Regulator: LP3972 PMIC regulator driver

This patch adds regulator drivers for National Semiconductors LP3972 PMIC.
This LP3972 PMIC controller has 3 DC/DC voltage converters and 5 low drop-out
(LDO) regulators. LP3972 PMIC controller uses I2C interface.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 649 insertions, 0 deletions

diff --git a/drivers/regulator/lp3972.c b/drivers/regulator/lp3972.c
new file mode 100644
index 000000000000..0d9b47569c1b
--- /dev/null
+++ b/drivers/regulator/lp3972.c
@@ -0,0 +1,649 @@
+/*
+ * Regulator driver for National Semiconductors LP3972 PMIC chip
+ *
+ * Based on lp3971.c
+ *
+ * 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.
+ *
+ */
+
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/lp3972.h>
+#include <linux/slab.h>
+
+struct lp3972 {
+        struct device *dev;
+        struct mutex io_lock;
+        struct i2c_client *i2c;
+        int num_regulators;
+        struct regulator_dev **rdev;
+};
+
+/* LP3972 Control Registers */
+#define LP3972_SCR_REG          0x07
+#define LP3972_OVER1_REG        0x10
+#define LP3972_OVSR1_REG        0x11
+#define LP3972_OVER2_REG        0x12
+#define LP3972_OVSR2_REG        0x13
+#define LP3972_VCC1_REG         0x20
+#define LP3972_ADTV1_REG        0x23
+#define LP3972_ADTV2_REG        0x24
+#define LP3972_AVRC_REG         0x25
+#define LP3972_CDTC1_REG        0x26
+#define LP3972_CDTC2_REG        0x27
+#define LP3972_SDTV1_REG        0x29
+#define LP3972_SDTV2_REG        0x2A
+#define LP3972_MDTV1_REG        0x32
+#define LP3972_MDTV2_REG        0x33
+#define LP3972_L2VCR_REG        0x39
+#define LP3972_L34VCR_REG       0x3A
+#define LP3972_SCR1_REG         0x80
+#define LP3972_SCR2_REG         0x81
+#define LP3972_OEN3_REG         0x82
+#define LP3972_OSR3_REG         0x83
+#define LP3972_LOER4_REG        0x84
+#define LP3972_B2TV_REG         0x85
+#define LP3972_B3TV_REG         0x86
+#define LP3972_B32RC_REG        0x87
+#define LP3972_ISRA_REG         0x88
+#define LP3972_BCCR_REG         0x89
+#define LP3972_II1RR_REG        0x8E
+#define LP3972_II2RR_REG        0x8F
+
+#define LP3972_SYS_CONTROL1_REG         LP3972_SCR1_REG
+/* System control register 1 initial value,
+ * bits 5, 6 and 7 are EPROM programmable */
+#define SYS_CONTROL1_INIT_VAL           0x02
+#define SYS_CONTROL1_INIT_MASK          0x1F
+
+#define LP3972_VOL_CHANGE_REG           LP3972_VCC1_REG
+#define LP3972_VOL_CHANGE_FLAG_GO       0x01
+#define LP3972_VOL_CHANGE_FLAG_MASK     0x03
+
+/* LDO output enable mask */
+#define LP3972_OEN3_L1EN        BIT(0)
+#define LP3972_OVER2_LDO2_EN    BIT(2)
+#define LP3972_OVER2_LDO3_EN    BIT(3)
+#define LP3972_OVER2_LDO4_EN    BIT(4)
+#define LP3972_OVER1_S_EN       BIT(2)
+
+static const int ldo1_voltage_map[] = {
+        1700, 1725, 1750, 1775, 1800, 1825, 1850, 1875,
+        1900, 1925, 1950, 1975, 2000,
+};
+
+static const int ldo23_voltage_map[] = {
+        1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500,
+        2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300,
+};
+
+static const int ldo4_voltage_map[] = {
+        1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350,
+        1400, 1500, 1800, 1900, 2500, 2800, 3000, 3300,
+};
+
+static const int ldo5_voltage_map[] = {
