151 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Driver to power on the Analogix ANX7428 USB Type-C crosspoint switch4 * on MeeGoPad top-set boxes.5 *6 * The MeeGoPad T8 and T9 are Cherry Trail top-set boxes which7 * use an ANX7428 to provide a Type-C port with USB3.1 Gen 1 and8 * DisplayPort over Type-C alternate mode support.9 *10 * The ANX7428 has a microcontroller which takes care of the PD11 * negotiation and automatically sets the builtin Crosspoint Switch12 * to send the right signal to the 4 highspeed pairs of the Type-C13 * connector. It also takes care of HPD and AUX channel routing for14 * DP alternate mode.15 *16 * IOW the ANX7428 operates fully autonomous and to the x5-Z8350 SoC17 * things look like there simply is a USB-3 Type-A connector and a18 * separate DisplayPort connector. Except that the BIOS does not19 * power on the ANX7428 at boot. This driver takes care of powering20 * on the ANX7428.21 *22 * It should be possible to tell the micro-controller which data- and/or23 * power-role to negotiate and to swap the role(s) after negotiation24 * but the MeeGoPad top-set boxes always draw their power from a separate25 * power-connector and they only support USB host-mode. So this functionality26 * is unnecessary and due to lack of documentation this is tricky to support.27 *28 * For a more complete ANX7428 driver see drivers/usb/misc/anx7418/ of29 * the LineageOS kernel for the LG G5 (International) aka the LG H850:30 * https://github.com/LineageOS/android_kernel_lge_msm8996/31 *32 * (C) Copyright 2024 Hans de Goede <hansg@kernel.org>33 */34 35#include <linux/acpi.h>36#include <linux/bits.h>37#include <linux/delay.h>38#include <linux/dev_printk.h>39#include <linux/dmi.h>40#include <linux/err.h>41#include <linux/gpio/consumer.h>42#include <linux/i2c.h>43#include <linux/iopoll.h>44#include <linux/module.h>45#include <linux/types.h>46 47/* Register addresses and fields */48#define VENDOR_ID 0x0049#define DEVICE_ID 0x0250 51#define TX_STATUS 0x1652#define STATUS_SUCCESS BIT(0)53#define STATUS_ERROR BIT(1)54#define OCM_STARTUP BIT(7)55 56static bool force;57module_param(force, bool, 0444);58MODULE_PARM_DESC(force, "Force the driver to probe on unknown boards");59 60static const struct acpi_gpio_params enable_gpio = { 0, 0, false };61static const struct acpi_gpio_params reset_gpio = { 1, 0, true };62 63static const struct acpi_gpio_mapping meegopad_anx7428_gpios[] = {64 { "enable-gpios", &enable_gpio, 1 },65 { "reset-gpios", &reset_gpio, 1 },66 { }67};68 69static const struct dmi_system_id meegopad_anx7428_ids[] = {70 {71 /* Meegopad T08 */72 .matches = {73 DMI_MATCH(DMI_SYS_VENDOR, "Default string"),74 DMI_MATCH(DMI_PRODUCT_NAME, "Default string"),75 DMI_MATCH(DMI_BOARD_NAME, "T3 MRD"),76 DMI_MATCH(DMI_BOARD_VERSION, "V1.1"),77 },78 },79 { }80};81 82static int anx7428_probe(struct i2c_client *client)83{84 struct device *dev = &client->dev;85 struct gpio_desc *gpio;86 int ret, val;87 88 if (!dmi_check_system(meegopad_anx7428_ids) && !force) {89 dev_warn(dev, "Not probing unknown board, pass meegopad_anx7428.force=1 to probe");90 return -ENODEV;91 }92 93 ret = devm_acpi_dev_add_driver_gpios(dev, meegopad_anx7428_gpios);94 if (ret)95 return ret;96 97 /*98 * Set GPIOs to desired values while getting them, they are not needed99 * afterwards. Ordering and delays come from android_kernel_lge_msm8996.100 */101 gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);102 if (IS_ERR(gpio))103 return dev_err_probe(dev, PTR_ERR(gpio), "getting enable GPIO\n");104 105 fsleep(10000);106 107 gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);108 if (IS_ERR(gpio))109 return dev_err_probe(dev, PTR_ERR(gpio), "getting reset GPIO\n");110 111 /* Wait for the OCM (On Chip Microcontroller) to start */112 ret = read_poll_timeout(i2c_smbus_read_byte_data, val,113 val >= 0 && (val & OCM_STARTUP),114 5000, 50000, true, client, TX_STATUS);115 if (ret)116 return dev_err_probe(dev, ret,117 "On Chip Microcontroller did not start, status: 0x%02x\n",118 val);119 120 ret = i2c_smbus_read_word_data(client, VENDOR_ID);121 if (ret < 0)122 return dev_err_probe(dev, ret, "reading vendor-id register\n");123 val = ret;124 125 ret = i2c_smbus_read_word_data(client, DEVICE_ID);126 if (ret < 0)127 return dev_err_probe(dev, ret, "reading device-id register\n");128 129 dev_dbg(dev, "Powered on ANX7428 id %04x:%04x\n", val, ret);130 return 0;131}132 133static const struct acpi_device_id anx7428_acpi_match[] = {134 { "ANXO7418" }, /* ACPI says 7418 (max 2 DP lanes version) but HW is 7428 */135 { }136};137MODULE_DEVICE_TABLE(acpi, anx7428_acpi_match);138 139static struct i2c_driver anx7428_driver = {140 .driver = {141 .name = "meegopad_anx7428",142 .acpi_match_table = anx7428_acpi_match,143 },144 .probe = anx7428_probe,145};146module_i2c_driver(anx7428_driver);147 148MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");149MODULE_DESCRIPTION("MeeGoPad ANX7428 driver");150MODULE_LICENSE("GPL");151