regulator: add driver for MAX8660/8661

Tested with a MX25-based custom board.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 510 insertions, 0 deletions

diff --git a/drivers/regulator/max8660.c b/drivers/regulator/max8660.c
new file mode 100644
index 000000000000..acc2fb7b6087
--- /dev/null
+++ b/drivers/regulator/max8660.c
@@ -0,0 +1,510 @@
+/*
+ * max8660.c  --  Voltage regulation for the Maxim 8660/8661
+ *
+ * based on max1586.c and wm8400-regulator.c
+ *
+ * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Some info:
+ *
+ * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
+ *
+ * This chip is a bit nasty because it is a write-only device. Thus, the driver
+ * uses shadow registers to keep track of its values. The main problem appears
+ * to be the initialization: When Linux boots up, we cannot know if the chip is
+ * in the default state or not, so we would have to pass such information in
+ * platform_data. As this adds a bit of complexity to the driver, this is left
+ * out for now until it is really needed.
+ *
+ * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
+ *
+ * If the driver is feature complete, it might be worth to check if one set of
+ * functions for V3-V7 is sufficient. For maximum flexibility during
+ * development, they are separated for now.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/max8660.h>
+
+#define MAX8660_DCDC_MIN_UV	 725000
+#define MAX8660_DCDC_MAX_UV	1800000
+#define MAX8660_DCDC_STEP	  25000
+#define MAX8660_DCDC_MAX_SEL	0x2b
+
+#define MAX8660_LDO5_MIN_UV	1700000
+#define MAX8660_LDO5_MAX_UV	2000000
+#define MAX8660_LDO5_STEP	  25000
+#define MAX8660_LDO5_MAX_SEL	0x0c
+
+#define MAX8660_LDO67_MIN_UV	1800000
+#define MAX8660_LDO67_MAX_UV	3300000
+#define MAX8660_LDO67_STEP	 100000
+#define MAX8660_LDO67_MAX_SEL	0x0f
+
+enum {
+	MAX8660_OVER1,
+	MAX8660_OVER2,
+	MAX8660_VCC1,
+	MAX8660_ADTV1,
+	MAX8660_ADTV2,
+	MAX8660_SDTV1,
+	MAX8660_SDTV2,
+	MAX8660_MDTV1,
+	MAX8660_MDTV2,
+	MAX8660_L12VCR,
+	MAX8660_FPWM,
+	MAX8660_N_REGS,	/* not a real register */
+};
+
+struct max8660 {
+	struct i2c_client *client;
+	u8 shadow_regs[MAX8660_N_REGS];		/* as chip is write only */
+	struct regulator_dev *rdev[];
+};
+
+static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
+{
+	static const u8 max8660_addresses[MAX8660_N_REGS] =
+	  { 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80 };
+
+	int ret;
+	u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
+	dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
+			max8660_addresses[reg], reg_val);
+
+	ret = i2c_smbus_write_byte_data(max8660->client,
+			max8660_addresses[reg], reg_val);
+	if (ret == 0)
+		max8660->shadow_regs[reg] = reg_val;
+
+	return ret;
+}
+
+
+/*
+ * DCDC functions
+ */
+
+static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 val = max8660->shadow_regs[MAX8660_OVER1];
+	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
+	return !!(val & mask);
+}
+
+static int max8660_dcdc_enable(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
+	return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
+}
+
+static int max8660_dcdc_disable(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
+	return max8660_write(max8660, MAX8660_OVER1, mask, 0);
+}
+
+static int max8660_dcdc_list(struct regulator_dev *rdev, unsigned selector)
+{
+	if (selector > MAX8660_DCDC_MAX_SEL)
+		return -EINVAL;
+	return MAX8660_DCDC_MIN_UV + selector * MAX8660_DCDC_STEP;
+}
+
+static int max8660_dcdc_get(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
+	u8 selector = max8660->shadow_regs[reg];
+	return MAX8660_DCDC_MIN_UV + selector * MAX8660_DCDC_STEP;
+}
+
+static int max8660_dcdc_set(struct regulator_dev *rdev, int min_uV, int max_uV)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 reg, selector, bits;
+	int ret;
+
+	if (min_uV < MAX8660_DCDC_MIN_UV || min_uV > MAX8660_DCDC_MAX_UV)
+		return -EINVAL;
+	if (max_uV < MAX8660_DCDC_MIN_UV || max_uV > MAX8660_DCDC_MAX_UV)
+		return -EINVAL;
+
+	selector = (min_uV - (MAX8660_DCDC_MIN_UV - MAX8660_DCDC_STEP + 1))
+			/ MAX8660_DCDC_STEP;
+
+	ret = max8660_dcdc_list(rdev, selector);
+	if (ret < 0 || ret > max_uV)
+		return -EINVAL;
+
+	reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
+	ret = max8660_write(max8660, reg, 0, selector);
+	if (ret)
+		return ret;
+
+	/* Select target voltage register and activate regulation */
+	bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
+	return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
+}
+
+static struct regulator_ops max8660_dcdc_ops = {
+	.is_enabled = max8660_dcdc_is_enabled,
+	.list_voltage = max8660_dcdc_list,
+	.set_voltage = max8660_dcdc_set,
+	.get_voltage = max8660_dcdc_get,
+};
+
+
+/*
+ * LDO5 functions
+ */
+
+static int max8660_ldo5_list(struct regulator_dev *rdev, unsigned selector)
+{
+	if (selector > MAX8660_LDO5_MAX_SEL)
+		return -EINVAL;
+	return MAX8660_LDO5_MIN_UV + selector * MAX8660_LDO5_STEP;
+}
+
