BM_POWER_STS_DC_OK	(1 << 9)
+#define BM_POWER_REG_MODE       (1 << 17)
+#define BM_POWER_LEVEL_TRG      0x1f
+
+#define MXS_REG5V_NOT_USB 0
+#define MXS_REG5V_IS_USB 1
+
+
+struct mxs_regulator {
+	struct regulator_desc rdesc;
+	struct regulator_init_data *initdata;
+	struct mxs_regulator *parent;
+
+	spinlock_t         lock;
+	wait_queue_head_t  wait_q;
+	struct notifier_block nb;
+
+	const char *name;
+	void __iomem *base_addr;
+	void __iomem *power_addr;
+	int mode;
+	int cur_uV;
+	int cur_uA;
+	int max_uA;
+	u32 max_reg_val;
+};
+
+static int mxs_set_voltage(struct regulator_dev *reg, int min_uV, int max_uV,
+			   unsigned *selector)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+	struct regulation_constraints *con = &sreg->initdata->constraints;
+	void __iomem *power_sts = sreg->power_addr + HW_POWER_STS;
+	u32 val, regs, i;
+
+	pr_debug("%s: uv %d, min %d, max %d\n", __func__,
+		max_uV, con->min_uV, con->max_uV);
+
+	if (max_uV < con->min_uV || max_uV > con->max_uV)
+		return -EINVAL;
+
+	val = (max_uV - con->min_uV) * sreg->max_reg_val /
+			(con->max_uV - con->min_uV);
+
+	regs = (__raw_readl(sreg->base_addr) & ~BM_POWER_LEVEL_TRG);
+	pr_debug("%s: calculated val %d\n", __func__, val);
+	__raw_writel(val | regs, sreg->base_addr);
+	for (i = 20; i; i--) {
+		if (__raw_readl(power_sts) & BM_POWER_STS_DC_OK)
+			break;
+		udelay(1);
+	}
+
+	if (i)
+		goto out;
+
+	__raw_writel(val | regs, sreg->base_addr);
+	for (i = 40000; i; i--) {
+		if (__raw_readl(power_sts) & BM_POWER_STS_DC_OK)
+			break;
+		udelay(1);
+	}
+
+	if (i)
+		goto out;
+
+	for (i = 40000; i; i--) {
+		if (__raw_readl(power_sts) & BM_POWER_STS_DC_OK)
+			break;
+		udelay(1);
+	}
+
+out:
+	return !i;
+}
+
+
+static int mxs_get_voltage(struct regulator_dev *reg)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+	struct regulation_constraints *con = &sreg->initdata->constraints;
+	int uv;
+	u32 val = __raw_readl(sreg->base_addr) & BM_POWER_LEVEL_TRG;
+
+	if (val > sreg->max_reg_val)
+		val = sreg->max_reg_val;
+
+	uv = con->min_uV + val *
+		(con->max_uV - con->min_uV) / sreg->max_reg_val;
+
+	return uv;
+}
+
+static int main_add_current(struct mxs_regulator *sreg,
+			    int uA)
+{
+	pr_debug("%s: enter reg %s, uA=%d\n", __func__, sreg->name, uA);
+
+	if (uA > 0 && (sreg->cur_uA + uA > sreg->max_uA))
+		return -EINVAL;
+
+	sreg->cur_uA += uA;
+
+	return 0;
+}
+
+static int mxs_set_current_limit(struct regulator_dev *reg, int min_uA,
+				 int max_uA)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+	struct mxs_regulator *parent = sreg->parent;
+	int ret = 0;
+	unsigned long flags;
+
+	pr_debug("%s: enter reg %s, uA=%d\n",
+		 __func__, sreg->name, max_uA);
+
+	if (parent) {
+		spin_lock_irqsave(&parent->lock, flags);
+		ret = main_add_current(parent, max_uA - sreg->cur_uA);
+		spin_unlock_irqrestore(&parent->lock, flags);
+	}
+
+	if ((!ret) || (!parent))
+		goto out;
+
+	if (sreg->mode == REGULATOR_MODE_FAST)
+		return ret;
