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