[PATCH 3/4] regulator: Add a regulator driver for the PM8008 PMIC

[Satya Priya <skakit@codeaurora.org>]

From: satya priya <skakit@codeaurora.org>

Qualcomm Technologies, Inc. PM8008 is an I2C controlled PMIC
containing 7 LDO regulators.  Add a PM8008 regulator driver to
support PMIC regulator management via the regulator framework.

Signed-off-by: satya priya <skakit@codeaurora.org>
---
 drivers/regulator/Kconfig                 |   9 +
 drivers/regulator/Makefile                |   1 +
 drivers/regulator/qcom-pm8008-regulator.c | 441 ++++++++++++++++++++++++++++++
 3 files changed, 451 insertions(+)
 create mode 100644 drivers/regulator/qcom-pm8008-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index e35cca5..888ce30 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -916,6 +916,15 @@ config REGULATOR_PWM
 	  This driver supports PWM controlled voltage regulators. PWM
 	  duty cycle can increase or decrease the voltage.
 
+config REGULATOR_QCOM_PM8008
+	tristate "Qualcomm Technologies, Inc. PM8008 PMIC regulators"
+	depends on MFD_QCOM_PM8008
+	help
+	  Select this option to get support for the voltage regulators
+	  of Qualcomm Technologies, Inc. PM8008 PMIC chip. PM8008 has 7 LDO
+	  regulators. This driver provides support for basic operations like
+	  set/get voltage and enable/disable.
+
 config REGULATOR_QCOM_RPM
 	tristate "Qualcomm RPM regulator driver"
 	depends on MFD_QCOM_RPM
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 9e382b5..5e935ff 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_REGULATOR_MT6380)	+= mt6380-regulator.o
 obj-$(CONFIG_REGULATOR_MT6397)	+= mt6397-regulator.o
 obj-$(CONFIG_REGULATOR_MTK_DVFSRC) += mtk-dvfsrc-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_LABIBB) += qcom-labibb-regulator.o
+obj-$(CONFIG_REGULATOR_QCOM_PM8008) += qcom-pm8008-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
diff --git a/drivers/regulator/qcom-pm8008-regulator.c b/drivers/regulator/qcom-pm8008-regulator.c
new file mode 100644
index 0000000..fdc2f16
--- /dev/null
+++ b/drivers/regulator/qcom-pm8008-regulator.c
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+#define STARTUP_DELAY_USEC		20
+#define VSET_STEP_MV			8
+#define VSET_STEP_UV			(VSET_STEP_MV * 1000)
+
+#define LDO_ENABLE_REG(base)		(base + 0x46)
+#define ENABLE_BIT			BIT(7)
+
+#define LDO_STATUS1_REG(base)		(base + 0x08)
+#define VREG_READY_BIT			BIT(7)
+
+#define LDO_VSET_LB_REG(base)		(base + 0x40)
+
+#define LDO_STEPPER_CTL_REG(base)	(base + 0x3b)
+#define STEP_RATE_MASK			GENMASK(1, 0)
+
+#define PM8008_MAX_LDO			7
+
+struct regulator_data {
+	char		*name;
+	char		*supply_name;
+	int		min_uv;
+	int		max_uv;
+	int		min_dropout_uv;
+};
+
+struct pm8008_regulator {
+	struct device		*dev;
+	struct regmap		*regmap;
+	struct regulator_desc	rdesc;
+	struct regulator_dev	*rdev;
+	struct device_node	*of_node;
+	u16			base;
+	int			step_rate;
+};
+
+static const struct regulator_data reg_data[PM8008_MAX_LDO] = {
+	/* name  parent      min_uv  max_uv  headroom_uv */
+	{"l1", "vdd_l1_l2",  528000, 1504000, 225000},
+	{"l2", "vdd_l1_l2",  528000, 1504000, 225000},
+	{"l3", "vdd_l3_l4", 1504000, 3400000, 200000},
+	{"l4", "vdd_l3_l4", 1504000, 3400000, 200000},
+	{"l5", "vdd_l5",    1504000, 3400000, 300000},
+	{"l6", "vdd_l6",    1504000, 3400000, 300000},
+	{"l7", "vdd_l7",    1504000, 3400000, 300000},
+};
+
+static int pm8008_read(struct regmap *regmap,  u16 reg, u8 *val, int count)
+{
+	int rc;
+
+	rc = regmap_bulk_read(regmap, reg, val, count);
