[PATCH v3] Add ltc3562 voltage regulator driver

From: Mike Looijmans
Date: Tue Nov 04 2014 - 01:51:12 EST

The ltc3562 is an I2C controlled regulator supporting 4 independent
outputs.

Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
---

v3: Add .of_match_table and prefix lltc
Clarify why regmap cannot be used
Add lltc,operating-mode (0..3) DT property
regulator child nodes are optional


.../devicetree/bindings/regulator/ltc3562.txt | 57 ++++
drivers/regulator/Kconfig | 7 +
drivers/regulator/Makefile | 1 +
drivers/regulator/ltc3562.c | 337 ++++++++++++++++++++
4 files changed, 402 insertions(+)
create mode 100644 Documentation/devicetree/bindings/regulator/ltc3562.txt
create mode 100644 drivers/regulator/ltc3562.c

diff --git a/Documentation/devicetree/bindings/regulator/ltc3562.txt b/Documentation/devicetree/bindings/regulator/ltc3562.txt
new file mode 100644
index 0000000..d73c865
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/ltc3562.txt
@@ -0,0 +1,57 @@
+Linear Technology LTC3562 I2C controlled 4-output regulator
+
+Required properties:
+- compatible: "lltc,ltc3562"
+- reg: I2C slave address
+
+Required child node:
+- regulators: Contains optional regulator child nodes R400B, R600B, R400A
+ and R600A specifying the initialization data as documented in
+ Documentation/devicetree/bindings/regulator/regulator.txt.
+
+Each regulator is defined using the standard binding for regulators. The
+nodes for R400A and R600A additionally need to specify the resistor values of
+their external feedback voltage dividers:
+
+Required properties (A-type only):
+- lltc,fb-voltage-divider: An array of two integers containing the resistor
+ values R1 and R2 of the feedback voltage divider. Both values must remain in
+ the range 1..1000, only their quotient matters.
+
+Optional properties:
+- lltc,operating-mode: Operating mode as specified in table 3 of the datasheet.
+ This value is passed as the lower two bits of the first data byte, and sets
+ the operating mode: 0=Pulse-skip (default), 1=LDO, 2=Forced-burst, 3=Burst.
+
+Example:
+
+ ltc3562: ltc3562@65 {
+ compatible = "ltc3562";
+ reg = <0x65>;
+ regulators {
+ R400B_reg: R400B {
+ regulator-min-microvolt = <600000>;
+ regulator-max-microvolt = <3300000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ R600B_reg: R600B {
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ R400A_reg: R400A {
+ regulator-min-microvolt = <425000>;
+ regulator-max-microvolt = <8000000>;
+ lltc,fb-voltage-divider = <1, 1>;
+ };
+ R600A_reg: R600A {
+ regulator-min-microvolt = <425000>;
+ regulator-max-microvolt = <1800000>;
+ lltc,fb-voltage-divider = <316, 100>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ };
+ };
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 55d7b7b..4012601 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -300,6 +300,13 @@ config REGULATOR_LP8788
help
This driver supports LP8788 voltage regulator chip.

