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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "adc.h"
#include "board.h"
#include "common.h"
#include "console.h"
#include "debug.h"
#include "hooks.h"
#include "registers.h"
#include "timer.h"
#include "util.h"
#include "usb_pd.h"
/* ------------------------- Power supply control ------------------------ */
/* GPIO level setting helpers through BSRR register */
#define GPIO_SET(n) (1 << (n))
#define GPIO_RESET(n) (1 << ((n) + 16))
/* Output voltage selection */
enum volt {
VO_5V = GPIO_RESET(13) | GPIO_RESET(14),
VO_12V = GPIO_SET(13) | GPIO_RESET(14),
VO_13V = GPIO_RESET(13) | GPIO_SET(14),
VO_20V = GPIO_SET(13) | GPIO_SET(14),
};
static inline void set_output_voltage(enum volt v)
{
/* set voltage_select on PA13/PA14 */
STM32_GPIO_BSRR(GPIO_A) = v;
}
static inline void output_enable(void)
{
/* GPF0 (FET driver shutdown) = 0 */
STM32_GPIO_BSRR(GPIO_F) = GPIO_RESET(0);
}
static inline void output_disable(void)
{
/* GPF0 (FET driver shutdown) = 1 */
STM32_GPIO_BSRR(GPIO_F) = GPIO_SET(0);
}
static inline int output_is_enabled(void)
{
/* GPF0 = FET driver shutdown */
return !(STM32_GPIO_IDR(GPIO_F) & 1);
}
/* ----- fault conditions ----- */
enum faults {
FAULT_OK = 0,
FAULT_OCP, /* Over-Current Protection */
FAULT_OVP, /* Under or Over-Voltage Protection */
};
/* current fault condition */
static enum faults fault;
/* expiration date of the last fault condition */
static timestamp_t fault_deadline;
/* ADC in 12-bit mode */
#define ADC_SCALE (1 << 12)
/* ADC power supply : VDDA = 3.3V */
#define VDDA_MV 3300
/* Current sense resistor : 5 milliOhm */
#define R_SENSE 5
/* VBUS voltage is measured through 10k / 100k voltage divider = /11 */
#define VOLT_DIV ((10+110)/10)
/* The current sensing op-amp has a x101 gain */
#define CURR_GAIN 101
/* convert VBUS voltage in raw ADC value */
#define VBUS_MV(mv) ((mv)*ADC_SCALE/VOLT_DIV/VDDA_MV)
/* convert VBUS current in raw ADC value */
#define VBUS_MA(ma) ((ma)*ADC_SCALE*R_SENSE/1000*CURR_GAIN/VDDA_MV)
/* Max current : 10% over 3A = 3.3A */
#define MAX_CURRENT VBUS_MA(3300)
/* reset over-current after 1 second */
#define OCP_TIMEOUT SECOND
/* Under-voltage limit is 0.8x Vnom */
#define UVP_MV(mv) VBUS_MV((mv) * 8 / 10)
/* Over-voltage limit is 1.2x Vnom */
#define OVP_MV(mv) VBUS_MV((mv) * 12 / 10)
/* ----------------------- USB Power delivery policy ---------------------- */
/* Power Delivery Objects */
const uint32_t pd_src_pdo[] = {
PDO_FIXED(5000, 500, PDO_FIXED_EXTERNAL),
PDO_FIXED(5000, 3000, 0),
PDO_FIXED(12000, 3000, 0),
PDO_FIXED(20000, 2000, 0),
};
const int pd_src_pdo_cnt = ARRAY_SIZE(pd_src_pdo);
/* PDO voltages (should match the table above) */
static const struct {
enum volt select; /* GPIO configuration to select the voltage */
int uvp; /* under-voltage limit in mV */
int ovp; /* over-voltage limit in mV */
} voltages[ARRAY_SIZE(pd_src_pdo)] = {
{VO_5V, UVP_MV(5000), OVP_MV(5000)},
{VO_5V, UVP_MV(5000), OVP_MV(5000)},
{VO_12V, UVP_MV(12000), OVP_MV(12000)},
{VO_20V, UVP_MV(20000), OVP_MV(20000)},
};
/* currently selected PDO entry */
static int volt_idx;
int pd_request_voltage(uint32_t rdo)
{
int op_ma = rdo & 0x3FF;
int max_ma = (rdo >> 10) & 0x3FF;
int idx = rdo >> 28;
uint32_t pdo;
uint32_t pdo_ma;
/* fault condition not cleared : reject transitions */
if (fault != FAULT_OK)
return EC_ERROR_INVAL;
if (!idx || idx > pd_src_pdo_cnt)
return EC_ERROR_INVAL; /* Invalid index */
/* check current ... */
pdo = pd_src_pdo[idx - 1];
pdo_ma = (pdo & 0x3ff);
if (op_ma > pdo_ma)
return EC_ERROR_INVAL; /* too much op current */
if (max_ma > pdo_ma)
return EC_ERROR_INVAL; /* too much max current */
debug_printf("Switch to %d V %d mA (for %d/%d mA)\n",
((pdo >> 10) & 0x3ff) * 50, (pdo & 0x3ff) * 10,
((rdo >> 10) & 0x3ff) * 10, (rdo & 0x3ff) * 10);
output_disable();
/* TODO discharge ? */
volt_idx = idx - 1;
set_output_voltage(voltages[volt_idx].select);
return EC_SUCCESS;
}
int pd_set_power_supply_ready(void)
{
/* fault condition not cleared : do not turn on power */
if (fault != FAULT_OK)
return EC_ERROR_INVAL;
output_enable();
return EC_SUCCESS; /* we are ready */
}
void pd_power_supply_reset(void)
{
output_disable();
/* TODO discharge ? */
volt_idx = 0;
set_output_voltage(VO_5V);
/* TODO transition delay */
}
int pd_board_checks(void)
{
int vbus_volt, vbus_amp;
vbus_volt = adc_read_channel(ADC_CH_V_SENSE);
vbus_amp = adc_read_channel(ADC_CH_A_SENSE);
if (vbus_amp > MAX_CURRENT) {
debug_printf("OverCurrent : %d mA\n",
vbus_amp * VDDA_MV / CURR_GAIN * 1000 / R_SENSE / ADC_SCALE);
fault = FAULT_OCP;
/* reset over-current after 1 second */
fault_deadline.val = get_time().val + OCP_TIMEOUT;
return EC_ERROR_INVAL;
}
if (output_is_enabled() && (vbus_volt > voltages[volt_idx].ovp)) {
debug_printf("OverVoltage : %d mV\n",
vbus_volt * VDDA_MV * VOLT_DIV / ADC_SCALE);
/* TODO(crosbug.com/p/28331) discharge */
fault = FAULT_OVP;
/* no timeout */
fault_deadline.val = get_time().val;
return EC_ERROR_INVAL;
}
/* everything is good *and* the error condition has expired */
if ((fault != FAULT_OK) && (get_time().val > fault_deadline.val)) {
fault = FAULT_OK;
debug_printf("Reset fault\n");
}
return EC_SUCCESS;
}
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