+           0,    0,    0,    0,    0,  850,  875,  900,
+         925,  950,  975, 1000, 1025, 1050, 1075, 1100,
+        1125, 1150, 1175, 1200, 1225, 1250, 1275, 1300,
+        1325, 1350, 1375, 1400, 1425, 1450, 1475, 1500,
+};
+
+static const int buck1_voltage_map[] = {
+         725,  750,  775,  800,  825,  850,  875,  900,
+         925,  950,  975, 1000, 1025, 1050, 1075, 1100,
+        1125, 1150, 1175, 1200, 1225, 1250, 1275, 1300,
+        1325, 1350, 1375, 1400, 1425, 1450, 1475, 1500,
+};
+
+static const int buck23_voltage_map[] = {
+           0,  800,  850,  900,  950, 1000, 1050, 1100,
+        1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500,
+        1550, 1600, 1650, 1700, 1800, 1900, 2500, 2800,
+        3000, 3300,
+};
+
+static const int *ldo_voltage_map[] = {
+        ldo1_voltage_map,
+        ldo23_voltage_map,
+        ldo23_voltage_map,
+        ldo4_voltage_map,
+        ldo5_voltage_map,
+};
+
+static const int *buck_voltage_map[] = {
+        buck1_voltage_map,
+        buck23_voltage_map,
+        buck23_voltage_map,
+};
+
+static const int ldo_output_enable_mask[] = {
+        LP3972_OEN3_L1EN,
+        LP3972_OVER2_LDO2_EN,
+        LP3972_OVER2_LDO3_EN,
+        LP3972_OVER2_LDO4_EN,
+        LP3972_OVER1_S_EN,
+};
+
+static const int ldo_output_enable_addr[] = {
+        LP3972_OEN3_REG,
+        LP3972_OVER2_REG,
+        LP3972_OVER2_REG,
+        LP3972_OVER2_REG,
+        LP3972_OVER1_REG,
+};
+
+static const int ldo_vol_ctl_addr[] = {
+        LP3972_MDTV1_REG,
+        LP3972_L2VCR_REG,
+        LP3972_L34VCR_REG,
+        LP3972_L34VCR_REG,
+        LP3972_SDTV1_REG,
+};
+
+static const int buck_vol_enable_addr[] = {
+        LP3972_OVER1_REG,
+        LP3972_OEN3_REG,
+        LP3972_OEN3_REG,
+};
+
+static const int buck_base_addr[] = {
+        LP3972_ADTV1_REG,
+        LP3972_B2TV_REG,
+        LP3972_B3TV_REG,
+};
+
+#define LP3972_LDO_VOL_VALUE_MAP(x) (ldo_voltage_map[x])
+#define LP3972_LDO_OUTPUT_ENABLE_MASK(x) (ldo_output_enable_mask[x])
+#define LP3972_LDO_OUTPUT_ENABLE_REG(x) (ldo_output_enable_addr[x])
+
+/*      LDO voltage control registers shift:
+        LP3972_LDO1 -> 0, LP3972_LDO2 -> 4
+        LP3972_LDO3 -> 0, LP3972_LDO4 -> 4
+        LP3972_LDO5 -> 0
+*/
+#define LP3972_LDO_VOL_CONTR_SHIFT(x) (((x) & 1) << 2)
+#define LP3972_LDO_VOL_CONTR_REG(x) (ldo_vol_ctl_addr[x])
+#define LP3972_LDO_VOL_CHANGE_SHIFT(x) ((x) ? 4 : 6)
+
+#define LP3972_LDO_VOL_MASK(x) (((x) % 4) ? 0x0f : 0x1f)
+#define LP3972_LDO_VOL_MIN_IDX(x) (((x) == 4) ? 0x05 : 0x00)
+#define LP3972_LDO_VOL_MAX_IDX(x) ((x) ? (((x) == 4) ? 0x1f : 0x0f) : 0x0c)
+
+#define LP3972_BUCK_VOL_VALUE_MAP(x) (buck_voltage_map[x])
+#define LP3972_BUCK_VOL_ENABLE_REG(x) (buck_vol_enable_addr[x])
+#define LP3972_BUCK_VOL1_REG(x) (buck_base_addr[x])
+#define LP3972_BUCK_VOL_MASK 0x1f
+#define LP3972_BUCK_VOL_MIN_IDX(x) ((x) ? 0x01 : 0x00)
+#define LP3972_BUCK_VOL_MAX_IDX(x) ((x) ? 0x19 : 0x1f)
+
+static int lp3972_i2c_read(struct i2c_client *i2c, char reg, int count,
+        u16 *dest)
+{
+        int ret;
+
+        if (count != 1)
+                return -EIO;
+        ret = i2c_smbus_read_byte_data(i2c, reg);
+        if (ret < 0)
+                return -EIO;
+
+        *dest = ret;
+        return 0;
+}
