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Subject[PATCH v2] regulator: Add LTC3676 support
Date
This patch adds support for the Linear Technology LTC3676
8-output I2C voltage regulator IC.

Cc: Jaffer Kapasi <jkapasi@linear.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
v2:
- use kernel coding style for switch statements
- change over-temp warning to dev_warn
- explicitly handle all modes for suspend_mode
- use the core support for parsing regulators and subnodes from OF
- remove the need for private struct with r1/r2
---
.../devicetree/bindings/regulator/ltc3676.txt | 94 +++++
drivers/regulator/Kconfig | 8 +
drivers/regulator/Makefile | 1 +
drivers/regulator/ltc3676.c | 420 +++++++++++++++++++++
4 files changed, 523 insertions(+)
create mode 100644 Documentation/devicetree/bindings/regulator/ltc3676.txt
create mode 100644 drivers/regulator/ltc3676.c

diff --git a/Documentation/devicetree/bindings/regulator/ltc3676.txt b/Documentation/devicetree/bindings/regulator/ltc3676.txt
new file mode 100644
index 0000000..d4eb366
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/ltc3676.txt
@@ -0,0 +1,94 @@
+Linear Technology LTC3676 8-output regulators
+
+Required properties:
+- compatible: "lltc,ltc3676"
+- reg: I2C slave address
+
+Required child node:
+- regulators: Contains eight regulator child nodes sw1, sw2, sw3, sw4,
+ ldo1, ldo2, ldo3, and ldo4, 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 sw1, sw2, sw3, sw4, ldo1, ldo2 and ldo4 additionally need to specify
+the resistor values of their external feedback voltage dividers:
+
+Required properties (not on ldo3):
+- lltc,fb-voltage-divider: An array of two integers containing the resistor
+ values R1 and R2 of the feedback voltage divider in ohms.
+
+Regulators sw1, sw2, sw3, sw4 can regulate the feedback reference from:
+412.5mV to 800mV in 12.5 mV steps. The output voltage thus ranges between
+0.4125 * (1 + R1/R2) V and 0.8 * (1 + R1/R2) V.
+
+Regulators ldo1, ldo2, and ldo4 have a fixed 0.725 V reference and thus output
+0.725 * (1 + R1/R2) V. The ldo3 regulator is fixed to 1.8 V. The ldo1 standby
+regulator can not be disabled and thus should have the regulator-always-on
+property set.
+
+Example:
+
+ ltc3676: pmic@3c {
+ compatible = "lltc,ltc3676";
+ reg = <0x3c>;
+
+ regulators {
+ sw1_reg: sw1 {
+ regulator-min-microvolt = <674400>;
+ regulator-max-microvolt = <1308000>;
+ lltc,fb-voltage-divider = <127000 200000>;
+ regulator-ramp-delay = <7000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+
+ sw2_reg: sw2 {
+ regulator-min-microvolt = <1033310>;
+ regulator-max-microvolt = <200400>;
+ lltc,fb-voltage-divider = <301000 200000>;
+ regulator-ramp-delay = <7000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+
+ sw3_reg: sw3 {
+ regulator-min-microvolt = <674400>;
+ regulator-max-microvolt = <130800>;
+ lltc,fb-voltage-divider = <127000 200000>;
+ regulator-ramp-delay = <7000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+
+ sw4_reg: sw4 {
+ regulator-min-microvolt = <868310>;
+ regulator-max-microvolt = <168400>;
+ lltc,fb-voltage-divider = <221000 200000>;
+ regulator-ramp-delay = <7000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+
+ ldo2_reg: ldo2 {
+ regulator-min-microvolt = <2490375>;
+ regulator-max-microvolt = <2490375>;
+ lltc,fb-voltage-divider = <487000 200000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+
+ ldo3_reg: ldo3 {
+ regulator-min-microvolt = <1800000>;
+ regulator-max-microvolt = <1800000>;
+ regulator-boot-on;
+ };
+
+ ldo4_reg: ldo4 {
+ regulator-min-microvolt = <3023250>;
+ regulator-max-microvolt = <3023250>;
+ lltc,fb-voltage-divider = <634000 200000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ };
+ };
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 6c88e31..527bd6a 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -353,6 +353,14 @@ config REGULATOR_LTC3589
This enables support for the LTC3589, LTC3589-1, and LTC3589-2
8-output regulators controlled via I2C.