+config REGULATOR_LTC3562
+ tristate "LCT3562 quad output voltage regulator"
+ depends on I2C
+ help
+ This enables support for the LCT3562 quad output voltage regulator
+ controlled via I2C.
+
config REGULATOR_LTC3589
tristate "LTC3589 8-output voltage regulator"
depends on I2C
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 1029ed3..9a15146 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_REGULATOR_LP872X) += lp872x.o
obj-$(CONFIG_REGULATOR_LP8788) += lp8788-buck.o
obj-$(CONFIG_REGULATOR_LP8788) += lp8788-ldo.o
obj-$(CONFIG_REGULATOR_LP8755) += lp8755.o
+obj-$(CONFIG_REGULATOR_LTC3562) += ltc3562.o
obj-$(CONFIG_REGULATOR_LTC3589) += ltc3589.o
obj-$(CONFIG_REGULATOR_MAX14577) += max14577.o
obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o
diff --git a/drivers/regulator/ltc3562.c b/drivers/regulator/ltc3562.c
new file mode 100644
index 0000000..69963f8
--- /dev/null
+++ b/drivers/regulator/ltc3562.c
@@ -0,0 +1,337 @@
+/*
+ * Regulator driver for Linear Technology LTC3562
+ *
+ * Copyright (C) 2014 Topic Embedded Products
+ *
+ * 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.
+ */
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/slab.h>
+#include <linux/regulator/of_regulator.h>
+
+#define LTC3562_NUM_REGULATORS 4
+
+#define REGULATOR_TYPE_A_NUM_VOLTAGES 16
+#define REGULATOR_TYPE_A_MIN_UV 425000
+#define REGULATOR_TYPE_A_UV_STEP 25000
+
+#define REGULATOR_TYPE_B_NUM_VOLTAGES 128
+#define REGULATOR_TYPE_B_MIN_UV 600000
+#define REGULATOR_TYPE_B_UV_STEP 25000
+
+/* the LTC3562 does not have a register map, instead it receives a two-byte
+ * command set. The first byte sets the mask for the output(s) to be programmed
+ * and the second byte hold the "enable" bit and the DAC code. */
+struct ltc3562_status {
+ u8 addr_mode; /* sub-address byte: program mask an operating mode */
+ u8 enable_daccode; /* data byte: Enable bit and DAC code */
+};
+
+struct ltc3562 {
+ struct device *dev;
+ struct i2c_client *i2c;
+ struct mutex mutex;
+ struct regulator_dev *rdev[LTC3562_NUM_REGULATORS];
+ struct ltc3562_status rstatus[LTC3562_NUM_REGULATORS];
+};
+
+#define LTC3562_R400B_ID 0x00
+#define LTC3562_R600B_ID 0x01
+#define LTC3562_R400A_ID 0x02
+#define LTC3562_R600A_ID 0x03
+
+#define OPERATING_MODE_MASK 0x03
+
+#define PROGRAM_R400B_MASK 0x10
+#define PROGRAM_R600B_MASK 0x20
+#define PROGRAM_R400A_MASK 0x40
+#define PROGRAM_R600A_MASK 0x80
+
+#define OPERATING_MODE_PULSE_SKIP 0x00
+#define OPERATING_MODE_LDO 0x01
+#define OPERATING_MODE_FOCED_BURST 0x02
+#define OPERATING_MODE_BURST 0x03
+
+#define REGULATOR_ENABLE_BIT 0x80
+
+static int ltc3562_update(struct ltc3562 *ltc3562,
+ struct ltc3562_status *status)
+{
+ return i2c_smbus_write_byte_data(
+ ltc3562->i2c, status->addr_mode, status->enable_daccode);
+}
+
+static int ltc3562_regulator_enable(struct regulator_dev *dev)
+{
+ int ret;
+ struct ltc3562 *ltc3562 = rdev_get_drvdata(dev);
+ int id = rdev_get_id(dev);
+ struct ltc3562_status *status = &ltc3562->rstatus[id];
+
+ mutex_lock(&ltc3562->mutex);
+
+ status->enable_daccode |= REGULATOR_ENABLE_BIT;
+ ret = ltc3562_update(ltc3562, status);
+
+ mutex_unlock(&ltc3562->mutex);
+
+ return ret;
+}
+
+static int ltc3562_regulator_disable(struct regulator_dev *dev)