+
+static int lp3972_i2c_write(struct i2c_client *i2c, char reg, int count,
+        const u16 *src)
+{
+        if (count != 1)
+                return -EIO;
+        return i2c_smbus_write_byte_data(i2c, reg, *src);
+}
+
+static u8 lp3972_reg_read(struct lp3972 *lp3972, u8 reg)
+{
+        u16 val = 0;
+
+        mutex_lock(&lp3972->io_lock);
+
+        lp3972_i2c_read(lp3972->i2c, reg, 1, &val);
+
+        dev_dbg(lp3972->dev, "reg read 0x%02x -> 0x%02x\n", (int)reg,
+                (unsigned)val&0xff);
+
+        mutex_unlock(&lp3972->io_lock);
+
+        return val & 0xff;
+}
+
+static int lp3972_set_bits(struct lp3972 *lp3972, u8 reg, u16 mask, u16 val)
+{
+        u16 tmp;
+        int ret;
+
+        mutex_lock(&lp3972->io_lock);
+
+        ret = lp3972_i2c_read(lp3972->i2c, reg, 1, &tmp);
+        tmp = (tmp & ~mask) | val;
+        if (ret == 0) {
+                ret = lp3972_i2c_write(lp3972->i2c, reg, 1, &tmp);
+                dev_dbg(lp3972->dev, "reg write 0x%02x -> 0x%02x\n", (int)reg,
+                        (unsigned)val&0xff);
+        }
+        mutex_unlock(&lp3972->io_lock);
+
+        return ret;
+}
+
+static int lp3972_ldo_list_voltage(struct regulator_dev *dev, unsigned index)
+{
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        return 1000 * LP3972_LDO_VOL_VALUE_MAP(ldo)[index];
+}
+
+static int lp3972_ldo_is_enabled(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        u16 mask = LP3972_LDO_OUTPUT_ENABLE_MASK(ldo);
+        u16 val;
+
+        val = lp3972_reg_read(lp3972, LP3972_LDO_OUTPUT_ENABLE_REG(ldo));
+        return !!(val & mask);
+}
+
+static int lp3972_ldo_enable(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        u16 mask = LP3972_LDO_OUTPUT_ENABLE_MASK(ldo);
+
+        return lp3972_set_bits(lp3972, LP3972_LDO_OUTPUT_ENABLE_REG(ldo),
+                                mask, mask);
+}
+
+static int lp3972_ldo_disable(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        u16 mask = LP3972_LDO_OUTPUT_ENABLE_MASK(ldo);
+
+        return lp3972_set_bits(lp3972, LP3972_LDO_OUTPUT_ENABLE_REG(ldo),
+                                mask, 0);
+}
+
+static int lp3972_ldo_get_voltage(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        u16 mask = LP3972_LDO_VOL_MASK(ldo);
+        u16 val, reg;
+
+        reg = lp3972_reg_read(lp3972, LP3972_LDO_VOL_CONTR_REG(ldo));
+        val = (reg >> LP3972_LDO_VOL_CONTR_SHIFT(ldo)) & mask;
+
+        return 1000 * LP3972_LDO_VOL_VALUE_MAP(ldo)[val];
+}
+
+static int lp3972_ldo_set_voltage(struct regulator_dev *dev,
+                                  int min_uV, int max_uV)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int ldo = rdev_get_id(dev) - LP3972_LDO1;
+        int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
+        const int *vol_map = LP3972_LDO_VOL_VALUE_MAP(ldo);
+        u16 val;
+        int shift, ret;
+
+        if (min_vol < vol_map[LP3972_LDO_VOL_MIN_IDX(ldo)] ||
+            min_vol > vol_map[LP3972_LDO_VOL_MAX_IDX(ldo)])
+                return -EINVAL;
+
+        for (val = LP3972_LDO_VOL_MIN_IDX(ldo);
+                val <= LP3972_LDO_VOL_MAX_IDX(ldo); val++)
+                if (vol_map[val] >= min_vol)
+                        break;
+
