u-boot/drivers/power/tps6586x.c

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/*
* Copyright (c) 2011 The Chromium OS Authors.
* (C) Copyright 2010,2011 NVIDIA Corporation <www.nvidia.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; 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 <common.h>
#include <tps6586x.h>
#include <asm/io.h>
#include <i2c.h>
static int bus_num; /* I2C bus we are on */
#define I2C_ADDRESS 0x34 /* chip requires this address */
static char inited; /* 1 if we have been inited */
enum {
/* Registers that we access */
SUPPLY_CONTROL1 = 0x20,
SUPPLY_CONTROL2,
SM1_VOLTAGE_V1 = 0x23,
SM1_VOLTAGE_V2,
SM0_VOLTAGE_V1 = 0x26,
SM0_VOLTAGE_V2,
PFM_MODE = 0x47,
/* Bits in the supply control registers */
CTRL_SM1_RAMP = 0x01,
CTRL_SM1_SUPPLY2 = 0x02,
CTRL_SM0_RAMP = 0x04,
CTRL_SM0_SUPPLY2 = 0x08,
};
#define MAX_I2C_RETRY 3
int tps6586x_read(int reg)
{
int i;
uchar data;
int retval = -1;
int old_bus_num;
old_bus_num = i2c_get_bus_num();
i2c_set_bus_num(bus_num);
for (i = 0; i < MAX_I2C_RETRY; ++i) {
if (!i2c_read(I2C_ADDRESS, reg, 1, &data, 1)) {
retval = (int)data;
goto exit;
}
/* i2c access failed, retry */
udelay(100);
}
exit:
i2c_set_bus_num(old_bus_num);
debug("pmu_read %x=%x\n", reg, retval);
if (retval < 0)
debug("%s: failed to read register %#x: %d\n", __func__, reg,
retval);
return retval;
}
int tps6586x_write(int reg, uchar *data, uint len)
{
int i;
int retval = -1;
int old_bus_num;
old_bus_num = i2c_get_bus_num();
i2c_set_bus_num(bus_num);
for (i = 0; i < MAX_I2C_RETRY; ++i) {
if (!i2c_write(I2C_ADDRESS, reg, 1, data, len)) {
retval = 0;
goto exit;
}
/* i2c access failed, retry */
udelay(100);
}
exit:
i2c_set_bus_num(old_bus_num);
debug("pmu_write %x=%x: ", reg, retval);
for (i = 0; i < len; i++)
debug("%x ", data[i]);
if (retval)
debug("%s: failed to write register %#x\n", __func__, reg);
return retval;
}
/*
* Get current voltage of SM0 and SM1
*
* @param sm0 Place to put SM0 voltage
* @param sm1 Place to put SM1 voltage
* @return 0 if ok, -1 on error
*/
static int read_voltages(int *sm0, int *sm1)
{
int ctrl1, ctrl2;
int is_v2;
/*
* Each vdd has two supply sources, ie, v1 and v2.
* The supply control reg1 and reg2 determine the current selection.
*/
ctrl1 = tps6586x_read(SUPPLY_CONTROL1);
ctrl2 = tps6586x_read(SUPPLY_CONTROL2);
if (ctrl1 == -1 || ctrl2 == -1)
return -1;
/* Figure out whether V1 or V2 is selected */
is_v2 = (ctrl1 | ctrl2) & CTRL_SM0_SUPPLY2;
*sm0 = tps6586x_read(is_v2 ? SM0_VOLTAGE_V2 : SM0_VOLTAGE_V1);
*sm1 = tps6586x_read(is_v2 ? SM1_VOLTAGE_V2 : SM1_VOLTAGE_V1);
if (*sm0 == -1 || *sm1 == -1)
return -1;
return 0;
}
static int set_voltage(int reg, int data, int rate)
{
uchar control_bit;
uchar buff[3];
control_bit = (reg == SM0_VOLTAGE_V1 ? CTRL_SM0_RAMP : CTRL_SM1_RAMP);
/*
* Only one supply is needed in u-boot. set both v1 and v2 to
* same value.
*
* When both v1 and v2 are set to same value, we just need to set
* control1 reg to trigger the supply selection.
*/
buff[0] = buff[1] = (uchar)data;
buff[2] = rate;
/* write v1, v2 and rate, then trigger */
if (tps6586x_write(reg, buff, 3) ||
tps6586x_write(SUPPLY_CONTROL1, &control_bit, 1))
return -1;
return 0;
}
static int calculate_next_voltage(int voltage, int target, int step)
{
int diff = voltage < target ? step : -step;
if (abs(target - voltage) > step)
voltage += diff;
else
voltage = target;
return voltage;
}
int tps6586x_set_pwm_mode(int mask)
{
uchar val;
int ret;
assert(inited);
ret = tps6586x_read(PFM_MODE);
if (ret != -1) {
val = (uchar)ret;
val |= mask;
ret = tps6586x_write(PFM_MODE, &val, 1);
}
if (ret == -1)
debug("%s: Failed to read/write PWM mode reg\n", __func__);
return ret;
}
int tps6586x_adjust_sm0_sm1(int sm0_target, int sm1_target, int step, int rate,
int min_sm0_over_sm1)
{
int sm0, sm1;
int bad;
assert(inited);
/* get current voltage settings */
if (read_voltages(&sm0, &sm1)) {
debug("%s: Cannot read voltage settings\n", __func__);
return -1;
}
/*
* if vdd_core < vdd_cpu + rel
* skip
*
* This condition may happen when system reboots due to kernel crash.
*/
if (min_sm0_over_sm1 != -1 && sm0 < sm1 + min_sm0_over_sm1) {
debug("%s: SM0 is %d, SM1 is %d, but min_sm0_over_sm1 is %d\n",
__func__, sm0, sm1, min_sm0_over_sm1);
return -1;
}
/*
* Since vdd_core and vdd_cpu may both stand at either greater or less
* than their nominal voltage, the adjustment may go either directions.
*
* Make sure vdd_core is always higher than vdd_cpu with certain margin.
* So, find out which vdd to adjust first in each step.
*
* case 1: both sm0 and sm1 need to move up
* adjust sm0 before sm1
*
* case 2: both sm0 and sm1 need to move down
* adjust sm1 before sm0
*
* case 3: sm0 moves down and sm1 moves up
* adjusting either one first is fine.
*
* Adjust vdd_core and vdd_cpu one step at a time until they reach
* their nominal values.
*/
bad = 0;
while (!bad && (sm0 != sm0_target || sm1 != sm1_target)) {
int adjust_sm0_late = 0; /* flag to adjust vdd_core later */
debug("%d-%d %d-%d ", sm0, sm0_target, sm1, sm1_target);
if (sm0 != sm0_target) {
/*
* if case 1 and case 3, set new sm0 first.
* otherwise, hold down until new sm1 is set.
*/
sm0 = calculate_next_voltage(sm0, sm0_target, step);
if (sm1 < sm1_target)
bad |= set_voltage(SM0_VOLTAGE_V1, sm0, rate);
else
adjust_sm0_late = 1;
}
if (sm1 != sm1_target) {
sm1 = calculate_next_voltage(sm1, sm1_target, step);
bad |= set_voltage(SM1_VOLTAGE_V1, sm1, rate);
}
if (adjust_sm0_late)
bad |= set_voltage(SM0_VOLTAGE_V1, sm0, rate);
debug("%d\n", adjust_sm0_late);
}
debug("%d-%d %d-%d done\n", sm0, sm0_target, sm1, sm1_target);
return bad ? -1 : 0;
}
int tps6586x_init(int bus)
{
bus_num = bus;
inited = 1;
return 0;
}