+
+	while (ret) {
+		wait_event(parent->wait_q ,
+			   (max_uA - sreg->cur_uA <
+			    parent->max_uA -
+			    parent->cur_uA));
+		spin_lock_irqsave(&parent->lock, flags);
+		ret = main_add_current(parent, max_uA - sreg->cur_uA);
+		spin_unlock_irqrestore(&parent->lock, flags);
+	}
+out:
+	if (parent && (max_uA - sreg->cur_uA < 0))
+		wake_up_all(&parent->wait_q);
+	sreg->cur_uA = max_uA;
+	return 0;
+}
+
+static int mxs_get_current_limit(struct regulator_dev *reg)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+
+	return sreg->cur_uA;
+}
+
+static int mxs_set_mode(struct regulator_dev *reg, unsigned int mode)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+	int ret = 0;
+	u32 val;
+
+	switch (mode) {
+	case REGULATOR_MODE_FAST:
+		val = __raw_readl(sreg->base_addr);
+		__raw_writel(val | BM_POWER_REG_MODE, sreg->base_addr);
+		break;
+
+	case REGULATOR_MODE_NORMAL:
+		val = __raw_readl(sreg->base_addr);
+		__raw_writel(val & ~BM_POWER_REG_MODE, sreg->base_addr);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
+static unsigned int mxs_get_mode(struct regulator_dev *reg)
+{
+	struct mxs_regulator *sreg = rdev_get_drvdata(reg);
+	u32 val = __raw_readl(sreg->base_addr) & BM_POWER_REG_MODE;
+
+	return val ? REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
+}
+
+static struct regulator_ops mxs_rops = {
+	.set_voltage	= mxs_set_voltage,
+	.get_voltage	= mxs_get_voltage,
+	.set_current_limit	= mxs_set_current_limit,
+	.get_current_limit	= mxs_get_current_limit,
+	.set_mode	= mxs_set_mode,
+	.get_mode	= mxs_get_mode,
+};
+
+static int reg_callback(struct notifier_block *self,
+			unsigned long event, void *data)
+{
+	unsigned long flags;
+	struct mxs_regulator *sreg =
+		container_of(self, struct mxs_regulator , nb);
+
+	switch (event) {
+	case MXS_REG5V_IS_USB:
+		spin_lock_irqsave(&sreg->lock, flags);
+		sreg->max_uA = 500000;
+		spin_unlock_irqrestore(&sreg->lock, flags);
+		break;
+	case MXS_REG5V_NOT_USB:
+		spin_lock_irqsave(&sreg->lock, flags);
+		sreg->max_uA = 0x7fffffff;
+		spin_unlock_irqrestore(&sreg->lock, flags);
+		break;
+	}
+
+	return 0;
+}
+
+static int mxs_regulator_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *parent;
+	struct regulator_desc *rdesc;
+	struct regulator_dev *rdev;
+	struct mxs_regulator *sreg;
+	struct regulator_init_data *initdata;
+	struct regulation_constraints *con;
+	struct regulator_config config = { };
+	void __iomem *base_addr = NULL;
+	void __iomem *power_addr = NULL;
+	u64 regaddr64 = 0;
+	const u32 *regaddr_p;
+	u32 val = 0;
+	int ret;
+
+	if (!np) {
+		dev_err(dev, "missing device tree\n");
+		return -EINVAL;
+	}
+
+	/* get device base address */
+	base_addr = of_iomap(np, 0);
+	if (!base_addr)
+		return -ENXIO;
+
+	parent = of_get_parent(np);
+	if (!parent)
+		return -ENXIO;
+
+	power_addr = of_iomap(parent, 0);
+	if (!power_addr)
+		return -ENXIO;
+
+	regaddr_p = of_get_address(np, 0, NULL, NULL);
+	if (regaddr_p)