+        if (val > LP3972_LDO_VOL_MAX_IDX(ldo) || vol_map[val] > max_vol)
+                return -EINVAL;
+
+        shift = LP3972_LDO_VOL_CONTR_SHIFT(ldo);
+        ret = lp3972_set_bits(lp3972, LP3972_LDO_VOL_CONTR_REG(ldo),
+                LP3972_LDO_VOL_MASK(ldo) << shift, val << shift);
+
+        if (ret)
+                return ret;
+
+        switch (ldo) {
+        case LP3972_LDO1:
+        case LP3972_LDO5:
+                shift = LP3972_LDO_VOL_CHANGE_SHIFT(ldo);
+                ret = lp3972_set_bits(lp3972, LP3972_VOL_CHANGE_REG,
+                        LP3972_VOL_CHANGE_FLAG_MASK << shift,
+                        LP3972_VOL_CHANGE_FLAG_GO << shift);
+                if (ret)
+                        return ret;
+
+                ret = lp3972_set_bits(lp3972, LP3972_VOL_CHANGE_REG,
+                        LP3972_VOL_CHANGE_FLAG_MASK << shift, 0);
+                break;
+        }
+
+        return ret;
+}
+
+static struct regulator_ops lp3972_ldo_ops = {
+        .list_voltage = lp3972_ldo_list_voltage,
+        .is_enabled = lp3972_ldo_is_enabled,
+        .enable = lp3972_ldo_enable,
+        .disable = lp3972_ldo_disable,
+        .get_voltage = lp3972_ldo_get_voltage,
+        .set_voltage = lp3972_ldo_set_voltage,
+};
+
+static int lp3972_dcdc_list_voltage(struct regulator_dev *dev, unsigned index)
+{
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        return 1000 * buck_voltage_map[buck][index];
+}
+
+static int lp3972_dcdc_is_enabled(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        u16 mask = 1 << (buck * 2);
+        u16 val;
+
+        val = lp3972_reg_read(lp3972, LP3972_BUCK_VOL_ENABLE_REG(buck));
+        return !!(val & mask);
+}
+
+static int lp3972_dcdc_enable(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        u16 mask = 1 << (buck * 2);
+        u16 val;
+
+        val = lp3972_set_bits(lp3972, LP3972_BUCK_VOL_ENABLE_REG(buck),
+                                mask, mask);
+        return val;
+}
+
+static int lp3972_dcdc_disable(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        u16 mask = 1 << (buck * 2);
+        u16 val;
+
+        val = lp3972_set_bits(lp3972, LP3972_BUCK_VOL_ENABLE_REG(buck),
+                                mask, 0);
+        return val;
+}
+
+static int lp3972_dcdc_get_voltage(struct regulator_dev *dev)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        u16 reg;
+        int val;
+
+        reg = lp3972_reg_read(lp3972, LP3972_BUCK_VOL1_REG(buck));
+        reg &= LP3972_BUCK_VOL_MASK;
+        if (reg <= LP3972_BUCK_VOL_MAX_IDX(buck))
+                val = 1000 * buck_voltage_map[buck][reg];
+        else {
+                val = 0;
+                dev_warn(&dev->dev, "chip reported incorrect voltage value.\n");
+        }
+
+        return val;
+}
+
+static int lp3972_dcdc_set_voltage(struct regulator_dev *dev,
+                                  int min_uV, int max_uV)
+{
+        struct lp3972 *lp3972 = rdev_get_drvdata(dev);
+        int buck = rdev_get_id(dev) - LP3972_DCDC1;
+        int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
+        const int *vol_map = buck_voltage_map[buck];
+        u16 val;
+        int ret;
+
+        if (min_vol < vol_map[LP3972_BUCK_VOL_MIN_IDX(buck)] ||
+            min_vol > vol_map[LP3972_BUCK_VOL_MAX_IDX(buck)])
