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/* Copyright 2020 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.
*
* Parade PS8740 (and PS8742)
* USB Type-C Redriving Switch for USB Host / DisplayPort.
*/
#include "common.h"
#include "i2c.h"
#include "ps8740.h"
#include "usb_mux.h"
#include "util.h"
int ps8740_read(const struct usb_mux *me, uint8_t reg, int *val)
{
return i2c_read8(me->i2c_port, me->i2c_addr_flags,
reg, val);
}
int ps8740_write(const struct usb_mux *me, uint8_t reg, uint8_t val)
{
return i2c_write8(me->i2c_port, me->i2c_addr_flags,
reg, val);
}
static int ps8740_init(const struct usb_mux *me)
{
int id1;
int id2;
int res;
/* Reset chip back to power-on state */
res = ps8740_write(me, PS8740_REG_MODE, PS8740_MODE_POWER_DOWN);
if (res)
return res;
/*
* Verify chip ID registers.
*/
res = ps8740_read(me, PS8740_REG_CHIP_ID1, &id1);
if (res)
return res;
res = ps8740_read(me, PS8740_REG_CHIP_ID2, &id2);
if (res)
return res;
if (id1 != PS8740_CHIP_ID1 || id2 != PS8740_CHIP_ID2)
return EC_ERROR_UNKNOWN;
/*
* Verify revision ID registers.
*/
res = ps8740_read(me, PS8740_REG_REVISION_ID1, &id1);
if (res)
return res;
res = ps8740_read(me, PS8740_REG_REVISION_ID2, &id2);
if (res)
return res;
if (id1 != PS8740_REVISION_ID1)
return EC_ERROR_UNKNOWN;
/* PS8740 may have REVISION_ID2 as 0xa or 0xb */
if (id2 != PS8740_REVISION_ID2_0 && id2 != PS8740_REVISION_ID2_1)
return EC_ERROR_UNKNOWN;
return EC_SUCCESS;
}
/* Writes control register to set switch mode */
static int ps8740_set_mux(const struct usb_mux *me, mux_state_t mux_state,
bool *ack_required)
{
uint8_t reg = 0;
/* This driver does not use host command ACKs */
*ack_required = false;
if (mux_state & USB_PD_MUX_USB_ENABLED)
reg |= PS8740_MODE_USB_ENABLED;
if (mux_state & USB_PD_MUX_DP_ENABLED)
reg |= PS8740_MODE_DP_ENABLED;
if (mux_state & USB_PD_MUX_POLARITY_INVERTED)
reg |= PS8740_MODE_POLARITY_INVERTED;
return ps8740_write(me, PS8740_REG_MODE, reg);
}
/* Reads control register and updates mux_state accordingly */
static int ps8740_get_mux(const struct usb_mux *me, mux_state_t *mux_state)
{
int reg;
int res;
res = ps8740_read(me, PS8740_REG_STATUS, ®);
if (res)
return res;
*mux_state = 0;
if (reg & PS8740_STATUS_USB_ENABLED)
*mux_state |= USB_PD_MUX_USB_ENABLED;
if (reg & PS8740_STATUS_DP_ENABLED)
*mux_state |= USB_PD_MUX_DP_ENABLED;
if (reg & PS8740_STATUS_POLARITY_INVERTED)
*mux_state |= USB_PD_MUX_POLARITY_INVERTED;
return EC_SUCCESS;
}
/* Tune USB Tx/Rx Equalization */
int ps8740_tune_usb_eq(const struct usb_mux *me, uint8_t tx, uint8_t rx)
{
int ret;
ret = ps8740_write(me, PS8740_REG_USB_EQ_TX, tx);
ret |= ps8740_write(me, PS8740_REG_USB_EQ_RX, rx);
return ret;
}
const struct usb_mux_driver ps8740_usb_mux_driver = {
.init = ps8740_init,
.set = ps8740_set_mux,
.get = ps8740_get_mux,
};
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