365 lines
9.1 KiB
C
365 lines
9.1 KiB
C
/*
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* max8952.c - Voltage and current regulation for the Maxim 8952
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*
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* Copyright (C) 2010 Samsung Electronics
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* MyungJoo Ham <myungjoo.ham@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/i2c.h>
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#include <linux/err.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/regulator/max8952.h>
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#include <linux/gpio.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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/* Registers */
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enum {
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MAX8952_REG_MODE0,
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MAX8952_REG_MODE1,
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MAX8952_REG_MODE2,
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MAX8952_REG_MODE3,
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MAX8952_REG_CONTROL,
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MAX8952_REG_SYNC,
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MAX8952_REG_RAMP,
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MAX8952_REG_CHIP_ID1,
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MAX8952_REG_CHIP_ID2,
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};
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struct max8952_data {
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struct i2c_client *client;
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struct device *dev;
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struct max8952_platform_data *pdata;
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struct regulator_dev *rdev;
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bool vid0;
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bool vid1;
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bool en;
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};
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static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
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{
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int ret = i2c_smbus_read_byte_data(max8952->client, reg);
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if (ret > 0)
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ret &= 0xff;
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return ret;
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}
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static int max8952_write_reg(struct max8952_data *max8952,
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u8 reg, u8 value)
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{
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return i2c_smbus_write_byte_data(max8952->client, reg, value);
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}
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static int max8952_voltage(struct max8952_data *max8952, u8 mode)
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{
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return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000;
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}
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static int max8952_list_voltage(struct regulator_dev *rdev,
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unsigned int selector)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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if (rdev_get_id(rdev) != 0)
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return -EINVAL;
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return max8952_voltage(max8952, selector);
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}
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static int max8952_is_enabled(struct regulator_dev *rdev)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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return max8952->en;
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}
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static int max8952_enable(struct regulator_dev *rdev)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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/* If not valid, assume "ALWAYS_HIGH" */
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if (gpio_is_valid(max8952->pdata->gpio_en))
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gpio_set_value(max8952->pdata->gpio_en, 1);
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max8952->en = true;
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return 0;
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}
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static int max8952_disable(struct regulator_dev *rdev)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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/* If not valid, assume "ALWAYS_HIGH" -> not permitted */
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if (gpio_is_valid(max8952->pdata->gpio_en))
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gpio_set_value(max8952->pdata->gpio_en, 0);
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else
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return -EPERM;
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max8952->en = false;
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return 0;
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}
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static int max8952_get_voltage(struct regulator_dev *rdev)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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u8 vid = 0;
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if (max8952->vid0)
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vid += 1;
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if (max8952->vid1)
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vid += 2;
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return max8952_voltage(max8952, vid);
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}
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static int max8952_set_voltage(struct regulator_dev *rdev,
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int min_uV, int max_uV, unsigned *selector)
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{
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struct max8952_data *max8952 = rdev_get_drvdata(rdev);
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s8 vid = -1, i;
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if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
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!gpio_is_valid(max8952->pdata->gpio_vid1)) {
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/* DVS not supported */
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return -EPERM;
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}
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for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) {
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int volt = max8952_voltage(max8952, i);
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/* Set the voltage as low as possible within the range */
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if (volt <= max_uV && volt >= min_uV)
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if (vid == -1 || max8952_voltage(max8952, vid) > volt)
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vid = i;
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}
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if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) {
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max8952->vid0 = (vid % 2 == 1);
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max8952->vid1 = (((vid >> 1) % 2) == 1);
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*selector = vid;
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gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
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gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
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} else
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return -EINVAL;
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return 0;
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}
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static struct regulator_ops max8952_ops = {
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.list_voltage = max8952_list_voltage,
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.is_enabled = max8952_is_enabled,
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.enable = max8952_enable,
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.disable = max8952_disable,
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.get_voltage = max8952_get_voltage,
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.set_voltage = max8952_set_voltage,
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.set_suspend_disable = max8952_disable,
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};
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static struct regulator_desc regulator = {
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.name = "MAX8952_VOUT",
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.id = 0,
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.n_voltages = MAX8952_NUM_DVS_MODE,
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.ops = &max8952_ops,
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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};
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static int __devinit max8952_pmic_probe(struct i2c_client *client,
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const struct i2c_device_id *i2c_id)
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{
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struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
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struct max8952_platform_data *pdata = client->dev.platform_data;
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struct max8952_data *max8952;
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int ret = 0, err = 0;
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if (!pdata) {
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dev_err(&client->dev, "Require the platform data\n");
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return -EINVAL;
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}
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
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return -EIO;
