regulator: Add LTC3589 support

This patch adds support for the Linear Technology LTC3589, LTC3589-1,
and LTC3589-2 8-output I2C voltage regulator ICs.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

3 files changed, 572 insertions, 0 deletions

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 903eb37f047..5599a61bd88 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -265,6 +265,12 @@ config REGULATOR_LP8788
 	help
 	  This driver supports LP8788 voltage regulator chip.
 
+config REGULATOR_LTC3589
+	bool "LTC3589 8-output voltage regulator"
+	help
+	  This enables support for the LTC3589, LTC3589-1, and LTC3589-2
+	  8-output regulators controlled via I2C.
+
 config REGULATOR_MAX14577
 	tristate "Maxim 14577 regulator"
 	depends on MFD_MAX14577
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 12ef277a48b..16d429ba8ba 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -37,6 +37,7 @@ 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-$(CONFIG_REGULATOR_LTC3589) += ltc3589.o
 obj-$(CONFIG_REGULATOR_MAX14577) += max14577.o
 obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o
 obj-$(CONFIG_REGULATOR_MAX8649)	+= max8649.o
diff --git a/drivers/regulator/ltc3589.c b/drivers/regulator/ltc3589.c
new file mode 100644
index 00000000000..fef64ee3118
--- /dev/null
+++ b/drivers/regulator/ltc3589.c
@@ -0,0 +1,565 @@
+/*
+ * Linear Technology LTC3589,LTC3589-1 regulator support
+ *
+ * Copyright (c) 2014 Philipp Zabel <p.zabel@pengutronix.de>, Pengutronix
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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/of_regulator.h>
+
+#define DRIVER_NAME		"ltc3589"
+
+#define LTC3589_IRQSTAT		0x02
+#define LTC3589_SCR1		0x07
+#define LTC3589_OVEN		0x10
+#define LTC3589_SCR2		0x12
+#define LTC3589_PGSTAT		0x13
+#define LTC3589_VCCR		0x20
+#define LTC3589_CLIRQ		0x21
+#define LTC3589_B1DTV1		0x23
+#define LTC3589_B1DTV2		0x24
+#define LTC3589_VRRCR		0x25
+#define LTC3589_B2DTV1		0x26
+#define LTC3589_B2DTV2		0x27
+#define LTC3589_B3DTV1		0x29
+#define LTC3589_B3DTV2		0x2a
+#define LTC3589_L2DTV1		0x32
+#define LTC3589_L2DTV2		0x33
+
+#define LTC3589_IRQSTAT_PGOOD_TIMEOUT	BIT(3)
+#define LTC3589_IRQSTAT_UNDERVOLT_WARN	BIT(4)
+#define LTC3589_IRQSTAT_UNDERVOLT_FAULT	BIT(5)
+#define LTC3589_IRQSTAT_THERMAL_WARN	BIT(6)
+#define LTC3589_IRQSTAT_THERMAL_FAULT	BIT(7)
+
+#define LTC3589_OVEN_SW1		BIT(0)
+#define LTC3589_OVEN_SW2		BIT(1)
+#define LTC3589_OVEN_SW3		BIT(2)
+#define LTC3589_OVEN_BB_OUT		BIT(3)
+#define LTC3589_OVEN_LDO2		BIT(4)
+#define LTC3589_OVEN_LDO3		BIT(5)
+#define LTC3589_OVEN_LDO4		BIT(6)
+#define LTC3589_OVEN_SW_CTRL		BIT(7)
+
+#define LTC3589_VCCR_SW1_GO		BIT(0)
+#define LTC3589_VCCR_SW2_GO		BIT(2)
+#define LTC3589_VCCR_SW3_GO		BIT(4)
+#define LTC3589_VCCR_LDO2_GO		BIT(6)
+
+enum ltc3589_variant {
+	LTC3589,
+	LTC3589_1,
+	LTC3589_2,
+};
+
+enum ltc3589_reg {
+	LTC3589_SW1,
+	LTC3589_SW2,
+	LTC3589_SW3,
+	LTC3589_BB_OUT,
+	LTC3589_LDO1,
+	LTC3589_LDO2,
+	LTC3589_LDO3,
+	LTC3589_LDO4,
+	LTC3589_NUM_REGULATORS,
+};
+
+struct ltc3589_regulator {