+{
+ int ret;
+ struct ltc3562 *ltc3562 = rdev_get_drvdata(dev);
+ int id = rdev_get_id(dev);
+ struct ltc3562_status *status = &ltc3562->rstatus[id];
+
+ mutex_lock(&ltc3562->mutex);
+
+ status->enable_daccode &= ~(REGULATOR_ENABLE_BIT);
+ ret = ltc3562_update(ltc3562, status);
+
+ mutex_unlock(&ltc3562->mutex);
+
+ return ret;
+}
+
+static int ltc3562_regulator_is_enabled(struct regulator_dev *dev)
+{
+ int ret;
+ struct ltc3562 *ltc3562 = rdev_get_drvdata(dev);
+ int id = rdev_get_id(dev);
+ struct ltc3562_status *status = &ltc3562->rstatus[id];
+
+ mutex_lock(&ltc3562->mutex);
+
+ ret = (status->enable_daccode & REGULATOR_ENABLE_BIT) ? 1 : 0;
+
+ mutex_unlock(&ltc3562->mutex);
+
+ return ret;
+}
+
+static int ltc3562_set_voltage_sel(struct regulator_dev *dev,
+ unsigned int selector)
+{
+ int ret;
+ struct ltc3562 *ltc3562 = rdev_get_drvdata(dev);
+ int id = rdev_get_id(dev);
+ struct ltc3562_status *status = &ltc3562->rstatus[id];
+
+ mutex_lock(&ltc3562->mutex);
+
+ status->enable_daccode =
+ (status->enable_daccode & REGULATOR_ENABLE_BIT) | selector;
+ ret = ltc3562_update(ltc3562, status);
+
+ mutex_unlock(&ltc3562->mutex);
+
+ return ret;
+}
+
+static int ltc3562_get_voltage_sel(struct regulator_dev *dev)
+{
+ int ret;
+ struct ltc3562 *ltc3562 = rdev_get_drvdata(dev);
+ int id = rdev_get_id(dev);
+ struct ltc3562_status *status = &ltc3562->rstatus[id];
+
+ mutex_lock(&ltc3562->mutex);
+
+ ret = status->enable_daccode & ~(REGULATOR_ENABLE_BIT);
+
+ mutex_unlock(&ltc3562->mutex);
+
+ return ret;
+}
+
+static struct regulator_ops ltc3562_regulator_ops = {
+ .is_enabled = ltc3562_regulator_is_enabled,
+ .enable = ltc3562_regulator_enable,
+ .disable = ltc3562_regulator_disable,
+ .set_voltage_sel = ltc3562_set_voltage_sel,
+ .get_voltage_sel = ltc3562_get_voltage_sel,
+ .list_voltage = regulator_list_voltage_linear,
+ .map_voltage = regulator_map_voltage_linear,
+};
+
+static struct regulator_desc ltc3562_regulators[] = {
+ {
+ .name = "R400B",
+ .id = LTC3562_R400B_ID,
+ .ops = &ltc3562_regulator_ops,
+ .min_uV = REGULATOR_TYPE_B_MIN_UV,
+ .uV_step = REGULATOR_TYPE_B_UV_STEP,
+ .n_voltages = REGULATOR_TYPE_B_NUM_VOLTAGES,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ },
+ {
+ .name = "R600B",
+ .id = LTC3562_R600B_ID,
+ .ops = &ltc3562_regulator_ops,
+ .min_uV = REGULATOR_TYPE_B_MIN_UV,
+ .uV_step = REGULATOR_TYPE_B_UV_STEP,
+ .n_voltages = REGULATOR_TYPE_B_NUM_VOLTAGES,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ },
+ {
+ .name = "R400A",
+ .id = LTC3562_R400A_ID,
+ .ops = &ltc3562_regulator_ops,
+ .min_uV = REGULATOR_TYPE_A_MIN_UV,
+ .uV_step = REGULATOR_TYPE_A_UV_STEP,
+ .n_voltages = REGULATOR_TYPE_A_NUM_VOLTAGES,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ },
+ {
+ .name = "R600A",
+ .id = LTC3562_R600A_ID,
+ .ops = &ltc3562_regulator_ops,
+ .min_uV = REGULATOR_TYPE_A_MIN_UV,
+ .uV_step = REGULATOR_TYPE_A_UV_STEP,
+ .n_voltages = REGULATOR_TYPE_A_NUM_VOLTAGES,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ },
+};
+
+/* Write dummy data to detect presence of the physical device. */
+static int ltc3562_dummy_write(struct i2c_client *i2c)
+{
+ return i2c_smbus_write_byte_data(i2c, 0, 0);
+}
+