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max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL);
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if (!max8952)
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return -ENOMEM;
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max8952->client = client;
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max8952->dev = &client->dev;
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max8952->pdata = pdata;
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max8952->rdev = regulator_register(®ulator, max8952->dev,
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&pdata->reg_data, max8952, NULL);
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if (IS_ERR(max8952->rdev)) {
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ret = PTR_ERR(max8952->rdev);
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dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
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goto err_reg;
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}
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max8952->en = !!(pdata->reg_data.constraints.boot_on);
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max8952->vid0 = (pdata->default_mode % 2) == 1;
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max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1;
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if (gpio_is_valid(pdata->gpio_en)) {
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if (!gpio_request(pdata->gpio_en, "MAX8952 EN"))
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gpio_direction_output(pdata->gpio_en, max8952->en);
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else
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err = 1;
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} else
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err = 2;
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if (err) {
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dev_info(max8952->dev, "EN gpio invalid: assume that EN"
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"is always High\n");
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max8952->en = 1;
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pdata->gpio_en = -1; /* Mark invalid */
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}
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err = 0;
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if (gpio_is_valid(pdata->gpio_vid0) &&
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gpio_is_valid(pdata->gpio_vid1)) {
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if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
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gpio_direction_output(pdata->gpio_vid0,
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(pdata->default_mode) % 2);
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else
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err = 1;
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if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
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gpio_direction_output(pdata->gpio_vid1,
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(pdata->default_mode >> 1) % 2);
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else {
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if (!err)
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gpio_free(pdata->gpio_vid0);
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err = 2;
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}
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} else
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err = 3;
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if (err) {
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dev_warn(max8952->dev, "VID0/1 gpio invalid: "
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"DVS not available.\n");
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max8952->vid0 = 0;
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max8952->vid1 = 0;
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/* Mark invalid */
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pdata->gpio_vid0 = -1;
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pdata->gpio_vid1 = -1;
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/* Disable Pulldown of EN only */
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max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
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dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
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" do not have proper controls.\n");
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} else {
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/*
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* Disable Pulldown on EN, VID0, VID1 to reduce
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* leakage current of MAX8952 assuming that MAX8952
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* is turned on (EN==1). Note that without having VID0/1
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* properly connected, turning pulldown off can be
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* problematic. Thus, turn this off only when they are
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* controllable by GPIO.
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*/
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max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
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}
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max8952_write_reg(max8952, MAX8952_REG_MODE0,
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(max8952_read_reg(max8952,
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MAX8952_REG_MODE0) & 0xC0) |
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(pdata->dvs_mode[0] & 0x3F));
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max8952_write_reg(max8952, MAX8952_REG_MODE1,
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(max8952_read_reg(max8952,
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MAX8952_REG_MODE1) & 0xC0) |
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(pdata->dvs_mode[1] & 0x3F));
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max8952_write_reg(max8952, MAX8952_REG_MODE2,
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(max8952_read_reg(max8952,
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MAX8952_REG_MODE2) & 0xC0) |
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(pdata->dvs_mode[2] & 0x3F));
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max8952_write_reg(max8952, MAX8952_REG_MODE3,
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(max8952_read_reg(max8952,
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MAX8952_REG_MODE3) & 0xC0) |
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(pdata->dvs_mode[3] & 0x3F));
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max8952_write_reg(max8952, MAX8952_REG_SYNC,
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(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
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((pdata->sync_freq & 0x3) << 6));
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max8952_write_reg(max8952, MAX8952_REG_RAMP,
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(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
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((pdata->ramp_speed & 0x7) << 5));
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i2c_set_clientdata(client, max8952);
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return 0;
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err_reg:
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kfree(max8952);
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return ret;
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}
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static int __devexit max8952_pmic_remove(struct i2c_client *client)
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{
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struct max8952_data *max8952 = i2c_get_clientdata(client);
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struct max8952_platform_data *pdata = max8952->pdata;
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struct regulator_dev *rdev = max8952->rdev;
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regulator_unregister(rdev);
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gpio_free(pdata->gpio_vid0);
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gpio_free(pdata->gpio_vid1);
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gpio_free(pdata->gpio_en);
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kfree(max8952);
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return 0;
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}
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static const struct i2c_device_id max8952_ids[] = {
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{ "max8952", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, max8952_ids);
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static struct i2c_driver max8952_pmic_driver = {
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.probe = max8952_pmic_probe,
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.remove = __devexit_p(max8952_pmic_remove),
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.driver = {
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.name = "max8952",
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},
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.id_table = max8952_ids,
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};
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static int __init max8952_pmic_init(void)
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{
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return i2c_add_driver(&max8952_pmic_driver);
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}
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subsys_initcall(max8952_pmic_init);
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static void __exit max8952_pmic_exit(void)
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{
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i2c_del_driver(&max8952_pmic_driver);
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}
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module_exit(max8952_pmic_exit);
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MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
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MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
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MODULE_LICENSE("GPL");
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