+	struct regulator_desc desc;
+
+	/* External feedback voltage divider */
+	unsigned int r1;
+	unsigned int r2;
+};
+
+struct ltc3589 {
+	struct regmap *regmap;
+	struct device *dev;
+	enum ltc3589_variant variant;
+	struct ltc3589_regulator regulator_descs[LTC3589_NUM_REGULATORS];
+	struct regulator_dev *regulators[LTC3589_NUM_REGULATORS];
+};
+
+static const int ltc3589_ldo4[] = {
+	2800000, 2500000, 1800000, 3300000,
+};
+
+static const int ltc3589_12_ldo4[] = {
+	1200000, 1800000, 2500000, 3200000,
+};
+
+static int ltc3589_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
+{
+	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
+	int sel, shift;
+
+	if (unlikely(ramp_delay <= 0))
+		return -EINVAL;
+
+	/* VRRCR slew rate offsets are the same as VCCR go bit offsets */
+	shift = ffs(rdev->desc->apply_bit) - 1;
+
+	/* The slew rate can be set to 0.88, 1.75, 3.5, or 7 mV/uS */
+	for (sel = 0; sel < 4; sel++) {
+		if ((880 << sel) >= ramp_delay) {
+			return regmap_update_bits(ltc3589->regmap,
+						  LTC3589_VRRCR,
+						  0x3 << shift, sel << shift);
+		}
+	}
+	return -EINVAL;
+}
+
+static int ltc3589_set_suspend_voltage(struct regulator_dev *rdev, int uV)
+{
+	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
+	int sel;
+
+	sel = regulator_map_voltage_linear(rdev, uV, uV);
+	if (sel < 0)
+		return sel;
+
+	/* DTV2 register follows right after the corresponding DTV1 register */
+	return regmap_update_bits(ltc3589->regmap, rdev->desc->vsel_reg + 1,
+				  rdev->desc->vsel_mask, sel);
+}
+
+static int ltc3589_set_suspend_mode(struct regulator_dev *rdev,
+				    unsigned int mode)
+{
+	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
+	int mask, bit = 0;
+
+	/* VCCR reference selects are right next to the VCCR go bits */
+	mask = rdev->desc->apply_bit << 1;
+
+	if (mode == REGULATOR_MODE_STANDBY)
+		bit = mask;	/* Select DTV2 */
+
+	mask |= rdev->desc->apply_bit;
+	bit |= rdev->desc->apply_bit;
+	return regmap_update_bits(ltc3589->regmap, LTC3589_VCCR, mask, bit);
+}
+
+static int ltc3589_list_voltage_fixed(struct regulator_dev *rdev,
+				      unsigned int selector)
+{
+	if (selector)
+		return -EINVAL;
+
+	return rdev->desc->fixed_uV;
+}
+
+/* SW1, SW2, SW3, LDO2 */
+static struct regulator_ops ltc3589_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_ramp_delay = ltc3589_set_ramp_delay,
+	.set_voltage_time_sel = regulator_set_voltage_time_sel,
+	.set_suspend_voltage = ltc3589_set_suspend_voltage,
+	.set_suspend_mode = ltc3589_set_suspend_mode,
+};
+
+/* BB_OUT, LDO3 */
+static struct regulator_ops ltc3589_fixed_regulator_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.list_voltage = ltc3589_list_voltage_fixed,
+};
+
+/* LDO1 */
+static struct regulator_ops ltc3589_standby_regulator_ops = {
+	.list_voltage = ltc3589_list_voltage_fixed,
+};
+
+/* LDO4 */
+static struct regulator_ops ltc3589_table_regulator_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.list_voltage = regulator_list_voltage_table,
+	.set_voltage_sel = regulator_set_voltage_sel_regmap,