+	if (rc < 0)
+		pr_err("failed to read %#x, rc=%d\n", reg, rc);
+
+	return rc;
+}
+
+static int pm8008_write(struct regmap *regmap, u16 reg, u8 *val, int count)
+{
+	int rc;
+
+	pr_debug("Writing [%*ph] from address %#x\n", count, val, reg);
+	rc = regmap_bulk_write(regmap, reg, val, count);
+	if (rc < 0)
+		pr_err("failed to write %#x rc=%d\n", reg, rc);
+
+	return rc;
+}
+
+static int pm8008_masked_write(struct regmap *regmap, u16 reg, u8 mask,
+				u8 val)
+{
+	int rc;
+
+	pr_debug("Writing %#x to %#x with mask %#x\n", val, reg, mask);
+	rc = regmap_update_bits(regmap, reg, mask, val);
+	if (rc < 0)
+		pr_err("failed to write %#x to %#x with mask %#x rc=%d\n",
+				val, reg, mask, rc);
+
+	return rc;
+}
+
+static int pm8008_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	u8 vset_raw[2];
+	int rc;
+
+	rc = pm8008_read(pm8008_reg->regmap,
+			LDO_VSET_LB_REG(pm8008_reg->base),
+			vset_raw, 2);
+	if (rc < 0) {
+		pr_err("failed to read regulator voltage rc=%d\n", rc);
+		return rc;
+	}
+
+	return (vset_raw[1] << 8 | vset_raw[0]) * 1000;
+}
+
+static int pm8008_regulator_is_enabled(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc;
+	u8 reg;
+
+	rc = pm8008_read(pm8008_reg->regmap,
+			LDO_ENABLE_REG(pm8008_reg->base), &reg, 1);
+	if (rc < 0) {
+		pr_err("failed to read enable reg rc=%d\n", rc);
+		return rc;
+	}
+
+	return !!(reg & ENABLE_BIT);
+}
+
+static int pm8008_regulator_enable(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc, current_uv, delay_us, delay_ms, retry_count = 10;
+	u8 reg;
+
+	current_uv = pm8008_regulator_get_voltage(rdev);
+	if (current_uv < 0) {
+		pr_err("failed to get current voltage rc=%d\n", current_uv);
+		return current_uv;
+	}
+
+	rc = pm8008_masked_write(pm8008_reg->regmap,
+				LDO_ENABLE_REG(pm8008_reg->base),
+				ENABLE_BIT, ENABLE_BIT);
+	if (rc < 0) {
+		pr_err("failed to enable regulator rc=%d\n", rc);
+		return rc;
+	}
+
+	/*
+	 * Wait for the VREG_READY status bit to be set using a timeout delay
+	 * calculated from the current commanded voltage.
+	 */
+	delay_us = STARTUP_DELAY_USEC
+			+ DIV_ROUND_UP(current_uv, pm8008_reg->step_rate);
+	delay_ms = DIV_ROUND_UP(delay_us, 1000);
+
+	/* Retry 10 times for VREG_READY before bailing out */
+	while (retry_count--) {
+		if (delay_ms > 20)
+			msleep(delay_ms);
+		else
+			usleep_range(delay_us, delay_us + 100);
+
+		rc = pm8008_read(pm8008_reg->regmap,
+				LDO_STATUS1_REG(pm8008_reg->base), &reg, 1);
+		if (rc < 0) {
+			pr_err("failed to read regulator status rc=%d\n", rc);
+			goto disable_ldo;
+		}
+		if (reg & VREG_READY_BIT) {
+			pr_debug("regulator enabled\n");
+			return 0;
+		}
+	}
+
+	pr_err("failed to enable regulator, VREG_READY not set\n");
+	rc = -ETIME;
+
+disable_ldo:
+	pm8008_masked_write(pm8008_reg->regmap,
+			LDO_ENABLE_REG(pm8008_reg->base), ENABLE_BIT, 0);
+
+	return rc;
+}
+
+static int pm8008_regulator_disable(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = pm8008_masked_write(pm8008_reg->regmap,
+				LDO_ENABLE_REG(pm8008_reg->base),
+				ENABLE_BIT, 0);
+	if (rc < 0) {
+		pr_err("failed to disable regulator rc=%d\n", rc);
+		return rc;
+	}
+
+	pr_debug("regulator disabled\n");
+	return 0;
+}
+
+static int pm8008_write_voltage(struct pm8008_regulator *pm8008_reg, int min_uv,
+				int max_uv)
+{
+	int rc = 0, mv;
+	u8 vset_raw[2];
+
+	mv = DIV_ROUND_UP(min_uv, 1000);
+
+	/*
+	 * Each LSB of regulator is 1mV and the voltage setpoint
+	 * should be multiple of 8mV(step).
