regulator: AB3100 support

This adds support for the regulators found in the AB3100
Mixed-Signal IC.

It further also defines platform data for the ST-Ericsson
U300 platform and extends the AB3100 MFD driver so that
platform/board data with regulation constraints and an init
function can be passed down all the way from the board to
the regulators.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 694 insertions, 0 deletions

diff --git a/drivers/regulator/ab3100.c b/drivers/regulator/ab3100.c
new file mode 100644
index 000000000000..156979d1f41e
--- /dev/null
+++ b/drivers/regulator/ab3100.c
@@ -0,0 +1,694 @@
+/*
+ * drivers/regulator/ab3100.c
+ *
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * Low-level control of the AB3100 IC Low Dropout (LDO)
+ * regulators, external regulator and buck converter
+ * Author: Mattias Wallin <mattias.wallin@stericsson.com>
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/mfd/ab3100.h>
+
+/* LDO registers and some handy masking definitions for AB3100 */
+#define AB3100_LDO_A		0x40
+#define AB3100_LDO_C		0x41
+#define AB3100_LDO_D		0x42
+#define AB3100_LDO_E		0x43
+#define AB3100_LDO_E_SLEEP	0x44
+#define AB3100_LDO_F		0x45
+#define AB3100_LDO_G		0x46
+#define AB3100_LDO_H		0x47
+#define AB3100_LDO_H_SLEEP_MODE	0
+#define AB3100_LDO_H_SLEEP_EN	2
+#define AB3100_LDO_ON		4
+#define AB3100_LDO_H_VSEL_AC	5
+#define AB3100_LDO_K		0x48
+#define AB3100_LDO_EXT		0x49
+#define AB3100_BUCK		0x4A
+#define AB3100_BUCK_SLEEP	0x4B
+#define AB3100_REG_ON_MASK	0x10
+
+/**
+ * struct ab3100_regulator
+ * A struct passed around the individual regulator functions
+ * @platform_device: platform device holding this regulator
+ * @ab3100: handle to the AB3100 parent chip
+ * @plfdata: AB3100 platform data passed in at probe time
+ * @regreg: regulator register number in the AB3100
+ * @fixed_voltage: a fixed voltage for this regulator, if this
+ *          0 the voltages array is used instead.
+ * @typ_voltages: an array of available typical voltages for
+ *          this regulator
+ * @voltages_len: length of the array of available voltages
+ */
+struct ab3100_regulator {
+	struct regulator_dev *rdev;
+	struct ab3100 *ab3100;
+	struct ab3100_platform_data *plfdata;
+	u8 regreg;
+	int fixed_voltage;
+	int const *typ_voltages;
+	u8 voltages_len;
+};
+
+/* The order in which registers are initialized */
+static const u8 ab3100_reg_init_order[AB3100_NUM_REGULATORS+2] = {
+	AB3100_LDO_A,
+	AB3100_LDO_C,
+	AB3100_LDO_E,
+	AB3100_LDO_E_SLEEP,
+	AB3100_LDO_F,
+	AB3100_LDO_G,
+	AB3100_LDO_H,
+	AB3100_LDO_K,
+	AB3100_LDO_EXT,
+	AB3100_BUCK,
+	AB3100_BUCK_SLEEP,
+	AB3100_LDO_D,
+};
+
+/* Preset (hardware defined) voltages for these regulators */
+#define LDO_A_VOLTAGE 2750000
+#define LDO_C_VOLTAGE 2650000
+#define LDO_D_VOLTAGE 2650000
+
+static const int const ldo_e_buck_typ_voltages[] = {
+	1800000,
+	1400000,
+	1300000,
+	1200000,
+	1100000,
+	1050000,
+	900000,
+};
+
+static const int const ldo_f_typ_voltages[] = {
+	1800000,
+	1400000,
+	1300000,
+	1200000,
+	1100000,
+	1050000,
