diff options
Diffstat (limited to 'drivers/power/tps6586x.c')
| -rw-r--r-- | drivers/power/tps6586x.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/power/tps6586x.c b/drivers/power/tps6586x.c new file mode 100644 index 000000000..f3f2ec6e5 --- /dev/null +++ b/drivers/power/tps6586x.c @@ -0,0 +1,280 @@ +/* + * 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; +} |