+	.get_voltage_sel = regulator_get_voltage_sel_regmap,
+};
+
+
+#define LTC3589_REG(_name, _ops, en_bit, dtv1_reg, dtv_mask, go_bit)	\
+	[LTC3589_ ## _name] = {						\
+		.desc = {						\
+			.name = #_name,					\
+			.n_voltages = (dtv_mask) + 1,			\
+			.min_uV = (go_bit) ? 362500 : 0,		\
+			.uV_step = (go_bit) ? 12500 : 0,		\
+			.ramp_delay = (go_bit) ? 1750 : 0,		\
+			.fixed_uV = (dtv_mask) ? 0 : 800000,		\
+			.ops = &ltc3589_ ## _ops ## _regulator_ops,	\
+			.type = REGULATOR_VOLTAGE,			\
+			.id = LTC3589_ ## _name,			\
+			.owner = THIS_MODULE,				\
+			.vsel_reg = (dtv1_reg),			\
+			.vsel_mask = (dtv_mask),			\
+			.apply_reg = (go_bit) ? LTC3589_VCCR : 0,	\
+			.apply_bit = (go_bit),				\
+			.enable_reg = (en_bit) ? LTC3589_OVEN : 0,	\
+			.enable_mask = (en_bit),			\
+		},							\
+	}
+
+#define LTC3589_LINEAR_REG(_name, _dtv1)				\
+	LTC3589_REG(_name, linear, LTC3589_OVEN_ ## _name,		\
+		    LTC3589_ ## _dtv1, 0x1f,				\
+		    LTC3589_VCCR_ ## _name ## _GO)
+
+#define LTC3589_FIXED_REG(_name) \
+	LTC3589_REG(_name, fixed, LTC3589_OVEN_ ## _name, 0, 0, 0)
+
+static struct ltc3589_regulator ltc3589_regulators[LTC3589_NUM_REGULATORS] = {
+	LTC3589_LINEAR_REG(SW1, B1DTV1),
+	LTC3589_LINEAR_REG(SW2, B2DTV1),
+	LTC3589_LINEAR_REG(SW3, B3DTV1),
+	LTC3589_FIXED_REG(BB_OUT),
+	LTC3589_REG(LDO1, standby, 0, 0, 0, 0),
+	LTC3589_LINEAR_REG(LDO2, L2DTV1),
+	LTC3589_FIXED_REG(LDO3),
+	LTC3589_REG(LDO4, table, LTC3589_OVEN_LDO4, LTC3589_L2DTV2, 0x60, 0),
+};
+
+#ifdef CONFIG_OF
+static struct of_regulator_match ltc3589_matches[LTC3589_NUM_REGULATORS] = {
+	{ .name = "sw1",    },
+	{ .name = "sw2",    },
+	{ .name = "sw3",    },
+	{ .name = "bb-out", },
+	{ .name = "ldo1",   }, /* standby */
+	{ .name = "ldo2",   },
+	{ .name = "ldo3",   },
+	{ .name = "ldo4",   },
+};
+
+static int ltc3589_parse_regulators_dt(struct ltc3589 *ltc3589)
+{
+	struct device *dev = ltc3589->dev;
+	struct device_node *node;
+	int i, ret;
+
+	node = of_find_node_by_name(dev->of_node, "regulators");
+	if (!node) {
+		dev_err(dev, "regulators node not found\n");
+		return -EINVAL;
+	}
+
+	ret = of_regulator_match(dev, node, ltc3589_matches,
+				 ARRAY_SIZE(ltc3589_matches));
+	of_node_put(node);
+	if (ret < 0) {
+		dev_err(dev, "Error parsing regulator init data: %d\n", ret);
+		return ret;
+	}
+	if (ret != LTC3589_NUM_REGULATORS) {
+		dev_err(dev, "Only %d regulators described in device tree\n",
+			ret);
+		return -EINVAL;
+	}
+
+	/* Parse feedback voltage dividers. LDO3 and LDO4 don't have them */
+	for (i = 0; i < LTC3589_LDO3; i++) {
+		struct ltc3589_regulator *desc = &ltc3589->regulator_descs[i];
+		struct device_node *np = ltc3589_matches[i].of_node;
+		u32 vdiv[2];
+
+		ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider",
+						 vdiv, 2);
+		if (ret) {
+			dev_err(dev, "Failed to parse voltage divider: %d\n",
+				ret);
+			return ret;
+		}
+
+		desc->r1 = vdiv[0];
+		desc->r2 = vdiv[1];
+	}
+
+	return 0;
+}
+
+static inline struct regulator_init_data *match_init_data(int index)
+{
+	return ltc3589_matches[index].init_data;
