diff options
Diffstat (limited to 'driver/usb_mux/ps874x.c')
-rw-r--r-- | driver/usb_mux/ps874x.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/driver/usb_mux/ps874x.c b/driver/usb_mux/ps874x.c new file mode 100644 index 0000000000..bf00553d28 --- /dev/null +++ b/driver/usb_mux/ps874x.c @@ -0,0 +1,125 @@ +/* Copyright 2017 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 PS874X USB Type-C Redriving Switch for USB Host / DisplayPort. + */ + +#include "common.h" +#include "i2c.h" +#include "ps874x.h" +#include "usb_mux.h" +#include "util.h" + +static inline int ps874x_read(int port, uint8_t reg, int *val) +{ + return i2c_read8(I2C_PORT_USB_MUX, MUX_ADDR(port), reg, val); +} + +static inline int ps874x_write(int port, uint8_t reg, uint8_t val) +{ + return i2c_write8(I2C_PORT_USB_MUX, MUX_ADDR(port), reg, val); +} + +static int ps874x_init(int port) +{ + int val; + int res; + + /* Reset chip back to power-on state */ + res = ps874x_write(port, PS874X_REG_MODE, PS874X_MODE_POWER_DOWN); + if (res) + return res; + + /* + * Verify revision / chip ID registers. + */ + res = ps874x_read(port, PS874X_REG_REVISION_ID1, &val); + if (res) + return res; + +#ifdef CONFIG_USB_MUX_PS8743 + /* + * From Parade: PS8743 may have REVISION_ID1 as 0 or 1 + * Rev 1 is derived from Rev 0 and have same functionality. + */ + if (val != PS874X_REVISION_ID1_0 && val != PS874X_REVISION_ID1_1) + return EC_ERROR_UNKNOWN; +#else + if (val != PS874X_REVISION_ID1) + return EC_ERROR_UNKNOWN; +#endif + + res = ps874x_read(port, PS874X_REG_REVISION_ID2, &val); + if (res) + return res; + if (val != PS874X_REVISION_ID2) + return EC_ERROR_UNKNOWN; + + res = ps874x_read(port, PS874X_REG_CHIP_ID1, &val); + if (res) + return res; + if (val != PS874X_CHIP_ID1) + return EC_ERROR_UNKNOWN; + + res = ps874x_read(port, PS874X_REG_CHIP_ID2, &val); + if (res) + return res; + if (val != PS874X_CHIP_ID2) + return EC_ERROR_UNKNOWN; + + return EC_SUCCESS; +} + +/* Writes control register to set switch mode */ +static int ps874x_set_mux(int port, mux_state_t mux_state) +{ + uint8_t reg = 0; + + if (mux_state & MUX_USB_ENABLED) + reg |= PS874X_MODE_USB_ENABLED; + if (mux_state & MUX_DP_ENABLED) + reg |= PS874X_MODE_DP_ENABLED; + if (mux_state & MUX_POLARITY_INVERTED) + reg |= PS874X_MODE_POLARITY_INVERTED; + + return ps874x_write(port, PS874X_REG_MODE, reg); +} + +/* Reads control register and updates mux_state accordingly */ +static int ps874x_get_mux(int port, mux_state_t *mux_state) +{ + int reg; + int res; + + res = ps874x_read(port, PS874X_REG_STATUS, ®); + if (res) + return res; + + *mux_state = 0; + if (reg & PS874X_STATUS_USB_ENABLED) + *mux_state |= MUX_USB_ENABLED; + if (reg & PS874X_STATUS_DP_ENABLED) + *mux_state |= MUX_DP_ENABLED; + if (reg & PS874X_STATUS_POLARITY_INVERTED) + *mux_state |= MUX_POLARITY_INVERTED; + + return EC_SUCCESS; +} + +/* Tune USB Tx/Rx Equalization */ +int ps874x_tune_usb_eq(int port, uint8_t tx, uint8_t rx) +{ + int ret; + + ret = ps874x_write(port, PS874X_REG_USB_EQ_TX, tx); + ret |= ps874x_write(port, PS874X_REG_USB_EQ_RX, rx); + + return ret; +} + +const struct usb_mux_driver ps874x_usb_mux_driver = { + .init = ps874x_init, + .set = ps874x_set_mux, + .get = ps874x_get_mux, +}; |