regulator: Fairchild fan53555 support

This driver supports Fairchild FAN53555 Digitally Programmable
TinyBuck Regulator. The FAN53555 is a step-down switching voltage
regulator that delivers a digitally programmable output from an
input voltage supply of 2.5V to 5.5V. The output voltage is
programmed through an I2C interface.

Signed-off-by: Yunfan Zhang <yfzhang@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 325 insertions, 0 deletions

diff --git a/drivers/regulator/fan53555.c b/drivers/regulator/fan53555.c
new file mode 100644
index 000000000000..890f2b34b39a
--- /dev/null
+++ b/drivers/regulator/fan53555.c
@@ -0,0 +1,325 @@
+/*
+ * FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
+ *
+ * Supported Part Numbers:
+ * FAN53555UC00X/01X/03X/04X/05X
+ *
+ * Copyright (c) 2012 Marvell Technology Ltd.
+ * Yunfan Zhang <yfzhang@marvell.com>
+ *
+ * This package 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/module.h>
+#include <linux/param.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/regulator/fan53555.h>
+
+/* Voltage setting */
+#define FAN53555_VSEL0          0x00
+#define FAN53555_VSEL1          0x01
+/* Control register */
+#define FAN53555_CONTROL        0x02
+/* IC Type */
+#define FAN53555_ID1            0x03
+/* IC mask version */
+#define FAN53555_ID2            0x04
+/* Monitor register */
+#define FAN53555_MONITOR        0x05
+
+/* VSEL bit definitions */
+#define VSEL_BUCK_EN    (1 << 7)
+#define VSEL_MODE               (1 << 6)
+#define VSEL_NSEL_MASK  0x3F
+/* Chip ID and Verison */
+#define DIE_ID          0x0F    /* ID1 */
+#define DIE_REV         0x0F    /* ID2 */
+/* Control bit definitions */
+#define CTL_OUTPUT_DISCHG       (1 << 7)
+#define CTL_SLEW_MASK           (0x7 << 4)
+#define CTL_SLEW_SHIFT          4
+#define CTL_RESET                       (1 << 2)
+
+#define FAN53555_NVOLTAGES      64      /* Numbers of voltages */
+
+/* IC Type */
+enum {
+        FAN53555_CHIP_ID_00 = 0,
+        FAN53555_CHIP_ID_01,
+        FAN53555_CHIP_ID_02,
+        FAN53555_CHIP_ID_03,
+        FAN53555_CHIP_ID_04,
+        FAN53555_CHIP_ID_05,
+};
+
+struct fan53555_device_info {
+        struct regmap *regmap;
+        struct device *dev;
+        struct regulator_desc desc;
+        struct regulator_dev *rdev;
+        struct regulator_init_data *regulator;
+        /* IC Type and Rev */
+        int chip_id;
+        int chip_rev;
+        /* Voltage setting register */
+        unsigned int vol_reg;
+        unsigned int sleep_reg;
+        /* Voltage range and step(linear) */
+        unsigned int vsel_min;
+        unsigned int vsel_max;
+        unsigned int vsel_step;
+        /* Voltage slew rate limiting */
+        unsigned int slew_rate;
+        /* Sleep voltage cache */
+        unsigned int sleep_vol_cache;
+};
+
+static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV)
+{
+        struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+        int ret;
+
+        if (di->sleep_vol_cache == uV)
+                return 0;
+        ret = regulator_map_voltage_linear(rdev, uV, uV);
+        if (ret < 0)
+                return -EINVAL;
+        ret = regmap_update_bits(di->regmap, di->sleep_reg,
+                                        VSEL_NSEL_MASK, ret);
+        if (ret < 0)
+                return -EINVAL;
+        /* Cache the sleep voltage setting.