+}
+
+static inline struct device_node *match_of_node(int index)
+{
+	return ltc3589_matches[index].of_node;
+}
+#else
+static inline int ltc3589_parse_regulators_dt(struct ltc3589 *ltc3589)
+{
+	return 0;
+}
+
+static inline struct regulator_init_data *match_init_data(int index)
+{
+	return NULL;
+}
+
+static inline struct device_node *match_of_node(int index)
+{
+	return NULL;
+}
+#endif
+
+static bool ltc3589_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTC3589_IRQSTAT:
+	case LTC3589_SCR1:
+	case LTC3589_OVEN:
+	case LTC3589_SCR2:
+	case LTC3589_VCCR:
+	case LTC3589_CLIRQ:
+	case LTC3589_B1DTV1:
+	case LTC3589_B1DTV2:
+	case LTC3589_VRRCR:
+	case LTC3589_B2DTV1:
+	case LTC3589_B2DTV2:
+	case LTC3589_B3DTV1:
+	case LTC3589_B3DTV2:
+	case LTC3589_L2DTV1:
+	case LTC3589_L2DTV2:
+		return true;
+	}
+	return false;
+}
+
+static bool ltc3589_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTC3589_IRQSTAT:
+	case LTC3589_SCR1:
+	case LTC3589_OVEN:
+	case LTC3589_SCR2:
+	case LTC3589_PGSTAT:
+	case LTC3589_VCCR:
+	case LTC3589_B1DTV1:
+	case LTC3589_B1DTV2:
+	case LTC3589_VRRCR:
+	case LTC3589_B2DTV1:
+	case LTC3589_B2DTV2:
+	case LTC3589_B3DTV1:
+	case LTC3589_B3DTV2:
+	case LTC3589_L2DTV1:
+	case LTC3589_L2DTV2:
+		return true;
+	}
+	return false;
+}
+
+static bool ltc3589_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTC3589_IRQSTAT:
+	case LTC3589_PGSTAT:
+		return true;
+	}
+	return false;
+}
+
+struct reg_default ltc3589_reg_defaults[] = {
+	{ LTC3589_SCR1,   0x00 },
+	{ LTC3589_OVEN,   0x00 },
+	{ LTC3589_SCR2,   0x00 },
+	{ LTC3589_VCCR,   0x00 },
+	{ LTC3589_B1DTV1, 0x19 },
+	{ LTC3589_B1DTV2, 0x19 },
+	{ LTC3589_VRRCR,  0xff },
+	{ LTC3589_B2DTV1, 0x19 },
+	{ LTC3589_B2DTV2, 0x19 },
+	{ LTC3589_B3DTV1, 0x19 },
+	{ LTC3589_B3DTV2, 0x19 },
+	{ LTC3589_L2DTV1, 0x19 },
+	{ LTC3589_L2DTV2, 0x19 },
+};
+
+static const struct regmap_config ltc3589_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.writeable_reg = ltc3589_writeable_reg,
+	.readable_reg = ltc3589_readable_reg,
+	.volatile_reg = ltc3589_volatile_reg,
+	.max_register = LTC3589_L2DTV2,
+	.reg_defaults = ltc3589_reg_defaults,
+	.num_reg_defaults = ARRAY_SIZE(ltc3589_reg_defaults),
+	.use_single_rw = true,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+
+static irqreturn_t ltc3589_isr(int irq, void *dev_id)
+{
+	struct ltc3589 *ltc3589 = dev_id;
+	unsigned int i, irqstat, event;
+
+	regmap_read(ltc3589->regmap, LTC3589_IRQSTAT, &irqstat);
+
+	if (irqstat & LTC3589_IRQSTAT_THERMAL_WARN) {
+		event = REGULATOR_EVENT_OVER_TEMP;
+		for (i = 0; i < LTC3589_NUM_REGULATORS; i++)
+			regulator_notifier_call_chain(ltc3589->regulators[i],
+						      event, NULL);
+	}
+
+	if (irqstat & LTC3589_IRQSTAT_UNDERVOLT_WARN) {
+		event = REGULATOR_EVENT_UNDER_VOLTAGE;
+		for (i = 0; i < LTC3589_NUM_REGULATORS; i++)
+			regulator_notifier_call_chain(ltc3589->regulators[i],
+						      event, NULL);
+	}
+
+	/* Clear warning condition */
+	regmap_write(ltc3589->regmap, LTC3589_CLIRQ, 0);
+
+	return IRQ_HANDLED;
+}
+