+static int max8660_ldo5_get(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
+
+	return MAX8660_LDO5_MIN_UV + selector * MAX8660_LDO5_STEP;
+}
+
+static int max8660_ldo5_set(struct regulator_dev *rdev, int min_uV, int max_uV)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 selector;
+	int ret;
+
+	if (min_uV < MAX8660_LDO5_MIN_UV || min_uV > MAX8660_LDO5_MAX_UV)
+		return -EINVAL;
+	if (max_uV < MAX8660_LDO5_MIN_UV || max_uV > MAX8660_LDO5_MAX_UV)
+		return -EINVAL;
+
+	selector = (min_uV - (MAX8660_LDO5_MIN_UV - MAX8660_LDO5_STEP + 1))
+			/ MAX8660_LDO5_STEP;
+	ret = max8660_ldo5_list(rdev, selector);
+	if (ret < 0 || ret > max_uV)
+		return -EINVAL;
+
+	ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
+	if (ret)
+		return ret;
+
+	/* Select target voltage register and activate regulation */
+	return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
+}
+
+static struct regulator_ops max8660_ldo5_ops = {
+	.list_voltage = max8660_ldo5_list,
+	.set_voltage = max8660_ldo5_set,
+	.get_voltage = max8660_ldo5_get,
+};
+
+
+/*
+ * LDO67 functions
+ */
+
+static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 val = max8660->shadow_regs[MAX8660_OVER2];
+	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
+	return !!(val & mask);
+}
+
+static int max8660_ldo67_enable(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
+	return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
+}
+
+static int max8660_ldo67_disable(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
+	return max8660_write(max8660, MAX8660_OVER2, mask, 0);
+}
+
+static int max8660_ldo67_list(struct regulator_dev *rdev, unsigned selector)
+{
+	if (selector > MAX8660_LDO67_MAX_SEL)
+		return -EINVAL;
+	return MAX8660_LDO67_MIN_UV + selector * MAX8660_LDO67_STEP;
+}
+
+static int max8660_ldo67_get(struct regulator_dev *rdev)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
+	u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
+
+	return MAX8660_LDO67_MIN_UV + selector * MAX8660_LDO67_STEP;
+}
+
+static int max8660_ldo67_set(struct regulator_dev *rdev, int min_uV, int max_uV)
+{
+	struct max8660 *max8660 = rdev_get_drvdata(rdev);
+	u8 selector;
+	int ret;
+
+	if (min_uV < MAX8660_LDO67_MIN_UV || min_uV > MAX8660_LDO67_MAX_UV)
+		return -EINVAL;
+	if (max_uV < MAX8660_LDO67_MIN_UV || max_uV > MAX8660_LDO67_MAX_UV)
+		return -EINVAL;
+
+	selector = (min_uV - (MAX8660_LDO67_MIN_UV - MAX8660_LDO67_STEP + 1))
+			/ MAX8660_LDO67_STEP;
+
+	ret = max8660_ldo67_list(rdev, selector);
+	if (ret < 0 || ret > max_uV)
+		return -EINVAL;
+
+	if (rdev_get_id(rdev) == MAX8660_V6)
+		return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
+	else
+		return max8660_write(max8660, MAX8660_L12VCR, 0x0f, selector << 4);
+}
+
+static struct regulator_ops max8660_ldo67_ops = {
+	.is_enabled = max8660_ldo67_is_enabled,
+	.enable = max8660_ldo67_enable,
+	.disable = max8660_ldo67_disable,
+	.list_voltage = max8660_ldo67_list,
+	.get_voltage = max8660_ldo67_get,
+	.set_voltage = max8660_ldo67_set,
+};
+
+static struct regulator_desc max8660_reg[] = {
+	{
+		.name = "V3(DCDC)",
+		.id = MAX8660_V3,
+		.ops = &max8660_dcdc_ops,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
+		.owner = THIS_MODULE,
+	},
+	{
+		.name = "V4(DCDC)",
+		.id = MAX8660_V4,
+		.ops = &max8660_dcdc_ops,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
+		.owner = THIS_MODULE,
+	},
+	{
+		.name = "V5(LDO)",
+		.id = MAX8660_V5,
+		.ops = &max8660_ldo5_ops,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = MAX8660_LDO5_MAX_SEL + 1,
+		.owner = THIS_MODULE,
+	},
+	{
+		.name = "V6(LDO)",
+		.id = MAX8660_V6,
+		.ops = &max8660_ldo67_ops,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
+		.owner = THIS_MODULE,
+	},
+	{
+		.name = "V7(LDO)",
+		.id = MAX8660_V7,
+		.ops = &max8660_ldo67_ops,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int max8660_probe(struct i2c_client *client,
+			      const struct i2c_device_id *i2c_id)
+{
+	struct regulator_dev **rdev;
+	struct max8660_platform_data *pdata = client->dev.platform_data;
+	struct max8660 *max8660;
+	int boot_on, i, id, ret = -EINVAL;
+
+	if (pdata->num_subdevs > MAX8660_V_END) {
+		dev_err(&client->dev, "Too much regulators found!\n");
+		goto out;
+	}
+
+	max8660 = kzalloc(sizeof(struct max8660) +
+			sizeof(struct regulator_dev *) * MAX8660_V_END,
+			GFP_KERNEL);
+	if (!max8660) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	max8660->client = client;
+	rdev = max8660->rdev;
+
+	if (pdata->en34_is_high) {
+		/* Simulate always on */
+		max8660->shadow_regs[MAX8660_OVER1] = 5;
+	} else {
+		/* Otherwise devices can be toggled via software */
+		max8660_dcdc_ops.enable = max8660_dcdc_enable;
+		max8660_dcdc_ops.disable = max8660_dcdc_disable;
+	}
+
+	/*
+	 * First, set up shadow registers to prevent glitches. As some
+	 * registers are shared between regulators, everything must be properly
+	 * set up for all regulators in advance.
