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/*
* max8973-regulator.c -- Maxim max8973
*
* Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
*
* Copyright (c) 2012, NVIDIA Corporation.
*
* Author: Laxman Dewangan <ldewangan@nvidia.com>
*
* 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.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
* whether express or implied; 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
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/max8973-regulator.h>
#include <linux/regulator/of_regulator.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>
/* Register definitions */
#define MAX8973_VOUT 0x0
#define MAX8973_VOUT_DVS 0x1
#define MAX8973_CONTROL1 0x2
#define MAX8973_CONTROL2 0x3
#define MAX8973_CHIPID1 0x4
#define MAX8973_CHIPID2 0x5
#define MAX8973_MAX_VOUT_REG 2
/* MAX8973_VOUT */
#define MAX8973_VOUT_ENABLE BIT(7)
#define MAX8973_VOUT_MASK 0x7F
/* MAX8973_VOUT_DVS */
#define MAX8973_DVS_VOUT_MASK 0x7F
/* MAX8973_CONTROL1 */
#define MAX8973_SNS_ENABLE BIT(7)
#define MAX8973_FPWM_EN_M BIT(6)
#define MAX8973_NFSR_ENABLE BIT(5)
#define MAX8973_AD_ENABLE BIT(4)
#define MAX8973_BIAS_ENABLE BIT(3)
#define MAX8973_FREQSHIFT_9PER BIT(2)
#define MAX8973_RAMP_12mV_PER_US 0x0
#define MAX8973_RAMP_25mV_PER_US 0x1
#define MAX8973_RAMP_50mV_PER_US 0x2
#define MAX8973_RAMP_200mV_PER_US 0x3
#define MAX8973_RAMP_MASK 0x3
/* MAX8973_CONTROL2 */
#define MAX8973_WDTMR_ENABLE BIT(6)
#define MAX8973_DISCH_ENBABLE BIT(5)
#define MAX8973_FT_ENABLE BIT(4)
#define MAX8973_CKKADV_TRIP_DISABLE 0xC
#define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0
#define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4
#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8
#define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000
#define MAX8973_INDUCTOR_MIN_30_PER 0x0
#define MAX8973_INDUCTOR_NOMINAL 0x1
#define MAX8973_INDUCTOR_PLUS_30_PER 0x2
#define MAX8973_INDUCTOR_PLUS_60_PER 0x3
#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000
#define MAX8973_MIN_VOLATGE 606250
#define MAX8973_MAX_VOLATGE 1400000
#define MAX8973_VOLATGE_STEP 6250
#define MAX8973_BUCK_N_VOLTAGE 0x80
enum device_id {
MAX8973,
MAX77621
};
/* Maxim 8973 chip information */
struct max8973_chip {
struct device *dev;
struct regulator_desc desc;
struct regmap *regmap;
bool enable_external_control;
int enable_gpio;
int dvs_gpio;
int lru_index[MAX8973_MAX_VOUT_REG];
int curr_vout_val[MAX8973_MAX_VOUT_REG];
int curr_vout_reg;
int curr_gpio_val;
struct regulator_ops ops;
enum device_id id;
};
/*
* find_voltage_set_register: Find new voltage configuration register (VOUT).
* The finding of the new VOUT register will be based on the LRU mechanism.
* Each VOUT register will have different voltage configured . This
* Function will look if any of the VOUT register have requested voltage set
* or not.
* - If it is already there then it will make that register as most
* recently used and return as found so that caller need not to set
* the VOUT register but need to set the proper gpios to select this
* VOUT register.
* - If requested voltage is not found then it will use the least
* recently mechanism to get new VOUT register for new configuration
* and will return not_found so that caller need to set new VOUT
* register and then gpios (both).
*/
static bool find_voltage_set_register(struct max8973_chip *tps,
int req_vsel, int *vout_reg, int *gpio_val)
{
int i;
bool found = false;
int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
int found_index = MAX8973_MAX_VOUT_REG - 1;
for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
new_vout_reg = tps->lru_index[i];
found_index = i;
found = true;
goto update_lru_index;
}
}
update_lru_index:
for (i = found_index; i > 0; i--)
tps->lru_index[i] = tps->lru_index[i - 1];
tps->lru_index[0] = new_vout_reg;
*gpio_val = new_vout_reg;
*vout_reg = MAX8973_VOUT + new_vout_reg;
return found;
}
static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
{
struct max8973_chip *max = rdev_get_drvdata(rdev);
unsigned int data;
int ret;
ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
if (ret < 0) {
dev_err(max->dev, "register %d read failed, err = %d\n",
max->curr_vout_reg, ret);
return ret;
}
return data & MAX8973_VOUT_MASK;
}
static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
unsigned vsel)
{
struct max8973_chip *max = rdev_get_drvdata(rdev);
int ret;
bool found = false;
int vout_reg = max->curr_vout_reg;
int gpio_val = max->curr_gpio_val;
/*
* If gpios are available to select the VOUT register then least
* recently used register for new configuration.
*/
if (gpio_is_valid(max->dvs_gpio))
found = find_voltage_set_register(max, vsel,
&vout_reg, &gpio_val);
if (!found) {
ret = regmap_update_bits(max->regmap, vout_reg,
MAX8973_VOUT_MASK, vsel);
if (ret < 0) {
dev_err(max->dev, "register %d update failed, err %d\n",
vout_reg, ret);
return ret;
}
max->curr_vout_reg = vout_reg;
max->curr_vout_val[gpio_val] = vsel;
}
/* Select proper VOUT register vio gpios */
if (gpio_is_valid(max->dvs_gpio)) {
gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
max->curr_gpio_val = gpio_val;
}
return 0;
}
static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
struct max8973_chip *max = rdev_get_drvdata(rdev);
int ret;
int pwm;
/* Enable force PWM mode in FAST mode only. */
switch (mode) {
case REGULATOR_MODE_FAST:
pwm = MAX8973_FPWM_EN_M;
break;
case REGULATOR_MODE_NORMAL:
pwm = 0;
break;
default:
return -EINVAL;
}
ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
MAX8973_FPWM_EN_M, pwm);
if (ret < 0)
dev_err(max->dev, "register %d update failed, err %d\n",
MAX8973_CONTROL1, ret);
return ret;
}
static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
{
struct max8973_chip *max = rdev_get_drvdata(rdev);
unsigned int data;
int ret;
ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
if (ret < 0) {
dev_err(max->dev, "register %d read failed, err %d\n",
MAX8973_CONTROL1, ret);
return ret;
}
return (data & MAX8973_FPWM_EN_M) ?
REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
}
static int max8973_set_ramp_delay(struct regulator_dev *rdev,
int ramp_delay)
{
struct max8973_chip *max = rdev_get_drvdata(rdev);
unsigned int control;
int ret;
int ret_val;
/* Set ramp delay */
if (ramp_delay < 25000
|