+static int ltc3562_i2c_probe(struct i2c_client *i2c,
+ const struct i2c_device_id *id)
+{
+ int i, error;
+ unsigned long uV;
+ struct ltc3562 *ltc3562;
+ struct regulator_config rconfig = { };
+ struct device_node *np_regulators, *np;
+ struct device_node *np_child;
+ u32 value;
+
+ ltc3562 = devm_kzalloc(&i2c->dev,
+ sizeof(struct ltc3562), GFP_KERNEL);
+ if (ltc3562 == NULL)
+ return -ENOMEM;
+
+ ltc3562->i2c = i2c;
+ i2c_set_clientdata(i2c, ltc3562);
+
+ mutex_init(&ltc3562->mutex);
+
+ if (ltc3562_dummy_write(i2c) < 0) {
+ dev_err(&i2c->dev,
+ "Could not find device LTC3562 on i2c bus\n");
+ return -ENODEV;
+ }
+
+ np = of_node_get(i2c->dev.of_node);
+ np_regulators = of_get_child_by_name(np, "regulators");
+
+ if (np_regulators == NULL) {
+ dev_err(&i2c->dev, "Could not find regulators node\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < LTC3562_NUM_REGULATORS; ++i) {
+ np_child = of_get_child_by_name(np_regulators,
+ ltc3562_regulators[i].name);
+ if (np_child == NULL)
+ continue;
+
+ if ((ltc3562_regulators[i].id == LTC3562_R400A_ID) ||
+ (ltc3562_regulators[i].id == LTC3562_R600A_ID)) {
+ /* If regulator is A type get resistor values */
+ u32 vdiv[2];
+
+ error = of_property_read_u32_array(np_child,
+ "lltc,fb-voltage-divider", vdiv, 2);
+ if (error) {
+ dev_err(&i2c->dev,
+ "Failed to parse voltage divider: %d\n",
+ error);
+ return error;
+ }
+
+ uV = ltc3562_regulators[i].min_uV / 1000;
+ ltc3562_regulators[i].min_uV =
+ (uV + mult_frac(uV, vdiv[0], vdiv[1])) * 1000;
+
+ uV = ltc3562_regulators[i].uV_step / 1000;
+ ltc3562_regulators[i].uV_step =
+ (uV + mult_frac(uV, vdiv[0], vdiv[1])) * 1000;
+ }
+
+ /* Set operating mode and address mask */
+ error = of_property_read_u32(np_child,
+ "lltc,operating-mode", &value);
+ if (error || (value > OPERATING_MODE_BURST))
+ value = OPERATING_MODE_PULSE_SKIP;
+ ltc3562->rstatus[i].addr_mode =
+ (PROGRAM_R400B_MASK << i) | value;
+
+ rconfig.dev = &i2c->dev;
+ rconfig.init_data =
+ of_get_regulator_init_data(&i2c->dev, np_child);
+ rconfig.driver_data = ltc3562;
+ rconfig.of_node = np_child;
+
+ ltc3562->rdev[i] = devm_regulator_register(&i2c->dev,
+ &ltc3562_regulators[i], &rconfig);
+
+ if (IS_ERR(ltc3562->rdev[i])) {
+ error = PTR_ERR(ltc3562->rdev[i]);
+ dev_err(&i2c->dev,
+ "could not register regulator, Error %d\n",
+ error);
+ }
+ }
+
+ dev_dbg(&i2c->dev, "LTC3562 Driver loaded\n");
+
+ return 0;
+}
+
+static const struct of_device_id ltc3562_match_id[] = {
+ { .compatible = "lltc,ltc3562", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ltc3562_match_id);
+
+static const struct i2c_device_id ltc3562_i2c_id[] = {
+ { "ltc3562", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ltc3562_i2c_id);
+
+static struct i2c_driver ltc3562_i2c_driver = {
+ .driver = {
+ .name = "LTC3562",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(ltc3562_match_id),
+ },
+ .probe = ltc3562_i2c_probe,
+ .id_table = ltc3562_i2c_id,
+};
+
+module_i2c_driver(ltc3562_i2c_driver);
+
+MODULE_DESCRIPTION("LTC3562 Regulator Driver");
+MODULE_AUTHOR("auryn.verwegen@xxxxxxxx");
+MODULE_AUTHOR("mike.looijmans@xxxxxxxx");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5

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