+	 */
+	mv = DIV_ROUND_UP(mv, VSET_STEP_MV) * VSET_STEP_MV;
+	if (mv * 1000 > max_uv) {
+		pr_err("requested voltage (%d uV) above maximum limit (%d uV)\n",
+				mv*1000, max_uv);
+		return -EINVAL;
+	}
+
+	vset_raw[0] = mv & 0xff;
+	vset_raw[1] = (mv & 0xff00) >> 8;
+	rc = pm8008_write(pm8008_reg->regmap, LDO_VSET_LB_REG(pm8008_reg->base),
+			vset_raw, 2);
+	if (rc < 0) {
+		pr_err("failed to write voltage rc=%d\n", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int pm8008_regulator_set_voltage_time(struct regulator_dev *rdev,
+				int old_uV, int new_uv)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+
+	return DIV_ROUND_UP(abs(new_uv - old_uV), pm8008_reg->step_rate);
+}
+
+static int pm8008_regulator_set_voltage(struct regulator_dev *rdev,
+				int min_uv, int max_uv, unsigned int *selector)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = pm8008_write_voltage(pm8008_reg, min_uv, max_uv);
+	if (rc < 0)
+		return rc;
+
+	*selector = DIV_ROUND_UP(min_uv - pm8008_reg->rdesc.min_uV,
+				VSET_STEP_UV);
+
+	pr_debug("voltage set to %d\n", min_uv);
+	return 0;
+}
+
+static const struct regulator_ops pm8008_regulator_ops = {
+	.enable		= pm8008_regulator_enable,
+	.disable		= pm8008_regulator_disable,
+	.is_enabled		= pm8008_regulator_is_enabled,
+	.set_voltage		= pm8008_regulator_set_voltage,
+	.get_voltage		= pm8008_regulator_get_voltage,
+	.list_voltage		= regulator_list_voltage_linear,
+	.set_voltage_time	= pm8008_regulator_set_voltage_time,
+};
+
+static int pm8008_register_ldo(struct pm8008_regulator *pm8008_reg,
+						const char *name)
+{
+	struct regulator_config reg_config = {};
+	struct regulator_init_data *init_data;
+	struct device *dev = pm8008_reg->dev;
+	struct device_node *reg_node = pm8008_reg->of_node;
+	int rc, i, init_voltage;
+	u32 base = 0;
+	u8 reg;
+
+	/* get regulator data */
+	for (i = 0; i < PM8008_MAX_LDO; i++)
+		if (strstr(name, reg_data[i].name))
+			break;
+
+	if (i == PM8008_MAX_LDO) {
+		dev_err(dev, "Invalid regulator name %s\n", name);
+		return -EINVAL;
+	}
+
+	rc = of_property_read_u32(reg_node, "reg", &base);
+	if (rc < 0) {
+		dev_err(dev, "%s: failed to get regulator base rc=%d\n", name, rc);
+		return rc;
+	}
+	pm8008_reg->base = base;
+
+	init_voltage = -EINVAL;
+	of_property_read_u32(reg_node, "qcom,init-voltage", &init_voltage);
+
+	/* get slew rate */
+	rc = pm8008_read(pm8008_reg->regmap,
+			LDO_STEPPER_CTL_REG(pm8008_reg->base), &reg, 1);
+	if (rc < 0) {
+		dev_err(dev, "%s: failed to read step rate configuration rc=%d\n",
+				name, rc);
+		return rc;
+	}
+	pm8008_reg->step_rate = 38400 >> (reg & STEP_RATE_MASK);
+
+	init_data = of_get_regulator_init_data(dev, reg_node,
+						&pm8008_reg->rdesc);
+	if (init_data == NULL) {
+		dev_err(dev, "%s: failed to get regulator data\n", name);
+		return -ENODATA;
+	}
+	if (!init_data->constraints.name) {
+		dev_err(dev, "%s: regulator name missing\n", name);
+		return -EINVAL;
+	}
+
+	/* configure the initial voltage for the regulator */
+	if (init_voltage > 0) {
+		rc = pm8008_write_voltage(pm8008_reg, init_voltage,
+					init_data->constraints.max_uV);