+                return -EINVAL;
+
+        for (val = LP3972_BUCK_VOL_MIN_IDX(buck);
+                val <= LP3972_BUCK_VOL_MAX_IDX(buck); val++)
+                if (vol_map[val] >= min_vol)
+                        break;
+
+        if (val > LP3972_BUCK_VOL_MAX_IDX(buck) ||
+            vol_map[val] > max_vol)
+                return -EINVAL;
+
+        ret = lp3972_set_bits(lp3972, LP3972_BUCK_VOL1_REG(buck),
+                                LP3972_BUCK_VOL_MASK, val);
+        if (ret)
+                return ret;
+
+        if (buck != 0)
+                return ret;
+
+        ret = lp3972_set_bits(lp3972, LP3972_VOL_CHANGE_REG,
+                LP3972_VOL_CHANGE_FLAG_MASK, LP3972_VOL_CHANGE_FLAG_GO);
+        if (ret)
+                return ret;
+
+        return lp3972_set_bits(lp3972, LP3972_VOL_CHANGE_REG,
+                                LP3972_VOL_CHANGE_FLAG_MASK, 0);
+}
+
+static struct regulator_ops lp3972_dcdc_ops = {
+        .list_voltage = lp3972_dcdc_list_voltage,
+        .is_enabled = lp3972_dcdc_is_enabled,
+        .enable = lp3972_dcdc_enable,
+        .disable = lp3972_dcdc_disable,
+        .get_voltage = lp3972_dcdc_get_voltage,
+        .set_voltage = lp3972_dcdc_set_voltage,
+};
+
+static struct regulator_desc regulators[] = {
+        {
+                .name = "LDO1",
+                .id = LP3972_LDO1,
+                .ops = &lp3972_ldo_ops,
+                .n_voltages = ARRAY_SIZE(ldo1_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "LDO2",
+                .id = LP3972_LDO2,
+                .ops = &lp3972_ldo_ops,
+                .n_voltages = ARRAY_SIZE(ldo23_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "LDO3",
+                .id = LP3972_LDO3,
+                .ops = &lp3972_ldo_ops,
+                .n_voltages = ARRAY_SIZE(ldo23_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "LDO4",
+                .id = LP3972_LDO4,
+                .ops = &lp3972_ldo_ops,
+                .n_voltages = ARRAY_SIZE(ldo4_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "LDO5",
+                .id = LP3972_LDO5,
+                .ops = &lp3972_ldo_ops,
+                .n_voltages = ARRAY_SIZE(ldo5_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "DCDC1",
+                .id = LP3972_DCDC1,
+                .ops = &lp3972_dcdc_ops,
+                .n_voltages = ARRAY_SIZE(buck1_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "DCDC2",
+                .id = LP3972_DCDC2,
+                .ops = &lp3972_dcdc_ops,
+                .n_voltages = ARRAY_SIZE(buck23_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+        {
+                .name = "DCDC3",
+                .id = LP3972_DCDC3,
+                .ops = &lp3972_dcdc_ops,
+                .n_voltages = ARRAY_SIZE(buck23_voltage_map),
+                .type = REGULATOR_VOLTAGE,
+                .owner = THIS_MODULE,
+        },
+};
+
+static int setup_regulators(struct lp3972 *lp3972,
+        struct lp3972_platform_data *pdata)
+{
+        int i, err;
+
+        lp3972->num_regulators = pdata->num_regulators;
+        lp3972->rdev = kcalloc(pdata->num_regulators,
+                                sizeof(struct regulator_dev *), GFP_KERNEL);
+        if (!lp3972->rdev) {