+	 */
+	max8660->shadow_regs[MAX8660_ADTV1] =
+		max8660->shadow_regs[MAX8660_ADTV2] =
+		max8660->shadow_regs[MAX8660_SDTV1] =
+		max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
+	max8660->shadow_regs[MAX8660_MDTV1] =
+		max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
+
+	for (i = 0; i < pdata->num_subdevs; i++) {
+
+		if (!pdata->subdevs[i].platform_data)
+			goto err_free;
+
+		boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
+
+		switch (pdata->subdevs[i].id) {
+		case MAX8660_V3:
+			if (boot_on)
+				max8660->shadow_regs[MAX8660_OVER1] |= 1;
+			break;
+
+		case MAX8660_V4:
+			if (boot_on)
+				max8660->shadow_regs[MAX8660_OVER1] |= 4;
+			break;
+
+		case MAX8660_V5:
+			break;
+
+		case MAX8660_V6:
+			if (boot_on)
+				max8660->shadow_regs[MAX8660_OVER2] |= 2;
+			break;
+
+		case MAX8660_V7:
+			if (!strcmp(i2c_id->name, "max8661")) {
+				dev_err(&client->dev, "Regulator not on this chip!\n");
+				goto err_free;
+			}
+
+			if (boot_on)
+				max8660->shadow_regs[MAX8660_OVER2] |= 4;
+			break;
+
+		default:
+			dev_err(&client->dev, "invalid regulator %s\n",
+				 pdata->subdevs[i].name);
+			goto err_free;
+		}
+	}
+
+	/* Finally register devices */
+	for (i = 0; i < pdata->num_subdevs; i++) {
+
+		id = pdata->subdevs[i].id;
+
+		rdev[i] = regulator_register(&max8660_reg[id], &client->dev,
+					     pdata->subdevs[i].platform_data,
+					     max8660);
+		if (IS_ERR(rdev[i])) {
+			ret = PTR_ERR(rdev[i]);
+			dev_err(&client->dev, "failed to register %s\n",
+				max8660_reg[id].name);
+			goto err_unregister;
+		}
+	}
+
+	i2c_set_clientdata(client, rdev);
+	dev_info(&client->dev, "Maxim 8660/8661 regulator driver loaded\n");
+	return 0;
+
+err_unregister:
+	while (--i >= 0)
+		regulator_unregister(rdev[i]);
+err_free:
+	kfree(max8660);
+out:
+	return ret;
+}
+
+static int max8660_remove(struct i2c_client *client)
+{
+	struct regulator_dev **rdev = i2c_get_clientdata(client);
+	int i;
+
+	for (i = 0; i < MAX8660_V_END; i++)
+		if (rdev[i])
+			regulator_unregister(rdev[i]);
+	kfree(rdev);
+	i2c_set_clientdata(client, NULL);
+
+	return 0;
+}
+
+static const struct i2c_device_id max8660_id[] = {
+	{ "max8660", 0 },
+	{ "max8661", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max8660_id);
+
+static struct i2c_driver max8660_driver = {
+	.probe = max8660_probe,
+	.remove = max8660_remove,
+	.driver		= {
+		.name	= "max8660",
+	},
+	.id_table	= max8660_id,
+};
+
+static int __init max8660_init(void)
+{
+	return i2c_add_driver(&max8660_driver);
+}
+subsys_initcall(max8660_init);
+
+static void __exit max8660_exit(void)
+{
+	i2c_del_driver(&max8660_driver);
+}
+module_exit(max8660_exit);
+
+/* Module information */
+MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
+MODULE_AUTHOR("Wolfram Sang");
+MODULE_LICENSE("GPL v2");