+		regaddr64 = of_translate_address(np, regaddr_p);
+
+	if (!regaddr64) {
+		dev_err(dev, "no or invalid reg property set\n");
+		return -EINVAL;
+	}
+
+	initdata = of_get_regulator_init_data(dev, np);
+	if (!initdata)
+		return -EINVAL;
+
+	ret = of_property_read_u32(np, "mxs-max-reg-val",
+				   &val);
+	if (!val) {
+		dev_err(dev, "no or invalid mxs-max-reg-val property set\n");
+		return ret;
+	}
+
+	dev_info(dev, "regulator found\n");
+
+	sreg = devm_kzalloc(dev, sizeof(*sreg), GFP_KERNEL);
+	if (!sreg)
+		return -ENOMEM;
+	sreg->initdata = initdata;
+	sreg->name = of_get_property(np, "regulator-name", NULL);
+	sreg->cur_uA = 0;
+	sreg->cur_uV = 0;
+	sreg->base_addr = base_addr;
+	sreg->power_addr = power_addr;
+	init_waitqueue_head(&sreg->wait_q);
+	spin_lock_init(&sreg->lock);
+	sreg->max_reg_val = val;
+
+	rdesc = &sreg->rdesc;
+	rdesc->name = sreg->name;
+	rdesc->owner = THIS_MODULE;
+	rdesc->ops = &mxs_rops;
+
+	if (strcmp(rdesc->name, "overall_current") == 0)
+		rdesc->type = REGULATOR_CURRENT;
+	else
+		rdesc->type = REGULATOR_VOLTAGE;
+
+	con = &initdata->constraints;
+	rdesc->n_voltages = sreg->max_reg_val;
+	rdesc->min_uV = con->min_uV;
+	rdesc->uV_step = (con->max_uV - con->min_uV) / sreg->max_reg_val;
+	rdesc->linear_min_sel = 0;
+	rdesc->vsel_reg = regaddr64;
+	rdesc->vsel_mask = BM_POWER_LEVEL_TRG;
+
+	config.dev = &pdev->dev;
+	config.init_data = initdata;
+	config.driver_data = sreg;
+	config.of_node = np;
+
+	pr_debug("probing regulator %s %s %d\n",
+			sreg->name,
+			rdesc->name,
+			pdev->id);
+
+	/* register regulator */
+	rdev = devm_regulator_register(dev, rdesc, &config);
+
+	if (IS_ERR(rdev)) {
+		dev_err(&pdev->dev, "failed to register %s\n",
+			rdesc->name);
+		return PTR_ERR(rdev);
+	}
+
+	if (sreg->max_uA) {
+		struct regulator *regu;
+
+		regu = regulator_get(NULL, sreg->name);
+		sreg->nb.notifier_call = reg_callback;
+		regulator_register_notifier(regu, &sreg->nb);
+	}
+
+	platform_set_drvdata(pdev, rdev);
+
+	of_property_read_u32(np, "mxs-default-microvolt",
+				   &val);
+
+	if (val)
+		mxs_set_voltage(rdev, val, val, NULL);
+
+	return 0;
+}
+
+static struct of_device_id of_mxs_regulator_match_tbl[] = {
+	{ .compatible = "fsl,mxs-regulator", },
+	{ /* end */ }
+};
+
+static struct platform_driver mxs_regulator_driver = {
+	.driver = {
+		.name	= "mxs-regulator",
+		.owner  = THIS_MODULE,
+		.of_match_table = of_mxs_regulator_match_tbl,
+	},
+	.probe	= mxs_regulator_probe,
+};
+
+static int __init mxs_regulator_init(void)
+{
+	return platform_driver_register(&mxs_regulator_driver);
+}
+postcore_initcall(mxs_regulator_init);
+
+static void __exit mxs_regulator_exit(void)
+{
+	platform_driver_unregister(&mxs_regulator_driver);
+}
+module_exit(mxs_regulator_exit);
+
+MODULE_AUTHOR("Embedded Alley Solutions <source@embeddedalley.com>");
+MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
+MODULE_DESCRIPTION("Freescale STMP378X voltage regulators");
+MODULE_LICENSE("GPL v2");
-- 
1.8.1.4