+                err = -ENOMEM;
+                goto err_nomem;
+        }
+
+        /* Instantiate the regulators */
+        for (i = 0; i < pdata->num_regulators; i++) {
+                struct lp3972_regulator_subdev *reg = &pdata->regulators[i];
+                lp3972->rdev[i] = regulator_register(&regulators[reg->id],
+                                        lp3972->dev, reg->initdata, lp3972);
+
+                if (IS_ERR(lp3972->rdev[i])) {
+                        err = PTR_ERR(lp3972->rdev[i]);
+                        dev_err(lp3972->dev, "regulator init failed: %d\n",
+                                err);
+                        goto error;
+                }
+        }
+
+        return 0;
+error:
+        while (--i >= 0)
+                regulator_unregister(lp3972->rdev[i]);
+        kfree(lp3972->rdev);
+        lp3972->rdev = NULL;
+err_nomem:
+        return err;
+}
+
+static int __devinit lp3972_i2c_probe(struct i2c_client *i2c,
+                            const struct i2c_device_id *id)
+{
+        struct lp3972 *lp3972;
+        struct lp3972_platform_data *pdata = i2c->dev.platform_data;
+        int ret;
+        u16 val;
+
+        if (!pdata) {
+                dev_dbg(&i2c->dev, "No platform init data supplied\n");
+                return -ENODEV;
+        }
+
+        lp3972 = kzalloc(sizeof(struct lp3972), GFP_KERNEL);
+        if (!lp3972)
+                return -ENOMEM;
+
+        lp3972->i2c = i2c;
+        lp3972->dev = &i2c->dev;
+
+        mutex_init(&lp3972->io_lock);
+
+        /* Detect LP3972 */
+        ret = lp3972_i2c_read(i2c, LP3972_SYS_CONTROL1_REG, 1, &val);
+        if (ret == 0 && (val & SYS_CONTROL1_INIT_MASK) != SYS_CONTROL1_INIT_VAL)
+                ret = -ENODEV;
+        if (ret < 0) {
+                dev_err(&i2c->dev, "failed to detect device\n");
+                goto err_detect;
+        }
+
+        ret = setup_regulators(lp3972, pdata);
+        if (ret < 0)
+                goto err_detect;
+
+        i2c_set_clientdata(i2c, lp3972);
+        return 0;
+
+err_detect:
+        kfree(lp3972);
+        return ret;
+}
+
+static int __devexit lp3972_i2c_remove(struct i2c_client *i2c)
+{
+        struct lp3972 *lp3972 = i2c_get_clientdata(i2c);
+        int i;
+
+        for (i = 0; i < lp3972->num_regulators; i++)
+                regulator_unregister(lp3972->rdev[i]);
+        kfree(lp3972->rdev);
+        kfree(lp3972);
+
+        return 0;
+}
+
+static const struct i2c_device_id lp3972_i2c_id[] = {
+        { "lp3972", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, lp3972_i2c_id);
+
+static struct i2c_driver lp3972_i2c_driver = {
+        .driver = {
+                .name = "lp3972",
+                .owner = THIS_MODULE,
+        },
+        .probe    = lp3972_i2c_probe,
+        .remove   = __devexit_p(lp3972_i2c_remove),
+        .id_table = lp3972_i2c_id,
+};
+
+static int __init lp3972_module_init(void)
+{
+        return i2c_add_driver(&lp3972_i2c_driver);
+}
+subsys_initcall(lp3972_module_init);
+
+static void __exit lp3972_module_exit(void)
+{
+        i2c_del_driver(&lp3972_i2c_driver);
+}
+module_exit(lp3972_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Axel Lin <axel.lin@gmail.com>");
+MODULE_DESCRIPTION("LP3972 PMIC driver");