+	2500000,
+	2650000,
+};
+
+static const int const ldo_g_typ_voltages[] = {
+	2850000,
+	2750000,
+	1800000,
+	1500000,
+};
+
+static const int const ldo_h_typ_voltages[] = {
+	2750000,
+	1800000,
+	1500000,
+	1200000,
+};
+
+static const int const ldo_k_typ_voltages[] = {
+	2750000,
+	1800000,
+};
+
+
+/* The regulator devices */
+static struct ab3100_regulator
+ab3100_regulators[AB3100_NUM_REGULATORS] = {
+	{
+		.regreg = AB3100_LDO_A,
+		.fixed_voltage = LDO_A_VOLTAGE,
+	},
+	{
+		.regreg = AB3100_LDO_C,
+		.fixed_voltage = LDO_C_VOLTAGE,
+	},
+	{
+		.regreg = AB3100_LDO_D,
+		.fixed_voltage = LDO_D_VOLTAGE,
+	},
+	{
+		.regreg = AB3100_LDO_E,
+		.typ_voltages = ldo_e_buck_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_e_buck_typ_voltages),
+	},
+	{
+		.regreg = AB3100_LDO_F,
+		.typ_voltages = ldo_f_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_f_typ_voltages),
+	},
+	{
+		.regreg = AB3100_LDO_G,
+		.typ_voltages = ldo_g_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_g_typ_voltages),
+	},
+	{
+		.regreg = AB3100_LDO_H,
+		.typ_voltages = ldo_h_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_h_typ_voltages),
+	},
+	{
+		.regreg = AB3100_LDO_K,
+		.typ_voltages = ldo_k_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_k_typ_voltages),
+	},
+	{
+		.regreg = AB3100_LDO_EXT,
+		/* No voltages for the external regulator */
+	},
+	{
+		.regreg = AB3100_BUCK,
+		.typ_voltages = ldo_e_buck_typ_voltages,
+		.voltages_len = ARRAY_SIZE(ldo_e_buck_typ_voltages),
+	},
+};
+
+/*
+ * General functions for enable, disable and is_enabled used for
+ * LDO: A,C,E,F,G,H,K,EXT and BUCK
+ */
+static int ab3100_enable_regulator(struct regulator_dev *reg)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	int err;
+	u8 regval;
+
+	err = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
+						&regval);
+	if (err) {
+		dev_warn(&reg->dev, "failed to get regid %d value\n",
+			 abreg->regreg);
+		return err;
+	}
+
+	/* The regulator is already on, no reason to go further */
+	if (regval & AB3100_REG_ON_MASK)
+		return 0;
+
+	regval |= AB3100_REG_ON_MASK;
+
+	err = ab3100_set_register_interruptible(abreg->ab3100, abreg->regreg,
+						regval);
+	if (err) {
+		dev_warn(&reg->dev, "failed to set regid %d value\n",
+			 abreg->regreg);
+		return err;
+	}
+
+	/* Per-regulator power on delay from spec */
+	switch (abreg->regreg) {
+	case AB3100_LDO_A: /* Fallthrough */
+	case AB3100_LDO_C: /* Fallthrough */
+	case AB3100_LDO_D: /* Fallthrough */
+	case AB3100_LDO_E: /* Fallthrough */
+	case AB3100_LDO_H: /* Fallthrough */
+	case AB3100_LDO_K:
+		udelay(200);
+		break;
+	case AB3100_LDO_F:
+		udelay(600);
+		break;
+	case AB3100_LDO_G:
+		udelay(400);
+		break;
+	case AB3100_BUCK:
+		mdelay(1);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int ab3100_disable_regulator(struct regulator_dev *reg)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	int err;
+	u8 regval;
+
+	/*
+	 * LDO D is a special regulator. When it is disabled, the entire
+	 * system is shut down. So this is handled specially.