+		if (rc < 0)
+			dev_err(dev, "%s: failed to set initial voltage rc=%d\n",
+					name, rc);
+	}
+
+	init_data->constraints.input_uV = init_data->constraints.max_uV;
+	init_data->constraints.valid_ops_mask |= REGULATOR_CHANGE_STATUS
+						| REGULATOR_CHANGE_VOLTAGE;
+	reg_config.dev = dev;
+	reg_config.init_data = init_data;
+	reg_config.driver_data = pm8008_reg;
+	reg_config.of_node = reg_node;
+
+	pm8008_reg->rdesc.type = REGULATOR_VOLTAGE;
+	pm8008_reg->rdesc.ops = &pm8008_regulator_ops;
+	pm8008_reg->rdesc.name = init_data->constraints.name;
+	pm8008_reg->rdesc.supply_name = reg_data[i].supply_name;
+	pm8008_reg->rdesc.uV_step = VSET_STEP_UV;
+	pm8008_reg->rdesc.min_uV = reg_data[i].min_uv;
+	pm8008_reg->rdesc.n_voltages
+		= ((reg_data[i].max_uv - reg_data[i].min_uv)
+			/ pm8008_reg->rdesc.uV_step) + 1;
+
+	pm8008_reg->rdesc.min_dropout_uV = reg_data[i].min_dropout_uv;
+	of_property_read_u32(reg_node, "qcom,min-dropout-voltage",
+			     &pm8008_reg->rdesc.min_dropout_uV);
+
+	pm8008_reg->rdev = devm_regulator_register(dev, &pm8008_reg->rdesc,
+						&reg_config);
+	if (IS_ERR(pm8008_reg->rdev)) {
+		rc = PTR_ERR(pm8008_reg->rdev);
+		dev_err(dev, "%s: failed to register regulator rc=%d\n",
+				pm8008_reg->rdesc.name, rc);
+		return rc;
+	}
+
+	pr_debug("%s regulator registered\n", name);
+
+	return 0;
+}
+
+static int pm8008_parse_regulator(struct regmap *regmap, struct device *dev)
+{
+	int rc = 0;
+	const char *name;
+	struct device_node *child;
+	struct pm8008_regulator *pm8008_reg;
+
+	/* parse each subnode and register regulator for regulator child */
+	for_each_available_child_of_node(dev->of_node, child) {
+		pm8008_reg = devm_kzalloc(dev, sizeof(*pm8008_reg), GFP_KERNEL);
+		if (!pm8008_reg)
+			return -ENOMEM;
+
+		pm8008_reg->regmap = regmap;
+		pm8008_reg->of_node = child;
+		pm8008_reg->dev = dev;
+
+		rc = of_property_read_string(child, "regulator-name", &name);
+		if (rc)
+			continue;
+
+		rc = pm8008_register_ldo(pm8008_reg, name);
+		if (rc < 0) {
+			dev_err(dev, "failed to register regulator %s rc=%d\n",
+					name, rc);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int pm8008_regulator_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	struct regmap *regmap;
+
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap) {
+		dev_err(&pdev->dev, "parent regmap is missing\n");
+		return -EINVAL;
+	}
+
+	rc = pm8008_parse_regulator(regmap, &pdev->dev);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "failed to parse device tree rc=%d\n", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id pm8008_regulator_match_table[] = {
+	{ .compatible = "qcom,pm8008-regulator", },
+	{ },
+};
+
+static struct platform_driver pm8008_regulator_driver = {
+	.driver	= {
+		.name		= "qcom,pm8008-regulator",
+		.of_match_table	= pm8008_regulator_match_table,
+	},
+	.probe		= pm8008_regulator_probe,
+};
+
+module_platform_driver(pm8008_regulator_driver);
+
+MODULE_DESCRIPTION("Qualcomm PM8008 PMIC Regulator Driver");
+MODULE_LICENSE("GPL v2");
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
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