+config REGULATOR_LTC3676
+ tristate "LTC3676 8-output voltage regulator"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ This enables support for the LTC3676
+ 8-output regulators controlled via I2C.
+
config REGULATOR_MAX14577
tristate "Maxim 14577/77836 regulator"
depends on MFD_MAX14577
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index f3da9ee..2142a5d 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_REGULATOR_LP8788) += lp8788-buck.o
obj-$(CONFIG_REGULATOR_LP8788) += lp8788-ldo.o
obj-$(CONFIG_REGULATOR_LP8755) += lp8755.o
obj-$(CONFIG_REGULATOR_LTC3589) += ltc3589.o
+obj-$(CONFIG_REGULATOR_LTC3676) += ltc3676.o
obj-$(CONFIG_REGULATOR_MAX14577) += max14577-regulator.o
obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o
obj-$(CONFIG_REGULATOR_MAX77620) += max77620-regulator.o
diff --git a/drivers/regulator/ltc3676.c b/drivers/regulator/ltc3676.c
new file mode 100644
index 0000000..e2b476c
--- /dev/null
+++ b/drivers/regulator/ltc3676.c
@@ -0,0 +1,420 @@
+/*
+ * Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
+ *
+ * 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.
+ *
+ */
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+#define DRIVER_NAME "ltc3676"
+
+/* LTC3676 Registers */
+#define LTC3676_BUCK1 0x01
+#define LTC3676_BUCK2 0x02
+#define LTC3676_BUCK3 0x03
+#define LTC3676_BUCK4 0x04
+#define LTC3676_LDOA 0x05
+#define LTC3676_LDOB 0x06
+#define LTC3676_SQD1 0x07
+#define LTC3676_SQD2 0x08
+#define LTC3676_CNTRL 0x09
+#define LTC3676_DVB1A 0x0A
+#define LTC3676_DVB1B 0x0B
+#define LTC3676_DVB2A 0x0C
+#define LTC3676_DVB2B 0x0D
+#define LTC3676_DVB3A 0x0E
+#define LTC3676_DVB3B 0x0F
+#define LTC3676_DVB4A 0x10
+#define LTC3676_DVB4B 0x11
+#define LTC3676_MSKIRQ 0x12
+#define LTC3676_MSKPG 0x13
+#define LTC3676_USER 0x14
+#define LTC3676_IRQSTAT 0x15
+#define LTC3676_PGSTATL 0x16
+#define LTC3676_PGSTATRT 0x17
+#define LTC3676_HRST 0x1E
+#define LTC3676_CLIRQ 0x1F
+
+#define LTC3676_DVBxA_REF_SELECT BIT(5)
+
+#define LTC3676_IRQSTAT_PGOOD_TIMEOUT BIT(3)
+#define LTC3676_IRQSTAT_UNDERVOLT_WARN BIT(4)
+#define LTC3676_IRQSTAT_UNDERVOLT_FAULT BIT(5)
+#define LTC3676_IRQSTAT_THERMAL_WARN BIT(6)
+#define LTC3676_IRQSTAT_THERMAL_FAULT BIT(7)
+
+enum ltc3676_reg {
+ LTC3676_SW1,
+ LTC3676_SW2,
+ LTC3676_SW3,
+ LTC3676_SW4,
+ LTC3676_LDO1,
+ LTC3676_LDO2,
+ LTC3676_LDO3,
+ LTC3676_LDO4,
+ LTC3676_NUM_REGULATORS,
+};
+
+struct ltc3676 {
+ struct regmap *regmap;
+ struct device *dev;
+ struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
+ struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
+};
+
+static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
+{
+ struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
+ struct device *dev = ltc3676->dev;
+ int dcdc = rdev_get_id(rdev);
+ int sel;
+
+ dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
+ sel = regulator_map_voltage_linear(rdev, uV, uV);
+ if (sel < 0)
+ return sel;
+
+ /* DVBB register follows right after the corresponding DVBA register */
+ return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
+ rdev->desc->vsel_mask, sel);
+}
+
+static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
+ unsigned int mode)
+{
+ struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
+ struct device *dev = ltc3676->dev;
+ int mask, val;
+ int dcdc = rdev_get_id(rdev);
+
+ dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
+
+ mask = LTC3676_DVBxA_REF_SELECT;
+ switch (mode) {
+ case REGULATOR_MODE_STANDBY:
+ val = 0; /* select DVBxA */
+ break;
+ case REGULATOR_MODE_NORMAL:
+ val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
+ break;
+ default:
+ dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
+ rdev->desc->name, mode);
+ return -EINVAL;
+ }
+
+ return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
+ mask, val);
+}
+
+static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
+{
+ uint64_t tmp;
+ if (uV == 0)
+ return 0;
+ tmp = (uint64_t)uV * r1;