+         * Might not be the real voltage which is rounded */
+        di->sleep_vol_cache = uV;
+
+        return 0;
+}
+
+static int fan53555_set_mode(struct regulator_dev *rdev, unsigned int mode)
+{
+        struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+
+        switch (mode) {
+        case REGULATOR_MODE_FAST:
+                regmap_update_bits(di->regmap, di->vol_reg,
+                                VSEL_MODE, VSEL_MODE);
+                break;
+        case REGULATOR_MODE_NORMAL:
+                regmap_update_bits(di->regmap, di->vol_reg, VSEL_MODE, 0);
+                break;
+        default:
+                return -EINVAL;
+        }
+        return 0;
+}
+
+static unsigned int fan53555_get_mode(struct regulator_dev *rdev)
+{
+        struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+        unsigned int val;
+        int ret = 0;
+
+        ret = regmap_read(di->regmap, di->vol_reg, &val);
+        if (ret < 0)
+                return ret;
+        if (val & VSEL_MODE)
+                return REGULATOR_MODE_FAST;
+        else
+                return REGULATOR_MODE_NORMAL;
+}
+
+static struct regulator_ops fan53555_regulator_ops = {
+        .set_voltage_sel = regulator_set_voltage_sel_regmap,
+        .get_voltage_sel = regulator_get_voltage_sel_regmap,
+        .map_voltage = regulator_map_voltage_linear,
+        .list_voltage = regulator_list_voltage_linear,
+        .set_suspend_voltage = fan53555_set_suspend_voltage,
+        .enable = regulator_enable_regmap,
+        .disable = regulator_disable_regmap,
+        .is_enabled = regulator_is_enabled_regmap,
+        .set_mode = fan53555_set_mode,
+        .get_mode = fan53555_get_mode,
+};
+
+/* For 00,01,03,05 options:
+ * VOUT = 0.60V + NSELx * 10mV, from 0.60 to 1.23V.
+ * For 04 option:
+ * VOUT = 0.603V + NSELx * 12.826mV, from 0.603 to 1.411V.
+ * */
+static int fan53555_device_setup(struct fan53555_device_info *di,
+                                struct fan53555_platform_data *pdata)
+{
+        unsigned int reg, data, mask;
+
+        /* Setup voltage control register */
+        switch (pdata->sleep_vsel_id) {
+        case FAN53555_VSEL_ID_0:
+                di->sleep_reg = FAN53555_VSEL0;
+                di->vol_reg = FAN53555_VSEL1;
+                break;
+        case FAN53555_VSEL_ID_1:
+                di->sleep_reg = FAN53555_VSEL1;
+                di->vol_reg = FAN53555_VSEL0;
+                break;
+        default:
+                dev_err(di->dev, "Invalid VSEL ID!\n");
+                return -EINVAL;
+        }
+        /* Init voltage range and step */
+        switch (di->chip_id) {
+        case FAN53555_CHIP_ID_00:
+        case FAN53555_CHIP_ID_01:
+        case FAN53555_CHIP_ID_03:
+        case FAN53555_CHIP_ID_05:
+                di->vsel_min = 600000;
+                di->vsel_max = 1230000;
+                di->vsel_step = 10000;
+                break;
+        case FAN53555_CHIP_ID_04:
+                di->vsel_min = 603000;
+                di->vsel_max = 1411000;
+                di->vsel_step = 12826;
+                break;
+        default:
+                dev_err(di->dev,
+                        "Chip ID[%d]\n not supported!\n", di->chip_id);
+                return -EINVAL;
+        }
+        /* Init slew rate */
+        if (pdata->slew_rate & 0x7)
+                di->slew_rate = pdata->slew_rate;
+        else
+                di->slew_rate = FAN53555_SLEW_RATE_64MV;
+        reg = FAN53555_CONTROL;
+        data = di->slew_rate << CTL_SLEW_SHIFT;
+        mask = CTL_SLEW_MASK;
+        return regmap_update_bits(di->regmap, reg, mask, data);
+}
+
+static int fan53555_regulator_register(struct fan53555_device_info *di,
+                        struct regulator_config *config)
+{
+        struct regulator_desc *rdesc = &di->desc;
+
+        rdesc->name = "fan53555-reg";