+	 */
+	if (abreg->regreg == AB3100_LDO_D) {
+		int i;
+
+		dev_info(&reg->dev, "disabling LDO D - shut down system\n");
+		/*
+		 * Set regulators to default values, ignore any errors,
+		 * we're going DOWN
+		 */
+		for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
+			(void) ab3100_set_register_interruptible(abreg->ab3100,
+					ab3100_reg_init_order[i],
+					abreg->plfdata->reg_initvals[i]);
+		}
+
+		/* Setting LDO D to 0x00 cuts the power to the SoC */
+		return ab3100_set_register_interruptible(abreg->ab3100,
+							 AB3100_LDO_D, 0x00U);
+
+	}
+
+	/*
+	 * All other regulators are handled here
+	 */
+	err = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
+						&regval);
+	if (err) {
+		dev_err(&reg->dev, "unable to get register 0x%x\n",
+			abreg->regreg);
+		return err;
+	}
+	regval &= ~AB3100_REG_ON_MASK;
+	return ab3100_set_register_interruptible(abreg->ab3100, abreg->regreg,
+						 regval);
+}
+
+static int ab3100_is_enabled_regulator(struct regulator_dev *reg)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	u8 regval;
+	int err;
+
+	err = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
+						&regval);
+	if (err) {
+		dev_err(&reg->dev, "unable to get register 0x%x\n",
+			abreg->regreg);
+		return err;
+	}
+
+	return regval & AB3100_REG_ON_MASK;
+}
+
+static int ab3100_list_voltage_regulator(struct regulator_dev *reg,
+					 unsigned selector)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+
+	if (selector > abreg->voltages_len)
+		return -EINVAL;
+	return abreg->typ_voltages[selector];
+}
+
+static int ab3100_get_voltage_regulator(struct regulator_dev *reg)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	u8 regval;
+	int err;
+
+	/* Return the voltage for fixed regulators immediately */
+	if (abreg->fixed_voltage)
+		return abreg->fixed_voltage;
+
+	/*
+	 * For variable types, read out setting and index into
+	 * supplied voltage list.
+	 */
+	err = ab3100_get_register_interruptible(abreg->ab3100,
+						abreg->regreg, &regval);
+	if (err) {
+		dev_warn(&reg->dev,
+			 "failed to get regulator value in register %02x\n",
+			 abreg->regreg);
+		return err;
+	}
+
+	/* The 3 highest bits index voltages */
+	regval &= 0xE0;
+	regval >>= 5;
+
+	if (regval > abreg->voltages_len) {
+		dev_err(&reg->dev,
+			"regulator register %02x contains an illegal voltage setting\n",
+			abreg->regreg);
+		return -EINVAL;
+	}
+
+	return abreg->typ_voltages[regval];
+}
+
+static int ab3100_get_best_voltage_index(struct regulator_dev *reg,
+				   int min_uV, int max_uV)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	int i;
+	int bestmatch;
+	int bestindex;
+
+	/*
+	 * Locate the minimum voltage fitting the criteria on
+	 * this regulator. The switchable voltages are not
+	 * in strict falling order so we need to check them
+	 * all for the best match.
+	 */
+	bestmatch = INT_MAX;
+	bestindex = -1;
+	for (i = 0; i < abreg->voltages_len; i++) {
+		if (abreg->typ_voltages[i] <= max_uV &&
+		    abreg->typ_voltages[i] >= min_uV &&
+		    abreg->typ_voltages[i] < bestmatch) {
+			bestmatch = abreg->typ_voltages[i];
+			bestindex = i;
+		}
+	}
+
+	if (bestindex < 0) {
+		dev_warn(&reg->dev, "requested %d<=x<=%d uV, out of range!\n",
+			 min_uV, max_uV);
+		return -EINVAL;
+	}
+	return bestindex;
+}
+
+static int ab3100_set_voltage_regulator(struct regulator_dev *reg,
+					int min_uV, int max_uV)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	u8 regval;
+	int err;
+	int bestindex;
+
+	bestindex = ab3100_get_best_voltage_index(reg, min_uV, max_uV);
+	if (bestindex < 0)
+		return bestindex;
+
+	err = ab3100_get_register_interruptible(abreg->ab3100,
+						abreg->regreg, &regval);
+	if (err) {
+		dev_warn(&reg->dev,
+			 "failed to get regulator register %02x\n",
+			 abreg->regreg);
+		return err;
+	}
+
+	/* The highest three bits control the variable regulators */
+	regval &= ~0xE0;
+	regval |= (bestindex << 5);
+
+	err = ab3100_set_register_interruptible(abreg->ab3100,
+						abreg->regreg, regval);
+	if (err)
+		dev_warn(&reg->dev, "failed to set regulator register %02x\n",
+			abreg->regreg);
+
+	return err;
+}
+
+static int ab3100_set_suspend_voltage_regulator(struct regulator_dev *reg,
+						int uV)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+	u8 regval;
+	int err;
+	int bestindex;
+	u8 targetreg;
+
+	if (abreg->regreg == AB3100_LDO_E)
+		targetreg = AB3100_LDO_E_SLEEP;
+	else if (abreg->regreg == AB3100_BUCK)
+		targetreg = AB3100_BUCK_SLEEP;
+	else
+		return -EINVAL;
+
+	/* LDO E and BUCK have special suspend voltages you can set */
+	bestindex = ab3100_get_best_voltage_index(reg, uV, uV);
+
+	err = ab3100_get_register_interruptible(abreg->ab3100,
+						targetreg, &regval);
+	if (err) {
+		dev_warn(&reg->dev,
+			 "failed to get regulator register %02x\n",
+			 targetreg);
+		return err;
+	}
+
+	/* The highest three bits control the variable regulators */
+	regval &= ~0xE0;
+	regval |= (bestindex << 5);
+
+	err = ab3100_set_register_interruptible(abreg->ab3100,
+						targetreg, regval);
+	if (err)
+		dev_warn(&reg->dev, "failed to set regulator register %02x\n",
+			abreg->regreg);
+
+	return err;
+}
+
+/*
+ * The external regulator can just define a fixed voltage.