+ do_div(tmp, r2);
+ return uV + (unsigned int)tmp;
+}
+
+static int ltc3676_of_parse_cb(struct device_node *np,
+ const struct regulator_desc *desc,
+ struct regulator_config *config)
+{
+ struct ltc3676 *ltc3676 = config->driver_data;
+ struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
+ u32 r[2];
+ int ret;
+
+ /* LDO3 has a fixed output */
+ if (desc->id == LTC3676_LDO3)
+ return 0;
+
+ ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
+ if (ret) {
+ dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
+ ret);
+ return ret;
+ }
+
+ rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
+ rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
+ rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
+
+ return 0;
+}
+
+/* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
+static struct regulator_ops ltc3676_linear_regulator_ops = {
+ .enable = regulator_enable_regmap,
+ .disable = regulator_disable_regmap,
+ .is_enabled = regulator_is_enabled_regmap,
+ .list_voltage = regulator_list_voltage_linear,
+ .set_voltage_sel = regulator_set_voltage_sel_regmap,
+ .get_voltage_sel = regulator_get_voltage_sel_regmap,
+ .set_suspend_voltage = ltc3676_set_suspend_voltage,
+ .set_suspend_mode = ltc3676_set_suspend_mode,
+};
+
+/* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
+static struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
+};
+
+/* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
+static struct regulator_ops ltc3676_fixed_regulator_ops = {
+ .enable = regulator_enable_regmap,
+ .disable = regulator_disable_regmap,
+ .is_enabled = regulator_is_enabled_regmap,
+};
+
+#define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask) \
+ [LTC3676_ ## _id] = { \
+ .name = #_name, \
+ .of_match = of_match_ptr(#_name), \
+ .regulators_node = of_match_ptr("regulators"), \
+ .of_parse_cb = ltc3676_of_parse_cb, \
+ .n_voltages = (dvb_mask) + 1, \
+ .min_uV = (dvba_reg) ? 412500 : 0, \
+ .uV_step = (dvba_reg) ? 12500 : 0, \
+ .ramp_delay = (dvba_reg) ? 800 : 0, \
+ .fixed_uV = (dvb_mask) ? 0 : 725000, \
+ .ops = &ltc3676_ ## _ops ## _regulator_ops, \
+ .type = REGULATOR_VOLTAGE, \
+ .id = LTC3676_ ## _id, \
+ .owner = THIS_MODULE, \
+ .vsel_reg = (dvba_reg), \
+ .vsel_mask = (dvb_mask), \
+ .enable_reg = (en_reg), \
+ .enable_mask = (1 << en_bit), \
+ }
+
+#define LTC3676_LINEAR_REG(_id, _name, _en, _dvba) \
+ LTC3676_REG(_id, _name, linear, \
+ LTC3676_ ## _en, 7, \
+ LTC3676_ ## _dvba, 0x1f)
+
+#define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit) \
+ LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
+
+static struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
+ LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
+ LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
+ LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
+ LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
+ LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
+ LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
+ LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
+ LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
+};
+
+static bool ltc3676_writeable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case LTC3676_IRQSTAT:
+ case LTC3676_BUCK1:
+ case LTC3676_BUCK2:
+ case LTC3676_BUCK3:
+ case LTC3676_BUCK4:
+ case LTC3676_LDOA:
+ case LTC3676_LDOB:
+ case LTC3676_SQD1:
+ case LTC3676_SQD2:
+ case LTC3676_CNTRL:
+ case LTC3676_DVB1A:
+ case LTC3676_DVB1B:
+ case LTC3676_DVB2A:
+ case LTC3676_DVB2B:
+ case LTC3676_DVB3A:
+ case LTC3676_DVB3B:
+ case LTC3676_DVB4A:
+ case LTC3676_DVB4B:
+ case LTC3676_MSKIRQ:
+ case LTC3676_MSKPG:
+ case LTC3676_USER:
+ case LTC3676_HRST:
+ case LTC3676_CLIRQ:
+ return true;
+ }
+ return false;
+}
+
+static bool ltc3676_readable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case LTC3676_IRQSTAT:
+ case LTC3676_BUCK1:
+ case LTC3676_BUCK2:
+ case LTC3676_BUCK3:
+ case LTC3676_BUCK4:
+ case LTC3676_LDOA:
+ case LTC3676_LDOB:
+ case LTC3676_SQD1:
+ case LTC3676_SQD2:
+ case LTC3676_CNTRL:
+ case LTC3676_DVB1A:
+ case LTC3676_DVB1B:
+ case LTC3676_DVB2A:
+ case LTC3676_DVB2B:
+ case LTC3676_DVB3A:
+ case LTC3676_DVB3B:
+ case LTC3676_DVB4A:
+ case LTC3676_DVB4B:
+ case LTC3676_MSKIRQ:
+ case LTC3676_MSKPG:
+ case LTC3676_USER:
+ case LTC3676_HRST:
+ case LTC3676_CLIRQ:
+ return true;
+ }
+ return false;
+}
+
+static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case LTC3676_IRQSTAT:
+ case LTC3676_PGSTATL:
+ case LTC3676_PGSTATRT:
+ return true;
+ }
+ return false;
+}
+
+static const struct regmap_config ltc3676_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .writeable_reg = ltc3676_writeable_reg,
+ .readable_reg = ltc3676_readable_reg,
+ .volatile_reg = ltc3676_volatile_reg,
+ .max_register = LTC3676_CLIRQ,
+ .use_single_rw = true,
+ .cache_type = REGCACHE_RBTREE,
+};
+
+static irqreturn_t ltc3676_isr(int irq, void *dev_id)
+{
+ struct ltc3676 *ltc3676 = dev_id;
+ struct device *dev = ltc3676->dev;
+ unsigned int i, irqstat, event;
+
+ regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
+
+ dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
+ if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
+ dev_warn(dev, "Over-temperature Warning\n");
+ event = REGULATOR_EVENT_OVER_TEMP;
+ for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
+ regulator_notifier_call_chain(ltc3676->regulators[i],
+ event, NULL);
+ }
+
+ if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
+ dev_info(dev, "Undervoltage Warning\n");
+ event = REGULATOR_EVENT_UNDER_VOLTAGE;
+ for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
+ regulator_notifier_call_chain(ltc3676->regulators[i],
+ event, NULL);
+ }
+
+ /* Clear warning condition */
+ regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
+
+ return IRQ_HANDLED;
+}
+
+static int ltc3676_regulator_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct regulator_init_data *init_data = dev_get_platdata(dev);
+ struct regulator_desc *descs;
+ struct ltc3676 *ltc3676;
+ int i, ret;
+
+ ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
+ if (!ltc3676)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, ltc3676);
+ ltc3676->dev = dev;
+
+ descs = ltc3676->regulator_descs;
+ memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
+ descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
+
+ ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
+ if (IS_ERR(ltc3676->regmap)) {
+ ret = PTR_ERR(ltc3676->regmap);
+ dev_err(dev, "failed to initialize regmap: %d\n", ret);
+ return ret;
+ }
+
+ for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
+ struct regulator_desc *desc = &ltc3676->regulator_descs[i];
+ struct regulator_config config = { };
+
+ if (init_data)
+ config.init_data = &init_data[i];
+
+ config.dev = dev;
+ config.driver_data = ltc3676;
+
+ ltc3676->regulators[i] = devm_regulator_register(dev, desc,
+ &config);
+ if (IS_ERR(ltc3676->regulators[i])) {
+ ret = PTR_ERR(ltc3676->regulators[i]);
+ dev_err(dev, "failed to register regulator %s: %d\n",
+ desc->name, ret);
+ return ret;
+ }
+ }
+
+ regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
+ if (client->irq) {
+ ret = devm_request_threaded_irq(dev, client->irq, NULL,
+ ltc3676_isr,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ client->name, ltc3676);
+ if (ret) {
+ dev_err(dev, "Failed to request IRQ: %d\n", ret);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id ltc3676_i2c_id[] = {
+ { "ltc3676" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
+
+static struct i2c_driver ltc3676_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ },
+ .probe = ltc3676_regulator_probe,
+ .id_table = ltc3676_i2c_id,
+};
+module_i2c_driver(ltc3676_driver);
+
+MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
+MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC1376");
+MODULE_LICENSE("GPL v2");
--
1.9.1
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