+static inline unsigned int ltc3589_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 void ltc3589_apply_fb_voltage_divider(struct ltc3589_regulator *rdesc)
+{
+	struct regulator_desc *desc = &rdesc->desc;
+
+	if (!rdesc->r1 || !rdesc->r2)
+		return;
+
+	desc->min_uV = ltc3589_scale(desc->min_uV, rdesc->r1, rdesc->r2);
+	desc->uV_step = ltc3589_scale(desc->uV_step, rdesc->r1, rdesc->r2);
+	desc->fixed_uV = ltc3589_scale(desc->fixed_uV, rdesc->r1, rdesc->r2);
+}
+
+static int ltc3589_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ltc3589_regulator *descs;
+	struct ltc3589 *ltc3589;
+	int i, ret;
+
+	ltc3589 = devm_kzalloc(dev, sizeof(*ltc3589), GFP_KERNEL);
+	if (!ltc3589)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, ltc3589);
+	ltc3589->variant = id->driver_data;
+	ltc3589->dev = dev;
+
+	descs = ltc3589->regulator_descs;
+	memcpy(descs, ltc3589_regulators, sizeof(ltc3589_regulators));
+	if (ltc3589->variant == LTC3589) {
+		descs[LTC3589_LDO3].desc.fixed_uV = 1800000;
+		descs[LTC3589_LDO4].desc.volt_table = ltc3589_ldo4;
+	} else {
+		descs[LTC3589_LDO3].desc.fixed_uV = 2800000;
+		descs[LTC3589_LDO4].desc.volt_table = ltc3589_12_ldo4;
+	}
+
+	ltc3589->regmap = devm_regmap_init_i2c(client, &ltc3589_regmap_config);
+	if (IS_ERR(ltc3589->regmap)) {
+		ret = PTR_ERR(ltc3589->regmap);
+		dev_err(dev, "failed to initialize regmap: %d\n", ret);
+		return ret;
+	}
+
+	ret = ltc3589_parse_regulators_dt(ltc3589);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < LTC3589_NUM_REGULATORS; i++) {
+		struct ltc3589_regulator *rdesc = &ltc3589->regulator_descs[i];
+		struct regulator_desc *desc = &rdesc->desc;
+		struct regulator_init_data *init_data;
+		struct regulator_config config = { };
+
+		init_data = match_init_data(i);
+
+		if (i < LTC3589_LDO3)
+			ltc3589_apply_fb_voltage_divider(rdesc);
+
+		config.dev = dev;
+		config.init_data = init_data;
+		config.driver_data = ltc3589;
+		config.of_node = match_of_node(i);
+
+		ltc3589->regulators[i] = devm_regulator_register(dev, desc,
+								 &config);
+		if (IS_ERR(ltc3589->regulators[i])) {
+			ret = PTR_ERR(ltc3589->regulators[i]);
+			dev_err(dev, "failed to register regulator %s: %d\n",
+				desc->name, ret);
+			return ret;
+		}
+	}
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL, ltc3589_isr,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					client->name, ltc3589);
+	if (ret) {
+		dev_err(dev, "Failed to request IRQ: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct i2c_device_id ltc3589_i2c_id[] = {
+	{ "ltc3589",   LTC3589   },
+	{ "ltc3589-1", LTC3589_1 },
+	{ "ltc3589-2", LTC3589_2 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc3589_i2c_id);
+
+static struct i2c_driver ltc3589_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = ltc3589_probe,
+	.id_table = ltc3589_i2c_id,
+};
+module_i2c_driver(ltc3589_driver);
+
+MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
+MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3589(-1,2)");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("i2c:ltc3589");