+ */
+static int ab3100_get_voltage_regulator_external(struct regulator_dev *reg)
+{
+	struct ab3100_regulator *abreg = reg->reg_data;
+
+	return abreg->plfdata->external_voltage;
+}
+
+static struct regulator_ops regulator_ops_fixed = {
+	.enable      = ab3100_enable_regulator,
+	.disable     = ab3100_disable_regulator,
+	.is_enabled  = ab3100_is_enabled_regulator,
+	.get_voltage = ab3100_get_voltage_regulator,
+};
+
+static struct regulator_ops regulator_ops_variable = {
+	.enable      = ab3100_enable_regulator,
+	.disable     = ab3100_disable_regulator,
+	.is_enabled  = ab3100_is_enabled_regulator,
+	.get_voltage = ab3100_get_voltage_regulator,
+	.set_voltage = ab3100_set_voltage_regulator,
+	.list_voltage = ab3100_list_voltage_regulator,
+};
+
+static struct regulator_ops regulator_ops_variable_sleepable = {
+	.enable      = ab3100_enable_regulator,
+	.disable     = ab3100_disable_regulator,
+	.is_enabled  = ab3100_is_enabled_regulator,
+	.get_voltage = ab3100_get_voltage_regulator,
+	.set_voltage = ab3100_set_voltage_regulator,
+	.set_suspend_voltage = ab3100_set_suspend_voltage_regulator,
+	.list_voltage = ab3100_list_voltage_regulator,
+};
+
+/*
+ * LDO EXT is an external regulator so it is really
+ * not possible to set any voltage locally here, AB3100
+ * is an on/off switch plain an simple. The external
+ * voltage is defined in the board set-up if any.
+ */
+static struct regulator_ops regulator_ops_external = {
+	.enable      = ab3100_enable_regulator,
+	.disable     = ab3100_disable_regulator,
+	.is_enabled  = ab3100_is_enabled_regulator,
+	.get_voltage = ab3100_get_voltage_regulator_external,
+};
+
+static struct regulator_desc
+ab3100_regulator_desc[AB3100_NUM_REGULATORS] = {
+	{
+		.name = "LDO_A",
+		.id   = AB3100_LDO_A,
+		.ops  = &regulator_ops_fixed,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_C",
+		.id   = AB3100_LDO_C,
+		.ops  = &regulator_ops_fixed,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_D",
+		.id   = AB3100_LDO_D,
+		.ops  = &regulator_ops_fixed,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_E",
+		.id   = AB3100_LDO_E,
+		.ops  = &regulator_ops_variable_sleepable,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_F",
+		.id   = AB3100_LDO_F,
+		.ops  = &regulator_ops_variable,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_G",
+		.id   = AB3100_LDO_G,
+		.ops  = &regulator_ops_variable,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_H",
+		.id   = AB3100_LDO_H,
+		.ops  = &regulator_ops_variable,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_K",
+		.id   = AB3100_LDO_K,
+		.ops  = &regulator_ops_variable,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "LDO_EXT",
+		.id   = AB3100_LDO_EXT,
+		.ops  = &regulator_ops_external,
+		.type = REGULATOR_VOLTAGE,
+	},
+	{
+		.name = "BUCK",
+		.id   = AB3100_BUCK,
+		.ops  = &regulator_ops_variable_sleepable,
+		.type = REGULATOR_VOLTAGE,
+	},
+};
+
+/*
+ * NOTE: the following functions are regulators pluralis - it is the
+ * binding to the AB3100 core driver and the parent platform device
+ * for all the different regulators.