+        rdesc->ops = &fan53555_regulator_ops;
+        rdesc->type = REGULATOR_VOLTAGE;
+        rdesc->n_voltages = FAN53555_NVOLTAGES;
+        rdesc->enable_reg = di->vol_reg;
+        rdesc->enable_mask = VSEL_BUCK_EN;
+        rdesc->min_uV = di->vsel_min;
+        rdesc->uV_step = di->vsel_step;
+        rdesc->vsel_reg = di->vol_reg;
+        rdesc->vsel_mask = VSEL_NSEL_MASK;
+        rdesc->owner = THIS_MODULE;
+
+        di->rdev = regulator_register(&di->desc, config);
+        if (IS_ERR(di->rdev))
+                return PTR_ERR(di->rdev);
+        return 0;
+
+}
+
+static struct regmap_config fan53555_regmap_config = {
+        .reg_bits = 8,
+        .val_bits = 8,
+};
+
+static int __devinit fan53555_regulator_probe(struct i2c_client *client,
+                                const struct i2c_device_id *id)
+{
+        struct fan53555_device_info *di;
+        struct fan53555_platform_data *pdata;
+        struct regulator_config config = { };
+        unsigned int val;
+        int ret;
+
+        pdata = client->dev.platform_data;
+        if (!pdata || !pdata->regulator) {
+                dev_err(&client->dev, "Platform data not found!\n");
+                return -ENODEV;
+        }
+
+        di = devm_kzalloc(&client->dev, sizeof(struct fan53555_device_info),
+                                        GFP_KERNEL);
+        if (!di) {
+                dev_err(&client->dev, "Failed to allocate device info data!\n");
+                return -ENOMEM;
+        }
+        di->regmap = devm_regmap_init_i2c(client, &fan53555_regmap_config);
+        if (IS_ERR(di->regmap)) {
+                dev_err(&client->dev, "Failed to allocate regmap!\n");
+                return PTR_ERR(di->regmap);
+        }
+        di->dev = &client->dev;
+        di->regulator = pdata->regulator;
+        i2c_set_clientdata(client, di);
+        /* Get chip ID */
+        ret = regmap_read(di->regmap, FAN53555_ID1, &val);
+        if (ret < 0) {
+                dev_err(&client->dev, "Failed to get chip ID!\n");
+                return -ENODEV;
+        }
+        di->chip_id = val & DIE_ID;
+        /* Get chip revision */
+        ret = regmap_read(di->regmap, FAN53555_ID2, &val);
+        if (ret < 0) {
+                dev_err(&client->dev, "Failed to get chip Rev!\n");
+                return -ENODEV;
+        }
+        di->chip_rev = val & DIE_REV;
+        dev_info(&client->dev, "FAN53555 Option[%d] Rev[%d] Detected!\n",
+                                di->chip_id, di->chip_rev);
+        /* Device init */
+        ret = fan53555_device_setup(di, pdata);
+        if (ret < 0) {
+                dev_err(&client->dev, "Failed to setup device!\n");
+                return ret;
+        }
+        /* Register regulator */
+        config.dev = di->dev;
+        config.init_data = di->regulator;
+        config.regmap = di->regmap;
+        config.driver_data = di;
+        ret = fan53555_regulator_register(di, &config);
+        if (ret < 0)
+                dev_err(&client->dev, "Failed to register regulator!\n");
+        return ret;
+
+}
+
+static int __devexit fan53555_regulator_remove(struct i2c_client *client)
+{
+        struct fan53555_device_info *di = i2c_get_clientdata(client);
+
+        regulator_unregister(di->rdev);
+        return 0;
+}
+
+static const struct i2c_device_id fan53555_id[] = {
+        {"fan53555", -1},
+        { },
+};
+
+static struct i2c_driver fan53555_regulator_driver = {
+        .driver = {
+                .name = "fan53555-regulator",
+        },
+        .probe = fan53555_regulator_probe,
+        .remove = __devexit_p(fan53555_regulator_remove),
+        .id_table = fan53555_id,
+};
+
+module_i2c_driver(fan53555_regulator_driver);
+
+MODULE_AUTHOR("Yunfan Zhang <yfzhang@marvell.com>");
+MODULE_DESCRIPTION("FAN53555 regulator driver");
+MODULE_LICENSE("GPL v2");