+ */
+
+static int __init ab3100_regulators_probe(struct platform_device *pdev)
+{
+	struct ab3100_platform_data *plfdata = pdev->dev.platform_data;
+	struct ab3100 *ab3100 = platform_get_drvdata(pdev);
+	int err = 0;
+	u8 data;
+	int i;
+
+	/* Check chip state */
+	err = ab3100_get_register_interruptible(ab3100,
+						AB3100_LDO_D, &data);
+	if (err) {
+		dev_err(&pdev->dev, "could not read initial status of LDO_D\n");
+		return err;
+	}
+	if (data & 0x10)
+		dev_notice(&pdev->dev,
+			   "chip is already in active mode (Warm start)\n");
+	else
+		dev_notice(&pdev->dev,
+			   "chip is in inactive mode (Cold start)\n");
+
+	/* Set up regulators */
+	for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
+		err = ab3100_set_register_interruptible(ab3100,
+					ab3100_reg_init_order[i],
+					plfdata->reg_initvals[i]);
+		if (err) {
+			dev_err(&pdev->dev, "regulator initialization failed with error %d\n",
+				err);
+			return err;
+		}
+	}
+
+	if (err) {
+		dev_err(&pdev->dev,
+			"LDO D regulator initialization failed with error %d\n",
+			err);
+		return err;
+	}
+
+	/* Register the regulators */
+	for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
+		struct ab3100_regulator *reg = &ab3100_regulators[i];
+		struct regulator_dev *rdev;
+
+		/*
+		 * Initialize per-regulator struct.
+		 * Inherit platform data, this comes down from the
+		 * i2c boarddata, from the machine. So if you want to
+		 * see what it looks like for a certain machine, go
+		 * into the machine I2C setup.
+		 */
+		reg->ab3100 = ab3100;
+		reg->plfdata = plfdata;
+
+		/*
+		 * Register the regulator, pass around
+		 * the ab3100_regulator struct
+		 */
+		rdev = regulator_register(&ab3100_regulator_desc[i],
+					  &pdev->dev,
+					  &plfdata->reg_constraints[i],
+					  reg);
+
+		if (IS_ERR(rdev)) {
+			err = PTR_ERR(rdev);
+			dev_err(&pdev->dev,
+				"%s: failed to register regulator %s err %d\n",
+				__func__, ab3100_regulator_desc[i].name,
+				err);
+			i--;
+			/* remove the already registered regulators */
+			while (i > 0) {
+				regulator_unregister(ab3100_regulators[i].rdev);
+				i--;
+			}
+			return err;
+		}
+
+		/* Then set a pointer back to the registered regulator */
+		reg->rdev = rdev;
+	}
+
+	return 0;
+}
+
+static int __exit ab3100_regulators_remove(struct platform_device *pdev)
+{
+	int i;
+
+	for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
+		struct ab3100_regulator *reg = &ab3100_regulators[i];
+
+		regulator_unregister(reg->rdev);
+	}
+	return 0;
+}
+
+static struct platform_driver ab3100_regulators_driver = {
+	.driver = {
+		.name  = "ab3100-regulators",
+		.owner = THIS_MODULE,
+	},
+	.probe = ab3100_regulators_probe,
+	.remove = __exit_p(ab3100_regulators_remove),
+};
+
+static __init int ab3100_regulators_init(void)
+{
+	return platform_driver_register(&ab3100_regulators_driver);
+}
+
+static __exit void ab3100_regulators_exit(void)
+{
+	platform_driver_register(&ab3100_regulators_driver);
+}
+
+subsys_initcall(ab3100_regulators_init);
+module_exit(ab3100_regulators_exit);
+
+MODULE_AUTHOR("Mattias Wallin <mattias.wallin@stericsson.com>");
+MODULE_DESCRIPTION("AB3100 Regulator driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ab3100-regulators");